1457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 27999096fSHerbert Xu #include <crypto/hash.h> 3d879cb83SAl Viro #include <linux/export.h> 42f8b5444SChristoph Hellwig #include <linux/bvec.h> 54d0e9df5SAlbert van der Linde #include <linux/fault-inject-usercopy.h> 6d879cb83SAl Viro #include <linux/uio.h> 7d879cb83SAl Viro #include <linux/pagemap.h> 8*28961998SIra Weiny #include <linux/highmem.h> 9d879cb83SAl Viro #include <linux/slab.h> 10d879cb83SAl Viro #include <linux/vmalloc.h> 11241699cdSAl Viro #include <linux/splice.h> 12bfdc5970SChristoph Hellwig #include <linux/compat.h> 13d879cb83SAl Viro #include <net/checksum.h> 14d05f4435SSagi Grimberg #include <linux/scatterlist.h> 15d0ef4c36SMarco Elver #include <linux/instrumented.h> 16d879cb83SAl Viro 17241699cdSAl Viro #define PIPE_PARANOIA /* for now */ 18241699cdSAl Viro 19d879cb83SAl Viro #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ 20d879cb83SAl Viro size_t left; \ 21d879cb83SAl Viro size_t wanted = n; \ 22d879cb83SAl Viro __p = i->iov; \ 23d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len - skip); \ 24d879cb83SAl Viro if (likely(__v.iov_len)) { \ 25d879cb83SAl Viro __v.iov_base = __p->iov_base + skip; \ 26d879cb83SAl Viro left = (STEP); \ 27d879cb83SAl Viro __v.iov_len -= left; \ 28d879cb83SAl Viro skip += __v.iov_len; \ 29d879cb83SAl Viro n -= __v.iov_len; \ 30d879cb83SAl Viro } else { \ 31d879cb83SAl Viro left = 0; \ 32d879cb83SAl Viro } \ 33d879cb83SAl Viro while (unlikely(!left && n)) { \ 34d879cb83SAl Viro __p++; \ 35d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len); \ 36d879cb83SAl Viro if (unlikely(!__v.iov_len)) \ 37d879cb83SAl Viro continue; \ 38d879cb83SAl Viro __v.iov_base = __p->iov_base; \ 39d879cb83SAl Viro left = (STEP); \ 40d879cb83SAl Viro __v.iov_len -= left; \ 41d879cb83SAl Viro skip = __v.iov_len; \ 42d879cb83SAl Viro n -= __v.iov_len; \ 43d879cb83SAl Viro } \ 44d879cb83SAl Viro n = wanted - n; \ 45d879cb83SAl Viro } 46d879cb83SAl Viro 47d879cb83SAl Viro #define iterate_kvec(i, n, __v, __p, skip, STEP) { \ 48d879cb83SAl Viro size_t wanted = n; \ 49d879cb83SAl Viro __p = i->kvec; \ 50d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len - skip); \ 51d879cb83SAl Viro if (likely(__v.iov_len)) { \ 52d879cb83SAl Viro __v.iov_base = __p->iov_base + skip; \ 53d879cb83SAl Viro (void)(STEP); \ 54d879cb83SAl Viro skip += __v.iov_len; \ 55d879cb83SAl Viro n -= __v.iov_len; \ 56d879cb83SAl Viro } \ 57d879cb83SAl Viro while (unlikely(n)) { \ 58d879cb83SAl Viro __p++; \ 59d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len); \ 60d879cb83SAl Viro if (unlikely(!__v.iov_len)) \ 61d879cb83SAl Viro continue; \ 62d879cb83SAl Viro __v.iov_base = __p->iov_base; \ 63d879cb83SAl Viro (void)(STEP); \ 64d879cb83SAl Viro skip = __v.iov_len; \ 65d879cb83SAl Viro n -= __v.iov_len; \ 66d879cb83SAl Viro } \ 67d879cb83SAl Viro n = wanted; \ 68d879cb83SAl Viro } 69d879cb83SAl Viro 701bdc76aeSMing Lei #define iterate_bvec(i, n, __v, __bi, skip, STEP) { \ 711bdc76aeSMing Lei struct bvec_iter __start; \ 721bdc76aeSMing Lei __start.bi_size = n; \ 731bdc76aeSMing Lei __start.bi_bvec_done = skip; \ 741bdc76aeSMing Lei __start.bi_idx = 0; \ 751bdc76aeSMing Lei for_each_bvec(__v, i->bvec, __bi, __start) { \ 76d879cb83SAl Viro (void)(STEP); \ 77d879cb83SAl Viro } \ 78d879cb83SAl Viro } 79d879cb83SAl Viro 807ff50620SDavid Howells #define iterate_xarray(i, n, __v, skip, STEP) { \ 817ff50620SDavid Howells struct page *head = NULL; \ 827ff50620SDavid Howells size_t wanted = n, seg, offset; \ 837ff50620SDavid Howells loff_t start = i->xarray_start + skip; \ 847ff50620SDavid Howells pgoff_t index = start >> PAGE_SHIFT; \ 857ff50620SDavid Howells int j; \ 867ff50620SDavid Howells \ 877ff50620SDavid Howells XA_STATE(xas, i->xarray, index); \ 887ff50620SDavid Howells \ 897ff50620SDavid Howells rcu_read_lock(); \ 907ff50620SDavid Howells xas_for_each(&xas, head, ULONG_MAX) { \ 917ff50620SDavid Howells if (xas_retry(&xas, head)) \ 927ff50620SDavid Howells continue; \ 937ff50620SDavid Howells if (WARN_ON(xa_is_value(head))) \ 947ff50620SDavid Howells break; \ 957ff50620SDavid Howells if (WARN_ON(PageHuge(head))) \ 967ff50620SDavid Howells break; \ 977ff50620SDavid Howells for (j = (head->index < index) ? index - head->index : 0; \ 987ff50620SDavid Howells j < thp_nr_pages(head); j++) { \ 997ff50620SDavid Howells __v.bv_page = head + j; \ 1007ff50620SDavid Howells offset = (i->xarray_start + skip) & ~PAGE_MASK; \ 1017ff50620SDavid Howells seg = PAGE_SIZE - offset; \ 1027ff50620SDavid Howells __v.bv_offset = offset; \ 1037ff50620SDavid Howells __v.bv_len = min(n, seg); \ 1047ff50620SDavid Howells (void)(STEP); \ 1057ff50620SDavid Howells n -= __v.bv_len; \ 1067ff50620SDavid Howells skip += __v.bv_len; \ 1077ff50620SDavid Howells if (n == 0) \ 1087ff50620SDavid Howells break; \ 1097ff50620SDavid Howells } \ 1107ff50620SDavid Howells if (n == 0) \ 1117ff50620SDavid Howells break; \ 1127ff50620SDavid Howells } \ 1137ff50620SDavid Howells rcu_read_unlock(); \ 1147ff50620SDavid Howells n = wanted - n; \ 1157ff50620SDavid Howells } 1167ff50620SDavid Howells 1177ff50620SDavid Howells #define iterate_all_kinds(i, n, v, I, B, K, X) { \ 11833844e66SAl Viro if (likely(n)) { \ 119d879cb83SAl Viro size_t skip = i->iov_offset; \ 120d879cb83SAl Viro if (unlikely(i->type & ITER_BVEC)) { \ 121d879cb83SAl Viro struct bio_vec v; \ 1221bdc76aeSMing Lei struct bvec_iter __bi; \ 1231bdc76aeSMing Lei iterate_bvec(i, n, v, __bi, skip, (B)) \ 124d879cb83SAl Viro } else if (unlikely(i->type & ITER_KVEC)) { \ 125d879cb83SAl Viro const struct kvec *kvec; \ 126d879cb83SAl Viro struct kvec v; \ 127d879cb83SAl Viro iterate_kvec(i, n, v, kvec, skip, (K)) \ 1289ea9ce04SDavid Howells } else if (unlikely(i->type & ITER_DISCARD)) { \ 1297ff50620SDavid Howells } else if (unlikely(i->type & ITER_XARRAY)) { \ 1307ff50620SDavid Howells struct bio_vec v; \ 1317ff50620SDavid Howells iterate_xarray(i, n, v, skip, (X)); \ 132d879cb83SAl Viro } else { \ 133d879cb83SAl Viro const struct iovec *iov; \ 134d879cb83SAl Viro struct iovec v; \ 135d879cb83SAl Viro iterate_iovec(i, n, v, iov, skip, (I)) \ 136d879cb83SAl Viro } \ 13733844e66SAl Viro } \ 138d879cb83SAl Viro } 139d879cb83SAl Viro 1407ff50620SDavid Howells #define iterate_and_advance(i, n, v, I, B, K, X) { \ 141dd254f5aSAl Viro if (unlikely(i->count < n)) \ 142dd254f5aSAl Viro n = i->count; \ 14319f18459SAl Viro if (i->count) { \ 144d879cb83SAl Viro size_t skip = i->iov_offset; \ 145d879cb83SAl Viro if (unlikely(i->type & ITER_BVEC)) { \ 1461bdc76aeSMing Lei const struct bio_vec *bvec = i->bvec; \ 147d879cb83SAl Viro struct bio_vec v; \ 1481bdc76aeSMing Lei struct bvec_iter __bi; \ 1491bdc76aeSMing Lei iterate_bvec(i, n, v, __bi, skip, (B)) \ 1501bdc76aeSMing Lei i->bvec = __bvec_iter_bvec(i->bvec, __bi); \ 1511bdc76aeSMing Lei i->nr_segs -= i->bvec - bvec; \ 1521bdc76aeSMing Lei skip = __bi.bi_bvec_done; \ 153d879cb83SAl Viro } else if (unlikely(i->type & ITER_KVEC)) { \ 154d879cb83SAl Viro const struct kvec *kvec; \ 155d879cb83SAl Viro struct kvec v; \ 156d879cb83SAl Viro iterate_kvec(i, n, v, kvec, skip, (K)) \ 157d879cb83SAl Viro if (skip == kvec->iov_len) { \ 158d879cb83SAl Viro kvec++; \ 159d879cb83SAl Viro skip = 0; \ 160d879cb83SAl Viro } \ 161d879cb83SAl Viro i->nr_segs -= kvec - i->kvec; \ 162d879cb83SAl Viro i->kvec = kvec; \ 1639ea9ce04SDavid Howells } else if (unlikely(i->type & ITER_DISCARD)) { \ 1649ea9ce04SDavid Howells skip += n; \ 1657ff50620SDavid Howells } else if (unlikely(i->type & ITER_XARRAY)) { \ 1667ff50620SDavid Howells struct bio_vec v; \ 1677ff50620SDavid Howells iterate_xarray(i, n, v, skip, (X)) \ 168d879cb83SAl Viro } else { \ 169d879cb83SAl Viro const struct iovec *iov; \ 170d879cb83SAl Viro struct iovec v; \ 171d879cb83SAl Viro iterate_iovec(i, n, v, iov, skip, (I)) \ 172d879cb83SAl Viro if (skip == iov->iov_len) { \ 173d879cb83SAl Viro iov++; \ 174d879cb83SAl Viro skip = 0; \ 175d879cb83SAl Viro } \ 176d879cb83SAl Viro i->nr_segs -= iov - i->iov; \ 177d879cb83SAl Viro i->iov = iov; \ 178d879cb83SAl Viro } \ 179d879cb83SAl Viro i->count -= n; \ 180d879cb83SAl Viro i->iov_offset = skip; \ 181dd254f5aSAl Viro } \ 182d879cb83SAl Viro } 183d879cb83SAl Viro 18409fc68dcSAl Viro static int copyout(void __user *to, const void *from, size_t n) 18509fc68dcSAl Viro { 1864d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1874d0e9df5SAlbert van der Linde return n; 18896d4f267SLinus Torvalds if (access_ok(to, n)) { 189d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 19009fc68dcSAl Viro n = raw_copy_to_user(to, from, n); 19109fc68dcSAl Viro } 19209fc68dcSAl Viro return n; 19309fc68dcSAl Viro } 19409fc68dcSAl Viro 19509fc68dcSAl Viro static int copyin(void *to, const void __user *from, size_t n) 19609fc68dcSAl Viro { 1974d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1984d0e9df5SAlbert van der Linde return n; 19996d4f267SLinus Torvalds if (access_ok(from, n)) { 200d0ef4c36SMarco Elver instrument_copy_from_user(to, from, n); 20109fc68dcSAl Viro n = raw_copy_from_user(to, from, n); 20209fc68dcSAl Viro } 20309fc68dcSAl Viro return n; 20409fc68dcSAl Viro } 20509fc68dcSAl Viro 206d879cb83SAl Viro static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, 207d879cb83SAl Viro struct iov_iter *i) 208d879cb83SAl Viro { 209d879cb83SAl Viro size_t skip, copy, left, wanted; 210d879cb83SAl Viro const struct iovec *iov; 211d879cb83SAl Viro char __user *buf; 212d879cb83SAl Viro void *kaddr, *from; 213d879cb83SAl Viro 214d879cb83SAl Viro if (unlikely(bytes > i->count)) 215d879cb83SAl Viro bytes = i->count; 216d879cb83SAl Viro 217d879cb83SAl Viro if (unlikely(!bytes)) 218d879cb83SAl Viro return 0; 219d879cb83SAl Viro 22009fc68dcSAl Viro might_fault(); 221d879cb83SAl Viro wanted = bytes; 222d879cb83SAl Viro iov = i->iov; 223d879cb83SAl Viro skip = i->iov_offset; 224d879cb83SAl Viro buf = iov->iov_base + skip; 225d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 226d879cb83SAl Viro 2273fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { 228d879cb83SAl Viro kaddr = kmap_atomic(page); 229d879cb83SAl Viro from = kaddr + offset; 230d879cb83SAl Viro 231d879cb83SAl Viro /* first chunk, usually the only one */ 23209fc68dcSAl Viro left = copyout(buf, from, copy); 233d879cb83SAl Viro copy -= left; 234d879cb83SAl Viro skip += copy; 235d879cb83SAl Viro from += copy; 236d879cb83SAl Viro bytes -= copy; 237d879cb83SAl Viro 238d879cb83SAl Viro while (unlikely(!left && bytes)) { 239d879cb83SAl Viro iov++; 240d879cb83SAl Viro buf = iov->iov_base; 241d879cb83SAl Viro copy = min(bytes, iov->iov_len); 24209fc68dcSAl Viro left = copyout(buf, from, copy); 243d879cb83SAl Viro copy -= left; 244d879cb83SAl Viro skip = copy; 245d879cb83SAl Viro from += copy; 246d879cb83SAl Viro bytes -= copy; 247d879cb83SAl Viro } 248d879cb83SAl Viro if (likely(!bytes)) { 249d879cb83SAl Viro kunmap_atomic(kaddr); 250d879cb83SAl Viro goto done; 251d879cb83SAl Viro } 252d879cb83SAl Viro offset = from - kaddr; 253d879cb83SAl Viro buf += copy; 254d879cb83SAl Viro kunmap_atomic(kaddr); 255d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 256d879cb83SAl Viro } 257d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 2583fa6c507SMikulas Patocka 259d879cb83SAl Viro kaddr = kmap(page); 260d879cb83SAl Viro from = kaddr + offset; 26109fc68dcSAl Viro left = copyout(buf, from, copy); 262d879cb83SAl Viro copy -= left; 263d879cb83SAl Viro skip += copy; 264d879cb83SAl Viro from += copy; 265d879cb83SAl Viro bytes -= copy; 266d879cb83SAl Viro while (unlikely(!left && bytes)) { 267d879cb83SAl Viro iov++; 268d879cb83SAl Viro buf = iov->iov_base; 269d879cb83SAl Viro copy = min(bytes, iov->iov_len); 27009fc68dcSAl Viro left = copyout(buf, from, copy); 271d879cb83SAl Viro copy -= left; 272d879cb83SAl Viro skip = copy; 273d879cb83SAl Viro from += copy; 274d879cb83SAl Viro bytes -= copy; 275d879cb83SAl Viro } 276d879cb83SAl Viro kunmap(page); 2773fa6c507SMikulas Patocka 278d879cb83SAl Viro done: 279d879cb83SAl Viro if (skip == iov->iov_len) { 280d879cb83SAl Viro iov++; 281d879cb83SAl Viro skip = 0; 282d879cb83SAl Viro } 283d879cb83SAl Viro i->count -= wanted - bytes; 284d879cb83SAl Viro i->nr_segs -= iov - i->iov; 285d879cb83SAl Viro i->iov = iov; 286d879cb83SAl Viro i->iov_offset = skip; 287d879cb83SAl Viro return wanted - bytes; 288d879cb83SAl Viro } 289d879cb83SAl Viro 290d879cb83SAl Viro static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, 291d879cb83SAl Viro struct iov_iter *i) 292d879cb83SAl Viro { 293d879cb83SAl Viro size_t skip, copy, left, wanted; 294d879cb83SAl Viro const struct iovec *iov; 295d879cb83SAl Viro char __user *buf; 296d879cb83SAl Viro void *kaddr, *to; 297d879cb83SAl Viro 298d879cb83SAl Viro if (unlikely(bytes > i->count)) 299d879cb83SAl Viro bytes = i->count; 300d879cb83SAl Viro 301d879cb83SAl Viro if (unlikely(!bytes)) 302d879cb83SAl Viro return 0; 303d879cb83SAl Viro 30409fc68dcSAl Viro might_fault(); 305d879cb83SAl Viro wanted = bytes; 306d879cb83SAl Viro iov = i->iov; 307d879cb83SAl Viro skip = i->iov_offset; 308d879cb83SAl Viro buf = iov->iov_base + skip; 309d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 310d879cb83SAl Viro 3113fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { 312d879cb83SAl Viro kaddr = kmap_atomic(page); 313d879cb83SAl Viro to = kaddr + offset; 314d879cb83SAl Viro 315d879cb83SAl Viro /* first chunk, usually the only one */ 31609fc68dcSAl Viro left = copyin(to, buf, copy); 317d879cb83SAl Viro copy -= left; 318d879cb83SAl Viro skip += copy; 319d879cb83SAl Viro to += copy; 320d879cb83SAl Viro bytes -= copy; 321d879cb83SAl Viro 322d879cb83SAl Viro while (unlikely(!left && bytes)) { 323d879cb83SAl Viro iov++; 324d879cb83SAl Viro buf = iov->iov_base; 325d879cb83SAl Viro copy = min(bytes, iov->iov_len); 32609fc68dcSAl Viro left = copyin(to, buf, copy); 327d879cb83SAl Viro copy -= left; 328d879cb83SAl Viro skip = copy; 329d879cb83SAl Viro to += copy; 330d879cb83SAl Viro bytes -= copy; 331d879cb83SAl Viro } 332d879cb83SAl Viro if (likely(!bytes)) { 333d879cb83SAl Viro kunmap_atomic(kaddr); 334d879cb83SAl Viro goto done; 335d879cb83SAl Viro } 336d879cb83SAl Viro offset = to - kaddr; 337d879cb83SAl Viro buf += copy; 338d879cb83SAl Viro kunmap_atomic(kaddr); 339d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 340d879cb83SAl Viro } 341d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 3423fa6c507SMikulas Patocka 343d879cb83SAl Viro kaddr = kmap(page); 344d879cb83SAl Viro to = kaddr + offset; 34509fc68dcSAl Viro left = copyin(to, buf, copy); 346d879cb83SAl Viro copy -= left; 347d879cb83SAl Viro skip += copy; 348d879cb83SAl Viro to += copy; 349d879cb83SAl Viro bytes -= copy; 350d879cb83SAl Viro while (unlikely(!left && bytes)) { 351d879cb83SAl Viro iov++; 352d879cb83SAl Viro buf = iov->iov_base; 353d879cb83SAl Viro copy = min(bytes, iov->iov_len); 35409fc68dcSAl Viro left = copyin(to, buf, copy); 355d879cb83SAl Viro copy -= left; 356d879cb83SAl Viro skip = copy; 357d879cb83SAl Viro to += copy; 358d879cb83SAl Viro bytes -= copy; 359d879cb83SAl Viro } 360d879cb83SAl Viro kunmap(page); 3613fa6c507SMikulas Patocka 362d879cb83SAl Viro done: 363d879cb83SAl Viro if (skip == iov->iov_len) { 364d879cb83SAl Viro iov++; 365d879cb83SAl Viro skip = 0; 366d879cb83SAl Viro } 367d879cb83SAl Viro i->count -= wanted - bytes; 368d879cb83SAl Viro i->nr_segs -= iov - i->iov; 369d879cb83SAl Viro i->iov = iov; 370d879cb83SAl Viro i->iov_offset = skip; 371d879cb83SAl Viro return wanted - bytes; 372d879cb83SAl Viro } 373d879cb83SAl Viro 374241699cdSAl Viro #ifdef PIPE_PARANOIA 375241699cdSAl Viro static bool sanity(const struct iov_iter *i) 376241699cdSAl Viro { 377241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 3788cefc107SDavid Howells unsigned int p_head = pipe->head; 3798cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3808cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3818cefc107SDavid Howells unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); 3828cefc107SDavid Howells unsigned int i_head = i->head; 3838cefc107SDavid Howells unsigned int idx; 3848cefc107SDavid Howells 385241699cdSAl Viro if (i->iov_offset) { 386241699cdSAl Viro struct pipe_buffer *p; 3878cefc107SDavid Howells if (unlikely(p_occupancy == 0)) 388241699cdSAl Viro goto Bad; // pipe must be non-empty 3898cefc107SDavid Howells if (unlikely(i_head != p_head - 1)) 390241699cdSAl Viro goto Bad; // must be at the last buffer... 391241699cdSAl Viro 3928cefc107SDavid Howells p = &pipe->bufs[i_head & p_mask]; 393241699cdSAl Viro if (unlikely(p->offset + p->len != i->iov_offset)) 394241699cdSAl Viro goto Bad; // ... at the end of segment 395241699cdSAl Viro } else { 3968cefc107SDavid Howells if (i_head != p_head) 397241699cdSAl Viro goto Bad; // must be right after the last buffer 398241699cdSAl Viro } 399241699cdSAl Viro return true; 400241699cdSAl Viro Bad: 4018cefc107SDavid Howells printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); 4028cefc107SDavid Howells printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", 4038cefc107SDavid Howells p_head, p_tail, pipe->ring_size); 4048cefc107SDavid Howells for (idx = 0; idx < pipe->ring_size; idx++) 405241699cdSAl Viro printk(KERN_ERR "[%p %p %d %d]\n", 406241699cdSAl Viro pipe->bufs[idx].ops, 407241699cdSAl Viro pipe->bufs[idx].page, 408241699cdSAl Viro pipe->bufs[idx].offset, 409241699cdSAl Viro pipe->bufs[idx].len); 410241699cdSAl Viro WARN_ON(1); 411241699cdSAl Viro return false; 412241699cdSAl Viro } 413241699cdSAl Viro #else 414241699cdSAl Viro #define sanity(i) true 415241699cdSAl Viro #endif 416241699cdSAl Viro 417241699cdSAl Viro static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, 418241699cdSAl Viro struct iov_iter *i) 419241699cdSAl Viro { 420241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 421241699cdSAl Viro struct pipe_buffer *buf; 4228cefc107SDavid Howells unsigned int p_tail = pipe->tail; 4238cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 4248cefc107SDavid Howells unsigned int i_head = i->head; 425241699cdSAl Viro size_t off; 426241699cdSAl Viro 427241699cdSAl Viro if (unlikely(bytes > i->count)) 428241699cdSAl Viro bytes = i->count; 429241699cdSAl Viro 430241699cdSAl Viro if (unlikely(!bytes)) 431241699cdSAl Viro return 0; 432241699cdSAl Viro 433241699cdSAl Viro if (!sanity(i)) 434241699cdSAl Viro return 0; 435241699cdSAl Viro 436241699cdSAl Viro off = i->iov_offset; 4378cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 438241699cdSAl Viro if (off) { 439241699cdSAl Viro if (offset == off && buf->page == page) { 440241699cdSAl Viro /* merge with the last one */ 441241699cdSAl Viro buf->len += bytes; 442241699cdSAl Viro i->iov_offset += bytes; 443241699cdSAl Viro goto out; 444241699cdSAl Viro } 4458cefc107SDavid Howells i_head++; 4468cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 447241699cdSAl Viro } 4486718b6f8SDavid Howells if (pipe_full(i_head, p_tail, pipe->max_usage)) 449241699cdSAl Viro return 0; 4508cefc107SDavid Howells 451241699cdSAl Viro buf->ops = &page_cache_pipe_buf_ops; 4528cefc107SDavid Howells get_page(page); 4538cefc107SDavid Howells buf->page = page; 454241699cdSAl Viro buf->offset = offset; 455241699cdSAl Viro buf->len = bytes; 4568cefc107SDavid Howells 4578cefc107SDavid Howells pipe->head = i_head + 1; 458241699cdSAl Viro i->iov_offset = offset + bytes; 4598cefc107SDavid Howells i->head = i_head; 460241699cdSAl Viro out: 461241699cdSAl Viro i->count -= bytes; 462241699cdSAl Viro return bytes; 463241699cdSAl Viro } 464241699cdSAl Viro 465d879cb83SAl Viro /* 466171a0203SAnton Altaparmakov * Fault in one or more iovecs of the given iov_iter, to a maximum length of 467171a0203SAnton Altaparmakov * bytes. For each iovec, fault in each page that constitutes the iovec. 468171a0203SAnton Altaparmakov * 469171a0203SAnton Altaparmakov * Return 0 on success, or non-zero if the memory could not be accessed (i.e. 470171a0203SAnton Altaparmakov * because it is an invalid address). 471171a0203SAnton Altaparmakov */ 472d4690f1eSAl Viro int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) 473171a0203SAnton Altaparmakov { 474171a0203SAnton Altaparmakov size_t skip = i->iov_offset; 475171a0203SAnton Altaparmakov const struct iovec *iov; 476171a0203SAnton Altaparmakov int err; 477171a0203SAnton Altaparmakov struct iovec v; 478171a0203SAnton Altaparmakov 479171a0203SAnton Altaparmakov if (!(i->type & (ITER_BVEC|ITER_KVEC))) { 480171a0203SAnton Altaparmakov iterate_iovec(i, bytes, v, iov, skip, ({ 4814bce9f6eSAl Viro err = fault_in_pages_readable(v.iov_base, v.iov_len); 482171a0203SAnton Altaparmakov if (unlikely(err)) 483171a0203SAnton Altaparmakov return err; 484171a0203SAnton Altaparmakov 0;})) 485171a0203SAnton Altaparmakov } 486171a0203SAnton Altaparmakov return 0; 487171a0203SAnton Altaparmakov } 488d4690f1eSAl Viro EXPORT_SYMBOL(iov_iter_fault_in_readable); 489171a0203SAnton Altaparmakov 490aa563d7bSDavid Howells void iov_iter_init(struct iov_iter *i, unsigned int direction, 491d879cb83SAl Viro const struct iovec *iov, unsigned long nr_segs, 492d879cb83SAl Viro size_t count) 493d879cb83SAl Viro { 494aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 495aa563d7bSDavid Howells direction &= READ | WRITE; 496aa563d7bSDavid Howells 497d879cb83SAl Viro /* It will get better. Eventually... */ 498db68ce10SAl Viro if (uaccess_kernel()) { 499aa563d7bSDavid Howells i->type = ITER_KVEC | direction; 500d879cb83SAl Viro i->kvec = (struct kvec *)iov; 501d879cb83SAl Viro } else { 502aa563d7bSDavid Howells i->type = ITER_IOVEC | direction; 503d879cb83SAl Viro i->iov = iov; 504d879cb83SAl Viro } 505d879cb83SAl Viro i->nr_segs = nr_segs; 506d879cb83SAl Viro i->iov_offset = 0; 507d879cb83SAl Viro i->count = count; 508d879cb83SAl Viro } 509d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_init); 510d879cb83SAl Viro 511241699cdSAl Viro static inline bool allocated(struct pipe_buffer *buf) 512241699cdSAl Viro { 513241699cdSAl Viro return buf->ops == &default_pipe_buf_ops; 514241699cdSAl Viro } 515241699cdSAl Viro 5168cefc107SDavid Howells static inline void data_start(const struct iov_iter *i, 5178cefc107SDavid Howells unsigned int *iter_headp, size_t *offp) 518241699cdSAl Viro { 5198cefc107SDavid Howells unsigned int p_mask = i->pipe->ring_size - 1; 5208cefc107SDavid Howells unsigned int iter_head = i->head; 521241699cdSAl Viro size_t off = i->iov_offset; 5228cefc107SDavid Howells 5238cefc107SDavid Howells if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || 5248cefc107SDavid Howells off == PAGE_SIZE)) { 5258cefc107SDavid Howells iter_head++; 526241699cdSAl Viro off = 0; 527241699cdSAl Viro } 5288cefc107SDavid Howells *iter_headp = iter_head; 529241699cdSAl Viro *offp = off; 530241699cdSAl Viro } 531241699cdSAl Viro 532241699cdSAl Viro static size_t push_pipe(struct iov_iter *i, size_t size, 5338cefc107SDavid Howells int *iter_headp, size_t *offp) 534241699cdSAl Viro { 535241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5368cefc107SDavid Howells unsigned int p_tail = pipe->tail; 5378cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5388cefc107SDavid Howells unsigned int iter_head; 539241699cdSAl Viro size_t off; 540241699cdSAl Viro ssize_t left; 541241699cdSAl Viro 542241699cdSAl Viro if (unlikely(size > i->count)) 543241699cdSAl Viro size = i->count; 544241699cdSAl Viro if (unlikely(!size)) 545241699cdSAl Viro return 0; 546241699cdSAl Viro 547241699cdSAl Viro left = size; 5488cefc107SDavid Howells data_start(i, &iter_head, &off); 5498cefc107SDavid Howells *iter_headp = iter_head; 550241699cdSAl Viro *offp = off; 551241699cdSAl Viro if (off) { 552241699cdSAl Viro left -= PAGE_SIZE - off; 553241699cdSAl Viro if (left <= 0) { 5548cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len += size; 555241699cdSAl Viro return size; 556241699cdSAl Viro } 5578cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; 5588cefc107SDavid Howells iter_head++; 559241699cdSAl Viro } 5606718b6f8SDavid Howells while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { 5618cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; 562241699cdSAl Viro struct page *page = alloc_page(GFP_USER); 563241699cdSAl Viro if (!page) 564241699cdSAl Viro break; 5658cefc107SDavid Howells 5668cefc107SDavid Howells buf->ops = &default_pipe_buf_ops; 5678cefc107SDavid Howells buf->page = page; 5688cefc107SDavid Howells buf->offset = 0; 5698cefc107SDavid Howells buf->len = min_t(ssize_t, left, PAGE_SIZE); 5708cefc107SDavid Howells left -= buf->len; 5718cefc107SDavid Howells iter_head++; 5728cefc107SDavid Howells pipe->head = iter_head; 5738cefc107SDavid Howells 5748cefc107SDavid Howells if (left == 0) 575241699cdSAl Viro return size; 576241699cdSAl Viro } 577241699cdSAl Viro return size - left; 578241699cdSAl Viro } 579241699cdSAl Viro 580241699cdSAl Viro static size_t copy_pipe_to_iter(const void *addr, size_t bytes, 581241699cdSAl Viro struct iov_iter *i) 582241699cdSAl Viro { 583241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5848cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5858cefc107SDavid Howells unsigned int i_head; 586241699cdSAl Viro size_t n, off; 587241699cdSAl Viro 588241699cdSAl Viro if (!sanity(i)) 589241699cdSAl Viro return 0; 590241699cdSAl Viro 5918cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 592241699cdSAl Viro if (unlikely(!n)) 593241699cdSAl Viro return 0; 5948cefc107SDavid Howells do { 595241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 5968cefc107SDavid Howells memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); 5978cefc107SDavid Howells i->head = i_head; 598241699cdSAl Viro i->iov_offset = off + chunk; 599241699cdSAl Viro n -= chunk; 600241699cdSAl Viro addr += chunk; 6018cefc107SDavid Howells off = 0; 6028cefc107SDavid Howells i_head++; 6038cefc107SDavid Howells } while (n); 604241699cdSAl Viro i->count -= bytes; 605241699cdSAl Viro return bytes; 606241699cdSAl Viro } 607241699cdSAl Viro 608f9152895SAl Viro static __wsum csum_and_memcpy(void *to, const void *from, size_t len, 609f9152895SAl Viro __wsum sum, size_t off) 610f9152895SAl Viro { 611cc44c17bSAl Viro __wsum next = csum_partial_copy_nocheck(from, to, len); 612f9152895SAl Viro return csum_block_add(sum, next, off); 613f9152895SAl Viro } 614f9152895SAl Viro 61578e1f386SAl Viro static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, 61652cbd23aSWillem de Bruijn struct csum_state *csstate, 61752cbd23aSWillem de Bruijn struct iov_iter *i) 61878e1f386SAl Viro { 61978e1f386SAl Viro struct pipe_inode_info *pipe = i->pipe; 6208cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 62152cbd23aSWillem de Bruijn __wsum sum = csstate->csum; 62252cbd23aSWillem de Bruijn size_t off = csstate->off; 6238cefc107SDavid Howells unsigned int i_head; 62478e1f386SAl Viro size_t n, r; 62578e1f386SAl Viro 62678e1f386SAl Viro if (!sanity(i)) 62778e1f386SAl Viro return 0; 62878e1f386SAl Viro 6298cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &r); 63078e1f386SAl Viro if (unlikely(!n)) 63178e1f386SAl Viro return 0; 6328cefc107SDavid Howells do { 63378e1f386SAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - r); 6348cefc107SDavid Howells char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); 635f9152895SAl Viro sum = csum_and_memcpy(p + r, addr, chunk, sum, off); 63678e1f386SAl Viro kunmap_atomic(p); 6378cefc107SDavid Howells i->head = i_head; 63878e1f386SAl Viro i->iov_offset = r + chunk; 63978e1f386SAl Viro n -= chunk; 64078e1f386SAl Viro off += chunk; 64178e1f386SAl Viro addr += chunk; 6428cefc107SDavid Howells r = 0; 6438cefc107SDavid Howells i_head++; 6448cefc107SDavid Howells } while (n); 64578e1f386SAl Viro i->count -= bytes; 64652cbd23aSWillem de Bruijn csstate->csum = sum; 64752cbd23aSWillem de Bruijn csstate->off = off; 64878e1f386SAl Viro return bytes; 64978e1f386SAl Viro } 65078e1f386SAl Viro 651aa28de27SAl Viro size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 652d879cb83SAl Viro { 65336f7a8a4SAl Viro const char *from = addr; 65400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 655241699cdSAl Viro return copy_pipe_to_iter(addr, bytes, i); 65609fc68dcSAl Viro if (iter_is_iovec(i)) 65709fc68dcSAl Viro might_fault(); 658d879cb83SAl Viro iterate_and_advance(i, bytes, v, 65909fc68dcSAl Viro copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 660d879cb83SAl Viro memcpy_to_page(v.bv_page, v.bv_offset, 661d879cb83SAl Viro (from += v.bv_len) - v.bv_len, v.bv_len), 6627ff50620SDavid Howells memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 6637ff50620SDavid Howells memcpy_to_page(v.bv_page, v.bv_offset, 6647ff50620SDavid Howells (from += v.bv_len) - v.bv_len, v.bv_len) 665d879cb83SAl Viro ) 666d879cb83SAl Viro 667d879cb83SAl Viro return bytes; 668d879cb83SAl Viro } 669aa28de27SAl Viro EXPORT_SYMBOL(_copy_to_iter); 670d879cb83SAl Viro 671ec6347bbSDan Williams #ifdef CONFIG_ARCH_HAS_COPY_MC 672ec6347bbSDan Williams static int copyout_mc(void __user *to, const void *from, size_t n) 6738780356eSDan Williams { 67496d4f267SLinus Torvalds if (access_ok(to, n)) { 675d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 676ec6347bbSDan Williams n = copy_mc_to_user((__force void *) to, from, n); 6778780356eSDan Williams } 6788780356eSDan Williams return n; 6798780356eSDan Williams } 6808780356eSDan Williams 681ec6347bbSDan Williams static unsigned long copy_mc_to_page(struct page *page, size_t offset, 6828780356eSDan Williams const char *from, size_t len) 6838780356eSDan Williams { 6848780356eSDan Williams unsigned long ret; 6858780356eSDan Williams char *to; 6868780356eSDan Williams 6878780356eSDan Williams to = kmap_atomic(page); 688ec6347bbSDan Williams ret = copy_mc_to_kernel(to + offset, from, len); 6898780356eSDan Williams kunmap_atomic(to); 6908780356eSDan Williams 6918780356eSDan Williams return ret; 6928780356eSDan Williams } 6938780356eSDan Williams 694ec6347bbSDan Williams static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, 695ca146f6fSDan Williams struct iov_iter *i) 696ca146f6fSDan Williams { 697ca146f6fSDan Williams struct pipe_inode_info *pipe = i->pipe; 6988cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 6998cefc107SDavid Howells unsigned int i_head; 700ca146f6fSDan Williams size_t n, off, xfer = 0; 701ca146f6fSDan Williams 702ca146f6fSDan Williams if (!sanity(i)) 703ca146f6fSDan Williams return 0; 704ca146f6fSDan Williams 7058cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 706ca146f6fSDan Williams if (unlikely(!n)) 707ca146f6fSDan Williams return 0; 7088cefc107SDavid Howells do { 709ca146f6fSDan Williams size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 710ca146f6fSDan Williams unsigned long rem; 711ca146f6fSDan Williams 712ec6347bbSDan Williams rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, 7138cefc107SDavid Howells off, addr, chunk); 7148cefc107SDavid Howells i->head = i_head; 715ca146f6fSDan Williams i->iov_offset = off + chunk - rem; 716ca146f6fSDan Williams xfer += chunk - rem; 717ca146f6fSDan Williams if (rem) 718ca146f6fSDan Williams break; 719ca146f6fSDan Williams n -= chunk; 720ca146f6fSDan Williams addr += chunk; 7218cefc107SDavid Howells off = 0; 7228cefc107SDavid Howells i_head++; 7238cefc107SDavid Howells } while (n); 724ca146f6fSDan Williams i->count -= xfer; 725ca146f6fSDan Williams return xfer; 726ca146f6fSDan Williams } 727ca146f6fSDan Williams 728bf3eeb9bSDan Williams /** 729ec6347bbSDan Williams * _copy_mc_to_iter - copy to iter with source memory error exception handling 730bf3eeb9bSDan Williams * @addr: source kernel address 731bf3eeb9bSDan Williams * @bytes: total transfer length 732bf3eeb9bSDan Williams * @iter: destination iterator 733bf3eeb9bSDan Williams * 734ec6347bbSDan Williams * The pmem driver deploys this for the dax operation 735ec6347bbSDan Williams * (dax_copy_to_iter()) for dax reads (bypass page-cache and the 736ec6347bbSDan Williams * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes 737ec6347bbSDan Williams * successfully copied. 738bf3eeb9bSDan Williams * 739ec6347bbSDan Williams * The main differences between this and typical _copy_to_iter(). 740bf3eeb9bSDan Williams * 741bf3eeb9bSDan Williams * * Typical tail/residue handling after a fault retries the copy 742bf3eeb9bSDan Williams * byte-by-byte until the fault happens again. Re-triggering machine 743bf3eeb9bSDan Williams * checks is potentially fatal so the implementation uses source 744bf3eeb9bSDan Williams * alignment and poison alignment assumptions to avoid re-triggering 745bf3eeb9bSDan Williams * hardware exceptions. 746bf3eeb9bSDan Williams * 747bf3eeb9bSDan Williams * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. 748bf3eeb9bSDan Williams * Compare to copy_to_iter() where only ITER_IOVEC attempts might return 749bf3eeb9bSDan Williams * a short copy. 750bf3eeb9bSDan Williams */ 751ec6347bbSDan Williams size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 7528780356eSDan Williams { 7538780356eSDan Williams const char *from = addr; 7548780356eSDan Williams unsigned long rem, curr_addr, s_addr = (unsigned long) addr; 7558780356eSDan Williams 75600e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 757ec6347bbSDan Williams return copy_mc_pipe_to_iter(addr, bytes, i); 7588780356eSDan Williams if (iter_is_iovec(i)) 7598780356eSDan Williams might_fault(); 7608780356eSDan Williams iterate_and_advance(i, bytes, v, 761ec6347bbSDan Williams copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len, 762ec6347bbSDan Williams v.iov_len), 7638780356eSDan Williams ({ 764ec6347bbSDan Williams rem = copy_mc_to_page(v.bv_page, v.bv_offset, 7658780356eSDan Williams (from += v.bv_len) - v.bv_len, v.bv_len); 7668780356eSDan Williams if (rem) { 7678780356eSDan Williams curr_addr = (unsigned long) from; 7688780356eSDan Williams bytes = curr_addr - s_addr - rem; 7698780356eSDan Williams return bytes; 7708780356eSDan Williams } 7718780356eSDan Williams }), 7728780356eSDan Williams ({ 773ec6347bbSDan Williams rem = copy_mc_to_kernel(v.iov_base, (from += v.iov_len) 774ec6347bbSDan Williams - v.iov_len, v.iov_len); 7758780356eSDan Williams if (rem) { 7768780356eSDan Williams curr_addr = (unsigned long) from; 7778780356eSDan Williams bytes = curr_addr - s_addr - rem; 7788780356eSDan Williams return bytes; 7798780356eSDan Williams } 7807ff50620SDavid Howells }), 7817ff50620SDavid Howells ({ 7827ff50620SDavid Howells rem = copy_mc_to_page(v.bv_page, v.bv_offset, 7837ff50620SDavid Howells (from += v.bv_len) - v.bv_len, v.bv_len); 7847ff50620SDavid Howells if (rem) { 7857ff50620SDavid Howells curr_addr = (unsigned long) from; 7867ff50620SDavid Howells bytes = curr_addr - s_addr - rem; 7877ff50620SDavid Howells rcu_read_unlock(); 7883d14ec1fSDavid Howells i->iov_offset += bytes; 7893d14ec1fSDavid Howells i->count -= bytes; 7907ff50620SDavid Howells return bytes; 7917ff50620SDavid Howells } 7928780356eSDan Williams }) 7938780356eSDan Williams ) 7948780356eSDan Williams 7958780356eSDan Williams return bytes; 7968780356eSDan Williams } 797ec6347bbSDan Williams EXPORT_SYMBOL_GPL(_copy_mc_to_iter); 798ec6347bbSDan Williams #endif /* CONFIG_ARCH_HAS_COPY_MC */ 7998780356eSDan Williams 800aa28de27SAl Viro size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) 801d879cb83SAl Viro { 802d879cb83SAl Viro char *to = addr; 80300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 804241699cdSAl Viro WARN_ON(1); 805241699cdSAl Viro return 0; 806241699cdSAl Viro } 80709fc68dcSAl Viro if (iter_is_iovec(i)) 80809fc68dcSAl Viro might_fault(); 809d879cb83SAl Viro iterate_and_advance(i, bytes, v, 81009fc68dcSAl Viro copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 811d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 812d879cb83SAl Viro v.bv_offset, v.bv_len), 8137ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 8147ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 8157ff50620SDavid Howells v.bv_offset, v.bv_len) 816d879cb83SAl Viro ) 817d879cb83SAl Viro 818d879cb83SAl Viro return bytes; 819d879cb83SAl Viro } 820aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter); 821d879cb83SAl Viro 822aa28de27SAl Viro bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i) 823cbbd26b8SAl Viro { 824cbbd26b8SAl Viro char *to = addr; 82500e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 826cbbd26b8SAl Viro WARN_ON(1); 827cbbd26b8SAl Viro return false; 828cbbd26b8SAl Viro } 82933844e66SAl Viro if (unlikely(i->count < bytes)) 830cbbd26b8SAl Viro return false; 831cbbd26b8SAl Viro 83209fc68dcSAl Viro if (iter_is_iovec(i)) 83309fc68dcSAl Viro might_fault(); 834cbbd26b8SAl Viro iterate_all_kinds(i, bytes, v, ({ 83509fc68dcSAl Viro if (copyin((to += v.iov_len) - v.iov_len, 836cbbd26b8SAl Viro v.iov_base, v.iov_len)) 837cbbd26b8SAl Viro return false; 838cbbd26b8SAl Viro 0;}), 839cbbd26b8SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 840cbbd26b8SAl Viro v.bv_offset, v.bv_len), 8417ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 8427ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 8437ff50620SDavid Howells v.bv_offset, v.bv_len) 844cbbd26b8SAl Viro ) 845cbbd26b8SAl Viro 846cbbd26b8SAl Viro iov_iter_advance(i, bytes); 847cbbd26b8SAl Viro return true; 848cbbd26b8SAl Viro } 849aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_full); 850cbbd26b8SAl Viro 851aa28de27SAl Viro size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) 852d879cb83SAl Viro { 853d879cb83SAl Viro char *to = addr; 85400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 855241699cdSAl Viro WARN_ON(1); 856241699cdSAl Viro return 0; 857241699cdSAl Viro } 858d879cb83SAl Viro iterate_and_advance(i, bytes, v, 8593f763453SAl Viro __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, 860d879cb83SAl Viro v.iov_base, v.iov_len), 861d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 862d879cb83SAl Viro v.bv_offset, v.bv_len), 8637ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 8647ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 8657ff50620SDavid Howells v.bv_offset, v.bv_len) 866d879cb83SAl Viro ) 867d879cb83SAl Viro 868d879cb83SAl Viro return bytes; 869d879cb83SAl Viro } 870aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_nocache); 871d879cb83SAl Viro 8720aed55afSDan Williams #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE 873abd08d7dSDan Williams /** 874abd08d7dSDan Williams * _copy_from_iter_flushcache - write destination through cpu cache 875abd08d7dSDan Williams * @addr: destination kernel address 876abd08d7dSDan Williams * @bytes: total transfer length 877abd08d7dSDan Williams * @iter: source iterator 878abd08d7dSDan Williams * 879abd08d7dSDan Williams * The pmem driver arranges for filesystem-dax to use this facility via 880abd08d7dSDan Williams * dax_copy_from_iter() for ensuring that writes to persistent memory 881abd08d7dSDan Williams * are flushed through the CPU cache. It is differentiated from 882abd08d7dSDan Williams * _copy_from_iter_nocache() in that guarantees all data is flushed for 883abd08d7dSDan Williams * all iterator types. The _copy_from_iter_nocache() only attempts to 884abd08d7dSDan Williams * bypass the cache for the ITER_IOVEC case, and on some archs may use 885abd08d7dSDan Williams * instructions that strand dirty-data in the cache. 886abd08d7dSDan Williams */ 8876a37e940SLinus Torvalds size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 8880aed55afSDan Williams { 8890aed55afSDan Williams char *to = addr; 89000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 8910aed55afSDan Williams WARN_ON(1); 8920aed55afSDan Williams return 0; 8930aed55afSDan Williams } 8940aed55afSDan Williams iterate_and_advance(i, bytes, v, 8950aed55afSDan Williams __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, 8960aed55afSDan Williams v.iov_base, v.iov_len), 8970aed55afSDan Williams memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 8980aed55afSDan Williams v.bv_offset, v.bv_len), 8990aed55afSDan Williams memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, 9007ff50620SDavid Howells v.iov_len), 9017ff50620SDavid Howells memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 9027ff50620SDavid Howells v.bv_offset, v.bv_len) 9030aed55afSDan Williams ) 9040aed55afSDan Williams 9050aed55afSDan Williams return bytes; 9060aed55afSDan Williams } 9076a37e940SLinus Torvalds EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); 9080aed55afSDan Williams #endif 9090aed55afSDan Williams 910aa28de27SAl Viro bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i) 911cbbd26b8SAl Viro { 912cbbd26b8SAl Viro char *to = addr; 91300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 914cbbd26b8SAl Viro WARN_ON(1); 915cbbd26b8SAl Viro return false; 916cbbd26b8SAl Viro } 91733844e66SAl Viro if (unlikely(i->count < bytes)) 918cbbd26b8SAl Viro return false; 919cbbd26b8SAl Viro iterate_all_kinds(i, bytes, v, ({ 9203f763453SAl Viro if (__copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, 921cbbd26b8SAl Viro v.iov_base, v.iov_len)) 922cbbd26b8SAl Viro return false; 923cbbd26b8SAl Viro 0;}), 924cbbd26b8SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 925cbbd26b8SAl Viro v.bv_offset, v.bv_len), 9267ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 9277ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 9287ff50620SDavid Howells v.bv_offset, v.bv_len) 929cbbd26b8SAl Viro ) 930cbbd26b8SAl Viro 931cbbd26b8SAl Viro iov_iter_advance(i, bytes); 932cbbd26b8SAl Viro return true; 933cbbd26b8SAl Viro } 934aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_full_nocache); 935cbbd26b8SAl Viro 93672e809edSAl Viro static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) 93772e809edSAl Viro { 9386daef95bSEric Dumazet struct page *head; 9396daef95bSEric Dumazet size_t v = n + offset; 9406daef95bSEric Dumazet 9416daef95bSEric Dumazet /* 9426daef95bSEric Dumazet * The general case needs to access the page order in order 9436daef95bSEric Dumazet * to compute the page size. 9446daef95bSEric Dumazet * However, we mostly deal with order-0 pages and thus can 9456daef95bSEric Dumazet * avoid a possible cache line miss for requests that fit all 9466daef95bSEric Dumazet * page orders. 9476daef95bSEric Dumazet */ 9486daef95bSEric Dumazet if (n <= v && v <= PAGE_SIZE) 9496daef95bSEric Dumazet return true; 9506daef95bSEric Dumazet 9516daef95bSEric Dumazet head = compound_head(page); 9526daef95bSEric Dumazet v += (page - head) << PAGE_SHIFT; 953a90bcb86SPetar Penkov 954a50b854eSMatthew Wilcox (Oracle) if (likely(n <= v && v <= (page_size(head)))) 95572e809edSAl Viro return true; 95672e809edSAl Viro WARN_ON(1); 95772e809edSAl Viro return false; 95872e809edSAl Viro } 959d879cb83SAl Viro 960d879cb83SAl Viro size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 961d879cb83SAl Viro struct iov_iter *i) 962d879cb83SAl Viro { 96372e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 96472e809edSAl Viro return 0; 9657ff50620SDavid Howells if (i->type & (ITER_BVEC | ITER_KVEC | ITER_XARRAY)) { 966d879cb83SAl Viro void *kaddr = kmap_atomic(page); 967d879cb83SAl Viro size_t wanted = copy_to_iter(kaddr + offset, bytes, i); 968d879cb83SAl Viro kunmap_atomic(kaddr); 969d879cb83SAl Viro return wanted; 9709ea9ce04SDavid Howells } else if (unlikely(iov_iter_is_discard(i))) 9719ea9ce04SDavid Howells return bytes; 9729ea9ce04SDavid Howells else if (likely(!iov_iter_is_pipe(i))) 973d879cb83SAl Viro return copy_page_to_iter_iovec(page, offset, bytes, i); 974241699cdSAl Viro else 975241699cdSAl Viro return copy_page_to_iter_pipe(page, offset, bytes, i); 976d879cb83SAl Viro } 977d879cb83SAl Viro EXPORT_SYMBOL(copy_page_to_iter); 978d879cb83SAl Viro 979d879cb83SAl Viro size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, 980d879cb83SAl Viro struct iov_iter *i) 981d879cb83SAl Viro { 98272e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 98372e809edSAl Viro return 0; 9849ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 985241699cdSAl Viro WARN_ON(1); 986241699cdSAl Viro return 0; 987241699cdSAl Viro } 9887ff50620SDavid Howells if (i->type & (ITER_BVEC | ITER_KVEC | ITER_XARRAY)) { 989d879cb83SAl Viro void *kaddr = kmap_atomic(page); 990aa28de27SAl Viro size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); 991d879cb83SAl Viro kunmap_atomic(kaddr); 992d879cb83SAl Viro return wanted; 993d879cb83SAl Viro } else 994d879cb83SAl Viro return copy_page_from_iter_iovec(page, offset, bytes, i); 995d879cb83SAl Viro } 996d879cb83SAl Viro EXPORT_SYMBOL(copy_page_from_iter); 997d879cb83SAl Viro 998241699cdSAl Viro static size_t pipe_zero(size_t bytes, struct iov_iter *i) 999241699cdSAl Viro { 1000241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 10018cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10028cefc107SDavid Howells unsigned int i_head; 1003241699cdSAl Viro size_t n, off; 1004241699cdSAl Viro 1005241699cdSAl Viro if (!sanity(i)) 1006241699cdSAl Viro return 0; 1007241699cdSAl Viro 10088cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 1009241699cdSAl Viro if (unlikely(!n)) 1010241699cdSAl Viro return 0; 1011241699cdSAl Viro 10128cefc107SDavid Howells do { 1013241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 10148cefc107SDavid Howells memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); 10158cefc107SDavid Howells i->head = i_head; 1016241699cdSAl Viro i->iov_offset = off + chunk; 1017241699cdSAl Viro n -= chunk; 10188cefc107SDavid Howells off = 0; 10198cefc107SDavid Howells i_head++; 10208cefc107SDavid Howells } while (n); 1021241699cdSAl Viro i->count -= bytes; 1022241699cdSAl Viro return bytes; 1023241699cdSAl Viro } 1024241699cdSAl Viro 1025d879cb83SAl Viro size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 1026d879cb83SAl Viro { 102700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1028241699cdSAl Viro return pipe_zero(bytes, i); 1029d879cb83SAl Viro iterate_and_advance(i, bytes, v, 103009fc68dcSAl Viro clear_user(v.iov_base, v.iov_len), 1031d879cb83SAl Viro memzero_page(v.bv_page, v.bv_offset, v.bv_len), 10327ff50620SDavid Howells memset(v.iov_base, 0, v.iov_len), 10337ff50620SDavid Howells memzero_page(v.bv_page, v.bv_offset, v.bv_len) 1034d879cb83SAl Viro ) 1035d879cb83SAl Viro 1036d879cb83SAl Viro return bytes; 1037d879cb83SAl Viro } 1038d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_zero); 1039d879cb83SAl Viro 1040d879cb83SAl Viro size_t iov_iter_copy_from_user_atomic(struct page *page, 1041d879cb83SAl Viro struct iov_iter *i, unsigned long offset, size_t bytes) 1042d879cb83SAl Viro { 1043d879cb83SAl Viro char *kaddr = kmap_atomic(page), *p = kaddr + offset; 104472e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) { 104572e809edSAl Viro kunmap_atomic(kaddr); 104672e809edSAl Viro return 0; 104772e809edSAl Viro } 10489ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1049241699cdSAl Viro kunmap_atomic(kaddr); 1050241699cdSAl Viro WARN_ON(1); 1051241699cdSAl Viro return 0; 1052241699cdSAl Viro } 1053d879cb83SAl Viro iterate_all_kinds(i, bytes, v, 105409fc68dcSAl Viro copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 1055d879cb83SAl Viro memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 1056d879cb83SAl Viro v.bv_offset, v.bv_len), 10577ff50620SDavid Howells memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 10587ff50620SDavid Howells memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 10597ff50620SDavid Howells v.bv_offset, v.bv_len) 1060d879cb83SAl Viro ) 1061d879cb83SAl Viro kunmap_atomic(kaddr); 1062d879cb83SAl Viro return bytes; 1063d879cb83SAl Viro } 1064d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); 1065d879cb83SAl Viro 1066b9dc6f65SAl Viro static inline void pipe_truncate(struct iov_iter *i) 1067241699cdSAl Viro { 1068241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 10698cefc107SDavid Howells unsigned int p_tail = pipe->tail; 10708cefc107SDavid Howells unsigned int p_head = pipe->head; 10718cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10728cefc107SDavid Howells 10738cefc107SDavid Howells if (!pipe_empty(p_head, p_tail)) { 10748cefc107SDavid Howells struct pipe_buffer *buf; 10758cefc107SDavid Howells unsigned int i_head = i->head; 1076b9dc6f65SAl Viro size_t off = i->iov_offset; 10778cefc107SDavid Howells 1078b9dc6f65SAl Viro if (off) { 10798cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 10808cefc107SDavid Howells buf->len = off - buf->offset; 10818cefc107SDavid Howells i_head++; 1082b9dc6f65SAl Viro } 10838cefc107SDavid Howells while (p_head != i_head) { 10848cefc107SDavid Howells p_head--; 10858cefc107SDavid Howells pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); 1086241699cdSAl Viro } 10878cefc107SDavid Howells 10888cefc107SDavid Howells pipe->head = p_head; 1089241699cdSAl Viro } 1090b9dc6f65SAl Viro } 1091b9dc6f65SAl Viro 1092b9dc6f65SAl Viro static void pipe_advance(struct iov_iter *i, size_t size) 1093b9dc6f65SAl Viro { 1094b9dc6f65SAl Viro struct pipe_inode_info *pipe = i->pipe; 1095b9dc6f65SAl Viro if (unlikely(i->count < size)) 1096b9dc6f65SAl Viro size = i->count; 1097b9dc6f65SAl Viro if (size) { 1098b9dc6f65SAl Viro struct pipe_buffer *buf; 10998cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 11008cefc107SDavid Howells unsigned int i_head = i->head; 1101b9dc6f65SAl Viro size_t off = i->iov_offset, left = size; 11028cefc107SDavid Howells 1103b9dc6f65SAl Viro if (off) /* make it relative to the beginning of buffer */ 11048cefc107SDavid Howells left += off - pipe->bufs[i_head & p_mask].offset; 1105b9dc6f65SAl Viro while (1) { 11068cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 1107b9dc6f65SAl Viro if (left <= buf->len) 1108b9dc6f65SAl Viro break; 1109b9dc6f65SAl Viro left -= buf->len; 11108cefc107SDavid Howells i_head++; 1111b9dc6f65SAl Viro } 11128cefc107SDavid Howells i->head = i_head; 1113b9dc6f65SAl Viro i->iov_offset = buf->offset + left; 1114b9dc6f65SAl Viro } 1115b9dc6f65SAl Viro i->count -= size; 1116b9dc6f65SAl Viro /* ... and discard everything past that point */ 1117b9dc6f65SAl Viro pipe_truncate(i); 1118241699cdSAl Viro } 1119241699cdSAl Viro 112054c8195bSPavel Begunkov static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) 112154c8195bSPavel Begunkov { 112254c8195bSPavel Begunkov struct bvec_iter bi; 112354c8195bSPavel Begunkov 112454c8195bSPavel Begunkov bi.bi_size = i->count; 112554c8195bSPavel Begunkov bi.bi_bvec_done = i->iov_offset; 112654c8195bSPavel Begunkov bi.bi_idx = 0; 112754c8195bSPavel Begunkov bvec_iter_advance(i->bvec, &bi, size); 112854c8195bSPavel Begunkov 112954c8195bSPavel Begunkov i->bvec += bi.bi_idx; 113054c8195bSPavel Begunkov i->nr_segs -= bi.bi_idx; 113154c8195bSPavel Begunkov i->count = bi.bi_size; 113254c8195bSPavel Begunkov i->iov_offset = bi.bi_bvec_done; 113354c8195bSPavel Begunkov } 113454c8195bSPavel Begunkov 1135d879cb83SAl Viro void iov_iter_advance(struct iov_iter *i, size_t size) 1136d879cb83SAl Viro { 113700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 1138241699cdSAl Viro pipe_advance(i, size); 1139241699cdSAl Viro return; 1140241699cdSAl Viro } 11419ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) { 11429ea9ce04SDavid Howells i->count -= size; 11439ea9ce04SDavid Howells return; 11449ea9ce04SDavid Howells } 11457ff50620SDavid Howells if (unlikely(iov_iter_is_xarray(i))) { 11463d14ec1fSDavid Howells size = min(size, i->count); 11477ff50620SDavid Howells i->iov_offset += size; 11487ff50620SDavid Howells i->count -= size; 11497ff50620SDavid Howells return; 11507ff50620SDavid Howells } 115154c8195bSPavel Begunkov if (iov_iter_is_bvec(i)) { 115254c8195bSPavel Begunkov iov_iter_bvec_advance(i, size); 115354c8195bSPavel Begunkov return; 115454c8195bSPavel Begunkov } 11557ff50620SDavid Howells iterate_and_advance(i, size, v, 0, 0, 0, 0) 1156d879cb83SAl Viro } 1157d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_advance); 1158d879cb83SAl Viro 115927c0e374SAl Viro void iov_iter_revert(struct iov_iter *i, size_t unroll) 116027c0e374SAl Viro { 116127c0e374SAl Viro if (!unroll) 116227c0e374SAl Viro return; 11635b47d59aSAl Viro if (WARN_ON(unroll > MAX_RW_COUNT)) 11645b47d59aSAl Viro return; 116527c0e374SAl Viro i->count += unroll; 116600e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 116727c0e374SAl Viro struct pipe_inode_info *pipe = i->pipe; 11688cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 11698cefc107SDavid Howells unsigned int i_head = i->head; 117027c0e374SAl Viro size_t off = i->iov_offset; 117127c0e374SAl Viro while (1) { 11728cefc107SDavid Howells struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; 11738cefc107SDavid Howells size_t n = off - b->offset; 117427c0e374SAl Viro if (unroll < n) { 11754fa55cefSAl Viro off -= unroll; 117627c0e374SAl Viro break; 117727c0e374SAl Viro } 117827c0e374SAl Viro unroll -= n; 11798cefc107SDavid Howells if (!unroll && i_head == i->start_head) { 118027c0e374SAl Viro off = 0; 118127c0e374SAl Viro break; 118227c0e374SAl Viro } 11838cefc107SDavid Howells i_head--; 11848cefc107SDavid Howells b = &pipe->bufs[i_head & p_mask]; 11858cefc107SDavid Howells off = b->offset + b->len; 118627c0e374SAl Viro } 118727c0e374SAl Viro i->iov_offset = off; 11888cefc107SDavid Howells i->head = i_head; 118927c0e374SAl Viro pipe_truncate(i); 119027c0e374SAl Viro return; 119127c0e374SAl Viro } 11929ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 11939ea9ce04SDavid Howells return; 119427c0e374SAl Viro if (unroll <= i->iov_offset) { 119527c0e374SAl Viro i->iov_offset -= unroll; 119627c0e374SAl Viro return; 119727c0e374SAl Viro } 119827c0e374SAl Viro unroll -= i->iov_offset; 11997ff50620SDavid Howells if (iov_iter_is_xarray(i)) { 12007ff50620SDavid Howells BUG(); /* We should never go beyond the start of the specified 12017ff50620SDavid Howells * range since we might then be straying into pages that 12027ff50620SDavid Howells * aren't pinned. 12037ff50620SDavid Howells */ 12047ff50620SDavid Howells } else if (iov_iter_is_bvec(i)) { 120527c0e374SAl Viro const struct bio_vec *bvec = i->bvec; 120627c0e374SAl Viro while (1) { 120727c0e374SAl Viro size_t n = (--bvec)->bv_len; 120827c0e374SAl Viro i->nr_segs++; 120927c0e374SAl Viro if (unroll <= n) { 121027c0e374SAl Viro i->bvec = bvec; 121127c0e374SAl Viro i->iov_offset = n - unroll; 121227c0e374SAl Viro return; 121327c0e374SAl Viro } 121427c0e374SAl Viro unroll -= n; 121527c0e374SAl Viro } 121627c0e374SAl Viro } else { /* same logics for iovec and kvec */ 121727c0e374SAl Viro const struct iovec *iov = i->iov; 121827c0e374SAl Viro while (1) { 121927c0e374SAl Viro size_t n = (--iov)->iov_len; 122027c0e374SAl Viro i->nr_segs++; 122127c0e374SAl Viro if (unroll <= n) { 122227c0e374SAl Viro i->iov = iov; 122327c0e374SAl Viro i->iov_offset = n - unroll; 122427c0e374SAl Viro return; 122527c0e374SAl Viro } 122627c0e374SAl Viro unroll -= n; 122727c0e374SAl Viro } 122827c0e374SAl Viro } 122927c0e374SAl Viro } 123027c0e374SAl Viro EXPORT_SYMBOL(iov_iter_revert); 123127c0e374SAl Viro 1232d879cb83SAl Viro /* 1233d879cb83SAl Viro * Return the count of just the current iov_iter segment. 1234d879cb83SAl Viro */ 1235d879cb83SAl Viro size_t iov_iter_single_seg_count(const struct iov_iter *i) 1236d879cb83SAl Viro { 123700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1238241699cdSAl Viro return i->count; // it is a silly place, anyway 1239d879cb83SAl Viro if (i->nr_segs == 1) 1240d879cb83SAl Viro return i->count; 12417ff50620SDavid Howells if (unlikely(iov_iter_is_discard(i) || iov_iter_is_xarray(i))) 12429ea9ce04SDavid Howells return i->count; 12437ff50620SDavid Howells if (iov_iter_is_bvec(i)) 1244d879cb83SAl Viro return min(i->count, i->bvec->bv_len - i->iov_offset); 1245d879cb83SAl Viro else 1246d879cb83SAl Viro return min(i->count, i->iov->iov_len - i->iov_offset); 1247d879cb83SAl Viro } 1248d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_single_seg_count); 1249d879cb83SAl Viro 1250aa563d7bSDavid Howells void iov_iter_kvec(struct iov_iter *i, unsigned int direction, 1251d879cb83SAl Viro const struct kvec *kvec, unsigned long nr_segs, 1252d879cb83SAl Viro size_t count) 1253d879cb83SAl Viro { 1254aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 1255aa563d7bSDavid Howells i->type = ITER_KVEC | (direction & (READ | WRITE)); 1256d879cb83SAl Viro i->kvec = kvec; 1257d879cb83SAl Viro i->nr_segs = nr_segs; 1258d879cb83SAl Viro i->iov_offset = 0; 1259d879cb83SAl Viro i->count = count; 1260d879cb83SAl Viro } 1261d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_kvec); 1262d879cb83SAl Viro 1263aa563d7bSDavid Howells void iov_iter_bvec(struct iov_iter *i, unsigned int direction, 1264d879cb83SAl Viro const struct bio_vec *bvec, unsigned long nr_segs, 1265d879cb83SAl Viro size_t count) 1266d879cb83SAl Viro { 1267aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 1268aa563d7bSDavid Howells i->type = ITER_BVEC | (direction & (READ | WRITE)); 1269d879cb83SAl Viro i->bvec = bvec; 1270d879cb83SAl Viro i->nr_segs = nr_segs; 1271d879cb83SAl Viro i->iov_offset = 0; 1272d879cb83SAl Viro i->count = count; 1273d879cb83SAl Viro } 1274d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_bvec); 1275d879cb83SAl Viro 1276aa563d7bSDavid Howells void iov_iter_pipe(struct iov_iter *i, unsigned int direction, 1277241699cdSAl Viro struct pipe_inode_info *pipe, 1278241699cdSAl Viro size_t count) 1279241699cdSAl Viro { 1280aa563d7bSDavid Howells BUG_ON(direction != READ); 12818cefc107SDavid Howells WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); 1282aa563d7bSDavid Howells i->type = ITER_PIPE | READ; 1283241699cdSAl Viro i->pipe = pipe; 12848cefc107SDavid Howells i->head = pipe->head; 1285241699cdSAl Viro i->iov_offset = 0; 1286241699cdSAl Viro i->count = count; 12878cefc107SDavid Howells i->start_head = i->head; 1288241699cdSAl Viro } 1289241699cdSAl Viro EXPORT_SYMBOL(iov_iter_pipe); 1290241699cdSAl Viro 12919ea9ce04SDavid Howells /** 12927ff50620SDavid Howells * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray 12937ff50620SDavid Howells * @i: The iterator to initialise. 12947ff50620SDavid Howells * @direction: The direction of the transfer. 12957ff50620SDavid Howells * @xarray: The xarray to access. 12967ff50620SDavid Howells * @start: The start file position. 12977ff50620SDavid Howells * @count: The size of the I/O buffer in bytes. 12987ff50620SDavid Howells * 12997ff50620SDavid Howells * Set up an I/O iterator to either draw data out of the pages attached to an 13007ff50620SDavid Howells * inode or to inject data into those pages. The pages *must* be prevented 13017ff50620SDavid Howells * from evaporation, either by taking a ref on them or locking them by the 13027ff50620SDavid Howells * caller. 13037ff50620SDavid Howells */ 13047ff50620SDavid Howells void iov_iter_xarray(struct iov_iter *i, unsigned int direction, 13057ff50620SDavid Howells struct xarray *xarray, loff_t start, size_t count) 13067ff50620SDavid Howells { 13077ff50620SDavid Howells BUG_ON(direction & ~1); 13087ff50620SDavid Howells i->type = ITER_XARRAY | (direction & (READ | WRITE)); 13097ff50620SDavid Howells i->xarray = xarray; 13107ff50620SDavid Howells i->xarray_start = start; 13117ff50620SDavid Howells i->count = count; 13127ff50620SDavid Howells i->iov_offset = 0; 13137ff50620SDavid Howells } 13147ff50620SDavid Howells EXPORT_SYMBOL(iov_iter_xarray); 13157ff50620SDavid Howells 13167ff50620SDavid Howells /** 13179ea9ce04SDavid Howells * iov_iter_discard - Initialise an I/O iterator that discards data 13189ea9ce04SDavid Howells * @i: The iterator to initialise. 13199ea9ce04SDavid Howells * @direction: The direction of the transfer. 13209ea9ce04SDavid Howells * @count: The size of the I/O buffer in bytes. 13219ea9ce04SDavid Howells * 13229ea9ce04SDavid Howells * Set up an I/O iterator that just discards everything that's written to it. 13239ea9ce04SDavid Howells * It's only available as a READ iterator. 13249ea9ce04SDavid Howells */ 13259ea9ce04SDavid Howells void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) 13269ea9ce04SDavid Howells { 13279ea9ce04SDavid Howells BUG_ON(direction != READ); 13289ea9ce04SDavid Howells i->type = ITER_DISCARD | READ; 13299ea9ce04SDavid Howells i->count = count; 13309ea9ce04SDavid Howells i->iov_offset = 0; 13319ea9ce04SDavid Howells } 13329ea9ce04SDavid Howells EXPORT_SYMBOL(iov_iter_discard); 13339ea9ce04SDavid Howells 1334d879cb83SAl Viro unsigned long iov_iter_alignment(const struct iov_iter *i) 1335d879cb83SAl Viro { 1336d879cb83SAl Viro unsigned long res = 0; 1337d879cb83SAl Viro size_t size = i->count; 1338d879cb83SAl Viro 133900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 1340e0ff126eSJan Kara unsigned int p_mask = i->pipe->ring_size - 1; 1341e0ff126eSJan Kara 13428cefc107SDavid Howells if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) 1343241699cdSAl Viro return size | i->iov_offset; 1344241699cdSAl Viro return size; 1345241699cdSAl Viro } 13463d14ec1fSDavid Howells if (unlikely(iov_iter_is_xarray(i))) 13473d14ec1fSDavid Howells return (i->xarray_start + i->iov_offset) | i->count; 1348d879cb83SAl Viro iterate_all_kinds(i, size, v, 1349d879cb83SAl Viro (res |= (unsigned long)v.iov_base | v.iov_len, 0), 1350d879cb83SAl Viro res |= v.bv_offset | v.bv_len, 13517ff50620SDavid Howells res |= (unsigned long)v.iov_base | v.iov_len, 13527ff50620SDavid Howells res |= v.bv_offset | v.bv_len 1353d879cb83SAl Viro ) 1354d879cb83SAl Viro return res; 1355d879cb83SAl Viro } 1356d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_alignment); 1357d879cb83SAl Viro 1358357f435dSAl Viro unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 1359357f435dSAl Viro { 1360357f435dSAl Viro unsigned long res = 0; 1361357f435dSAl Viro size_t size = i->count; 1362357f435dSAl Viro 13639ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1364241699cdSAl Viro WARN_ON(1); 1365241699cdSAl Viro return ~0U; 1366241699cdSAl Viro } 1367241699cdSAl Viro 1368357f435dSAl Viro iterate_all_kinds(i, size, v, 1369357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.iov_base) | 1370357f435dSAl Viro (size != v.iov_len ? size : 0), 0), 1371357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.bv_offset) | 1372357f435dSAl Viro (size != v.bv_len ? size : 0)), 1373357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.iov_base) | 13747ff50620SDavid Howells (size != v.iov_len ? size : 0)), 13757ff50620SDavid Howells (res |= (!res ? 0 : (unsigned long)v.bv_offset) | 13767ff50620SDavid Howells (size != v.bv_len ? size : 0)) 1377357f435dSAl Viro ); 1378357f435dSAl Viro return res; 1379357f435dSAl Viro } 1380357f435dSAl Viro EXPORT_SYMBOL(iov_iter_gap_alignment); 1381357f435dSAl Viro 1382e76b6312SIlya Dryomov static inline ssize_t __pipe_get_pages(struct iov_iter *i, 1383241699cdSAl Viro size_t maxsize, 1384241699cdSAl Viro struct page **pages, 13858cefc107SDavid Howells int iter_head, 1386241699cdSAl Viro size_t *start) 1387241699cdSAl Viro { 1388241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 13898cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 13908cefc107SDavid Howells ssize_t n = push_pipe(i, maxsize, &iter_head, start); 1391241699cdSAl Viro if (!n) 1392241699cdSAl Viro return -EFAULT; 1393241699cdSAl Viro 1394241699cdSAl Viro maxsize = n; 1395241699cdSAl Viro n += *start; 13961689c73aSAl Viro while (n > 0) { 13978cefc107SDavid Howells get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); 13988cefc107SDavid Howells iter_head++; 1399241699cdSAl Viro n -= PAGE_SIZE; 1400241699cdSAl Viro } 1401241699cdSAl Viro 1402241699cdSAl Viro return maxsize; 1403241699cdSAl Viro } 1404241699cdSAl Viro 1405241699cdSAl Viro static ssize_t pipe_get_pages(struct iov_iter *i, 1406241699cdSAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1407241699cdSAl Viro size_t *start) 1408241699cdSAl Viro { 14098cefc107SDavid Howells unsigned int iter_head, npages; 1410241699cdSAl Viro size_t capacity; 1411241699cdSAl Viro 141233844e66SAl Viro if (!maxsize) 141333844e66SAl Viro return 0; 141433844e66SAl Viro 1415241699cdSAl Viro if (!sanity(i)) 1416241699cdSAl Viro return -EFAULT; 1417241699cdSAl Viro 14188cefc107SDavid Howells data_start(i, &iter_head, start); 14198cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 14208cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1421241699cdSAl Viro capacity = min(npages, maxpages) * PAGE_SIZE - *start; 1422241699cdSAl Viro 14238cefc107SDavid Howells return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); 1424241699cdSAl Viro } 1425241699cdSAl Viro 14267ff50620SDavid Howells static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, 14277ff50620SDavid Howells pgoff_t index, unsigned int nr_pages) 14287ff50620SDavid Howells { 14297ff50620SDavid Howells XA_STATE(xas, xa, index); 14307ff50620SDavid Howells struct page *page; 14317ff50620SDavid Howells unsigned int ret = 0; 14327ff50620SDavid Howells 14337ff50620SDavid Howells rcu_read_lock(); 14347ff50620SDavid Howells for (page = xas_load(&xas); page; page = xas_next(&xas)) { 14357ff50620SDavid Howells if (xas_retry(&xas, page)) 14367ff50620SDavid Howells continue; 14377ff50620SDavid Howells 14387ff50620SDavid Howells /* Has the page moved or been split? */ 14397ff50620SDavid Howells if (unlikely(page != xas_reload(&xas))) { 14407ff50620SDavid Howells xas_reset(&xas); 14417ff50620SDavid Howells continue; 14427ff50620SDavid Howells } 14437ff50620SDavid Howells 14447ff50620SDavid Howells pages[ret] = find_subpage(page, xas.xa_index); 14457ff50620SDavid Howells get_page(pages[ret]); 14467ff50620SDavid Howells if (++ret == nr_pages) 14477ff50620SDavid Howells break; 14487ff50620SDavid Howells } 14497ff50620SDavid Howells rcu_read_unlock(); 14507ff50620SDavid Howells return ret; 14517ff50620SDavid Howells } 14527ff50620SDavid Howells 14537ff50620SDavid Howells static ssize_t iter_xarray_get_pages(struct iov_iter *i, 14547ff50620SDavid Howells struct page **pages, size_t maxsize, 14557ff50620SDavid Howells unsigned maxpages, size_t *_start_offset) 14567ff50620SDavid Howells { 14577ff50620SDavid Howells unsigned nr, offset; 14587ff50620SDavid Howells pgoff_t index, count; 14597ff50620SDavid Howells size_t size = maxsize, actual; 14607ff50620SDavid Howells loff_t pos; 14617ff50620SDavid Howells 14627ff50620SDavid Howells if (!size || !maxpages) 14637ff50620SDavid Howells return 0; 14647ff50620SDavid Howells 14657ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 14667ff50620SDavid Howells index = pos >> PAGE_SHIFT; 14677ff50620SDavid Howells offset = pos & ~PAGE_MASK; 14687ff50620SDavid Howells *_start_offset = offset; 14697ff50620SDavid Howells 14707ff50620SDavid Howells count = 1; 14717ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 14727ff50620SDavid Howells size -= PAGE_SIZE - offset; 14737ff50620SDavid Howells count += size >> PAGE_SHIFT; 14747ff50620SDavid Howells size &= ~PAGE_MASK; 14757ff50620SDavid Howells if (size) 14767ff50620SDavid Howells count++; 14777ff50620SDavid Howells } 14787ff50620SDavid Howells 14797ff50620SDavid Howells if (count > maxpages) 14807ff50620SDavid Howells count = maxpages; 14817ff50620SDavid Howells 14827ff50620SDavid Howells nr = iter_xarray_populate_pages(pages, i->xarray, index, count); 14837ff50620SDavid Howells if (nr == 0) 14847ff50620SDavid Howells return 0; 14857ff50620SDavid Howells 14867ff50620SDavid Howells actual = PAGE_SIZE * nr; 14877ff50620SDavid Howells actual -= offset; 14887ff50620SDavid Howells if (nr == count && size > 0) { 14897ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 14907ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 14917ff50620SDavid Howells } 14927ff50620SDavid Howells return actual; 14937ff50620SDavid Howells } 14947ff50620SDavid Howells 1495d879cb83SAl Viro ssize_t iov_iter_get_pages(struct iov_iter *i, 1496d879cb83SAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1497d879cb83SAl Viro size_t *start) 1498d879cb83SAl Viro { 1499d879cb83SAl Viro if (maxsize > i->count) 1500d879cb83SAl Viro maxsize = i->count; 1501d879cb83SAl Viro 150200e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1503241699cdSAl Viro return pipe_get_pages(i, pages, maxsize, maxpages, start); 15047ff50620SDavid Howells if (unlikely(iov_iter_is_xarray(i))) 15057ff50620SDavid Howells return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); 15069ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 15079ea9ce04SDavid Howells return -EFAULT; 15089ea9ce04SDavid Howells 1509d879cb83SAl Viro iterate_all_kinds(i, maxsize, v, ({ 1510d879cb83SAl Viro unsigned long addr = (unsigned long)v.iov_base; 1511d879cb83SAl Viro size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); 1512d879cb83SAl Viro int n; 1513d879cb83SAl Viro int res; 1514d879cb83SAl Viro 1515d879cb83SAl Viro if (len > maxpages * PAGE_SIZE) 1516d879cb83SAl Viro len = maxpages * PAGE_SIZE; 1517d879cb83SAl Viro addr &= ~(PAGE_SIZE - 1); 1518d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 151973b0140bSIra Weiny res = get_user_pages_fast(addr, n, 152073b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, 152173b0140bSIra Weiny pages); 1522d879cb83SAl Viro if (unlikely(res < 0)) 1523d879cb83SAl Viro return res; 1524d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 1525d879cb83SAl Viro 0;}),({ 1526d879cb83SAl Viro /* can't be more than PAGE_SIZE */ 1527d879cb83SAl Viro *start = v.bv_offset; 1528d879cb83SAl Viro get_page(*pages = v.bv_page); 1529d879cb83SAl Viro return v.bv_len; 1530d879cb83SAl Viro }),({ 1531d879cb83SAl Viro return -EFAULT; 15327ff50620SDavid Howells }), 15337ff50620SDavid Howells 0 1534d879cb83SAl Viro ) 1535d879cb83SAl Viro return 0; 1536d879cb83SAl Viro } 1537d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages); 1538d879cb83SAl Viro 1539d879cb83SAl Viro static struct page **get_pages_array(size_t n) 1540d879cb83SAl Viro { 1541752ade68SMichal Hocko return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); 1542d879cb83SAl Viro } 1543d879cb83SAl Viro 1544241699cdSAl Viro static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 1545241699cdSAl Viro struct page ***pages, size_t maxsize, 1546241699cdSAl Viro size_t *start) 1547241699cdSAl Viro { 1548241699cdSAl Viro struct page **p; 15498cefc107SDavid Howells unsigned int iter_head, npages; 1550d7760d63SIlya Dryomov ssize_t n; 1551241699cdSAl Viro 155233844e66SAl Viro if (!maxsize) 155333844e66SAl Viro return 0; 155433844e66SAl Viro 1555241699cdSAl Viro if (!sanity(i)) 1556241699cdSAl Viro return -EFAULT; 1557241699cdSAl Viro 15588cefc107SDavid Howells data_start(i, &iter_head, start); 15598cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 15608cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1561241699cdSAl Viro n = npages * PAGE_SIZE - *start; 1562241699cdSAl Viro if (maxsize > n) 1563241699cdSAl Viro maxsize = n; 1564241699cdSAl Viro else 1565241699cdSAl Viro npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1566241699cdSAl Viro p = get_pages_array(npages); 1567241699cdSAl Viro if (!p) 1568241699cdSAl Viro return -ENOMEM; 15698cefc107SDavid Howells n = __pipe_get_pages(i, maxsize, p, iter_head, start); 1570241699cdSAl Viro if (n > 0) 1571241699cdSAl Viro *pages = p; 1572241699cdSAl Viro else 1573241699cdSAl Viro kvfree(p); 1574241699cdSAl Viro return n; 1575241699cdSAl Viro } 1576241699cdSAl Viro 15777ff50620SDavid Howells static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, 15787ff50620SDavid Howells struct page ***pages, size_t maxsize, 15797ff50620SDavid Howells size_t *_start_offset) 15807ff50620SDavid Howells { 15817ff50620SDavid Howells struct page **p; 15827ff50620SDavid Howells unsigned nr, offset; 15837ff50620SDavid Howells pgoff_t index, count; 15847ff50620SDavid Howells size_t size = maxsize, actual; 15857ff50620SDavid Howells loff_t pos; 15867ff50620SDavid Howells 15877ff50620SDavid Howells if (!size) 15887ff50620SDavid Howells return 0; 15897ff50620SDavid Howells 15907ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 15917ff50620SDavid Howells index = pos >> PAGE_SHIFT; 15927ff50620SDavid Howells offset = pos & ~PAGE_MASK; 15937ff50620SDavid Howells *_start_offset = offset; 15947ff50620SDavid Howells 15957ff50620SDavid Howells count = 1; 15967ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 15977ff50620SDavid Howells size -= PAGE_SIZE - offset; 15987ff50620SDavid Howells count += size >> PAGE_SHIFT; 15997ff50620SDavid Howells size &= ~PAGE_MASK; 16007ff50620SDavid Howells if (size) 16017ff50620SDavid Howells count++; 16027ff50620SDavid Howells } 16037ff50620SDavid Howells 16047ff50620SDavid Howells p = get_pages_array(count); 16057ff50620SDavid Howells if (!p) 16067ff50620SDavid Howells return -ENOMEM; 16077ff50620SDavid Howells *pages = p; 16087ff50620SDavid Howells 16097ff50620SDavid Howells nr = iter_xarray_populate_pages(p, i->xarray, index, count); 16107ff50620SDavid Howells if (nr == 0) 16117ff50620SDavid Howells return 0; 16127ff50620SDavid Howells 16137ff50620SDavid Howells actual = PAGE_SIZE * nr; 16147ff50620SDavid Howells actual -= offset; 16157ff50620SDavid Howells if (nr == count && size > 0) { 16167ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 16177ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 16187ff50620SDavid Howells } 16197ff50620SDavid Howells return actual; 16207ff50620SDavid Howells } 16217ff50620SDavid Howells 1622d879cb83SAl Viro ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 1623d879cb83SAl Viro struct page ***pages, size_t maxsize, 1624d879cb83SAl Viro size_t *start) 1625d879cb83SAl Viro { 1626d879cb83SAl Viro struct page **p; 1627d879cb83SAl Viro 1628d879cb83SAl Viro if (maxsize > i->count) 1629d879cb83SAl Viro maxsize = i->count; 1630d879cb83SAl Viro 163100e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1632241699cdSAl Viro return pipe_get_pages_alloc(i, pages, maxsize, start); 16337ff50620SDavid Howells if (unlikely(iov_iter_is_xarray(i))) 16347ff50620SDavid Howells return iter_xarray_get_pages_alloc(i, pages, maxsize, start); 16359ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 16369ea9ce04SDavid Howells return -EFAULT; 16379ea9ce04SDavid Howells 1638d879cb83SAl Viro iterate_all_kinds(i, maxsize, v, ({ 1639d879cb83SAl Viro unsigned long addr = (unsigned long)v.iov_base; 1640d879cb83SAl Viro size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); 1641d879cb83SAl Viro int n; 1642d879cb83SAl Viro int res; 1643d879cb83SAl Viro 1644d879cb83SAl Viro addr &= ~(PAGE_SIZE - 1); 1645d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 1646d879cb83SAl Viro p = get_pages_array(n); 1647d879cb83SAl Viro if (!p) 1648d879cb83SAl Viro return -ENOMEM; 164973b0140bSIra Weiny res = get_user_pages_fast(addr, n, 165073b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); 1651d879cb83SAl Viro if (unlikely(res < 0)) { 1652d879cb83SAl Viro kvfree(p); 1653d879cb83SAl Viro return res; 1654d879cb83SAl Viro } 1655d879cb83SAl Viro *pages = p; 1656d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 1657d879cb83SAl Viro 0;}),({ 1658d879cb83SAl Viro /* can't be more than PAGE_SIZE */ 1659d879cb83SAl Viro *start = v.bv_offset; 1660d879cb83SAl Viro *pages = p = get_pages_array(1); 1661d879cb83SAl Viro if (!p) 1662d879cb83SAl Viro return -ENOMEM; 1663d879cb83SAl Viro get_page(*p = v.bv_page); 1664d879cb83SAl Viro return v.bv_len; 1665d879cb83SAl Viro }),({ 1666d879cb83SAl Viro return -EFAULT; 16677ff50620SDavid Howells }), 0 1668d879cb83SAl Viro ) 1669d879cb83SAl Viro return 0; 1670d879cb83SAl Viro } 1671d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages_alloc); 1672d879cb83SAl Viro 1673d879cb83SAl Viro size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 1674d879cb83SAl Viro struct iov_iter *i) 1675d879cb83SAl Viro { 1676d879cb83SAl Viro char *to = addr; 1677d879cb83SAl Viro __wsum sum, next; 1678d879cb83SAl Viro size_t off = 0; 1679d879cb83SAl Viro sum = *csum; 16809ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1681241699cdSAl Viro WARN_ON(1); 1682241699cdSAl Viro return 0; 1683241699cdSAl Viro } 1684d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1685d879cb83SAl Viro next = csum_and_copy_from_user(v.iov_base, 1686d879cb83SAl Viro (to += v.iov_len) - v.iov_len, 1687c693cc46SAl Viro v.iov_len); 1688c693cc46SAl Viro if (next) { 1689d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1690d879cb83SAl Viro off += v.iov_len; 1691d879cb83SAl Viro } 1692c693cc46SAl Viro next ? 0 : v.iov_len; 1693d879cb83SAl Viro }), ({ 1694d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1695f9152895SAl Viro sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 1696f9152895SAl Viro p + v.bv_offset, v.bv_len, 1697f9152895SAl Viro sum, off); 1698d879cb83SAl Viro kunmap_atomic(p); 1699d879cb83SAl Viro off += v.bv_len; 1700d879cb83SAl Viro }),({ 1701f9152895SAl Viro sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, 1702f9152895SAl Viro v.iov_base, v.iov_len, 1703f9152895SAl Viro sum, off); 1704d879cb83SAl Viro off += v.iov_len; 17057ff50620SDavid Howells }), ({ 17067ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 17077ff50620SDavid Howells sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 17087ff50620SDavid Howells p + v.bv_offset, v.bv_len, 17097ff50620SDavid Howells sum, off); 17107ff50620SDavid Howells kunmap_atomic(p); 17117ff50620SDavid Howells off += v.bv_len; 1712d879cb83SAl Viro }) 1713d879cb83SAl Viro ) 1714d879cb83SAl Viro *csum = sum; 1715d879cb83SAl Viro return bytes; 1716d879cb83SAl Viro } 1717d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter); 1718d879cb83SAl Viro 1719cbbd26b8SAl Viro bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, 1720cbbd26b8SAl Viro struct iov_iter *i) 1721cbbd26b8SAl Viro { 1722cbbd26b8SAl Viro char *to = addr; 1723cbbd26b8SAl Viro __wsum sum, next; 1724cbbd26b8SAl Viro size_t off = 0; 1725cbbd26b8SAl Viro sum = *csum; 17269ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1727cbbd26b8SAl Viro WARN_ON(1); 1728cbbd26b8SAl Viro return false; 1729cbbd26b8SAl Viro } 1730cbbd26b8SAl Viro if (unlikely(i->count < bytes)) 1731cbbd26b8SAl Viro return false; 1732cbbd26b8SAl Viro iterate_all_kinds(i, bytes, v, ({ 1733cbbd26b8SAl Viro next = csum_and_copy_from_user(v.iov_base, 1734cbbd26b8SAl Viro (to += v.iov_len) - v.iov_len, 1735c693cc46SAl Viro v.iov_len); 1736c693cc46SAl Viro if (!next) 1737cbbd26b8SAl Viro return false; 1738cbbd26b8SAl Viro sum = csum_block_add(sum, next, off); 1739cbbd26b8SAl Viro off += v.iov_len; 1740cbbd26b8SAl Viro 0; 1741cbbd26b8SAl Viro }), ({ 1742cbbd26b8SAl Viro char *p = kmap_atomic(v.bv_page); 1743f9152895SAl Viro sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 1744f9152895SAl Viro p + v.bv_offset, v.bv_len, 1745f9152895SAl Viro sum, off); 1746cbbd26b8SAl Viro kunmap_atomic(p); 1747cbbd26b8SAl Viro off += v.bv_len; 1748cbbd26b8SAl Viro }),({ 1749f9152895SAl Viro sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, 1750f9152895SAl Viro v.iov_base, v.iov_len, 1751f9152895SAl Viro sum, off); 1752cbbd26b8SAl Viro off += v.iov_len; 17537ff50620SDavid Howells }), ({ 17547ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 17557ff50620SDavid Howells sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 17567ff50620SDavid Howells p + v.bv_offset, v.bv_len, 17577ff50620SDavid Howells sum, off); 17587ff50620SDavid Howells kunmap_atomic(p); 17597ff50620SDavid Howells off += v.bv_len; 1760cbbd26b8SAl Viro }) 1761cbbd26b8SAl Viro ) 1762cbbd26b8SAl Viro *csum = sum; 1763cbbd26b8SAl Viro iov_iter_advance(i, bytes); 1764cbbd26b8SAl Viro return true; 1765cbbd26b8SAl Viro } 1766cbbd26b8SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter_full); 1767cbbd26b8SAl Viro 176852cbd23aSWillem de Bruijn size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 1769d879cb83SAl Viro struct iov_iter *i) 1770d879cb83SAl Viro { 177152cbd23aSWillem de Bruijn struct csum_state *csstate = _csstate; 177236f7a8a4SAl Viro const char *from = addr; 1773d879cb83SAl Viro __wsum sum, next; 177452cbd23aSWillem de Bruijn size_t off; 177578e1f386SAl Viro 177678e1f386SAl Viro if (unlikely(iov_iter_is_pipe(i))) 177752cbd23aSWillem de Bruijn return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); 177878e1f386SAl Viro 177952cbd23aSWillem de Bruijn sum = csstate->csum; 178052cbd23aSWillem de Bruijn off = csstate->off; 178178e1f386SAl Viro if (unlikely(iov_iter_is_discard(i))) { 1782241699cdSAl Viro WARN_ON(1); /* for now */ 1783241699cdSAl Viro return 0; 1784241699cdSAl Viro } 1785d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1786d879cb83SAl Viro next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, 1787d879cb83SAl Viro v.iov_base, 1788c693cc46SAl Viro v.iov_len); 1789c693cc46SAl Viro if (next) { 1790d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1791d879cb83SAl Viro off += v.iov_len; 1792d879cb83SAl Viro } 1793c693cc46SAl Viro next ? 0 : v.iov_len; 1794d879cb83SAl Viro }), ({ 1795d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1796f9152895SAl Viro sum = csum_and_memcpy(p + v.bv_offset, 1797f9152895SAl Viro (from += v.bv_len) - v.bv_len, 1798f9152895SAl Viro v.bv_len, sum, off); 1799d879cb83SAl Viro kunmap_atomic(p); 1800d879cb83SAl Viro off += v.bv_len; 1801d879cb83SAl Viro }),({ 1802f9152895SAl Viro sum = csum_and_memcpy(v.iov_base, 1803f9152895SAl Viro (from += v.iov_len) - v.iov_len, 1804f9152895SAl Viro v.iov_len, sum, off); 1805d879cb83SAl Viro off += v.iov_len; 18067ff50620SDavid Howells }), ({ 18077ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 18087ff50620SDavid Howells sum = csum_and_memcpy(p + v.bv_offset, 18097ff50620SDavid Howells (from += v.bv_len) - v.bv_len, 18107ff50620SDavid Howells v.bv_len, sum, off); 18117ff50620SDavid Howells kunmap_atomic(p); 18127ff50620SDavid Howells off += v.bv_len; 1813d879cb83SAl Viro }) 1814d879cb83SAl Viro ) 181552cbd23aSWillem de Bruijn csstate->csum = sum; 181652cbd23aSWillem de Bruijn csstate->off = off; 1817d879cb83SAl Viro return bytes; 1818d879cb83SAl Viro } 1819d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_to_iter); 1820d879cb83SAl Viro 1821d05f4435SSagi Grimberg size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, 1822d05f4435SSagi Grimberg struct iov_iter *i) 1823d05f4435SSagi Grimberg { 18247999096fSHerbert Xu #ifdef CONFIG_CRYPTO_HASH 1825d05f4435SSagi Grimberg struct ahash_request *hash = hashp; 1826d05f4435SSagi Grimberg struct scatterlist sg; 1827d05f4435SSagi Grimberg size_t copied; 1828d05f4435SSagi Grimberg 1829d05f4435SSagi Grimberg copied = copy_to_iter(addr, bytes, i); 1830d05f4435SSagi Grimberg sg_init_one(&sg, addr, copied); 1831d05f4435SSagi Grimberg ahash_request_set_crypt(hash, &sg, NULL, copied); 1832d05f4435SSagi Grimberg crypto_ahash_update(hash); 1833d05f4435SSagi Grimberg return copied; 183427fad74aSYueHaibing #else 183527fad74aSYueHaibing return 0; 183627fad74aSYueHaibing #endif 1837d05f4435SSagi Grimberg } 1838d05f4435SSagi Grimberg EXPORT_SYMBOL(hash_and_copy_to_iter); 1839d05f4435SSagi Grimberg 1840d879cb83SAl Viro int iov_iter_npages(const struct iov_iter *i, int maxpages) 1841d879cb83SAl Viro { 1842d879cb83SAl Viro size_t size = i->count; 1843d879cb83SAl Viro int npages = 0; 1844d879cb83SAl Viro 1845d879cb83SAl Viro if (!size) 1846d879cb83SAl Viro return 0; 18479ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 18489ea9ce04SDavid Howells return 0; 1849d879cb83SAl Viro 185000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 1851241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 18528cefc107SDavid Howells unsigned int iter_head; 1853241699cdSAl Viro size_t off; 1854241699cdSAl Viro 1855241699cdSAl Viro if (!sanity(i)) 1856241699cdSAl Viro return 0; 1857241699cdSAl Viro 18588cefc107SDavid Howells data_start(i, &iter_head, &off); 1859241699cdSAl Viro /* some of this one + all after this one */ 18608cefc107SDavid Howells npages = pipe_space_for_user(iter_head, pipe->tail, pipe); 1861241699cdSAl Viro if (npages >= maxpages) 1862241699cdSAl Viro return maxpages; 18637ff50620SDavid Howells } else if (unlikely(iov_iter_is_xarray(i))) { 18647ff50620SDavid Howells unsigned offset; 18657ff50620SDavid Howells 18667ff50620SDavid Howells offset = (i->xarray_start + i->iov_offset) & ~PAGE_MASK; 18677ff50620SDavid Howells 18687ff50620SDavid Howells npages = 1; 18697ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 18707ff50620SDavid Howells size -= PAGE_SIZE - offset; 18717ff50620SDavid Howells npages += size >> PAGE_SHIFT; 18727ff50620SDavid Howells size &= ~PAGE_MASK; 18737ff50620SDavid Howells if (size) 18747ff50620SDavid Howells npages++; 18757ff50620SDavid Howells } 18767ff50620SDavid Howells if (npages >= maxpages) 18777ff50620SDavid Howells return maxpages; 1878241699cdSAl Viro } else iterate_all_kinds(i, size, v, ({ 1879d879cb83SAl Viro unsigned long p = (unsigned long)v.iov_base; 1880d879cb83SAl Viro npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) 1881d879cb83SAl Viro - p / PAGE_SIZE; 1882d879cb83SAl Viro if (npages >= maxpages) 1883d879cb83SAl Viro return maxpages; 1884d879cb83SAl Viro 0;}),({ 1885d879cb83SAl Viro npages++; 1886d879cb83SAl Viro if (npages >= maxpages) 1887d879cb83SAl Viro return maxpages; 1888d879cb83SAl Viro }),({ 1889d879cb83SAl Viro unsigned long p = (unsigned long)v.iov_base; 1890d879cb83SAl Viro npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) 1891d879cb83SAl Viro - p / PAGE_SIZE; 1892d879cb83SAl Viro if (npages >= maxpages) 1893d879cb83SAl Viro return maxpages; 18947ff50620SDavid Howells }), 18957ff50620SDavid Howells 0 1896d879cb83SAl Viro ) 1897d879cb83SAl Viro return npages; 1898d879cb83SAl Viro } 1899d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_npages); 1900d879cb83SAl Viro 1901d879cb83SAl Viro const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) 1902d879cb83SAl Viro { 1903d879cb83SAl Viro *new = *old; 190400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(new))) { 1905241699cdSAl Viro WARN_ON(1); 1906241699cdSAl Viro return NULL; 1907241699cdSAl Viro } 19087ff50620SDavid Howells if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) 19099ea9ce04SDavid Howells return NULL; 191000e23707SDavid Howells if (iov_iter_is_bvec(new)) 1911d879cb83SAl Viro return new->bvec = kmemdup(new->bvec, 1912d879cb83SAl Viro new->nr_segs * sizeof(struct bio_vec), 1913d879cb83SAl Viro flags); 1914d879cb83SAl Viro else 1915d879cb83SAl Viro /* iovec and kvec have identical layout */ 1916d879cb83SAl Viro return new->iov = kmemdup(new->iov, 1917d879cb83SAl Viro new->nr_segs * sizeof(struct iovec), 1918d879cb83SAl Viro flags); 1919d879cb83SAl Viro } 1920d879cb83SAl Viro EXPORT_SYMBOL(dup_iter); 1921bc917be8SAl Viro 1922bfdc5970SChristoph Hellwig static int copy_compat_iovec_from_user(struct iovec *iov, 1923bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1924bfdc5970SChristoph Hellwig { 1925bfdc5970SChristoph Hellwig const struct compat_iovec __user *uiov = 1926bfdc5970SChristoph Hellwig (const struct compat_iovec __user *)uvec; 1927bfdc5970SChristoph Hellwig int ret = -EFAULT, i; 1928bfdc5970SChristoph Hellwig 1929a959a978SChristoph Hellwig if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) 1930bfdc5970SChristoph Hellwig return -EFAULT; 1931bfdc5970SChristoph Hellwig 1932bfdc5970SChristoph Hellwig for (i = 0; i < nr_segs; i++) { 1933bfdc5970SChristoph Hellwig compat_uptr_t buf; 1934bfdc5970SChristoph Hellwig compat_ssize_t len; 1935bfdc5970SChristoph Hellwig 1936bfdc5970SChristoph Hellwig unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); 1937bfdc5970SChristoph Hellwig unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); 1938bfdc5970SChristoph Hellwig 1939bfdc5970SChristoph Hellwig /* check for compat_size_t not fitting in compat_ssize_t .. */ 1940bfdc5970SChristoph Hellwig if (len < 0) { 1941bfdc5970SChristoph Hellwig ret = -EINVAL; 1942bfdc5970SChristoph Hellwig goto uaccess_end; 1943bfdc5970SChristoph Hellwig } 1944bfdc5970SChristoph Hellwig iov[i].iov_base = compat_ptr(buf); 1945bfdc5970SChristoph Hellwig iov[i].iov_len = len; 1946bfdc5970SChristoph Hellwig } 1947bfdc5970SChristoph Hellwig 1948bfdc5970SChristoph Hellwig ret = 0; 1949bfdc5970SChristoph Hellwig uaccess_end: 1950bfdc5970SChristoph Hellwig user_access_end(); 1951bfdc5970SChristoph Hellwig return ret; 1952bfdc5970SChristoph Hellwig } 1953bfdc5970SChristoph Hellwig 1954bfdc5970SChristoph Hellwig static int copy_iovec_from_user(struct iovec *iov, 1955bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1956fb041b59SDavid Laight { 1957fb041b59SDavid Laight unsigned long seg; 1958bfdc5970SChristoph Hellwig 1959bfdc5970SChristoph Hellwig if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) 1960bfdc5970SChristoph Hellwig return -EFAULT; 1961bfdc5970SChristoph Hellwig for (seg = 0; seg < nr_segs; seg++) { 1962bfdc5970SChristoph Hellwig if ((ssize_t)iov[seg].iov_len < 0) 1963bfdc5970SChristoph Hellwig return -EINVAL; 1964bfdc5970SChristoph Hellwig } 1965bfdc5970SChristoph Hellwig 1966bfdc5970SChristoph Hellwig return 0; 1967bfdc5970SChristoph Hellwig } 1968bfdc5970SChristoph Hellwig 1969bfdc5970SChristoph Hellwig struct iovec *iovec_from_user(const struct iovec __user *uvec, 1970bfdc5970SChristoph Hellwig unsigned long nr_segs, unsigned long fast_segs, 1971bfdc5970SChristoph Hellwig struct iovec *fast_iov, bool compat) 1972bfdc5970SChristoph Hellwig { 1973bfdc5970SChristoph Hellwig struct iovec *iov = fast_iov; 1974bfdc5970SChristoph Hellwig int ret; 1975fb041b59SDavid Laight 1976fb041b59SDavid Laight /* 1977bfdc5970SChristoph Hellwig * SuS says "The readv() function *may* fail if the iovcnt argument was 1978bfdc5970SChristoph Hellwig * less than or equal to 0, or greater than {IOV_MAX}. Linux has 1979fb041b59SDavid Laight * traditionally returned zero for zero segments, so... 1980fb041b59SDavid Laight */ 1981bfdc5970SChristoph Hellwig if (nr_segs == 0) 1982bfdc5970SChristoph Hellwig return iov; 1983bfdc5970SChristoph Hellwig if (nr_segs > UIO_MAXIOV) 1984bfdc5970SChristoph Hellwig return ERR_PTR(-EINVAL); 1985fb041b59SDavid Laight if (nr_segs > fast_segs) { 1986fb041b59SDavid Laight iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); 1987bfdc5970SChristoph Hellwig if (!iov) 1988bfdc5970SChristoph Hellwig return ERR_PTR(-ENOMEM); 1989fb041b59SDavid Laight } 1990bfdc5970SChristoph Hellwig 1991bfdc5970SChristoph Hellwig if (compat) 1992bfdc5970SChristoph Hellwig ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); 1993bfdc5970SChristoph Hellwig else 1994bfdc5970SChristoph Hellwig ret = copy_iovec_from_user(iov, uvec, nr_segs); 1995bfdc5970SChristoph Hellwig if (ret) { 1996bfdc5970SChristoph Hellwig if (iov != fast_iov) 1997bfdc5970SChristoph Hellwig kfree(iov); 1998bfdc5970SChristoph Hellwig return ERR_PTR(ret); 1999fb041b59SDavid Laight } 2000bfdc5970SChristoph Hellwig 2001bfdc5970SChristoph Hellwig return iov; 2002bfdc5970SChristoph Hellwig } 2003bfdc5970SChristoph Hellwig 2004bfdc5970SChristoph Hellwig ssize_t __import_iovec(int type, const struct iovec __user *uvec, 2005bfdc5970SChristoph Hellwig unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, 2006bfdc5970SChristoph Hellwig struct iov_iter *i, bool compat) 2007bfdc5970SChristoph Hellwig { 2008bfdc5970SChristoph Hellwig ssize_t total_len = 0; 2009bfdc5970SChristoph Hellwig unsigned long seg; 2010bfdc5970SChristoph Hellwig struct iovec *iov; 2011bfdc5970SChristoph Hellwig 2012bfdc5970SChristoph Hellwig iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); 2013bfdc5970SChristoph Hellwig if (IS_ERR(iov)) { 2014bfdc5970SChristoph Hellwig *iovp = NULL; 2015bfdc5970SChristoph Hellwig return PTR_ERR(iov); 2016fb041b59SDavid Laight } 2017fb041b59SDavid Laight 2018fb041b59SDavid Laight /* 2019bfdc5970SChristoph Hellwig * According to the Single Unix Specification we should return EINVAL if 2020bfdc5970SChristoph Hellwig * an element length is < 0 when cast to ssize_t or if the total length 2021bfdc5970SChristoph Hellwig * would overflow the ssize_t return value of the system call. 2022fb041b59SDavid Laight * 2023fb041b59SDavid Laight * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the 2024fb041b59SDavid Laight * overflow case. 2025fb041b59SDavid Laight */ 2026fb041b59SDavid Laight for (seg = 0; seg < nr_segs; seg++) { 2027fb041b59SDavid Laight ssize_t len = (ssize_t)iov[seg].iov_len; 2028fb041b59SDavid Laight 2029bfdc5970SChristoph Hellwig if (!access_ok(iov[seg].iov_base, len)) { 2030bfdc5970SChristoph Hellwig if (iov != *iovp) 2031bfdc5970SChristoph Hellwig kfree(iov); 2032bfdc5970SChristoph Hellwig *iovp = NULL; 2033bfdc5970SChristoph Hellwig return -EFAULT; 2034fb041b59SDavid Laight } 2035bfdc5970SChristoph Hellwig 2036bfdc5970SChristoph Hellwig if (len > MAX_RW_COUNT - total_len) { 2037bfdc5970SChristoph Hellwig len = MAX_RW_COUNT - total_len; 2038fb041b59SDavid Laight iov[seg].iov_len = len; 2039fb041b59SDavid Laight } 2040bfdc5970SChristoph Hellwig total_len += len; 2041fb041b59SDavid Laight } 2042bfdc5970SChristoph Hellwig 2043bfdc5970SChristoph Hellwig iov_iter_init(i, type, iov, nr_segs, total_len); 2044bfdc5970SChristoph Hellwig if (iov == *iovp) 2045bfdc5970SChristoph Hellwig *iovp = NULL; 2046bfdc5970SChristoph Hellwig else 2047bfdc5970SChristoph Hellwig *iovp = iov; 2048bfdc5970SChristoph Hellwig return total_len; 2049fb041b59SDavid Laight } 2050fb041b59SDavid Laight 2051ffecee4fSVegard Nossum /** 2052ffecee4fSVegard Nossum * import_iovec() - Copy an array of &struct iovec from userspace 2053ffecee4fSVegard Nossum * into the kernel, check that it is valid, and initialize a new 2054ffecee4fSVegard Nossum * &struct iov_iter iterator to access it. 2055ffecee4fSVegard Nossum * 2056ffecee4fSVegard Nossum * @type: One of %READ or %WRITE. 2057bfdc5970SChristoph Hellwig * @uvec: Pointer to the userspace array. 2058ffecee4fSVegard Nossum * @nr_segs: Number of elements in userspace array. 2059ffecee4fSVegard Nossum * @fast_segs: Number of elements in @iov. 2060bfdc5970SChristoph Hellwig * @iovp: (input and output parameter) Pointer to pointer to (usually small 2061ffecee4fSVegard Nossum * on-stack) kernel array. 2062ffecee4fSVegard Nossum * @i: Pointer to iterator that will be initialized on success. 2063ffecee4fSVegard Nossum * 2064ffecee4fSVegard Nossum * If the array pointed to by *@iov is large enough to hold all @nr_segs, 2065ffecee4fSVegard Nossum * then this function places %NULL in *@iov on return. Otherwise, a new 2066ffecee4fSVegard Nossum * array will be allocated and the result placed in *@iov. This means that 2067ffecee4fSVegard Nossum * the caller may call kfree() on *@iov regardless of whether the small 2068ffecee4fSVegard Nossum * on-stack array was used or not (and regardless of whether this function 2069ffecee4fSVegard Nossum * returns an error or not). 2070ffecee4fSVegard Nossum * 207187e5e6daSJens Axboe * Return: Negative error code on error, bytes imported on success 2072ffecee4fSVegard Nossum */ 2073bfdc5970SChristoph Hellwig ssize_t import_iovec(int type, const struct iovec __user *uvec, 2074bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 2075bfdc5970SChristoph Hellwig struct iovec **iovp, struct iov_iter *i) 2076bc917be8SAl Viro { 207789cd35c5SChristoph Hellwig return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, 207889cd35c5SChristoph Hellwig in_compat_syscall()); 2079bc917be8SAl Viro } 2080bc917be8SAl Viro EXPORT_SYMBOL(import_iovec); 2081bc917be8SAl Viro 2082bc917be8SAl Viro int import_single_range(int rw, void __user *buf, size_t len, 2083bc917be8SAl Viro struct iovec *iov, struct iov_iter *i) 2084bc917be8SAl Viro { 2085bc917be8SAl Viro if (len > MAX_RW_COUNT) 2086bc917be8SAl Viro len = MAX_RW_COUNT; 208796d4f267SLinus Torvalds if (unlikely(!access_ok(buf, len))) 2088bc917be8SAl Viro return -EFAULT; 2089bc917be8SAl Viro 2090bc917be8SAl Viro iov->iov_base = buf; 2091bc917be8SAl Viro iov->iov_len = len; 2092bc917be8SAl Viro iov_iter_init(i, rw, iov, 1, len); 2093bc917be8SAl Viro return 0; 2094bc917be8SAl Viro } 2095e1267585SAl Viro EXPORT_SYMBOL(import_single_range); 209609cf698aSAl Viro 209709cf698aSAl Viro int iov_iter_for_each_range(struct iov_iter *i, size_t bytes, 209809cf698aSAl Viro int (*f)(struct kvec *vec, void *context), 209909cf698aSAl Viro void *context) 210009cf698aSAl Viro { 210109cf698aSAl Viro struct kvec w; 210209cf698aSAl Viro int err = -EINVAL; 210309cf698aSAl Viro if (!bytes) 210409cf698aSAl Viro return 0; 210509cf698aSAl Viro 210609cf698aSAl Viro iterate_all_kinds(i, bytes, v, -EINVAL, ({ 210709cf698aSAl Viro w.iov_base = kmap(v.bv_page) + v.bv_offset; 210809cf698aSAl Viro w.iov_len = v.bv_len; 210909cf698aSAl Viro err = f(&w, context); 211009cf698aSAl Viro kunmap(v.bv_page); 211109cf698aSAl Viro err;}), ({ 211209cf698aSAl Viro w = v; 21137ff50620SDavid Howells err = f(&w, context);}), ({ 21147ff50620SDavid Howells w.iov_base = kmap(v.bv_page) + v.bv_offset; 21157ff50620SDavid Howells w.iov_len = v.bv_len; 21167ff50620SDavid Howells err = f(&w, context); 21177ff50620SDavid Howells kunmap(v.bv_page); 21187ff50620SDavid Howells err;}) 211909cf698aSAl Viro ) 212009cf698aSAl Viro return err; 212109cf698aSAl Viro } 212209cf698aSAl Viro EXPORT_SYMBOL(iov_iter_for_each_range); 2123