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> 828961998SIra 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 960*08aa6479SAl Viro static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 961d879cb83SAl Viro struct iov_iter *i) 962d879cb83SAl Viro { 9637ff50620SDavid Howells if (i->type & (ITER_BVEC | ITER_KVEC | ITER_XARRAY)) { 964d879cb83SAl Viro void *kaddr = kmap_atomic(page); 965d879cb83SAl Viro size_t wanted = copy_to_iter(kaddr + offset, bytes, i); 966d879cb83SAl Viro kunmap_atomic(kaddr); 967d879cb83SAl Viro return wanted; 9689ea9ce04SDavid Howells } else if (unlikely(iov_iter_is_discard(i))) 9699ea9ce04SDavid Howells return bytes; 9709ea9ce04SDavid Howells else if (likely(!iov_iter_is_pipe(i))) 971d879cb83SAl Viro return copy_page_to_iter_iovec(page, offset, bytes, i); 972241699cdSAl Viro else 973241699cdSAl Viro return copy_page_to_iter_pipe(page, offset, bytes, i); 974d879cb83SAl Viro } 975*08aa6479SAl Viro 976*08aa6479SAl Viro size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 977*08aa6479SAl Viro struct iov_iter *i) 978*08aa6479SAl Viro { 979*08aa6479SAl Viro size_t res = 0; 980*08aa6479SAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 981*08aa6479SAl Viro return 0; 982*08aa6479SAl Viro page += offset / PAGE_SIZE; // first subpage 983*08aa6479SAl Viro offset %= PAGE_SIZE; 984*08aa6479SAl Viro while (1) { 985*08aa6479SAl Viro size_t n = __copy_page_to_iter(page, offset, 986*08aa6479SAl Viro min(bytes, (size_t)PAGE_SIZE - offset), i); 987*08aa6479SAl Viro res += n; 988*08aa6479SAl Viro bytes -= n; 989*08aa6479SAl Viro if (!bytes || !n) 990*08aa6479SAl Viro break; 991*08aa6479SAl Viro offset += n; 992*08aa6479SAl Viro if (offset == PAGE_SIZE) { 993*08aa6479SAl Viro page++; 994*08aa6479SAl Viro offset = 0; 995*08aa6479SAl Viro } 996*08aa6479SAl Viro } 997*08aa6479SAl Viro return res; 998*08aa6479SAl Viro } 999d879cb83SAl Viro EXPORT_SYMBOL(copy_page_to_iter); 1000d879cb83SAl Viro 1001d879cb83SAl Viro size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, 1002d879cb83SAl Viro struct iov_iter *i) 1003d879cb83SAl Viro { 100472e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 100572e809edSAl Viro return 0; 10069ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1007241699cdSAl Viro WARN_ON(1); 1008241699cdSAl Viro return 0; 1009241699cdSAl Viro } 10107ff50620SDavid Howells if (i->type & (ITER_BVEC | ITER_KVEC | ITER_XARRAY)) { 1011d879cb83SAl Viro void *kaddr = kmap_atomic(page); 1012aa28de27SAl Viro size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); 1013d879cb83SAl Viro kunmap_atomic(kaddr); 1014d879cb83SAl Viro return wanted; 1015d879cb83SAl Viro } else 1016d879cb83SAl Viro return copy_page_from_iter_iovec(page, offset, bytes, i); 1017d879cb83SAl Viro } 1018d879cb83SAl Viro EXPORT_SYMBOL(copy_page_from_iter); 1019d879cb83SAl Viro 1020241699cdSAl Viro static size_t pipe_zero(size_t bytes, struct iov_iter *i) 1021241699cdSAl Viro { 1022241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 10238cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10248cefc107SDavid Howells unsigned int i_head; 1025241699cdSAl Viro size_t n, off; 1026241699cdSAl Viro 1027241699cdSAl Viro if (!sanity(i)) 1028241699cdSAl Viro return 0; 1029241699cdSAl Viro 10308cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 1031241699cdSAl Viro if (unlikely(!n)) 1032241699cdSAl Viro return 0; 1033241699cdSAl Viro 10348cefc107SDavid Howells do { 1035241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 10368cefc107SDavid Howells memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); 10378cefc107SDavid Howells i->head = i_head; 1038241699cdSAl Viro i->iov_offset = off + chunk; 1039241699cdSAl Viro n -= chunk; 10408cefc107SDavid Howells off = 0; 10418cefc107SDavid Howells i_head++; 10428cefc107SDavid Howells } while (n); 1043241699cdSAl Viro i->count -= bytes; 1044241699cdSAl Viro return bytes; 1045241699cdSAl Viro } 1046241699cdSAl Viro 1047d879cb83SAl Viro size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 1048d879cb83SAl Viro { 104900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1050241699cdSAl Viro return pipe_zero(bytes, i); 1051d879cb83SAl Viro iterate_and_advance(i, bytes, v, 105209fc68dcSAl Viro clear_user(v.iov_base, v.iov_len), 1053d879cb83SAl Viro memzero_page(v.bv_page, v.bv_offset, v.bv_len), 10547ff50620SDavid Howells memset(v.iov_base, 0, v.iov_len), 10557ff50620SDavid Howells memzero_page(v.bv_page, v.bv_offset, v.bv_len) 1056d879cb83SAl Viro ) 1057d879cb83SAl Viro 1058d879cb83SAl Viro return bytes; 1059d879cb83SAl Viro } 1060d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_zero); 1061d879cb83SAl Viro 1062d879cb83SAl Viro size_t iov_iter_copy_from_user_atomic(struct page *page, 1063d879cb83SAl Viro struct iov_iter *i, unsigned long offset, size_t bytes) 1064d879cb83SAl Viro { 1065d879cb83SAl Viro char *kaddr = kmap_atomic(page), *p = kaddr + offset; 106672e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) { 106772e809edSAl Viro kunmap_atomic(kaddr); 106872e809edSAl Viro return 0; 106972e809edSAl Viro } 10709ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1071241699cdSAl Viro kunmap_atomic(kaddr); 1072241699cdSAl Viro WARN_ON(1); 1073241699cdSAl Viro return 0; 1074241699cdSAl Viro } 1075d879cb83SAl Viro iterate_all_kinds(i, bytes, v, 107609fc68dcSAl Viro copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 1077d879cb83SAl Viro memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 1078d879cb83SAl Viro v.bv_offset, v.bv_len), 10797ff50620SDavid Howells memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 10807ff50620SDavid Howells memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 10817ff50620SDavid Howells v.bv_offset, v.bv_len) 1082d879cb83SAl Viro ) 1083d879cb83SAl Viro kunmap_atomic(kaddr); 1084d879cb83SAl Viro return bytes; 1085d879cb83SAl Viro } 1086d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); 1087d879cb83SAl Viro 1088b9dc6f65SAl Viro static inline void pipe_truncate(struct iov_iter *i) 1089241699cdSAl Viro { 1090241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 10918cefc107SDavid Howells unsigned int p_tail = pipe->tail; 10928cefc107SDavid Howells unsigned int p_head = pipe->head; 10938cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10948cefc107SDavid Howells 10958cefc107SDavid Howells if (!pipe_empty(p_head, p_tail)) { 10968cefc107SDavid Howells struct pipe_buffer *buf; 10978cefc107SDavid Howells unsigned int i_head = i->head; 1098b9dc6f65SAl Viro size_t off = i->iov_offset; 10998cefc107SDavid Howells 1100b9dc6f65SAl Viro if (off) { 11018cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 11028cefc107SDavid Howells buf->len = off - buf->offset; 11038cefc107SDavid Howells i_head++; 1104b9dc6f65SAl Viro } 11058cefc107SDavid Howells while (p_head != i_head) { 11068cefc107SDavid Howells p_head--; 11078cefc107SDavid Howells pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); 1108241699cdSAl Viro } 11098cefc107SDavid Howells 11108cefc107SDavid Howells pipe->head = p_head; 1111241699cdSAl Viro } 1112b9dc6f65SAl Viro } 1113b9dc6f65SAl Viro 1114b9dc6f65SAl Viro static void pipe_advance(struct iov_iter *i, size_t size) 1115b9dc6f65SAl Viro { 1116b9dc6f65SAl Viro struct pipe_inode_info *pipe = i->pipe; 1117b9dc6f65SAl Viro if (unlikely(i->count < size)) 1118b9dc6f65SAl Viro size = i->count; 1119b9dc6f65SAl Viro if (size) { 1120b9dc6f65SAl Viro struct pipe_buffer *buf; 11218cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 11228cefc107SDavid Howells unsigned int i_head = i->head; 1123b9dc6f65SAl Viro size_t off = i->iov_offset, left = size; 11248cefc107SDavid Howells 1125b9dc6f65SAl Viro if (off) /* make it relative to the beginning of buffer */ 11268cefc107SDavid Howells left += off - pipe->bufs[i_head & p_mask].offset; 1127b9dc6f65SAl Viro while (1) { 11288cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 1129b9dc6f65SAl Viro if (left <= buf->len) 1130b9dc6f65SAl Viro break; 1131b9dc6f65SAl Viro left -= buf->len; 11328cefc107SDavid Howells i_head++; 1133b9dc6f65SAl Viro } 11348cefc107SDavid Howells i->head = i_head; 1135b9dc6f65SAl Viro i->iov_offset = buf->offset + left; 1136b9dc6f65SAl Viro } 1137b9dc6f65SAl Viro i->count -= size; 1138b9dc6f65SAl Viro /* ... and discard everything past that point */ 1139b9dc6f65SAl Viro pipe_truncate(i); 1140241699cdSAl Viro } 1141241699cdSAl Viro 114254c8195bSPavel Begunkov static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) 114354c8195bSPavel Begunkov { 114454c8195bSPavel Begunkov struct bvec_iter bi; 114554c8195bSPavel Begunkov 114654c8195bSPavel Begunkov bi.bi_size = i->count; 114754c8195bSPavel Begunkov bi.bi_bvec_done = i->iov_offset; 114854c8195bSPavel Begunkov bi.bi_idx = 0; 114954c8195bSPavel Begunkov bvec_iter_advance(i->bvec, &bi, size); 115054c8195bSPavel Begunkov 115154c8195bSPavel Begunkov i->bvec += bi.bi_idx; 115254c8195bSPavel Begunkov i->nr_segs -= bi.bi_idx; 115354c8195bSPavel Begunkov i->count = bi.bi_size; 115454c8195bSPavel Begunkov i->iov_offset = bi.bi_bvec_done; 115554c8195bSPavel Begunkov } 115654c8195bSPavel Begunkov 1157d879cb83SAl Viro void iov_iter_advance(struct iov_iter *i, size_t size) 1158d879cb83SAl Viro { 115900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 1160241699cdSAl Viro pipe_advance(i, size); 1161241699cdSAl Viro return; 1162241699cdSAl Viro } 11639ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) { 11649ea9ce04SDavid Howells i->count -= size; 11659ea9ce04SDavid Howells return; 11669ea9ce04SDavid Howells } 11677ff50620SDavid Howells if (unlikely(iov_iter_is_xarray(i))) { 11683d14ec1fSDavid Howells size = min(size, i->count); 11697ff50620SDavid Howells i->iov_offset += size; 11707ff50620SDavid Howells i->count -= size; 11717ff50620SDavid Howells return; 11727ff50620SDavid Howells } 117354c8195bSPavel Begunkov if (iov_iter_is_bvec(i)) { 117454c8195bSPavel Begunkov iov_iter_bvec_advance(i, size); 117554c8195bSPavel Begunkov return; 117654c8195bSPavel Begunkov } 11777ff50620SDavid Howells iterate_and_advance(i, size, v, 0, 0, 0, 0) 1178d879cb83SAl Viro } 1179d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_advance); 1180d879cb83SAl Viro 118127c0e374SAl Viro void iov_iter_revert(struct iov_iter *i, size_t unroll) 118227c0e374SAl Viro { 118327c0e374SAl Viro if (!unroll) 118427c0e374SAl Viro return; 11855b47d59aSAl Viro if (WARN_ON(unroll > MAX_RW_COUNT)) 11865b47d59aSAl Viro return; 118727c0e374SAl Viro i->count += unroll; 118800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 118927c0e374SAl Viro struct pipe_inode_info *pipe = i->pipe; 11908cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 11918cefc107SDavid Howells unsigned int i_head = i->head; 119227c0e374SAl Viro size_t off = i->iov_offset; 119327c0e374SAl Viro while (1) { 11948cefc107SDavid Howells struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; 11958cefc107SDavid Howells size_t n = off - b->offset; 119627c0e374SAl Viro if (unroll < n) { 11974fa55cefSAl Viro off -= unroll; 119827c0e374SAl Viro break; 119927c0e374SAl Viro } 120027c0e374SAl Viro unroll -= n; 12018cefc107SDavid Howells if (!unroll && i_head == i->start_head) { 120227c0e374SAl Viro off = 0; 120327c0e374SAl Viro break; 120427c0e374SAl Viro } 12058cefc107SDavid Howells i_head--; 12068cefc107SDavid Howells b = &pipe->bufs[i_head & p_mask]; 12078cefc107SDavid Howells off = b->offset + b->len; 120827c0e374SAl Viro } 120927c0e374SAl Viro i->iov_offset = off; 12108cefc107SDavid Howells i->head = i_head; 121127c0e374SAl Viro pipe_truncate(i); 121227c0e374SAl Viro return; 121327c0e374SAl Viro } 12149ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 12159ea9ce04SDavid Howells return; 121627c0e374SAl Viro if (unroll <= i->iov_offset) { 121727c0e374SAl Viro i->iov_offset -= unroll; 121827c0e374SAl Viro return; 121927c0e374SAl Viro } 122027c0e374SAl Viro unroll -= i->iov_offset; 12217ff50620SDavid Howells if (iov_iter_is_xarray(i)) { 12227ff50620SDavid Howells BUG(); /* We should never go beyond the start of the specified 12237ff50620SDavid Howells * range since we might then be straying into pages that 12247ff50620SDavid Howells * aren't pinned. 12257ff50620SDavid Howells */ 12267ff50620SDavid Howells } else if (iov_iter_is_bvec(i)) { 122727c0e374SAl Viro const struct bio_vec *bvec = i->bvec; 122827c0e374SAl Viro while (1) { 122927c0e374SAl Viro size_t n = (--bvec)->bv_len; 123027c0e374SAl Viro i->nr_segs++; 123127c0e374SAl Viro if (unroll <= n) { 123227c0e374SAl Viro i->bvec = bvec; 123327c0e374SAl Viro i->iov_offset = n - unroll; 123427c0e374SAl Viro return; 123527c0e374SAl Viro } 123627c0e374SAl Viro unroll -= n; 123727c0e374SAl Viro } 123827c0e374SAl Viro } else { /* same logics for iovec and kvec */ 123927c0e374SAl Viro const struct iovec *iov = i->iov; 124027c0e374SAl Viro while (1) { 124127c0e374SAl Viro size_t n = (--iov)->iov_len; 124227c0e374SAl Viro i->nr_segs++; 124327c0e374SAl Viro if (unroll <= n) { 124427c0e374SAl Viro i->iov = iov; 124527c0e374SAl Viro i->iov_offset = n - unroll; 124627c0e374SAl Viro return; 124727c0e374SAl Viro } 124827c0e374SAl Viro unroll -= n; 124927c0e374SAl Viro } 125027c0e374SAl Viro } 125127c0e374SAl Viro } 125227c0e374SAl Viro EXPORT_SYMBOL(iov_iter_revert); 125327c0e374SAl Viro 1254d879cb83SAl Viro /* 1255d879cb83SAl Viro * Return the count of just the current iov_iter segment. 1256d879cb83SAl Viro */ 1257d879cb83SAl Viro size_t iov_iter_single_seg_count(const struct iov_iter *i) 1258d879cb83SAl Viro { 125900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1260241699cdSAl Viro return i->count; // it is a silly place, anyway 1261d879cb83SAl Viro if (i->nr_segs == 1) 1262d879cb83SAl Viro return i->count; 12637ff50620SDavid Howells if (unlikely(iov_iter_is_discard(i) || iov_iter_is_xarray(i))) 12649ea9ce04SDavid Howells return i->count; 12657ff50620SDavid Howells if (iov_iter_is_bvec(i)) 1266d879cb83SAl Viro return min(i->count, i->bvec->bv_len - i->iov_offset); 1267d879cb83SAl Viro else 1268d879cb83SAl Viro return min(i->count, i->iov->iov_len - i->iov_offset); 1269d879cb83SAl Viro } 1270d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_single_seg_count); 1271d879cb83SAl Viro 1272aa563d7bSDavid Howells void iov_iter_kvec(struct iov_iter *i, unsigned int direction, 1273d879cb83SAl Viro const struct kvec *kvec, unsigned long nr_segs, 1274d879cb83SAl Viro size_t count) 1275d879cb83SAl Viro { 1276aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 1277aa563d7bSDavid Howells i->type = ITER_KVEC | (direction & (READ | WRITE)); 1278d879cb83SAl Viro i->kvec = kvec; 1279d879cb83SAl Viro i->nr_segs = nr_segs; 1280d879cb83SAl Viro i->iov_offset = 0; 1281d879cb83SAl Viro i->count = count; 1282d879cb83SAl Viro } 1283d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_kvec); 1284d879cb83SAl Viro 1285aa563d7bSDavid Howells void iov_iter_bvec(struct iov_iter *i, unsigned int direction, 1286d879cb83SAl Viro const struct bio_vec *bvec, unsigned long nr_segs, 1287d879cb83SAl Viro size_t count) 1288d879cb83SAl Viro { 1289aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 1290aa563d7bSDavid Howells i->type = ITER_BVEC | (direction & (READ | WRITE)); 1291d879cb83SAl Viro i->bvec = bvec; 1292d879cb83SAl Viro i->nr_segs = nr_segs; 1293d879cb83SAl Viro i->iov_offset = 0; 1294d879cb83SAl Viro i->count = count; 1295d879cb83SAl Viro } 1296d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_bvec); 1297d879cb83SAl Viro 1298aa563d7bSDavid Howells void iov_iter_pipe(struct iov_iter *i, unsigned int direction, 1299241699cdSAl Viro struct pipe_inode_info *pipe, 1300241699cdSAl Viro size_t count) 1301241699cdSAl Viro { 1302aa563d7bSDavid Howells BUG_ON(direction != READ); 13038cefc107SDavid Howells WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); 1304aa563d7bSDavid Howells i->type = ITER_PIPE | READ; 1305241699cdSAl Viro i->pipe = pipe; 13068cefc107SDavid Howells i->head = pipe->head; 1307241699cdSAl Viro i->iov_offset = 0; 1308241699cdSAl Viro i->count = count; 13098cefc107SDavid Howells i->start_head = i->head; 1310241699cdSAl Viro } 1311241699cdSAl Viro EXPORT_SYMBOL(iov_iter_pipe); 1312241699cdSAl Viro 13139ea9ce04SDavid Howells /** 13147ff50620SDavid Howells * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray 13157ff50620SDavid Howells * @i: The iterator to initialise. 13167ff50620SDavid Howells * @direction: The direction of the transfer. 13177ff50620SDavid Howells * @xarray: The xarray to access. 13187ff50620SDavid Howells * @start: The start file position. 13197ff50620SDavid Howells * @count: The size of the I/O buffer in bytes. 13207ff50620SDavid Howells * 13217ff50620SDavid Howells * Set up an I/O iterator to either draw data out of the pages attached to an 13227ff50620SDavid Howells * inode or to inject data into those pages. The pages *must* be prevented 13237ff50620SDavid Howells * from evaporation, either by taking a ref on them or locking them by the 13247ff50620SDavid Howells * caller. 13257ff50620SDavid Howells */ 13267ff50620SDavid Howells void iov_iter_xarray(struct iov_iter *i, unsigned int direction, 13277ff50620SDavid Howells struct xarray *xarray, loff_t start, size_t count) 13287ff50620SDavid Howells { 13297ff50620SDavid Howells BUG_ON(direction & ~1); 13307ff50620SDavid Howells i->type = ITER_XARRAY | (direction & (READ | WRITE)); 13317ff50620SDavid Howells i->xarray = xarray; 13327ff50620SDavid Howells i->xarray_start = start; 13337ff50620SDavid Howells i->count = count; 13347ff50620SDavid Howells i->iov_offset = 0; 13357ff50620SDavid Howells } 13367ff50620SDavid Howells EXPORT_SYMBOL(iov_iter_xarray); 13377ff50620SDavid Howells 13387ff50620SDavid Howells /** 13399ea9ce04SDavid Howells * iov_iter_discard - Initialise an I/O iterator that discards data 13409ea9ce04SDavid Howells * @i: The iterator to initialise. 13419ea9ce04SDavid Howells * @direction: The direction of the transfer. 13429ea9ce04SDavid Howells * @count: The size of the I/O buffer in bytes. 13439ea9ce04SDavid Howells * 13449ea9ce04SDavid Howells * Set up an I/O iterator that just discards everything that's written to it. 13459ea9ce04SDavid Howells * It's only available as a READ iterator. 13469ea9ce04SDavid Howells */ 13479ea9ce04SDavid Howells void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) 13489ea9ce04SDavid Howells { 13499ea9ce04SDavid Howells BUG_ON(direction != READ); 13509ea9ce04SDavid Howells i->type = ITER_DISCARD | READ; 13519ea9ce04SDavid Howells i->count = count; 13529ea9ce04SDavid Howells i->iov_offset = 0; 13539ea9ce04SDavid Howells } 13549ea9ce04SDavid Howells EXPORT_SYMBOL(iov_iter_discard); 13559ea9ce04SDavid Howells 1356d879cb83SAl Viro unsigned long iov_iter_alignment(const struct iov_iter *i) 1357d879cb83SAl Viro { 1358d879cb83SAl Viro unsigned long res = 0; 1359d879cb83SAl Viro size_t size = i->count; 1360d879cb83SAl Viro 136100e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 1362e0ff126eSJan Kara unsigned int p_mask = i->pipe->ring_size - 1; 1363e0ff126eSJan Kara 13648cefc107SDavid Howells if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) 1365241699cdSAl Viro return size | i->iov_offset; 1366241699cdSAl Viro return size; 1367241699cdSAl Viro } 13683d14ec1fSDavid Howells if (unlikely(iov_iter_is_xarray(i))) 13693d14ec1fSDavid Howells return (i->xarray_start + i->iov_offset) | i->count; 1370d879cb83SAl Viro iterate_all_kinds(i, size, v, 1371d879cb83SAl Viro (res |= (unsigned long)v.iov_base | v.iov_len, 0), 1372d879cb83SAl Viro res |= v.bv_offset | v.bv_len, 13737ff50620SDavid Howells res |= (unsigned long)v.iov_base | v.iov_len, 13747ff50620SDavid Howells res |= v.bv_offset | v.bv_len 1375d879cb83SAl Viro ) 1376d879cb83SAl Viro return res; 1377d879cb83SAl Viro } 1378d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_alignment); 1379d879cb83SAl Viro 1380357f435dSAl Viro unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 1381357f435dSAl Viro { 1382357f435dSAl Viro unsigned long res = 0; 1383357f435dSAl Viro size_t size = i->count; 1384357f435dSAl Viro 13859ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1386241699cdSAl Viro WARN_ON(1); 1387241699cdSAl Viro return ~0U; 1388241699cdSAl Viro } 1389241699cdSAl Viro 1390357f435dSAl Viro iterate_all_kinds(i, size, v, 1391357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.iov_base) | 1392357f435dSAl Viro (size != v.iov_len ? size : 0), 0), 1393357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.bv_offset) | 1394357f435dSAl Viro (size != v.bv_len ? size : 0)), 1395357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.iov_base) | 13967ff50620SDavid Howells (size != v.iov_len ? size : 0)), 13977ff50620SDavid Howells (res |= (!res ? 0 : (unsigned long)v.bv_offset) | 13987ff50620SDavid Howells (size != v.bv_len ? size : 0)) 1399357f435dSAl Viro ); 1400357f435dSAl Viro return res; 1401357f435dSAl Viro } 1402357f435dSAl Viro EXPORT_SYMBOL(iov_iter_gap_alignment); 1403357f435dSAl Viro 1404e76b6312SIlya Dryomov static inline ssize_t __pipe_get_pages(struct iov_iter *i, 1405241699cdSAl Viro size_t maxsize, 1406241699cdSAl Viro struct page **pages, 14078cefc107SDavid Howells int iter_head, 1408241699cdSAl Viro size_t *start) 1409241699cdSAl Viro { 1410241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 14118cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 14128cefc107SDavid Howells ssize_t n = push_pipe(i, maxsize, &iter_head, start); 1413241699cdSAl Viro if (!n) 1414241699cdSAl Viro return -EFAULT; 1415241699cdSAl Viro 1416241699cdSAl Viro maxsize = n; 1417241699cdSAl Viro n += *start; 14181689c73aSAl Viro while (n > 0) { 14198cefc107SDavid Howells get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); 14208cefc107SDavid Howells iter_head++; 1421241699cdSAl Viro n -= PAGE_SIZE; 1422241699cdSAl Viro } 1423241699cdSAl Viro 1424241699cdSAl Viro return maxsize; 1425241699cdSAl Viro } 1426241699cdSAl Viro 1427241699cdSAl Viro static ssize_t pipe_get_pages(struct iov_iter *i, 1428241699cdSAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1429241699cdSAl Viro size_t *start) 1430241699cdSAl Viro { 14318cefc107SDavid Howells unsigned int iter_head, npages; 1432241699cdSAl Viro size_t capacity; 1433241699cdSAl Viro 143433844e66SAl Viro if (!maxsize) 143533844e66SAl Viro return 0; 143633844e66SAl Viro 1437241699cdSAl Viro if (!sanity(i)) 1438241699cdSAl Viro return -EFAULT; 1439241699cdSAl Viro 14408cefc107SDavid Howells data_start(i, &iter_head, start); 14418cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 14428cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1443241699cdSAl Viro capacity = min(npages, maxpages) * PAGE_SIZE - *start; 1444241699cdSAl Viro 14458cefc107SDavid Howells return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); 1446241699cdSAl Viro } 1447241699cdSAl Viro 14487ff50620SDavid Howells static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, 14497ff50620SDavid Howells pgoff_t index, unsigned int nr_pages) 14507ff50620SDavid Howells { 14517ff50620SDavid Howells XA_STATE(xas, xa, index); 14527ff50620SDavid Howells struct page *page; 14537ff50620SDavid Howells unsigned int ret = 0; 14547ff50620SDavid Howells 14557ff50620SDavid Howells rcu_read_lock(); 14567ff50620SDavid Howells for (page = xas_load(&xas); page; page = xas_next(&xas)) { 14577ff50620SDavid Howells if (xas_retry(&xas, page)) 14587ff50620SDavid Howells continue; 14597ff50620SDavid Howells 14607ff50620SDavid Howells /* Has the page moved or been split? */ 14617ff50620SDavid Howells if (unlikely(page != xas_reload(&xas))) { 14627ff50620SDavid Howells xas_reset(&xas); 14637ff50620SDavid Howells continue; 14647ff50620SDavid Howells } 14657ff50620SDavid Howells 14667ff50620SDavid Howells pages[ret] = find_subpage(page, xas.xa_index); 14677ff50620SDavid Howells get_page(pages[ret]); 14687ff50620SDavid Howells if (++ret == nr_pages) 14697ff50620SDavid Howells break; 14707ff50620SDavid Howells } 14717ff50620SDavid Howells rcu_read_unlock(); 14727ff50620SDavid Howells return ret; 14737ff50620SDavid Howells } 14747ff50620SDavid Howells 14757ff50620SDavid Howells static ssize_t iter_xarray_get_pages(struct iov_iter *i, 14767ff50620SDavid Howells struct page **pages, size_t maxsize, 14777ff50620SDavid Howells unsigned maxpages, size_t *_start_offset) 14787ff50620SDavid Howells { 14797ff50620SDavid Howells unsigned nr, offset; 14807ff50620SDavid Howells pgoff_t index, count; 14817ff50620SDavid Howells size_t size = maxsize, actual; 14827ff50620SDavid Howells loff_t pos; 14837ff50620SDavid Howells 14847ff50620SDavid Howells if (!size || !maxpages) 14857ff50620SDavid Howells return 0; 14867ff50620SDavid Howells 14877ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 14887ff50620SDavid Howells index = pos >> PAGE_SHIFT; 14897ff50620SDavid Howells offset = pos & ~PAGE_MASK; 14907ff50620SDavid Howells *_start_offset = offset; 14917ff50620SDavid Howells 14927ff50620SDavid Howells count = 1; 14937ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 14947ff50620SDavid Howells size -= PAGE_SIZE - offset; 14957ff50620SDavid Howells count += size >> PAGE_SHIFT; 14967ff50620SDavid Howells size &= ~PAGE_MASK; 14977ff50620SDavid Howells if (size) 14987ff50620SDavid Howells count++; 14997ff50620SDavid Howells } 15007ff50620SDavid Howells 15017ff50620SDavid Howells if (count > maxpages) 15027ff50620SDavid Howells count = maxpages; 15037ff50620SDavid Howells 15047ff50620SDavid Howells nr = iter_xarray_populate_pages(pages, i->xarray, index, count); 15057ff50620SDavid Howells if (nr == 0) 15067ff50620SDavid Howells return 0; 15077ff50620SDavid Howells 15087ff50620SDavid Howells actual = PAGE_SIZE * nr; 15097ff50620SDavid Howells actual -= offset; 15107ff50620SDavid Howells if (nr == count && size > 0) { 15117ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 15127ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 15137ff50620SDavid Howells } 15147ff50620SDavid Howells return actual; 15157ff50620SDavid Howells } 15167ff50620SDavid Howells 1517d879cb83SAl Viro ssize_t iov_iter_get_pages(struct iov_iter *i, 1518d879cb83SAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1519d879cb83SAl Viro size_t *start) 1520d879cb83SAl Viro { 1521d879cb83SAl Viro if (maxsize > i->count) 1522d879cb83SAl Viro maxsize = i->count; 1523d879cb83SAl Viro 152400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1525241699cdSAl Viro return pipe_get_pages(i, pages, maxsize, maxpages, start); 15267ff50620SDavid Howells if (unlikely(iov_iter_is_xarray(i))) 15277ff50620SDavid Howells return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); 15289ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 15299ea9ce04SDavid Howells return -EFAULT; 15309ea9ce04SDavid Howells 1531d879cb83SAl Viro iterate_all_kinds(i, maxsize, v, ({ 1532d879cb83SAl Viro unsigned long addr = (unsigned long)v.iov_base; 1533d879cb83SAl Viro size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); 1534d879cb83SAl Viro int n; 1535d879cb83SAl Viro int res; 1536d879cb83SAl Viro 1537d879cb83SAl Viro if (len > maxpages * PAGE_SIZE) 1538d879cb83SAl Viro len = maxpages * PAGE_SIZE; 1539d879cb83SAl Viro addr &= ~(PAGE_SIZE - 1); 1540d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 154173b0140bSIra Weiny res = get_user_pages_fast(addr, n, 154273b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, 154373b0140bSIra Weiny pages); 1544d879cb83SAl Viro if (unlikely(res < 0)) 1545d879cb83SAl Viro return res; 1546d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 1547d879cb83SAl Viro 0;}),({ 1548d879cb83SAl Viro /* can't be more than PAGE_SIZE */ 1549d879cb83SAl Viro *start = v.bv_offset; 1550d879cb83SAl Viro get_page(*pages = v.bv_page); 1551d879cb83SAl Viro return v.bv_len; 1552d879cb83SAl Viro }),({ 1553d879cb83SAl Viro return -EFAULT; 15547ff50620SDavid Howells }), 15557ff50620SDavid Howells 0 1556d879cb83SAl Viro ) 1557d879cb83SAl Viro return 0; 1558d879cb83SAl Viro } 1559d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages); 1560d879cb83SAl Viro 1561d879cb83SAl Viro static struct page **get_pages_array(size_t n) 1562d879cb83SAl Viro { 1563752ade68SMichal Hocko return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); 1564d879cb83SAl Viro } 1565d879cb83SAl Viro 1566241699cdSAl Viro static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 1567241699cdSAl Viro struct page ***pages, size_t maxsize, 1568241699cdSAl Viro size_t *start) 1569241699cdSAl Viro { 1570241699cdSAl Viro struct page **p; 15718cefc107SDavid Howells unsigned int iter_head, npages; 1572d7760d63SIlya Dryomov ssize_t n; 1573241699cdSAl Viro 157433844e66SAl Viro if (!maxsize) 157533844e66SAl Viro return 0; 157633844e66SAl Viro 1577241699cdSAl Viro if (!sanity(i)) 1578241699cdSAl Viro return -EFAULT; 1579241699cdSAl Viro 15808cefc107SDavid Howells data_start(i, &iter_head, start); 15818cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 15828cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1583241699cdSAl Viro n = npages * PAGE_SIZE - *start; 1584241699cdSAl Viro if (maxsize > n) 1585241699cdSAl Viro maxsize = n; 1586241699cdSAl Viro else 1587241699cdSAl Viro npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1588241699cdSAl Viro p = get_pages_array(npages); 1589241699cdSAl Viro if (!p) 1590241699cdSAl Viro return -ENOMEM; 15918cefc107SDavid Howells n = __pipe_get_pages(i, maxsize, p, iter_head, start); 1592241699cdSAl Viro if (n > 0) 1593241699cdSAl Viro *pages = p; 1594241699cdSAl Viro else 1595241699cdSAl Viro kvfree(p); 1596241699cdSAl Viro return n; 1597241699cdSAl Viro } 1598241699cdSAl Viro 15997ff50620SDavid Howells static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, 16007ff50620SDavid Howells struct page ***pages, size_t maxsize, 16017ff50620SDavid Howells size_t *_start_offset) 16027ff50620SDavid Howells { 16037ff50620SDavid Howells struct page **p; 16047ff50620SDavid Howells unsigned nr, offset; 16057ff50620SDavid Howells pgoff_t index, count; 16067ff50620SDavid Howells size_t size = maxsize, actual; 16077ff50620SDavid Howells loff_t pos; 16087ff50620SDavid Howells 16097ff50620SDavid Howells if (!size) 16107ff50620SDavid Howells return 0; 16117ff50620SDavid Howells 16127ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 16137ff50620SDavid Howells index = pos >> PAGE_SHIFT; 16147ff50620SDavid Howells offset = pos & ~PAGE_MASK; 16157ff50620SDavid Howells *_start_offset = offset; 16167ff50620SDavid Howells 16177ff50620SDavid Howells count = 1; 16187ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 16197ff50620SDavid Howells size -= PAGE_SIZE - offset; 16207ff50620SDavid Howells count += size >> PAGE_SHIFT; 16217ff50620SDavid Howells size &= ~PAGE_MASK; 16227ff50620SDavid Howells if (size) 16237ff50620SDavid Howells count++; 16247ff50620SDavid Howells } 16257ff50620SDavid Howells 16267ff50620SDavid Howells p = get_pages_array(count); 16277ff50620SDavid Howells if (!p) 16287ff50620SDavid Howells return -ENOMEM; 16297ff50620SDavid Howells *pages = p; 16307ff50620SDavid Howells 16317ff50620SDavid Howells nr = iter_xarray_populate_pages(p, i->xarray, index, count); 16327ff50620SDavid Howells if (nr == 0) 16337ff50620SDavid Howells return 0; 16347ff50620SDavid Howells 16357ff50620SDavid Howells actual = PAGE_SIZE * nr; 16367ff50620SDavid Howells actual -= offset; 16377ff50620SDavid Howells if (nr == count && size > 0) { 16387ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 16397ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 16407ff50620SDavid Howells } 16417ff50620SDavid Howells return actual; 16427ff50620SDavid Howells } 16437ff50620SDavid Howells 1644d879cb83SAl Viro ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 1645d879cb83SAl Viro struct page ***pages, size_t maxsize, 1646d879cb83SAl Viro size_t *start) 1647d879cb83SAl Viro { 1648d879cb83SAl Viro struct page **p; 1649d879cb83SAl Viro 1650d879cb83SAl Viro if (maxsize > i->count) 1651d879cb83SAl Viro maxsize = i->count; 1652d879cb83SAl Viro 165300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1654241699cdSAl Viro return pipe_get_pages_alloc(i, pages, maxsize, start); 16557ff50620SDavid Howells if (unlikely(iov_iter_is_xarray(i))) 16567ff50620SDavid Howells return iter_xarray_get_pages_alloc(i, pages, maxsize, start); 16579ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 16589ea9ce04SDavid Howells return -EFAULT; 16599ea9ce04SDavid Howells 1660d879cb83SAl Viro iterate_all_kinds(i, maxsize, v, ({ 1661d879cb83SAl Viro unsigned long addr = (unsigned long)v.iov_base; 1662d879cb83SAl Viro size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); 1663d879cb83SAl Viro int n; 1664d879cb83SAl Viro int res; 1665d879cb83SAl Viro 1666d879cb83SAl Viro addr &= ~(PAGE_SIZE - 1); 1667d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 1668d879cb83SAl Viro p = get_pages_array(n); 1669d879cb83SAl Viro if (!p) 1670d879cb83SAl Viro return -ENOMEM; 167173b0140bSIra Weiny res = get_user_pages_fast(addr, n, 167273b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); 1673d879cb83SAl Viro if (unlikely(res < 0)) { 1674d879cb83SAl Viro kvfree(p); 1675d879cb83SAl Viro return res; 1676d879cb83SAl Viro } 1677d879cb83SAl Viro *pages = p; 1678d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 1679d879cb83SAl Viro 0;}),({ 1680d879cb83SAl Viro /* can't be more than PAGE_SIZE */ 1681d879cb83SAl Viro *start = v.bv_offset; 1682d879cb83SAl Viro *pages = p = get_pages_array(1); 1683d879cb83SAl Viro if (!p) 1684d879cb83SAl Viro return -ENOMEM; 1685d879cb83SAl Viro get_page(*p = v.bv_page); 1686d879cb83SAl Viro return v.bv_len; 1687d879cb83SAl Viro }),({ 1688d879cb83SAl Viro return -EFAULT; 16897ff50620SDavid Howells }), 0 1690d879cb83SAl Viro ) 1691d879cb83SAl Viro return 0; 1692d879cb83SAl Viro } 1693d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages_alloc); 1694d879cb83SAl Viro 1695d879cb83SAl Viro size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 1696d879cb83SAl Viro struct iov_iter *i) 1697d879cb83SAl Viro { 1698d879cb83SAl Viro char *to = addr; 1699d879cb83SAl Viro __wsum sum, next; 1700d879cb83SAl Viro size_t off = 0; 1701d879cb83SAl Viro sum = *csum; 17029ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1703241699cdSAl Viro WARN_ON(1); 1704241699cdSAl Viro return 0; 1705241699cdSAl Viro } 1706d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1707d879cb83SAl Viro next = csum_and_copy_from_user(v.iov_base, 1708d879cb83SAl Viro (to += v.iov_len) - v.iov_len, 1709c693cc46SAl Viro v.iov_len); 1710c693cc46SAl Viro if (next) { 1711d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1712d879cb83SAl Viro off += v.iov_len; 1713d879cb83SAl Viro } 1714c693cc46SAl Viro next ? 0 : v.iov_len; 1715d879cb83SAl Viro }), ({ 1716d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1717f9152895SAl Viro sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 1718f9152895SAl Viro p + v.bv_offset, v.bv_len, 1719f9152895SAl Viro sum, off); 1720d879cb83SAl Viro kunmap_atomic(p); 1721d879cb83SAl Viro off += v.bv_len; 1722d879cb83SAl Viro }),({ 1723f9152895SAl Viro sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, 1724f9152895SAl Viro v.iov_base, v.iov_len, 1725f9152895SAl Viro sum, off); 1726d879cb83SAl Viro off += v.iov_len; 17277ff50620SDavid Howells }), ({ 17287ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 17297ff50620SDavid Howells sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 17307ff50620SDavid Howells p + v.bv_offset, v.bv_len, 17317ff50620SDavid Howells sum, off); 17327ff50620SDavid Howells kunmap_atomic(p); 17337ff50620SDavid Howells off += v.bv_len; 1734d879cb83SAl Viro }) 1735d879cb83SAl Viro ) 1736d879cb83SAl Viro *csum = sum; 1737d879cb83SAl Viro return bytes; 1738d879cb83SAl Viro } 1739d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter); 1740d879cb83SAl Viro 1741cbbd26b8SAl Viro bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, 1742cbbd26b8SAl Viro struct iov_iter *i) 1743cbbd26b8SAl Viro { 1744cbbd26b8SAl Viro char *to = addr; 1745cbbd26b8SAl Viro __wsum sum, next; 1746cbbd26b8SAl Viro size_t off = 0; 1747cbbd26b8SAl Viro sum = *csum; 17489ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1749cbbd26b8SAl Viro WARN_ON(1); 1750cbbd26b8SAl Viro return false; 1751cbbd26b8SAl Viro } 1752cbbd26b8SAl Viro if (unlikely(i->count < bytes)) 1753cbbd26b8SAl Viro return false; 1754cbbd26b8SAl Viro iterate_all_kinds(i, bytes, v, ({ 1755cbbd26b8SAl Viro next = csum_and_copy_from_user(v.iov_base, 1756cbbd26b8SAl Viro (to += v.iov_len) - v.iov_len, 1757c693cc46SAl Viro v.iov_len); 1758c693cc46SAl Viro if (!next) 1759cbbd26b8SAl Viro return false; 1760cbbd26b8SAl Viro sum = csum_block_add(sum, next, off); 1761cbbd26b8SAl Viro off += v.iov_len; 1762cbbd26b8SAl Viro 0; 1763cbbd26b8SAl Viro }), ({ 1764cbbd26b8SAl Viro char *p = kmap_atomic(v.bv_page); 1765f9152895SAl Viro sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 1766f9152895SAl Viro p + v.bv_offset, v.bv_len, 1767f9152895SAl Viro sum, off); 1768cbbd26b8SAl Viro kunmap_atomic(p); 1769cbbd26b8SAl Viro off += v.bv_len; 1770cbbd26b8SAl Viro }),({ 1771f9152895SAl Viro sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, 1772f9152895SAl Viro v.iov_base, v.iov_len, 1773f9152895SAl Viro sum, off); 1774cbbd26b8SAl Viro off += v.iov_len; 17757ff50620SDavid Howells }), ({ 17767ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 17777ff50620SDavid Howells sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 17787ff50620SDavid Howells p + v.bv_offset, v.bv_len, 17797ff50620SDavid Howells sum, off); 17807ff50620SDavid Howells kunmap_atomic(p); 17817ff50620SDavid Howells off += v.bv_len; 1782cbbd26b8SAl Viro }) 1783cbbd26b8SAl Viro ) 1784cbbd26b8SAl Viro *csum = sum; 1785cbbd26b8SAl Viro iov_iter_advance(i, bytes); 1786cbbd26b8SAl Viro return true; 1787cbbd26b8SAl Viro } 1788cbbd26b8SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter_full); 1789cbbd26b8SAl Viro 179052cbd23aSWillem de Bruijn size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 1791d879cb83SAl Viro struct iov_iter *i) 1792d879cb83SAl Viro { 179352cbd23aSWillem de Bruijn struct csum_state *csstate = _csstate; 179436f7a8a4SAl Viro const char *from = addr; 1795d879cb83SAl Viro __wsum sum, next; 179652cbd23aSWillem de Bruijn size_t off; 179778e1f386SAl Viro 179878e1f386SAl Viro if (unlikely(iov_iter_is_pipe(i))) 179952cbd23aSWillem de Bruijn return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); 180078e1f386SAl Viro 180152cbd23aSWillem de Bruijn sum = csstate->csum; 180252cbd23aSWillem de Bruijn off = csstate->off; 180378e1f386SAl Viro if (unlikely(iov_iter_is_discard(i))) { 1804241699cdSAl Viro WARN_ON(1); /* for now */ 1805241699cdSAl Viro return 0; 1806241699cdSAl Viro } 1807d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1808d879cb83SAl Viro next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, 1809d879cb83SAl Viro v.iov_base, 1810c693cc46SAl Viro v.iov_len); 1811c693cc46SAl Viro if (next) { 1812d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1813d879cb83SAl Viro off += v.iov_len; 1814d879cb83SAl Viro } 1815c693cc46SAl Viro next ? 0 : v.iov_len; 1816d879cb83SAl Viro }), ({ 1817d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1818f9152895SAl Viro sum = csum_and_memcpy(p + v.bv_offset, 1819f9152895SAl Viro (from += v.bv_len) - v.bv_len, 1820f9152895SAl Viro v.bv_len, sum, off); 1821d879cb83SAl Viro kunmap_atomic(p); 1822d879cb83SAl Viro off += v.bv_len; 1823d879cb83SAl Viro }),({ 1824f9152895SAl Viro sum = csum_and_memcpy(v.iov_base, 1825f9152895SAl Viro (from += v.iov_len) - v.iov_len, 1826f9152895SAl Viro v.iov_len, sum, off); 1827d879cb83SAl Viro off += v.iov_len; 18287ff50620SDavid Howells }), ({ 18297ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 18307ff50620SDavid Howells sum = csum_and_memcpy(p + v.bv_offset, 18317ff50620SDavid Howells (from += v.bv_len) - v.bv_len, 18327ff50620SDavid Howells v.bv_len, sum, off); 18337ff50620SDavid Howells kunmap_atomic(p); 18347ff50620SDavid Howells off += v.bv_len; 1835d879cb83SAl Viro }) 1836d879cb83SAl Viro ) 183752cbd23aSWillem de Bruijn csstate->csum = sum; 183852cbd23aSWillem de Bruijn csstate->off = off; 1839d879cb83SAl Viro return bytes; 1840d879cb83SAl Viro } 1841d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_to_iter); 1842d879cb83SAl Viro 1843d05f4435SSagi Grimberg size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, 1844d05f4435SSagi Grimberg struct iov_iter *i) 1845d05f4435SSagi Grimberg { 18467999096fSHerbert Xu #ifdef CONFIG_CRYPTO_HASH 1847d05f4435SSagi Grimberg struct ahash_request *hash = hashp; 1848d05f4435SSagi Grimberg struct scatterlist sg; 1849d05f4435SSagi Grimberg size_t copied; 1850d05f4435SSagi Grimberg 1851d05f4435SSagi Grimberg copied = copy_to_iter(addr, bytes, i); 1852d05f4435SSagi Grimberg sg_init_one(&sg, addr, copied); 1853d05f4435SSagi Grimberg ahash_request_set_crypt(hash, &sg, NULL, copied); 1854d05f4435SSagi Grimberg crypto_ahash_update(hash); 1855d05f4435SSagi Grimberg return copied; 185627fad74aSYueHaibing #else 185727fad74aSYueHaibing return 0; 185827fad74aSYueHaibing #endif 1859d05f4435SSagi Grimberg } 1860d05f4435SSagi Grimberg EXPORT_SYMBOL(hash_and_copy_to_iter); 1861d05f4435SSagi Grimberg 1862d879cb83SAl Viro int iov_iter_npages(const struct iov_iter *i, int maxpages) 1863d879cb83SAl Viro { 1864d879cb83SAl Viro size_t size = i->count; 1865d879cb83SAl Viro int npages = 0; 1866d879cb83SAl Viro 1867d879cb83SAl Viro if (!size) 1868d879cb83SAl Viro return 0; 18699ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 18709ea9ce04SDavid Howells return 0; 1871d879cb83SAl Viro 187200e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 1873241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 18748cefc107SDavid Howells unsigned int iter_head; 1875241699cdSAl Viro size_t off; 1876241699cdSAl Viro 1877241699cdSAl Viro if (!sanity(i)) 1878241699cdSAl Viro return 0; 1879241699cdSAl Viro 18808cefc107SDavid Howells data_start(i, &iter_head, &off); 1881241699cdSAl Viro /* some of this one + all after this one */ 18828cefc107SDavid Howells npages = pipe_space_for_user(iter_head, pipe->tail, pipe); 1883241699cdSAl Viro if (npages >= maxpages) 1884241699cdSAl Viro return maxpages; 18857ff50620SDavid Howells } else if (unlikely(iov_iter_is_xarray(i))) { 18867ff50620SDavid Howells unsigned offset; 18877ff50620SDavid Howells 18887ff50620SDavid Howells offset = (i->xarray_start + i->iov_offset) & ~PAGE_MASK; 18897ff50620SDavid Howells 18907ff50620SDavid Howells npages = 1; 18917ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 18927ff50620SDavid Howells size -= PAGE_SIZE - offset; 18937ff50620SDavid Howells npages += size >> PAGE_SHIFT; 18947ff50620SDavid Howells size &= ~PAGE_MASK; 18957ff50620SDavid Howells if (size) 18967ff50620SDavid Howells npages++; 18977ff50620SDavid Howells } 18987ff50620SDavid Howells if (npages >= maxpages) 18997ff50620SDavid Howells return maxpages; 1900241699cdSAl Viro } else iterate_all_kinds(i, size, v, ({ 1901d879cb83SAl Viro unsigned long p = (unsigned long)v.iov_base; 1902d879cb83SAl Viro npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) 1903d879cb83SAl Viro - p / PAGE_SIZE; 1904d879cb83SAl Viro if (npages >= maxpages) 1905d879cb83SAl Viro return maxpages; 1906d879cb83SAl Viro 0;}),({ 1907d879cb83SAl Viro npages++; 1908d879cb83SAl Viro if (npages >= maxpages) 1909d879cb83SAl Viro return maxpages; 1910d879cb83SAl Viro }),({ 1911d879cb83SAl Viro unsigned long p = (unsigned long)v.iov_base; 1912d879cb83SAl Viro npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) 1913d879cb83SAl Viro - p / PAGE_SIZE; 1914d879cb83SAl Viro if (npages >= maxpages) 1915d879cb83SAl Viro return maxpages; 19167ff50620SDavid Howells }), 19177ff50620SDavid Howells 0 1918d879cb83SAl Viro ) 1919d879cb83SAl Viro return npages; 1920d879cb83SAl Viro } 1921d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_npages); 1922d879cb83SAl Viro 1923d879cb83SAl Viro const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) 1924d879cb83SAl Viro { 1925d879cb83SAl Viro *new = *old; 192600e23707SDavid Howells if (unlikely(iov_iter_is_pipe(new))) { 1927241699cdSAl Viro WARN_ON(1); 1928241699cdSAl Viro return NULL; 1929241699cdSAl Viro } 19307ff50620SDavid Howells if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) 19319ea9ce04SDavid Howells return NULL; 193200e23707SDavid Howells if (iov_iter_is_bvec(new)) 1933d879cb83SAl Viro return new->bvec = kmemdup(new->bvec, 1934d879cb83SAl Viro new->nr_segs * sizeof(struct bio_vec), 1935d879cb83SAl Viro flags); 1936d879cb83SAl Viro else 1937d879cb83SAl Viro /* iovec and kvec have identical layout */ 1938d879cb83SAl Viro return new->iov = kmemdup(new->iov, 1939d879cb83SAl Viro new->nr_segs * sizeof(struct iovec), 1940d879cb83SAl Viro flags); 1941d879cb83SAl Viro } 1942d879cb83SAl Viro EXPORT_SYMBOL(dup_iter); 1943bc917be8SAl Viro 1944bfdc5970SChristoph Hellwig static int copy_compat_iovec_from_user(struct iovec *iov, 1945bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1946bfdc5970SChristoph Hellwig { 1947bfdc5970SChristoph Hellwig const struct compat_iovec __user *uiov = 1948bfdc5970SChristoph Hellwig (const struct compat_iovec __user *)uvec; 1949bfdc5970SChristoph Hellwig int ret = -EFAULT, i; 1950bfdc5970SChristoph Hellwig 1951a959a978SChristoph Hellwig if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) 1952bfdc5970SChristoph Hellwig return -EFAULT; 1953bfdc5970SChristoph Hellwig 1954bfdc5970SChristoph Hellwig for (i = 0; i < nr_segs; i++) { 1955bfdc5970SChristoph Hellwig compat_uptr_t buf; 1956bfdc5970SChristoph Hellwig compat_ssize_t len; 1957bfdc5970SChristoph Hellwig 1958bfdc5970SChristoph Hellwig unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); 1959bfdc5970SChristoph Hellwig unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); 1960bfdc5970SChristoph Hellwig 1961bfdc5970SChristoph Hellwig /* check for compat_size_t not fitting in compat_ssize_t .. */ 1962bfdc5970SChristoph Hellwig if (len < 0) { 1963bfdc5970SChristoph Hellwig ret = -EINVAL; 1964bfdc5970SChristoph Hellwig goto uaccess_end; 1965bfdc5970SChristoph Hellwig } 1966bfdc5970SChristoph Hellwig iov[i].iov_base = compat_ptr(buf); 1967bfdc5970SChristoph Hellwig iov[i].iov_len = len; 1968bfdc5970SChristoph Hellwig } 1969bfdc5970SChristoph Hellwig 1970bfdc5970SChristoph Hellwig ret = 0; 1971bfdc5970SChristoph Hellwig uaccess_end: 1972bfdc5970SChristoph Hellwig user_access_end(); 1973bfdc5970SChristoph Hellwig return ret; 1974bfdc5970SChristoph Hellwig } 1975bfdc5970SChristoph Hellwig 1976bfdc5970SChristoph Hellwig static int copy_iovec_from_user(struct iovec *iov, 1977bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1978fb041b59SDavid Laight { 1979fb041b59SDavid Laight unsigned long seg; 1980bfdc5970SChristoph Hellwig 1981bfdc5970SChristoph Hellwig if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) 1982bfdc5970SChristoph Hellwig return -EFAULT; 1983bfdc5970SChristoph Hellwig for (seg = 0; seg < nr_segs; seg++) { 1984bfdc5970SChristoph Hellwig if ((ssize_t)iov[seg].iov_len < 0) 1985bfdc5970SChristoph Hellwig return -EINVAL; 1986bfdc5970SChristoph Hellwig } 1987bfdc5970SChristoph Hellwig 1988bfdc5970SChristoph Hellwig return 0; 1989bfdc5970SChristoph Hellwig } 1990bfdc5970SChristoph Hellwig 1991bfdc5970SChristoph Hellwig struct iovec *iovec_from_user(const struct iovec __user *uvec, 1992bfdc5970SChristoph Hellwig unsigned long nr_segs, unsigned long fast_segs, 1993bfdc5970SChristoph Hellwig struct iovec *fast_iov, bool compat) 1994bfdc5970SChristoph Hellwig { 1995bfdc5970SChristoph Hellwig struct iovec *iov = fast_iov; 1996bfdc5970SChristoph Hellwig int ret; 1997fb041b59SDavid Laight 1998fb041b59SDavid Laight /* 1999bfdc5970SChristoph Hellwig * SuS says "The readv() function *may* fail if the iovcnt argument was 2000bfdc5970SChristoph Hellwig * less than or equal to 0, or greater than {IOV_MAX}. Linux has 2001fb041b59SDavid Laight * traditionally returned zero for zero segments, so... 2002fb041b59SDavid Laight */ 2003bfdc5970SChristoph Hellwig if (nr_segs == 0) 2004bfdc5970SChristoph Hellwig return iov; 2005bfdc5970SChristoph Hellwig if (nr_segs > UIO_MAXIOV) 2006bfdc5970SChristoph Hellwig return ERR_PTR(-EINVAL); 2007fb041b59SDavid Laight if (nr_segs > fast_segs) { 2008fb041b59SDavid Laight iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); 2009bfdc5970SChristoph Hellwig if (!iov) 2010bfdc5970SChristoph Hellwig return ERR_PTR(-ENOMEM); 2011fb041b59SDavid Laight } 2012bfdc5970SChristoph Hellwig 2013bfdc5970SChristoph Hellwig if (compat) 2014bfdc5970SChristoph Hellwig ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); 2015bfdc5970SChristoph Hellwig else 2016bfdc5970SChristoph Hellwig ret = copy_iovec_from_user(iov, uvec, nr_segs); 2017bfdc5970SChristoph Hellwig if (ret) { 2018bfdc5970SChristoph Hellwig if (iov != fast_iov) 2019bfdc5970SChristoph Hellwig kfree(iov); 2020bfdc5970SChristoph Hellwig return ERR_PTR(ret); 2021fb041b59SDavid Laight } 2022bfdc5970SChristoph Hellwig 2023bfdc5970SChristoph Hellwig return iov; 2024bfdc5970SChristoph Hellwig } 2025bfdc5970SChristoph Hellwig 2026bfdc5970SChristoph Hellwig ssize_t __import_iovec(int type, const struct iovec __user *uvec, 2027bfdc5970SChristoph Hellwig unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, 2028bfdc5970SChristoph Hellwig struct iov_iter *i, bool compat) 2029bfdc5970SChristoph Hellwig { 2030bfdc5970SChristoph Hellwig ssize_t total_len = 0; 2031bfdc5970SChristoph Hellwig unsigned long seg; 2032bfdc5970SChristoph Hellwig struct iovec *iov; 2033bfdc5970SChristoph Hellwig 2034bfdc5970SChristoph Hellwig iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); 2035bfdc5970SChristoph Hellwig if (IS_ERR(iov)) { 2036bfdc5970SChristoph Hellwig *iovp = NULL; 2037bfdc5970SChristoph Hellwig return PTR_ERR(iov); 2038fb041b59SDavid Laight } 2039fb041b59SDavid Laight 2040fb041b59SDavid Laight /* 2041bfdc5970SChristoph Hellwig * According to the Single Unix Specification we should return EINVAL if 2042bfdc5970SChristoph Hellwig * an element length is < 0 when cast to ssize_t or if the total length 2043bfdc5970SChristoph Hellwig * would overflow the ssize_t return value of the system call. 2044fb041b59SDavid Laight * 2045fb041b59SDavid Laight * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the 2046fb041b59SDavid Laight * overflow case. 2047fb041b59SDavid Laight */ 2048fb041b59SDavid Laight for (seg = 0; seg < nr_segs; seg++) { 2049fb041b59SDavid Laight ssize_t len = (ssize_t)iov[seg].iov_len; 2050fb041b59SDavid Laight 2051bfdc5970SChristoph Hellwig if (!access_ok(iov[seg].iov_base, len)) { 2052bfdc5970SChristoph Hellwig if (iov != *iovp) 2053bfdc5970SChristoph Hellwig kfree(iov); 2054bfdc5970SChristoph Hellwig *iovp = NULL; 2055bfdc5970SChristoph Hellwig return -EFAULT; 2056fb041b59SDavid Laight } 2057bfdc5970SChristoph Hellwig 2058bfdc5970SChristoph Hellwig if (len > MAX_RW_COUNT - total_len) { 2059bfdc5970SChristoph Hellwig len = MAX_RW_COUNT - total_len; 2060fb041b59SDavid Laight iov[seg].iov_len = len; 2061fb041b59SDavid Laight } 2062bfdc5970SChristoph Hellwig total_len += len; 2063fb041b59SDavid Laight } 2064bfdc5970SChristoph Hellwig 2065bfdc5970SChristoph Hellwig iov_iter_init(i, type, iov, nr_segs, total_len); 2066bfdc5970SChristoph Hellwig if (iov == *iovp) 2067bfdc5970SChristoph Hellwig *iovp = NULL; 2068bfdc5970SChristoph Hellwig else 2069bfdc5970SChristoph Hellwig *iovp = iov; 2070bfdc5970SChristoph Hellwig return total_len; 2071fb041b59SDavid Laight } 2072fb041b59SDavid Laight 2073ffecee4fSVegard Nossum /** 2074ffecee4fSVegard Nossum * import_iovec() - Copy an array of &struct iovec from userspace 2075ffecee4fSVegard Nossum * into the kernel, check that it is valid, and initialize a new 2076ffecee4fSVegard Nossum * &struct iov_iter iterator to access it. 2077ffecee4fSVegard Nossum * 2078ffecee4fSVegard Nossum * @type: One of %READ or %WRITE. 2079bfdc5970SChristoph Hellwig * @uvec: Pointer to the userspace array. 2080ffecee4fSVegard Nossum * @nr_segs: Number of elements in userspace array. 2081ffecee4fSVegard Nossum * @fast_segs: Number of elements in @iov. 2082bfdc5970SChristoph Hellwig * @iovp: (input and output parameter) Pointer to pointer to (usually small 2083ffecee4fSVegard Nossum * on-stack) kernel array. 2084ffecee4fSVegard Nossum * @i: Pointer to iterator that will be initialized on success. 2085ffecee4fSVegard Nossum * 2086ffecee4fSVegard Nossum * If the array pointed to by *@iov is large enough to hold all @nr_segs, 2087ffecee4fSVegard Nossum * then this function places %NULL in *@iov on return. Otherwise, a new 2088ffecee4fSVegard Nossum * array will be allocated and the result placed in *@iov. This means that 2089ffecee4fSVegard Nossum * the caller may call kfree() on *@iov regardless of whether the small 2090ffecee4fSVegard Nossum * on-stack array was used or not (and regardless of whether this function 2091ffecee4fSVegard Nossum * returns an error or not). 2092ffecee4fSVegard Nossum * 209387e5e6daSJens Axboe * Return: Negative error code on error, bytes imported on success 2094ffecee4fSVegard Nossum */ 2095bfdc5970SChristoph Hellwig ssize_t import_iovec(int type, const struct iovec __user *uvec, 2096bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 2097bfdc5970SChristoph Hellwig struct iovec **iovp, struct iov_iter *i) 2098bc917be8SAl Viro { 209989cd35c5SChristoph Hellwig return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, 210089cd35c5SChristoph Hellwig in_compat_syscall()); 2101bc917be8SAl Viro } 2102bc917be8SAl Viro EXPORT_SYMBOL(import_iovec); 2103bc917be8SAl Viro 2104bc917be8SAl Viro int import_single_range(int rw, void __user *buf, size_t len, 2105bc917be8SAl Viro struct iovec *iov, struct iov_iter *i) 2106bc917be8SAl Viro { 2107bc917be8SAl Viro if (len > MAX_RW_COUNT) 2108bc917be8SAl Viro len = MAX_RW_COUNT; 210996d4f267SLinus Torvalds if (unlikely(!access_ok(buf, len))) 2110bc917be8SAl Viro return -EFAULT; 2111bc917be8SAl Viro 2112bc917be8SAl Viro iov->iov_base = buf; 2113bc917be8SAl Viro iov->iov_len = len; 2114bc917be8SAl Viro iov_iter_init(i, rw, iov, 1, len); 2115bc917be8SAl Viro return 0; 2116bc917be8SAl Viro } 2117e1267585SAl Viro EXPORT_SYMBOL(import_single_range); 2118