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; \ 12028f38db7SAl Viro if (likely(iter_is_iovec(i))) { \ 121d879cb83SAl Viro const struct iovec *iov; \ 122d879cb83SAl Viro struct iovec v; \ 123d879cb83SAl Viro iterate_iovec(i, n, v, iov, skip, (I)) \ 12428f38db7SAl Viro } else if (iov_iter_is_bvec(i)) { \ 12528f38db7SAl Viro struct bio_vec v; \ 12628f38db7SAl Viro struct bvec_iter __bi; \ 12728f38db7SAl Viro iterate_bvec(i, n, v, __bi, skip, (B)) \ 12828f38db7SAl Viro } else if (iov_iter_is_kvec(i)) { \ 12928f38db7SAl Viro const struct kvec *kvec; \ 13028f38db7SAl Viro struct kvec v; \ 13128f38db7SAl Viro iterate_kvec(i, n, v, kvec, skip, (K)) \ 13228f38db7SAl Viro } else if (iov_iter_is_xarray(i)) { \ 13328f38db7SAl Viro struct bio_vec v; \ 13428f38db7SAl Viro iterate_xarray(i, n, v, skip, (X)); \ 135d879cb83SAl Viro } \ 13633844e66SAl Viro } \ 137d879cb83SAl Viro } 138d879cb83SAl Viro 1397ff50620SDavid Howells #define iterate_and_advance(i, n, v, I, B, K, X) { \ 140dd254f5aSAl Viro if (unlikely(i->count < n)) \ 141dd254f5aSAl Viro n = i->count; \ 14219f18459SAl Viro if (i->count) { \ 143d879cb83SAl Viro size_t skip = i->iov_offset; \ 14428f38db7SAl Viro if (likely(iter_is_iovec(i))) { \ 145d879cb83SAl Viro const struct iovec *iov; \ 146d879cb83SAl Viro struct iovec v; \ 147d879cb83SAl Viro iterate_iovec(i, n, v, iov, skip, (I)) \ 148d879cb83SAl Viro if (skip == iov->iov_len) { \ 149d879cb83SAl Viro iov++; \ 150d879cb83SAl Viro skip = 0; \ 151d879cb83SAl Viro } \ 152d879cb83SAl Viro i->nr_segs -= iov - i->iov; \ 153d879cb83SAl Viro i->iov = iov; \ 15428f38db7SAl Viro } else if (iov_iter_is_bvec(i)) { \ 15528f38db7SAl Viro const struct bio_vec *bvec = i->bvec; \ 15628f38db7SAl Viro struct bio_vec v; \ 15728f38db7SAl Viro struct bvec_iter __bi; \ 15828f38db7SAl Viro iterate_bvec(i, n, v, __bi, skip, (B)) \ 15928f38db7SAl Viro i->bvec = __bvec_iter_bvec(i->bvec, __bi); \ 16028f38db7SAl Viro i->nr_segs -= i->bvec - bvec; \ 16128f38db7SAl Viro skip = __bi.bi_bvec_done; \ 16228f38db7SAl Viro } else if (iov_iter_is_kvec(i)) { \ 16328f38db7SAl Viro const struct kvec *kvec; \ 16428f38db7SAl Viro struct kvec v; \ 16528f38db7SAl Viro iterate_kvec(i, n, v, kvec, skip, (K)) \ 16628f38db7SAl Viro if (skip == kvec->iov_len) { \ 16728f38db7SAl Viro kvec++; \ 16828f38db7SAl Viro skip = 0; \ 16928f38db7SAl Viro } \ 17028f38db7SAl Viro i->nr_segs -= kvec - i->kvec; \ 17128f38db7SAl Viro i->kvec = kvec; \ 17228f38db7SAl Viro } else if (iov_iter_is_xarray(i)) { \ 17328f38db7SAl Viro struct bio_vec v; \ 17428f38db7SAl Viro iterate_xarray(i, n, v, skip, (X)) \ 175d879cb83SAl Viro } \ 176d879cb83SAl Viro i->count -= n; \ 177d879cb83SAl Viro i->iov_offset = skip; \ 178dd254f5aSAl Viro } \ 179d879cb83SAl Viro } 180d879cb83SAl Viro 18109fc68dcSAl Viro static int copyout(void __user *to, const void *from, size_t n) 18209fc68dcSAl Viro { 1834d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1844d0e9df5SAlbert van der Linde return n; 18596d4f267SLinus Torvalds if (access_ok(to, n)) { 186d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 18709fc68dcSAl Viro n = raw_copy_to_user(to, from, n); 18809fc68dcSAl Viro } 18909fc68dcSAl Viro return n; 19009fc68dcSAl Viro } 19109fc68dcSAl Viro 19209fc68dcSAl Viro static int copyin(void *to, const void __user *from, size_t n) 19309fc68dcSAl Viro { 1944d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1954d0e9df5SAlbert van der Linde return n; 19696d4f267SLinus Torvalds if (access_ok(from, n)) { 197d0ef4c36SMarco Elver instrument_copy_from_user(to, from, n); 19809fc68dcSAl Viro n = raw_copy_from_user(to, from, n); 19909fc68dcSAl Viro } 20009fc68dcSAl Viro return n; 20109fc68dcSAl Viro } 20209fc68dcSAl Viro 203d879cb83SAl Viro static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, 204d879cb83SAl Viro struct iov_iter *i) 205d879cb83SAl Viro { 206d879cb83SAl Viro size_t skip, copy, left, wanted; 207d879cb83SAl Viro const struct iovec *iov; 208d879cb83SAl Viro char __user *buf; 209d879cb83SAl Viro void *kaddr, *from; 210d879cb83SAl Viro 211d879cb83SAl Viro if (unlikely(bytes > i->count)) 212d879cb83SAl Viro bytes = i->count; 213d879cb83SAl Viro 214d879cb83SAl Viro if (unlikely(!bytes)) 215d879cb83SAl Viro return 0; 216d879cb83SAl Viro 21709fc68dcSAl Viro might_fault(); 218d879cb83SAl Viro wanted = bytes; 219d879cb83SAl Viro iov = i->iov; 220d879cb83SAl Viro skip = i->iov_offset; 221d879cb83SAl Viro buf = iov->iov_base + skip; 222d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 223d879cb83SAl Viro 2243fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { 225d879cb83SAl Viro kaddr = kmap_atomic(page); 226d879cb83SAl Viro from = kaddr + offset; 227d879cb83SAl Viro 228d879cb83SAl Viro /* first chunk, usually the only one */ 22909fc68dcSAl Viro left = copyout(buf, from, copy); 230d879cb83SAl Viro copy -= left; 231d879cb83SAl Viro skip += copy; 232d879cb83SAl Viro from += copy; 233d879cb83SAl Viro bytes -= copy; 234d879cb83SAl Viro 235d879cb83SAl Viro while (unlikely(!left && bytes)) { 236d879cb83SAl Viro iov++; 237d879cb83SAl Viro buf = iov->iov_base; 238d879cb83SAl Viro copy = min(bytes, iov->iov_len); 23909fc68dcSAl Viro left = copyout(buf, from, copy); 240d879cb83SAl Viro copy -= left; 241d879cb83SAl Viro skip = copy; 242d879cb83SAl Viro from += copy; 243d879cb83SAl Viro bytes -= copy; 244d879cb83SAl Viro } 245d879cb83SAl Viro if (likely(!bytes)) { 246d879cb83SAl Viro kunmap_atomic(kaddr); 247d879cb83SAl Viro goto done; 248d879cb83SAl Viro } 249d879cb83SAl Viro offset = from - kaddr; 250d879cb83SAl Viro buf += copy; 251d879cb83SAl Viro kunmap_atomic(kaddr); 252d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 253d879cb83SAl Viro } 254d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 2553fa6c507SMikulas Patocka 256d879cb83SAl Viro kaddr = kmap(page); 257d879cb83SAl Viro from = kaddr + offset; 25809fc68dcSAl Viro left = copyout(buf, from, copy); 259d879cb83SAl Viro copy -= left; 260d879cb83SAl Viro skip += copy; 261d879cb83SAl Viro from += copy; 262d879cb83SAl Viro bytes -= copy; 263d879cb83SAl Viro while (unlikely(!left && bytes)) { 264d879cb83SAl Viro iov++; 265d879cb83SAl Viro buf = iov->iov_base; 266d879cb83SAl Viro copy = min(bytes, iov->iov_len); 26709fc68dcSAl Viro left = copyout(buf, from, copy); 268d879cb83SAl Viro copy -= left; 269d879cb83SAl Viro skip = copy; 270d879cb83SAl Viro from += copy; 271d879cb83SAl Viro bytes -= copy; 272d879cb83SAl Viro } 273d879cb83SAl Viro kunmap(page); 2743fa6c507SMikulas Patocka 275d879cb83SAl Viro done: 276d879cb83SAl Viro if (skip == iov->iov_len) { 277d879cb83SAl Viro iov++; 278d879cb83SAl Viro skip = 0; 279d879cb83SAl Viro } 280d879cb83SAl Viro i->count -= wanted - bytes; 281d879cb83SAl Viro i->nr_segs -= iov - i->iov; 282d879cb83SAl Viro i->iov = iov; 283d879cb83SAl Viro i->iov_offset = skip; 284d879cb83SAl Viro return wanted - bytes; 285d879cb83SAl Viro } 286d879cb83SAl Viro 287d879cb83SAl Viro static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, 288d879cb83SAl Viro struct iov_iter *i) 289d879cb83SAl Viro { 290d879cb83SAl Viro size_t skip, copy, left, wanted; 291d879cb83SAl Viro const struct iovec *iov; 292d879cb83SAl Viro char __user *buf; 293d879cb83SAl Viro void *kaddr, *to; 294d879cb83SAl Viro 295d879cb83SAl Viro if (unlikely(bytes > i->count)) 296d879cb83SAl Viro bytes = i->count; 297d879cb83SAl Viro 298d879cb83SAl Viro if (unlikely(!bytes)) 299d879cb83SAl Viro return 0; 300d879cb83SAl Viro 30109fc68dcSAl Viro might_fault(); 302d879cb83SAl Viro wanted = bytes; 303d879cb83SAl Viro iov = i->iov; 304d879cb83SAl Viro skip = i->iov_offset; 305d879cb83SAl Viro buf = iov->iov_base + skip; 306d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 307d879cb83SAl Viro 3083fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { 309d879cb83SAl Viro kaddr = kmap_atomic(page); 310d879cb83SAl Viro to = kaddr + offset; 311d879cb83SAl Viro 312d879cb83SAl Viro /* first chunk, usually the only one */ 31309fc68dcSAl Viro left = copyin(to, buf, copy); 314d879cb83SAl Viro copy -= left; 315d879cb83SAl Viro skip += copy; 316d879cb83SAl Viro to += copy; 317d879cb83SAl Viro bytes -= copy; 318d879cb83SAl Viro 319d879cb83SAl Viro while (unlikely(!left && bytes)) { 320d879cb83SAl Viro iov++; 321d879cb83SAl Viro buf = iov->iov_base; 322d879cb83SAl Viro copy = min(bytes, iov->iov_len); 32309fc68dcSAl Viro left = copyin(to, buf, copy); 324d879cb83SAl Viro copy -= left; 325d879cb83SAl Viro skip = copy; 326d879cb83SAl Viro to += copy; 327d879cb83SAl Viro bytes -= copy; 328d879cb83SAl Viro } 329d879cb83SAl Viro if (likely(!bytes)) { 330d879cb83SAl Viro kunmap_atomic(kaddr); 331d879cb83SAl Viro goto done; 332d879cb83SAl Viro } 333d879cb83SAl Viro offset = to - kaddr; 334d879cb83SAl Viro buf += copy; 335d879cb83SAl Viro kunmap_atomic(kaddr); 336d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 337d879cb83SAl Viro } 338d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 3393fa6c507SMikulas Patocka 340d879cb83SAl Viro kaddr = kmap(page); 341d879cb83SAl Viro to = kaddr + offset; 34209fc68dcSAl Viro left = copyin(to, buf, copy); 343d879cb83SAl Viro copy -= left; 344d879cb83SAl Viro skip += copy; 345d879cb83SAl Viro to += copy; 346d879cb83SAl Viro bytes -= copy; 347d879cb83SAl Viro while (unlikely(!left && bytes)) { 348d879cb83SAl Viro iov++; 349d879cb83SAl Viro buf = iov->iov_base; 350d879cb83SAl Viro copy = min(bytes, iov->iov_len); 35109fc68dcSAl Viro left = copyin(to, buf, copy); 352d879cb83SAl Viro copy -= left; 353d879cb83SAl Viro skip = copy; 354d879cb83SAl Viro to += copy; 355d879cb83SAl Viro bytes -= copy; 356d879cb83SAl Viro } 357d879cb83SAl Viro kunmap(page); 3583fa6c507SMikulas Patocka 359d879cb83SAl Viro done: 360d879cb83SAl Viro if (skip == iov->iov_len) { 361d879cb83SAl Viro iov++; 362d879cb83SAl Viro skip = 0; 363d879cb83SAl Viro } 364d879cb83SAl Viro i->count -= wanted - bytes; 365d879cb83SAl Viro i->nr_segs -= iov - i->iov; 366d879cb83SAl Viro i->iov = iov; 367d879cb83SAl Viro i->iov_offset = skip; 368d879cb83SAl Viro return wanted - bytes; 369d879cb83SAl Viro } 370d879cb83SAl Viro 371241699cdSAl Viro #ifdef PIPE_PARANOIA 372241699cdSAl Viro static bool sanity(const struct iov_iter *i) 373241699cdSAl Viro { 374241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 3758cefc107SDavid Howells unsigned int p_head = pipe->head; 3768cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3778cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3788cefc107SDavid Howells unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); 3798cefc107SDavid Howells unsigned int i_head = i->head; 3808cefc107SDavid Howells unsigned int idx; 3818cefc107SDavid Howells 382241699cdSAl Viro if (i->iov_offset) { 383241699cdSAl Viro struct pipe_buffer *p; 3848cefc107SDavid Howells if (unlikely(p_occupancy == 0)) 385241699cdSAl Viro goto Bad; // pipe must be non-empty 3868cefc107SDavid Howells if (unlikely(i_head != p_head - 1)) 387241699cdSAl Viro goto Bad; // must be at the last buffer... 388241699cdSAl Viro 3898cefc107SDavid Howells p = &pipe->bufs[i_head & p_mask]; 390241699cdSAl Viro if (unlikely(p->offset + p->len != i->iov_offset)) 391241699cdSAl Viro goto Bad; // ... at the end of segment 392241699cdSAl Viro } else { 3938cefc107SDavid Howells if (i_head != p_head) 394241699cdSAl Viro goto Bad; // must be right after the last buffer 395241699cdSAl Viro } 396241699cdSAl Viro return true; 397241699cdSAl Viro Bad: 3988cefc107SDavid Howells printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); 3998cefc107SDavid Howells printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", 4008cefc107SDavid Howells p_head, p_tail, pipe->ring_size); 4018cefc107SDavid Howells for (idx = 0; idx < pipe->ring_size; idx++) 402241699cdSAl Viro printk(KERN_ERR "[%p %p %d %d]\n", 403241699cdSAl Viro pipe->bufs[idx].ops, 404241699cdSAl Viro pipe->bufs[idx].page, 405241699cdSAl Viro pipe->bufs[idx].offset, 406241699cdSAl Viro pipe->bufs[idx].len); 407241699cdSAl Viro WARN_ON(1); 408241699cdSAl Viro return false; 409241699cdSAl Viro } 410241699cdSAl Viro #else 411241699cdSAl Viro #define sanity(i) true 412241699cdSAl Viro #endif 413241699cdSAl Viro 414241699cdSAl Viro static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, 415241699cdSAl Viro struct iov_iter *i) 416241699cdSAl Viro { 417241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 418241699cdSAl Viro struct pipe_buffer *buf; 4198cefc107SDavid Howells unsigned int p_tail = pipe->tail; 4208cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 4218cefc107SDavid Howells unsigned int i_head = i->head; 422241699cdSAl Viro size_t off; 423241699cdSAl Viro 424241699cdSAl Viro if (unlikely(bytes > i->count)) 425241699cdSAl Viro bytes = i->count; 426241699cdSAl Viro 427241699cdSAl Viro if (unlikely(!bytes)) 428241699cdSAl Viro return 0; 429241699cdSAl Viro 430241699cdSAl Viro if (!sanity(i)) 431241699cdSAl Viro return 0; 432241699cdSAl Viro 433241699cdSAl Viro off = i->iov_offset; 4348cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 435241699cdSAl Viro if (off) { 436241699cdSAl Viro if (offset == off && buf->page == page) { 437241699cdSAl Viro /* merge with the last one */ 438241699cdSAl Viro buf->len += bytes; 439241699cdSAl Viro i->iov_offset += bytes; 440241699cdSAl Viro goto out; 441241699cdSAl Viro } 4428cefc107SDavid Howells i_head++; 4438cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 444241699cdSAl Viro } 4456718b6f8SDavid Howells if (pipe_full(i_head, p_tail, pipe->max_usage)) 446241699cdSAl Viro return 0; 4478cefc107SDavid Howells 448241699cdSAl Viro buf->ops = &page_cache_pipe_buf_ops; 4498cefc107SDavid Howells get_page(page); 4508cefc107SDavid Howells buf->page = page; 451241699cdSAl Viro buf->offset = offset; 452241699cdSAl Viro buf->len = bytes; 4538cefc107SDavid Howells 4548cefc107SDavid Howells pipe->head = i_head + 1; 455241699cdSAl Viro i->iov_offset = offset + bytes; 4568cefc107SDavid Howells i->head = i_head; 457241699cdSAl Viro out: 458241699cdSAl Viro i->count -= bytes; 459241699cdSAl Viro return bytes; 460241699cdSAl Viro } 461241699cdSAl Viro 462d879cb83SAl Viro /* 463171a0203SAnton Altaparmakov * Fault in one or more iovecs of the given iov_iter, to a maximum length of 464171a0203SAnton Altaparmakov * bytes. For each iovec, fault in each page that constitutes the iovec. 465171a0203SAnton Altaparmakov * 466171a0203SAnton Altaparmakov * Return 0 on success, or non-zero if the memory could not be accessed (i.e. 467171a0203SAnton Altaparmakov * because it is an invalid address). 468171a0203SAnton Altaparmakov */ 469d4690f1eSAl Viro int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) 470171a0203SAnton Altaparmakov { 471171a0203SAnton Altaparmakov size_t skip = i->iov_offset; 472171a0203SAnton Altaparmakov const struct iovec *iov; 473171a0203SAnton Altaparmakov int err; 474171a0203SAnton Altaparmakov struct iovec v; 475171a0203SAnton Altaparmakov 4760e8f0d67SAl Viro if (iter_is_iovec(i)) { 477171a0203SAnton Altaparmakov iterate_iovec(i, bytes, v, iov, skip, ({ 4784bce9f6eSAl Viro err = fault_in_pages_readable(v.iov_base, v.iov_len); 479171a0203SAnton Altaparmakov if (unlikely(err)) 480171a0203SAnton Altaparmakov return err; 481171a0203SAnton Altaparmakov 0;})) 482171a0203SAnton Altaparmakov } 483171a0203SAnton Altaparmakov return 0; 484171a0203SAnton Altaparmakov } 485d4690f1eSAl Viro EXPORT_SYMBOL(iov_iter_fault_in_readable); 486171a0203SAnton Altaparmakov 487aa563d7bSDavid Howells void iov_iter_init(struct iov_iter *i, unsigned int direction, 488d879cb83SAl Viro const struct iovec *iov, unsigned long nr_segs, 489d879cb83SAl Viro size_t count) 490d879cb83SAl Viro { 491aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 492*8cd54c1cSAl Viro WARN_ON_ONCE(uaccess_kernel()); 493*8cd54c1cSAl Viro *i = (struct iov_iter) { 494*8cd54c1cSAl Viro .iter_type = ITER_IOVEC, 495*8cd54c1cSAl Viro .data_source = direction, 496*8cd54c1cSAl Viro .iov = iov, 497*8cd54c1cSAl Viro .nr_segs = nr_segs, 498*8cd54c1cSAl Viro .iov_offset = 0, 499*8cd54c1cSAl Viro .count = count 500*8cd54c1cSAl Viro }; 501d879cb83SAl Viro } 502d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_init); 503d879cb83SAl Viro 504241699cdSAl Viro static inline bool allocated(struct pipe_buffer *buf) 505241699cdSAl Viro { 506241699cdSAl Viro return buf->ops == &default_pipe_buf_ops; 507241699cdSAl Viro } 508241699cdSAl Viro 5098cefc107SDavid Howells static inline void data_start(const struct iov_iter *i, 5108cefc107SDavid Howells unsigned int *iter_headp, size_t *offp) 511241699cdSAl Viro { 5128cefc107SDavid Howells unsigned int p_mask = i->pipe->ring_size - 1; 5138cefc107SDavid Howells unsigned int iter_head = i->head; 514241699cdSAl Viro size_t off = i->iov_offset; 5158cefc107SDavid Howells 5168cefc107SDavid Howells if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || 5178cefc107SDavid Howells off == PAGE_SIZE)) { 5188cefc107SDavid Howells iter_head++; 519241699cdSAl Viro off = 0; 520241699cdSAl Viro } 5218cefc107SDavid Howells *iter_headp = iter_head; 522241699cdSAl Viro *offp = off; 523241699cdSAl Viro } 524241699cdSAl Viro 525241699cdSAl Viro static size_t push_pipe(struct iov_iter *i, size_t size, 5268cefc107SDavid Howells int *iter_headp, size_t *offp) 527241699cdSAl Viro { 528241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5298cefc107SDavid Howells unsigned int p_tail = pipe->tail; 5308cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5318cefc107SDavid Howells unsigned int iter_head; 532241699cdSAl Viro size_t off; 533241699cdSAl Viro ssize_t left; 534241699cdSAl Viro 535241699cdSAl Viro if (unlikely(size > i->count)) 536241699cdSAl Viro size = i->count; 537241699cdSAl Viro if (unlikely(!size)) 538241699cdSAl Viro return 0; 539241699cdSAl Viro 540241699cdSAl Viro left = size; 5418cefc107SDavid Howells data_start(i, &iter_head, &off); 5428cefc107SDavid Howells *iter_headp = iter_head; 543241699cdSAl Viro *offp = off; 544241699cdSAl Viro if (off) { 545241699cdSAl Viro left -= PAGE_SIZE - off; 546241699cdSAl Viro if (left <= 0) { 5478cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len += size; 548241699cdSAl Viro return size; 549241699cdSAl Viro } 5508cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; 5518cefc107SDavid Howells iter_head++; 552241699cdSAl Viro } 5536718b6f8SDavid Howells while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { 5548cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; 555241699cdSAl Viro struct page *page = alloc_page(GFP_USER); 556241699cdSAl Viro if (!page) 557241699cdSAl Viro break; 5588cefc107SDavid Howells 5598cefc107SDavid Howells buf->ops = &default_pipe_buf_ops; 5608cefc107SDavid Howells buf->page = page; 5618cefc107SDavid Howells buf->offset = 0; 5628cefc107SDavid Howells buf->len = min_t(ssize_t, left, PAGE_SIZE); 5638cefc107SDavid Howells left -= buf->len; 5648cefc107SDavid Howells iter_head++; 5658cefc107SDavid Howells pipe->head = iter_head; 5668cefc107SDavid Howells 5678cefc107SDavid Howells if (left == 0) 568241699cdSAl Viro return size; 569241699cdSAl Viro } 570241699cdSAl Viro return size - left; 571241699cdSAl Viro } 572241699cdSAl Viro 573241699cdSAl Viro static size_t copy_pipe_to_iter(const void *addr, size_t bytes, 574241699cdSAl Viro struct iov_iter *i) 575241699cdSAl Viro { 576241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5778cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5788cefc107SDavid Howells unsigned int i_head; 579241699cdSAl Viro size_t n, off; 580241699cdSAl Viro 581241699cdSAl Viro if (!sanity(i)) 582241699cdSAl Viro return 0; 583241699cdSAl Viro 5848cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 585241699cdSAl Viro if (unlikely(!n)) 586241699cdSAl Viro return 0; 5878cefc107SDavid Howells do { 588241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 5898cefc107SDavid Howells memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); 5908cefc107SDavid Howells i->head = i_head; 591241699cdSAl Viro i->iov_offset = off + chunk; 592241699cdSAl Viro n -= chunk; 593241699cdSAl Viro addr += chunk; 5948cefc107SDavid Howells off = 0; 5958cefc107SDavid Howells i_head++; 5968cefc107SDavid Howells } while (n); 597241699cdSAl Viro i->count -= bytes; 598241699cdSAl Viro return bytes; 599241699cdSAl Viro } 600241699cdSAl Viro 601f9152895SAl Viro static __wsum csum_and_memcpy(void *to, const void *from, size_t len, 602f9152895SAl Viro __wsum sum, size_t off) 603f9152895SAl Viro { 604cc44c17bSAl Viro __wsum next = csum_partial_copy_nocheck(from, to, len); 605f9152895SAl Viro return csum_block_add(sum, next, off); 606f9152895SAl Viro } 607f9152895SAl Viro 60878e1f386SAl Viro static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, 60952cbd23aSWillem de Bruijn struct csum_state *csstate, 61052cbd23aSWillem de Bruijn struct iov_iter *i) 61178e1f386SAl Viro { 61278e1f386SAl Viro struct pipe_inode_info *pipe = i->pipe; 6138cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 61452cbd23aSWillem de Bruijn __wsum sum = csstate->csum; 61552cbd23aSWillem de Bruijn size_t off = csstate->off; 6168cefc107SDavid Howells unsigned int i_head; 61778e1f386SAl Viro size_t n, r; 61878e1f386SAl Viro 61978e1f386SAl Viro if (!sanity(i)) 62078e1f386SAl Viro return 0; 62178e1f386SAl Viro 6228cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &r); 62378e1f386SAl Viro if (unlikely(!n)) 62478e1f386SAl Viro return 0; 6258cefc107SDavid Howells do { 62678e1f386SAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - r); 6278cefc107SDavid Howells char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); 628f9152895SAl Viro sum = csum_and_memcpy(p + r, addr, chunk, sum, off); 62978e1f386SAl Viro kunmap_atomic(p); 6308cefc107SDavid Howells i->head = i_head; 63178e1f386SAl Viro i->iov_offset = r + chunk; 63278e1f386SAl Viro n -= chunk; 63378e1f386SAl Viro off += chunk; 63478e1f386SAl Viro addr += chunk; 6358cefc107SDavid Howells r = 0; 6368cefc107SDavid Howells i_head++; 6378cefc107SDavid Howells } while (n); 63878e1f386SAl Viro i->count -= bytes; 63952cbd23aSWillem de Bruijn csstate->csum = sum; 64052cbd23aSWillem de Bruijn csstate->off = off; 64178e1f386SAl Viro return bytes; 64278e1f386SAl Viro } 64378e1f386SAl Viro 644aa28de27SAl Viro size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 645d879cb83SAl Viro { 64636f7a8a4SAl Viro const char *from = addr; 64700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 648241699cdSAl Viro return copy_pipe_to_iter(addr, bytes, i); 64909fc68dcSAl Viro if (iter_is_iovec(i)) 65009fc68dcSAl Viro might_fault(); 651d879cb83SAl Viro iterate_and_advance(i, bytes, v, 65209fc68dcSAl Viro copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 653d879cb83SAl Viro memcpy_to_page(v.bv_page, v.bv_offset, 654d879cb83SAl Viro (from += v.bv_len) - v.bv_len, v.bv_len), 6557ff50620SDavid Howells memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 6567ff50620SDavid Howells memcpy_to_page(v.bv_page, v.bv_offset, 6577ff50620SDavid Howells (from += v.bv_len) - v.bv_len, v.bv_len) 658d879cb83SAl Viro ) 659d879cb83SAl Viro 660d879cb83SAl Viro return bytes; 661d879cb83SAl Viro } 662aa28de27SAl Viro EXPORT_SYMBOL(_copy_to_iter); 663d879cb83SAl Viro 664ec6347bbSDan Williams #ifdef CONFIG_ARCH_HAS_COPY_MC 665ec6347bbSDan Williams static int copyout_mc(void __user *to, const void *from, size_t n) 6668780356eSDan Williams { 66796d4f267SLinus Torvalds if (access_ok(to, n)) { 668d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 669ec6347bbSDan Williams n = copy_mc_to_user((__force void *) to, from, n); 6708780356eSDan Williams } 6718780356eSDan Williams return n; 6728780356eSDan Williams } 6738780356eSDan Williams 674ec6347bbSDan Williams static unsigned long copy_mc_to_page(struct page *page, size_t offset, 6758780356eSDan Williams const char *from, size_t len) 6768780356eSDan Williams { 6778780356eSDan Williams unsigned long ret; 6788780356eSDan Williams char *to; 6798780356eSDan Williams 6808780356eSDan Williams to = kmap_atomic(page); 681ec6347bbSDan Williams ret = copy_mc_to_kernel(to + offset, from, len); 6828780356eSDan Williams kunmap_atomic(to); 6838780356eSDan Williams 6848780356eSDan Williams return ret; 6858780356eSDan Williams } 6868780356eSDan Williams 687ec6347bbSDan Williams static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, 688ca146f6fSDan Williams struct iov_iter *i) 689ca146f6fSDan Williams { 690ca146f6fSDan Williams struct pipe_inode_info *pipe = i->pipe; 6918cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 6928cefc107SDavid Howells unsigned int i_head; 693ca146f6fSDan Williams size_t n, off, xfer = 0; 694ca146f6fSDan Williams 695ca146f6fSDan Williams if (!sanity(i)) 696ca146f6fSDan Williams return 0; 697ca146f6fSDan Williams 6988cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 699ca146f6fSDan Williams if (unlikely(!n)) 700ca146f6fSDan Williams return 0; 7018cefc107SDavid Howells do { 702ca146f6fSDan Williams size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 703ca146f6fSDan Williams unsigned long rem; 704ca146f6fSDan Williams 705ec6347bbSDan Williams rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, 7068cefc107SDavid Howells off, addr, chunk); 7078cefc107SDavid Howells i->head = i_head; 708ca146f6fSDan Williams i->iov_offset = off + chunk - rem; 709ca146f6fSDan Williams xfer += chunk - rem; 710ca146f6fSDan Williams if (rem) 711ca146f6fSDan Williams break; 712ca146f6fSDan Williams n -= chunk; 713ca146f6fSDan Williams addr += chunk; 7148cefc107SDavid Howells off = 0; 7158cefc107SDavid Howells i_head++; 7168cefc107SDavid Howells } while (n); 717ca146f6fSDan Williams i->count -= xfer; 718ca146f6fSDan Williams return xfer; 719ca146f6fSDan Williams } 720ca146f6fSDan Williams 721bf3eeb9bSDan Williams /** 722ec6347bbSDan Williams * _copy_mc_to_iter - copy to iter with source memory error exception handling 723bf3eeb9bSDan Williams * @addr: source kernel address 724bf3eeb9bSDan Williams * @bytes: total transfer length 725bf3eeb9bSDan Williams * @iter: destination iterator 726bf3eeb9bSDan Williams * 727ec6347bbSDan Williams * The pmem driver deploys this for the dax operation 728ec6347bbSDan Williams * (dax_copy_to_iter()) for dax reads (bypass page-cache and the 729ec6347bbSDan Williams * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes 730ec6347bbSDan Williams * successfully copied. 731bf3eeb9bSDan Williams * 732ec6347bbSDan Williams * The main differences between this and typical _copy_to_iter(). 733bf3eeb9bSDan Williams * 734bf3eeb9bSDan Williams * * Typical tail/residue handling after a fault retries the copy 735bf3eeb9bSDan Williams * byte-by-byte until the fault happens again. Re-triggering machine 736bf3eeb9bSDan Williams * checks is potentially fatal so the implementation uses source 737bf3eeb9bSDan Williams * alignment and poison alignment assumptions to avoid re-triggering 738bf3eeb9bSDan Williams * hardware exceptions. 739bf3eeb9bSDan Williams * 740bf3eeb9bSDan Williams * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. 741bf3eeb9bSDan Williams * Compare to copy_to_iter() where only ITER_IOVEC attempts might return 742bf3eeb9bSDan Williams * a short copy. 743bf3eeb9bSDan Williams */ 744ec6347bbSDan Williams size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 7458780356eSDan Williams { 7468780356eSDan Williams const char *from = addr; 7478780356eSDan Williams unsigned long rem, curr_addr, s_addr = (unsigned long) addr; 7488780356eSDan Williams 74900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 750ec6347bbSDan Williams return copy_mc_pipe_to_iter(addr, bytes, i); 7518780356eSDan Williams if (iter_is_iovec(i)) 7528780356eSDan Williams might_fault(); 7538780356eSDan Williams iterate_and_advance(i, bytes, v, 754ec6347bbSDan Williams copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len, 755ec6347bbSDan Williams v.iov_len), 7568780356eSDan Williams ({ 757ec6347bbSDan Williams rem = copy_mc_to_page(v.bv_page, v.bv_offset, 7588780356eSDan Williams (from += v.bv_len) - v.bv_len, v.bv_len); 7598780356eSDan Williams if (rem) { 7608780356eSDan Williams curr_addr = (unsigned long) from; 7618780356eSDan Williams bytes = curr_addr - s_addr - rem; 7628780356eSDan Williams return bytes; 7638780356eSDan Williams } 7648780356eSDan Williams }), 7658780356eSDan Williams ({ 766ec6347bbSDan Williams rem = copy_mc_to_kernel(v.iov_base, (from += v.iov_len) 767ec6347bbSDan Williams - v.iov_len, v.iov_len); 7688780356eSDan Williams if (rem) { 7698780356eSDan Williams curr_addr = (unsigned long) from; 7708780356eSDan Williams bytes = curr_addr - s_addr - rem; 7718780356eSDan Williams return bytes; 7728780356eSDan Williams } 7737ff50620SDavid Howells }), 7747ff50620SDavid Howells ({ 7757ff50620SDavid Howells rem = copy_mc_to_page(v.bv_page, v.bv_offset, 7767ff50620SDavid Howells (from += v.bv_len) - v.bv_len, v.bv_len); 7777ff50620SDavid Howells if (rem) { 7787ff50620SDavid Howells curr_addr = (unsigned long) from; 7797ff50620SDavid Howells bytes = curr_addr - s_addr - rem; 7807ff50620SDavid Howells rcu_read_unlock(); 7813d14ec1fSDavid Howells i->iov_offset += bytes; 7823d14ec1fSDavid Howells i->count -= bytes; 7837ff50620SDavid Howells return bytes; 7847ff50620SDavid Howells } 7858780356eSDan Williams }) 7868780356eSDan Williams ) 7878780356eSDan Williams 7888780356eSDan Williams return bytes; 7898780356eSDan Williams } 790ec6347bbSDan Williams EXPORT_SYMBOL_GPL(_copy_mc_to_iter); 791ec6347bbSDan Williams #endif /* CONFIG_ARCH_HAS_COPY_MC */ 7928780356eSDan Williams 793aa28de27SAl Viro size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) 794d879cb83SAl Viro { 795d879cb83SAl Viro char *to = addr; 79600e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 797241699cdSAl Viro WARN_ON(1); 798241699cdSAl Viro return 0; 799241699cdSAl Viro } 80009fc68dcSAl Viro if (iter_is_iovec(i)) 80109fc68dcSAl Viro might_fault(); 802d879cb83SAl Viro iterate_and_advance(i, bytes, v, 80309fc68dcSAl Viro copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 804d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 805d879cb83SAl Viro v.bv_offset, v.bv_len), 8067ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 8077ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 8087ff50620SDavid Howells v.bv_offset, v.bv_len) 809d879cb83SAl Viro ) 810d879cb83SAl Viro 811d879cb83SAl Viro return bytes; 812d879cb83SAl Viro } 813aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter); 814d879cb83SAl Viro 815aa28de27SAl Viro size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) 816d879cb83SAl Viro { 817d879cb83SAl Viro char *to = addr; 81800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 819241699cdSAl Viro WARN_ON(1); 820241699cdSAl Viro return 0; 821241699cdSAl Viro } 822d879cb83SAl Viro iterate_and_advance(i, bytes, v, 8233f763453SAl Viro __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, 824d879cb83SAl Viro v.iov_base, v.iov_len), 825d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 826d879cb83SAl Viro v.bv_offset, v.bv_len), 8277ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 8287ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 8297ff50620SDavid Howells v.bv_offset, v.bv_len) 830d879cb83SAl Viro ) 831d879cb83SAl Viro 832d879cb83SAl Viro return bytes; 833d879cb83SAl Viro } 834aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_nocache); 835d879cb83SAl Viro 8360aed55afSDan Williams #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE 837abd08d7dSDan Williams /** 838abd08d7dSDan Williams * _copy_from_iter_flushcache - write destination through cpu cache 839abd08d7dSDan Williams * @addr: destination kernel address 840abd08d7dSDan Williams * @bytes: total transfer length 841abd08d7dSDan Williams * @iter: source iterator 842abd08d7dSDan Williams * 843abd08d7dSDan Williams * The pmem driver arranges for filesystem-dax to use this facility via 844abd08d7dSDan Williams * dax_copy_from_iter() for ensuring that writes to persistent memory 845abd08d7dSDan Williams * are flushed through the CPU cache. It is differentiated from 846abd08d7dSDan Williams * _copy_from_iter_nocache() in that guarantees all data is flushed for 847abd08d7dSDan Williams * all iterator types. The _copy_from_iter_nocache() only attempts to 848abd08d7dSDan Williams * bypass the cache for the ITER_IOVEC case, and on some archs may use 849abd08d7dSDan Williams * instructions that strand dirty-data in the cache. 850abd08d7dSDan Williams */ 8516a37e940SLinus Torvalds size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 8520aed55afSDan Williams { 8530aed55afSDan Williams char *to = addr; 85400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 8550aed55afSDan Williams WARN_ON(1); 8560aed55afSDan Williams return 0; 8570aed55afSDan Williams } 8580aed55afSDan Williams iterate_and_advance(i, bytes, v, 8590aed55afSDan Williams __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, 8600aed55afSDan Williams v.iov_base, v.iov_len), 8610aed55afSDan Williams memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 8620aed55afSDan Williams v.bv_offset, v.bv_len), 8630aed55afSDan Williams memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, 8647ff50620SDavid Howells v.iov_len), 8657ff50620SDavid Howells memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 8667ff50620SDavid Howells v.bv_offset, v.bv_len) 8670aed55afSDan Williams ) 8680aed55afSDan Williams 8690aed55afSDan Williams return bytes; 8700aed55afSDan Williams } 8716a37e940SLinus Torvalds EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); 8720aed55afSDan Williams #endif 8730aed55afSDan Williams 87472e809edSAl Viro static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) 87572e809edSAl Viro { 8766daef95bSEric Dumazet struct page *head; 8776daef95bSEric Dumazet size_t v = n + offset; 8786daef95bSEric Dumazet 8796daef95bSEric Dumazet /* 8806daef95bSEric Dumazet * The general case needs to access the page order in order 8816daef95bSEric Dumazet * to compute the page size. 8826daef95bSEric Dumazet * However, we mostly deal with order-0 pages and thus can 8836daef95bSEric Dumazet * avoid a possible cache line miss for requests that fit all 8846daef95bSEric Dumazet * page orders. 8856daef95bSEric Dumazet */ 8866daef95bSEric Dumazet if (n <= v && v <= PAGE_SIZE) 8876daef95bSEric Dumazet return true; 8886daef95bSEric Dumazet 8896daef95bSEric Dumazet head = compound_head(page); 8906daef95bSEric Dumazet v += (page - head) << PAGE_SHIFT; 891a90bcb86SPetar Penkov 892a50b854eSMatthew Wilcox (Oracle) if (likely(n <= v && v <= (page_size(head)))) 89372e809edSAl Viro return true; 89472e809edSAl Viro WARN_ON(1); 89572e809edSAl Viro return false; 89672e809edSAl Viro } 897cbbd26b8SAl Viro 89808aa6479SAl Viro static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 899d879cb83SAl Viro struct iov_iter *i) 900d879cb83SAl Viro { 90128f38db7SAl Viro if (likely(iter_is_iovec(i))) 90228f38db7SAl Viro return copy_page_to_iter_iovec(page, offset, bytes, i); 90328f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 904d879cb83SAl Viro void *kaddr = kmap_atomic(page); 905d879cb83SAl Viro size_t wanted = copy_to_iter(kaddr + offset, bytes, i); 906d879cb83SAl Viro kunmap_atomic(kaddr); 907d879cb83SAl Viro return wanted; 90828f38db7SAl Viro } 90928f38db7SAl Viro if (iov_iter_is_pipe(i)) 91028f38db7SAl Viro return copy_page_to_iter_pipe(page, offset, bytes, i); 91128f38db7SAl Viro if (unlikely(iov_iter_is_discard(i))) { 912a506abc7SAl Viro if (unlikely(i->count < bytes)) 913a506abc7SAl Viro bytes = i->count; 914a506abc7SAl Viro i->count -= bytes; 9159ea9ce04SDavid Howells return bytes; 91628f38db7SAl Viro } 91728f38db7SAl Viro WARN_ON(1); 91828f38db7SAl Viro return 0; 919d879cb83SAl Viro } 92008aa6479SAl Viro 92108aa6479SAl Viro size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 92208aa6479SAl Viro struct iov_iter *i) 92308aa6479SAl Viro { 92408aa6479SAl Viro size_t res = 0; 92508aa6479SAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 92608aa6479SAl Viro return 0; 92708aa6479SAl Viro page += offset / PAGE_SIZE; // first subpage 92808aa6479SAl Viro offset %= PAGE_SIZE; 92908aa6479SAl Viro while (1) { 93008aa6479SAl Viro size_t n = __copy_page_to_iter(page, offset, 93108aa6479SAl Viro min(bytes, (size_t)PAGE_SIZE - offset), i); 93208aa6479SAl Viro res += n; 93308aa6479SAl Viro bytes -= n; 93408aa6479SAl Viro if (!bytes || !n) 93508aa6479SAl Viro break; 93608aa6479SAl Viro offset += n; 93708aa6479SAl Viro if (offset == PAGE_SIZE) { 93808aa6479SAl Viro page++; 93908aa6479SAl Viro offset = 0; 94008aa6479SAl Viro } 94108aa6479SAl Viro } 94208aa6479SAl Viro return res; 94308aa6479SAl Viro } 944d879cb83SAl Viro EXPORT_SYMBOL(copy_page_to_iter); 945d879cb83SAl Viro 946d879cb83SAl Viro size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, 947d879cb83SAl Viro struct iov_iter *i) 948d879cb83SAl Viro { 94972e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 95072e809edSAl Viro return 0; 95128f38db7SAl Viro if (likely(iter_is_iovec(i))) 95228f38db7SAl Viro return copy_page_from_iter_iovec(page, offset, bytes, i); 95328f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 954d879cb83SAl Viro void *kaddr = kmap_atomic(page); 955aa28de27SAl Viro size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); 956d879cb83SAl Viro kunmap_atomic(kaddr); 957d879cb83SAl Viro return wanted; 95828f38db7SAl Viro } 95928f38db7SAl Viro WARN_ON(1); 96028f38db7SAl Viro return 0; 961d879cb83SAl Viro } 962d879cb83SAl Viro EXPORT_SYMBOL(copy_page_from_iter); 963d879cb83SAl Viro 964241699cdSAl Viro static size_t pipe_zero(size_t bytes, struct iov_iter *i) 965241699cdSAl Viro { 966241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 9678cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9688cefc107SDavid Howells unsigned int i_head; 969241699cdSAl Viro size_t n, off; 970241699cdSAl Viro 971241699cdSAl Viro if (!sanity(i)) 972241699cdSAl Viro return 0; 973241699cdSAl Viro 9748cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 975241699cdSAl Viro if (unlikely(!n)) 976241699cdSAl Viro return 0; 977241699cdSAl Viro 9788cefc107SDavid Howells do { 979241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 9808cefc107SDavid Howells memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); 9818cefc107SDavid Howells i->head = i_head; 982241699cdSAl Viro i->iov_offset = off + chunk; 983241699cdSAl Viro n -= chunk; 9848cefc107SDavid Howells off = 0; 9858cefc107SDavid Howells i_head++; 9868cefc107SDavid Howells } while (n); 987241699cdSAl Viro i->count -= bytes; 988241699cdSAl Viro return bytes; 989241699cdSAl Viro } 990241699cdSAl Viro 991d879cb83SAl Viro size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 992d879cb83SAl Viro { 99300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 994241699cdSAl Viro return pipe_zero(bytes, i); 995d879cb83SAl Viro iterate_and_advance(i, bytes, v, 99609fc68dcSAl Viro clear_user(v.iov_base, v.iov_len), 997d879cb83SAl Viro memzero_page(v.bv_page, v.bv_offset, v.bv_len), 9987ff50620SDavid Howells memset(v.iov_base, 0, v.iov_len), 9997ff50620SDavid Howells memzero_page(v.bv_page, v.bv_offset, v.bv_len) 1000d879cb83SAl Viro ) 1001d879cb83SAl Viro 1002d879cb83SAl Viro return bytes; 1003d879cb83SAl Viro } 1004d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_zero); 1005d879cb83SAl Viro 1006d879cb83SAl Viro size_t iov_iter_copy_from_user_atomic(struct page *page, 1007d879cb83SAl Viro struct iov_iter *i, unsigned long offset, size_t bytes) 1008d879cb83SAl Viro { 1009d879cb83SAl Viro char *kaddr = kmap_atomic(page), *p = kaddr + offset; 101072e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) { 101172e809edSAl Viro kunmap_atomic(kaddr); 101272e809edSAl Viro return 0; 101372e809edSAl Viro } 10149ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1015241699cdSAl Viro kunmap_atomic(kaddr); 1016241699cdSAl Viro WARN_ON(1); 1017241699cdSAl Viro return 0; 1018241699cdSAl Viro } 1019d879cb83SAl Viro iterate_all_kinds(i, bytes, v, 102009fc68dcSAl Viro copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 1021d879cb83SAl Viro memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 1022d879cb83SAl Viro v.bv_offset, v.bv_len), 10237ff50620SDavid Howells memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 10247ff50620SDavid Howells memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 10257ff50620SDavid Howells v.bv_offset, v.bv_len) 1026d879cb83SAl Viro ) 1027d879cb83SAl Viro kunmap_atomic(kaddr); 1028d879cb83SAl Viro return bytes; 1029d879cb83SAl Viro } 1030d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); 1031d879cb83SAl Viro 1032b9dc6f65SAl Viro static inline void pipe_truncate(struct iov_iter *i) 1033241699cdSAl Viro { 1034241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 10358cefc107SDavid Howells unsigned int p_tail = pipe->tail; 10368cefc107SDavid Howells unsigned int p_head = pipe->head; 10378cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10388cefc107SDavid Howells 10398cefc107SDavid Howells if (!pipe_empty(p_head, p_tail)) { 10408cefc107SDavid Howells struct pipe_buffer *buf; 10418cefc107SDavid Howells unsigned int i_head = i->head; 1042b9dc6f65SAl Viro size_t off = i->iov_offset; 10438cefc107SDavid Howells 1044b9dc6f65SAl Viro if (off) { 10458cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 10468cefc107SDavid Howells buf->len = off - buf->offset; 10478cefc107SDavid Howells i_head++; 1048b9dc6f65SAl Viro } 10498cefc107SDavid Howells while (p_head != i_head) { 10508cefc107SDavid Howells p_head--; 10518cefc107SDavid Howells pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); 1052241699cdSAl Viro } 10538cefc107SDavid Howells 10548cefc107SDavid Howells pipe->head = p_head; 1055241699cdSAl Viro } 1056b9dc6f65SAl Viro } 1057b9dc6f65SAl Viro 1058b9dc6f65SAl Viro static void pipe_advance(struct iov_iter *i, size_t size) 1059b9dc6f65SAl Viro { 1060b9dc6f65SAl Viro struct pipe_inode_info *pipe = i->pipe; 1061b9dc6f65SAl Viro if (size) { 1062b9dc6f65SAl Viro struct pipe_buffer *buf; 10638cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10648cefc107SDavid Howells unsigned int i_head = i->head; 1065b9dc6f65SAl Viro size_t off = i->iov_offset, left = size; 10668cefc107SDavid Howells 1067b9dc6f65SAl Viro if (off) /* make it relative to the beginning of buffer */ 10688cefc107SDavid Howells left += off - pipe->bufs[i_head & p_mask].offset; 1069b9dc6f65SAl Viro while (1) { 10708cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 1071b9dc6f65SAl Viro if (left <= buf->len) 1072b9dc6f65SAl Viro break; 1073b9dc6f65SAl Viro left -= buf->len; 10748cefc107SDavid Howells i_head++; 1075b9dc6f65SAl Viro } 10768cefc107SDavid Howells i->head = i_head; 1077b9dc6f65SAl Viro i->iov_offset = buf->offset + left; 1078b9dc6f65SAl Viro } 1079b9dc6f65SAl Viro i->count -= size; 1080b9dc6f65SAl Viro /* ... and discard everything past that point */ 1081b9dc6f65SAl Viro pipe_truncate(i); 1082241699cdSAl Viro } 1083241699cdSAl Viro 108454c8195bSPavel Begunkov static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) 108554c8195bSPavel Begunkov { 108654c8195bSPavel Begunkov struct bvec_iter bi; 108754c8195bSPavel Begunkov 108854c8195bSPavel Begunkov bi.bi_size = i->count; 108954c8195bSPavel Begunkov bi.bi_bvec_done = i->iov_offset; 109054c8195bSPavel Begunkov bi.bi_idx = 0; 109154c8195bSPavel Begunkov bvec_iter_advance(i->bvec, &bi, size); 109254c8195bSPavel Begunkov 109354c8195bSPavel Begunkov i->bvec += bi.bi_idx; 109454c8195bSPavel Begunkov i->nr_segs -= bi.bi_idx; 109554c8195bSPavel Begunkov i->count = bi.bi_size; 109654c8195bSPavel Begunkov i->iov_offset = bi.bi_bvec_done; 109754c8195bSPavel Begunkov } 109854c8195bSPavel Begunkov 1099d879cb83SAl Viro void iov_iter_advance(struct iov_iter *i, size_t size) 1100d879cb83SAl Viro { 11013b3fc051SAl Viro if (unlikely(i->count < size)) 11023b3fc051SAl Viro size = i->count; 110300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 1104241699cdSAl Viro pipe_advance(i, size); 1105241699cdSAl Viro return; 1106241699cdSAl Viro } 11079ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) { 11089ea9ce04SDavid Howells i->count -= size; 11099ea9ce04SDavid Howells return; 11109ea9ce04SDavid Howells } 11117ff50620SDavid Howells if (unlikely(iov_iter_is_xarray(i))) { 11127ff50620SDavid Howells i->iov_offset += size; 11137ff50620SDavid Howells i->count -= size; 11147ff50620SDavid Howells return; 11157ff50620SDavid Howells } 111654c8195bSPavel Begunkov if (iov_iter_is_bvec(i)) { 111754c8195bSPavel Begunkov iov_iter_bvec_advance(i, size); 111854c8195bSPavel Begunkov return; 111954c8195bSPavel Begunkov } 11207ff50620SDavid Howells iterate_and_advance(i, size, v, 0, 0, 0, 0) 1121d879cb83SAl Viro } 1122d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_advance); 1123d879cb83SAl Viro 112427c0e374SAl Viro void iov_iter_revert(struct iov_iter *i, size_t unroll) 112527c0e374SAl Viro { 112627c0e374SAl Viro if (!unroll) 112727c0e374SAl Viro return; 11285b47d59aSAl Viro if (WARN_ON(unroll > MAX_RW_COUNT)) 11295b47d59aSAl Viro return; 113027c0e374SAl Viro i->count += unroll; 113100e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 113227c0e374SAl Viro struct pipe_inode_info *pipe = i->pipe; 11338cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 11348cefc107SDavid Howells unsigned int i_head = i->head; 113527c0e374SAl Viro size_t off = i->iov_offset; 113627c0e374SAl Viro while (1) { 11378cefc107SDavid Howells struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; 11388cefc107SDavid Howells size_t n = off - b->offset; 113927c0e374SAl Viro if (unroll < n) { 11404fa55cefSAl Viro off -= unroll; 114127c0e374SAl Viro break; 114227c0e374SAl Viro } 114327c0e374SAl Viro unroll -= n; 11448cefc107SDavid Howells if (!unroll && i_head == i->start_head) { 114527c0e374SAl Viro off = 0; 114627c0e374SAl Viro break; 114727c0e374SAl Viro } 11488cefc107SDavid Howells i_head--; 11498cefc107SDavid Howells b = &pipe->bufs[i_head & p_mask]; 11508cefc107SDavid Howells off = b->offset + b->len; 115127c0e374SAl Viro } 115227c0e374SAl Viro i->iov_offset = off; 11538cefc107SDavid Howells i->head = i_head; 115427c0e374SAl Viro pipe_truncate(i); 115527c0e374SAl Viro return; 115627c0e374SAl Viro } 11579ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 11589ea9ce04SDavid Howells return; 115927c0e374SAl Viro if (unroll <= i->iov_offset) { 116027c0e374SAl Viro i->iov_offset -= unroll; 116127c0e374SAl Viro return; 116227c0e374SAl Viro } 116327c0e374SAl Viro unroll -= i->iov_offset; 11647ff50620SDavid Howells if (iov_iter_is_xarray(i)) { 11657ff50620SDavid Howells BUG(); /* We should never go beyond the start of the specified 11667ff50620SDavid Howells * range since we might then be straying into pages that 11677ff50620SDavid Howells * aren't pinned. 11687ff50620SDavid Howells */ 11697ff50620SDavid Howells } else if (iov_iter_is_bvec(i)) { 117027c0e374SAl Viro const struct bio_vec *bvec = i->bvec; 117127c0e374SAl Viro while (1) { 117227c0e374SAl Viro size_t n = (--bvec)->bv_len; 117327c0e374SAl Viro i->nr_segs++; 117427c0e374SAl Viro if (unroll <= n) { 117527c0e374SAl Viro i->bvec = bvec; 117627c0e374SAl Viro i->iov_offset = n - unroll; 117727c0e374SAl Viro return; 117827c0e374SAl Viro } 117927c0e374SAl Viro unroll -= n; 118027c0e374SAl Viro } 118127c0e374SAl Viro } else { /* same logics for iovec and kvec */ 118227c0e374SAl Viro const struct iovec *iov = i->iov; 118327c0e374SAl Viro while (1) { 118427c0e374SAl Viro size_t n = (--iov)->iov_len; 118527c0e374SAl Viro i->nr_segs++; 118627c0e374SAl Viro if (unroll <= n) { 118727c0e374SAl Viro i->iov = iov; 118827c0e374SAl Viro i->iov_offset = n - unroll; 118927c0e374SAl Viro return; 119027c0e374SAl Viro } 119127c0e374SAl Viro unroll -= n; 119227c0e374SAl Viro } 119327c0e374SAl Viro } 119427c0e374SAl Viro } 119527c0e374SAl Viro EXPORT_SYMBOL(iov_iter_revert); 119627c0e374SAl Viro 1197d879cb83SAl Viro /* 1198d879cb83SAl Viro * Return the count of just the current iov_iter segment. 1199d879cb83SAl Viro */ 1200d879cb83SAl Viro size_t iov_iter_single_seg_count(const struct iov_iter *i) 1201d879cb83SAl Viro { 120228f38db7SAl Viro if (i->nr_segs > 1) { 120328f38db7SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 120428f38db7SAl Viro return min(i->count, i->iov->iov_len - i->iov_offset); 12057ff50620SDavid Howells if (iov_iter_is_bvec(i)) 1206d879cb83SAl Viro return min(i->count, i->bvec->bv_len - i->iov_offset); 120728f38db7SAl Viro } 120828f38db7SAl Viro return i->count; 1209d879cb83SAl Viro } 1210d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_single_seg_count); 1211d879cb83SAl Viro 1212aa563d7bSDavid Howells void iov_iter_kvec(struct iov_iter *i, unsigned int direction, 1213d879cb83SAl Viro const struct kvec *kvec, unsigned long nr_segs, 1214d879cb83SAl Viro size_t count) 1215d879cb83SAl Viro { 1216aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 1217*8cd54c1cSAl Viro *i = (struct iov_iter){ 1218*8cd54c1cSAl Viro .iter_type = ITER_KVEC, 1219*8cd54c1cSAl Viro .data_source = direction, 1220*8cd54c1cSAl Viro .kvec = kvec, 1221*8cd54c1cSAl Viro .nr_segs = nr_segs, 1222*8cd54c1cSAl Viro .iov_offset = 0, 1223*8cd54c1cSAl Viro .count = count 1224*8cd54c1cSAl Viro }; 1225d879cb83SAl Viro } 1226d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_kvec); 1227d879cb83SAl Viro 1228aa563d7bSDavid Howells void iov_iter_bvec(struct iov_iter *i, unsigned int direction, 1229d879cb83SAl Viro const struct bio_vec *bvec, unsigned long nr_segs, 1230d879cb83SAl Viro size_t count) 1231d879cb83SAl Viro { 1232aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 1233*8cd54c1cSAl Viro *i = (struct iov_iter){ 1234*8cd54c1cSAl Viro .iter_type = ITER_BVEC, 1235*8cd54c1cSAl Viro .data_source = direction, 1236*8cd54c1cSAl Viro .bvec = bvec, 1237*8cd54c1cSAl Viro .nr_segs = nr_segs, 1238*8cd54c1cSAl Viro .iov_offset = 0, 1239*8cd54c1cSAl Viro .count = count 1240*8cd54c1cSAl Viro }; 1241d879cb83SAl Viro } 1242d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_bvec); 1243d879cb83SAl Viro 1244aa563d7bSDavid Howells void iov_iter_pipe(struct iov_iter *i, unsigned int direction, 1245241699cdSAl Viro struct pipe_inode_info *pipe, 1246241699cdSAl Viro size_t count) 1247241699cdSAl Viro { 1248aa563d7bSDavid Howells BUG_ON(direction != READ); 12498cefc107SDavid Howells WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); 1250*8cd54c1cSAl Viro *i = (struct iov_iter){ 1251*8cd54c1cSAl Viro .iter_type = ITER_PIPE, 1252*8cd54c1cSAl Viro .data_source = false, 1253*8cd54c1cSAl Viro .pipe = pipe, 1254*8cd54c1cSAl Viro .head = pipe->head, 1255*8cd54c1cSAl Viro .start_head = pipe->head, 1256*8cd54c1cSAl Viro .iov_offset = 0, 1257*8cd54c1cSAl Viro .count = count 1258*8cd54c1cSAl Viro }; 1259241699cdSAl Viro } 1260241699cdSAl Viro EXPORT_SYMBOL(iov_iter_pipe); 1261241699cdSAl Viro 12629ea9ce04SDavid Howells /** 12637ff50620SDavid Howells * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray 12647ff50620SDavid Howells * @i: The iterator to initialise. 12657ff50620SDavid Howells * @direction: The direction of the transfer. 12667ff50620SDavid Howells * @xarray: The xarray to access. 12677ff50620SDavid Howells * @start: The start file position. 12687ff50620SDavid Howells * @count: The size of the I/O buffer in bytes. 12697ff50620SDavid Howells * 12707ff50620SDavid Howells * Set up an I/O iterator to either draw data out of the pages attached to an 12717ff50620SDavid Howells * inode or to inject data into those pages. The pages *must* be prevented 12727ff50620SDavid Howells * from evaporation, either by taking a ref on them or locking them by the 12737ff50620SDavid Howells * caller. 12747ff50620SDavid Howells */ 12757ff50620SDavid Howells void iov_iter_xarray(struct iov_iter *i, unsigned int direction, 12767ff50620SDavid Howells struct xarray *xarray, loff_t start, size_t count) 12777ff50620SDavid Howells { 12787ff50620SDavid Howells BUG_ON(direction & ~1); 1279*8cd54c1cSAl Viro *i = (struct iov_iter) { 1280*8cd54c1cSAl Viro .iter_type = ITER_XARRAY, 1281*8cd54c1cSAl Viro .data_source = direction, 1282*8cd54c1cSAl Viro .xarray = xarray, 1283*8cd54c1cSAl Viro .xarray_start = start, 1284*8cd54c1cSAl Viro .count = count, 1285*8cd54c1cSAl Viro .iov_offset = 0 1286*8cd54c1cSAl Viro }; 12877ff50620SDavid Howells } 12887ff50620SDavid Howells EXPORT_SYMBOL(iov_iter_xarray); 12897ff50620SDavid Howells 12907ff50620SDavid Howells /** 12919ea9ce04SDavid Howells * iov_iter_discard - Initialise an I/O iterator that discards data 12929ea9ce04SDavid Howells * @i: The iterator to initialise. 12939ea9ce04SDavid Howells * @direction: The direction of the transfer. 12949ea9ce04SDavid Howells * @count: The size of the I/O buffer in bytes. 12959ea9ce04SDavid Howells * 12969ea9ce04SDavid Howells * Set up an I/O iterator that just discards everything that's written to it. 12979ea9ce04SDavid Howells * It's only available as a READ iterator. 12989ea9ce04SDavid Howells */ 12999ea9ce04SDavid Howells void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) 13009ea9ce04SDavid Howells { 13019ea9ce04SDavid Howells BUG_ON(direction != READ); 1302*8cd54c1cSAl Viro *i = (struct iov_iter){ 1303*8cd54c1cSAl Viro .iter_type = ITER_DISCARD, 1304*8cd54c1cSAl Viro .data_source = false, 1305*8cd54c1cSAl Viro .count = count, 1306*8cd54c1cSAl Viro .iov_offset = 0 1307*8cd54c1cSAl Viro }; 13089ea9ce04SDavid Howells } 13099ea9ce04SDavid Howells EXPORT_SYMBOL(iov_iter_discard); 13109ea9ce04SDavid Howells 1311d879cb83SAl Viro unsigned long iov_iter_alignment(const struct iov_iter *i) 1312d879cb83SAl Viro { 1313d879cb83SAl Viro unsigned long res = 0; 1314d879cb83SAl Viro size_t size = i->count; 1315d879cb83SAl Viro 131600e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 1317e0ff126eSJan Kara unsigned int p_mask = i->pipe->ring_size - 1; 1318e0ff126eSJan Kara 13198cefc107SDavid Howells if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) 1320241699cdSAl Viro return size | i->iov_offset; 1321241699cdSAl Viro return size; 1322241699cdSAl Viro } 13233d14ec1fSDavid Howells if (unlikely(iov_iter_is_xarray(i))) 13243d14ec1fSDavid Howells return (i->xarray_start + i->iov_offset) | i->count; 1325d879cb83SAl Viro iterate_all_kinds(i, size, v, 1326d879cb83SAl Viro (res |= (unsigned long)v.iov_base | v.iov_len, 0), 1327d879cb83SAl Viro res |= v.bv_offset | v.bv_len, 13287ff50620SDavid Howells res |= (unsigned long)v.iov_base | v.iov_len, 13297ff50620SDavid Howells res |= v.bv_offset | v.bv_len 1330d879cb83SAl Viro ) 1331d879cb83SAl Viro return res; 1332d879cb83SAl Viro } 1333d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_alignment); 1334d879cb83SAl Viro 1335357f435dSAl Viro unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 1336357f435dSAl Viro { 1337357f435dSAl Viro unsigned long res = 0; 1338357f435dSAl Viro size_t size = i->count; 1339357f435dSAl Viro 13409ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1341241699cdSAl Viro WARN_ON(1); 1342241699cdSAl Viro return ~0U; 1343241699cdSAl Viro } 1344241699cdSAl Viro 1345357f435dSAl Viro iterate_all_kinds(i, size, v, 1346357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.iov_base) | 1347357f435dSAl Viro (size != v.iov_len ? size : 0), 0), 1348357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.bv_offset) | 1349357f435dSAl Viro (size != v.bv_len ? size : 0)), 1350357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.iov_base) | 13517ff50620SDavid Howells (size != v.iov_len ? size : 0)), 13527ff50620SDavid Howells (res |= (!res ? 0 : (unsigned long)v.bv_offset) | 13537ff50620SDavid Howells (size != v.bv_len ? size : 0)) 1354357f435dSAl Viro ); 1355357f435dSAl Viro return res; 1356357f435dSAl Viro } 1357357f435dSAl Viro EXPORT_SYMBOL(iov_iter_gap_alignment); 1358357f435dSAl Viro 1359e76b6312SIlya Dryomov static inline ssize_t __pipe_get_pages(struct iov_iter *i, 1360241699cdSAl Viro size_t maxsize, 1361241699cdSAl Viro struct page **pages, 13628cefc107SDavid Howells int iter_head, 1363241699cdSAl Viro size_t *start) 1364241699cdSAl Viro { 1365241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 13668cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 13678cefc107SDavid Howells ssize_t n = push_pipe(i, maxsize, &iter_head, start); 1368241699cdSAl Viro if (!n) 1369241699cdSAl Viro return -EFAULT; 1370241699cdSAl Viro 1371241699cdSAl Viro maxsize = n; 1372241699cdSAl Viro n += *start; 13731689c73aSAl Viro while (n > 0) { 13748cefc107SDavid Howells get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); 13758cefc107SDavid Howells iter_head++; 1376241699cdSAl Viro n -= PAGE_SIZE; 1377241699cdSAl Viro } 1378241699cdSAl Viro 1379241699cdSAl Viro return maxsize; 1380241699cdSAl Viro } 1381241699cdSAl Viro 1382241699cdSAl Viro static ssize_t pipe_get_pages(struct iov_iter *i, 1383241699cdSAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1384241699cdSAl Viro size_t *start) 1385241699cdSAl Viro { 13868cefc107SDavid Howells unsigned int iter_head, npages; 1387241699cdSAl Viro size_t capacity; 1388241699cdSAl Viro 138933844e66SAl Viro if (!maxsize) 139033844e66SAl Viro return 0; 139133844e66SAl Viro 1392241699cdSAl Viro if (!sanity(i)) 1393241699cdSAl Viro return -EFAULT; 1394241699cdSAl Viro 13958cefc107SDavid Howells data_start(i, &iter_head, start); 13968cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 13978cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1398241699cdSAl Viro capacity = min(npages, maxpages) * PAGE_SIZE - *start; 1399241699cdSAl Viro 14008cefc107SDavid Howells return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); 1401241699cdSAl Viro } 1402241699cdSAl Viro 14037ff50620SDavid Howells static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, 14047ff50620SDavid Howells pgoff_t index, unsigned int nr_pages) 14057ff50620SDavid Howells { 14067ff50620SDavid Howells XA_STATE(xas, xa, index); 14077ff50620SDavid Howells struct page *page; 14087ff50620SDavid Howells unsigned int ret = 0; 14097ff50620SDavid Howells 14107ff50620SDavid Howells rcu_read_lock(); 14117ff50620SDavid Howells for (page = xas_load(&xas); page; page = xas_next(&xas)) { 14127ff50620SDavid Howells if (xas_retry(&xas, page)) 14137ff50620SDavid Howells continue; 14147ff50620SDavid Howells 14157ff50620SDavid Howells /* Has the page moved or been split? */ 14167ff50620SDavid Howells if (unlikely(page != xas_reload(&xas))) { 14177ff50620SDavid Howells xas_reset(&xas); 14187ff50620SDavid Howells continue; 14197ff50620SDavid Howells } 14207ff50620SDavid Howells 14217ff50620SDavid Howells pages[ret] = find_subpage(page, xas.xa_index); 14227ff50620SDavid Howells get_page(pages[ret]); 14237ff50620SDavid Howells if (++ret == nr_pages) 14247ff50620SDavid Howells break; 14257ff50620SDavid Howells } 14267ff50620SDavid Howells rcu_read_unlock(); 14277ff50620SDavid Howells return ret; 14287ff50620SDavid Howells } 14297ff50620SDavid Howells 14307ff50620SDavid Howells static ssize_t iter_xarray_get_pages(struct iov_iter *i, 14317ff50620SDavid Howells struct page **pages, size_t maxsize, 14327ff50620SDavid Howells unsigned maxpages, size_t *_start_offset) 14337ff50620SDavid Howells { 14347ff50620SDavid Howells unsigned nr, offset; 14357ff50620SDavid Howells pgoff_t index, count; 14367ff50620SDavid Howells size_t size = maxsize, actual; 14377ff50620SDavid Howells loff_t pos; 14387ff50620SDavid Howells 14397ff50620SDavid Howells if (!size || !maxpages) 14407ff50620SDavid Howells return 0; 14417ff50620SDavid Howells 14427ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 14437ff50620SDavid Howells index = pos >> PAGE_SHIFT; 14447ff50620SDavid Howells offset = pos & ~PAGE_MASK; 14457ff50620SDavid Howells *_start_offset = offset; 14467ff50620SDavid Howells 14477ff50620SDavid Howells count = 1; 14487ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 14497ff50620SDavid Howells size -= PAGE_SIZE - offset; 14507ff50620SDavid Howells count += size >> PAGE_SHIFT; 14517ff50620SDavid Howells size &= ~PAGE_MASK; 14527ff50620SDavid Howells if (size) 14537ff50620SDavid Howells count++; 14547ff50620SDavid Howells } 14557ff50620SDavid Howells 14567ff50620SDavid Howells if (count > maxpages) 14577ff50620SDavid Howells count = maxpages; 14587ff50620SDavid Howells 14597ff50620SDavid Howells nr = iter_xarray_populate_pages(pages, i->xarray, index, count); 14607ff50620SDavid Howells if (nr == 0) 14617ff50620SDavid Howells return 0; 14627ff50620SDavid Howells 14637ff50620SDavid Howells actual = PAGE_SIZE * nr; 14647ff50620SDavid Howells actual -= offset; 14657ff50620SDavid Howells if (nr == count && size > 0) { 14667ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 14677ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 14687ff50620SDavid Howells } 14697ff50620SDavid Howells return actual; 14707ff50620SDavid Howells } 14717ff50620SDavid Howells 1472d879cb83SAl Viro ssize_t iov_iter_get_pages(struct iov_iter *i, 1473d879cb83SAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1474d879cb83SAl Viro size_t *start) 1475d879cb83SAl Viro { 1476d879cb83SAl Viro if (maxsize > i->count) 1477d879cb83SAl Viro maxsize = i->count; 1478d879cb83SAl Viro 147900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1480241699cdSAl Viro return pipe_get_pages(i, pages, maxsize, maxpages, start); 14817ff50620SDavid Howells if (unlikely(iov_iter_is_xarray(i))) 14827ff50620SDavid Howells return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); 14839ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 14849ea9ce04SDavid Howells return -EFAULT; 14859ea9ce04SDavid Howells 1486d879cb83SAl Viro iterate_all_kinds(i, maxsize, v, ({ 1487d879cb83SAl Viro unsigned long addr = (unsigned long)v.iov_base; 1488d879cb83SAl Viro size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); 1489d879cb83SAl Viro int n; 1490d879cb83SAl Viro int res; 1491d879cb83SAl Viro 1492d879cb83SAl Viro if (len > maxpages * PAGE_SIZE) 1493d879cb83SAl Viro len = maxpages * PAGE_SIZE; 1494d879cb83SAl Viro addr &= ~(PAGE_SIZE - 1); 1495d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 149673b0140bSIra Weiny res = get_user_pages_fast(addr, n, 149773b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, 149873b0140bSIra Weiny pages); 1499d879cb83SAl Viro if (unlikely(res < 0)) 1500d879cb83SAl Viro return res; 1501d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 1502d879cb83SAl Viro 0;}),({ 1503d879cb83SAl Viro /* can't be more than PAGE_SIZE */ 1504d879cb83SAl Viro *start = v.bv_offset; 1505d879cb83SAl Viro get_page(*pages = v.bv_page); 1506d879cb83SAl Viro return v.bv_len; 1507d879cb83SAl Viro }),({ 1508d879cb83SAl Viro return -EFAULT; 15097ff50620SDavid Howells }), 15107ff50620SDavid Howells 0 1511d879cb83SAl Viro ) 1512d879cb83SAl Viro return 0; 1513d879cb83SAl Viro } 1514d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages); 1515d879cb83SAl Viro 1516d879cb83SAl Viro static struct page **get_pages_array(size_t n) 1517d879cb83SAl Viro { 1518752ade68SMichal Hocko return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); 1519d879cb83SAl Viro } 1520d879cb83SAl Viro 1521241699cdSAl Viro static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 1522241699cdSAl Viro struct page ***pages, size_t maxsize, 1523241699cdSAl Viro size_t *start) 1524241699cdSAl Viro { 1525241699cdSAl Viro struct page **p; 15268cefc107SDavid Howells unsigned int iter_head, npages; 1527d7760d63SIlya Dryomov ssize_t n; 1528241699cdSAl Viro 152933844e66SAl Viro if (!maxsize) 153033844e66SAl Viro return 0; 153133844e66SAl Viro 1532241699cdSAl Viro if (!sanity(i)) 1533241699cdSAl Viro return -EFAULT; 1534241699cdSAl Viro 15358cefc107SDavid Howells data_start(i, &iter_head, start); 15368cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 15378cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1538241699cdSAl Viro n = npages * PAGE_SIZE - *start; 1539241699cdSAl Viro if (maxsize > n) 1540241699cdSAl Viro maxsize = n; 1541241699cdSAl Viro else 1542241699cdSAl Viro npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1543241699cdSAl Viro p = get_pages_array(npages); 1544241699cdSAl Viro if (!p) 1545241699cdSAl Viro return -ENOMEM; 15468cefc107SDavid Howells n = __pipe_get_pages(i, maxsize, p, iter_head, start); 1547241699cdSAl Viro if (n > 0) 1548241699cdSAl Viro *pages = p; 1549241699cdSAl Viro else 1550241699cdSAl Viro kvfree(p); 1551241699cdSAl Viro return n; 1552241699cdSAl Viro } 1553241699cdSAl Viro 15547ff50620SDavid Howells static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, 15557ff50620SDavid Howells struct page ***pages, size_t maxsize, 15567ff50620SDavid Howells size_t *_start_offset) 15577ff50620SDavid Howells { 15587ff50620SDavid Howells struct page **p; 15597ff50620SDavid Howells unsigned nr, offset; 15607ff50620SDavid Howells pgoff_t index, count; 15617ff50620SDavid Howells size_t size = maxsize, actual; 15627ff50620SDavid Howells loff_t pos; 15637ff50620SDavid Howells 15647ff50620SDavid Howells if (!size) 15657ff50620SDavid Howells return 0; 15667ff50620SDavid Howells 15677ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 15687ff50620SDavid Howells index = pos >> PAGE_SHIFT; 15697ff50620SDavid Howells offset = pos & ~PAGE_MASK; 15707ff50620SDavid Howells *_start_offset = offset; 15717ff50620SDavid Howells 15727ff50620SDavid Howells count = 1; 15737ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 15747ff50620SDavid Howells size -= PAGE_SIZE - offset; 15757ff50620SDavid Howells count += size >> PAGE_SHIFT; 15767ff50620SDavid Howells size &= ~PAGE_MASK; 15777ff50620SDavid Howells if (size) 15787ff50620SDavid Howells count++; 15797ff50620SDavid Howells } 15807ff50620SDavid Howells 15817ff50620SDavid Howells p = get_pages_array(count); 15827ff50620SDavid Howells if (!p) 15837ff50620SDavid Howells return -ENOMEM; 15847ff50620SDavid Howells *pages = p; 15857ff50620SDavid Howells 15867ff50620SDavid Howells nr = iter_xarray_populate_pages(p, i->xarray, index, count); 15877ff50620SDavid Howells if (nr == 0) 15887ff50620SDavid Howells return 0; 15897ff50620SDavid Howells 15907ff50620SDavid Howells actual = PAGE_SIZE * nr; 15917ff50620SDavid Howells actual -= offset; 15927ff50620SDavid Howells if (nr == count && size > 0) { 15937ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 15947ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 15957ff50620SDavid Howells } 15967ff50620SDavid Howells return actual; 15977ff50620SDavid Howells } 15987ff50620SDavid Howells 1599d879cb83SAl Viro ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 1600d879cb83SAl Viro struct page ***pages, size_t maxsize, 1601d879cb83SAl Viro size_t *start) 1602d879cb83SAl Viro { 1603d879cb83SAl Viro struct page **p; 1604d879cb83SAl Viro 1605d879cb83SAl Viro if (maxsize > i->count) 1606d879cb83SAl Viro maxsize = i->count; 1607d879cb83SAl Viro 160800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1609241699cdSAl Viro return pipe_get_pages_alloc(i, pages, maxsize, start); 16107ff50620SDavid Howells if (unlikely(iov_iter_is_xarray(i))) 16117ff50620SDavid Howells return iter_xarray_get_pages_alloc(i, pages, maxsize, start); 16129ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 16139ea9ce04SDavid Howells return -EFAULT; 16149ea9ce04SDavid Howells 1615d879cb83SAl Viro iterate_all_kinds(i, maxsize, v, ({ 1616d879cb83SAl Viro unsigned long addr = (unsigned long)v.iov_base; 1617d879cb83SAl Viro size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); 1618d879cb83SAl Viro int n; 1619d879cb83SAl Viro int res; 1620d879cb83SAl Viro 1621d879cb83SAl Viro addr &= ~(PAGE_SIZE - 1); 1622d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 1623d879cb83SAl Viro p = get_pages_array(n); 1624d879cb83SAl Viro if (!p) 1625d879cb83SAl Viro return -ENOMEM; 162673b0140bSIra Weiny res = get_user_pages_fast(addr, n, 162773b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); 1628d879cb83SAl Viro if (unlikely(res < 0)) { 1629d879cb83SAl Viro kvfree(p); 1630d879cb83SAl Viro return res; 1631d879cb83SAl Viro } 1632d879cb83SAl Viro *pages = p; 1633d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 1634d879cb83SAl Viro 0;}),({ 1635d879cb83SAl Viro /* can't be more than PAGE_SIZE */ 1636d879cb83SAl Viro *start = v.bv_offset; 1637d879cb83SAl Viro *pages = p = get_pages_array(1); 1638d879cb83SAl Viro if (!p) 1639d879cb83SAl Viro return -ENOMEM; 1640d879cb83SAl Viro get_page(*p = v.bv_page); 1641d879cb83SAl Viro return v.bv_len; 1642d879cb83SAl Viro }),({ 1643d879cb83SAl Viro return -EFAULT; 16447ff50620SDavid Howells }), 0 1645d879cb83SAl Viro ) 1646d879cb83SAl Viro return 0; 1647d879cb83SAl Viro } 1648d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages_alloc); 1649d879cb83SAl Viro 1650d879cb83SAl Viro size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 1651d879cb83SAl Viro struct iov_iter *i) 1652d879cb83SAl Viro { 1653d879cb83SAl Viro char *to = addr; 1654d879cb83SAl Viro __wsum sum, next; 1655d879cb83SAl Viro size_t off = 0; 1656d879cb83SAl Viro sum = *csum; 16579ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1658241699cdSAl Viro WARN_ON(1); 1659241699cdSAl Viro return 0; 1660241699cdSAl Viro } 1661d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1662d879cb83SAl Viro next = csum_and_copy_from_user(v.iov_base, 1663d879cb83SAl Viro (to += v.iov_len) - v.iov_len, 1664c693cc46SAl Viro v.iov_len); 1665c693cc46SAl Viro if (next) { 1666d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1667d879cb83SAl Viro off += v.iov_len; 1668d879cb83SAl Viro } 1669c693cc46SAl Viro next ? 0 : v.iov_len; 1670d879cb83SAl Viro }), ({ 1671d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1672f9152895SAl Viro sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 1673f9152895SAl Viro p + v.bv_offset, v.bv_len, 1674f9152895SAl Viro sum, off); 1675d879cb83SAl Viro kunmap_atomic(p); 1676d879cb83SAl Viro off += v.bv_len; 1677d879cb83SAl Viro }),({ 1678f9152895SAl Viro sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, 1679f9152895SAl Viro v.iov_base, v.iov_len, 1680f9152895SAl Viro sum, off); 1681d879cb83SAl Viro off += v.iov_len; 16827ff50620SDavid Howells }), ({ 16837ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 16847ff50620SDavid Howells sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 16857ff50620SDavid Howells p + v.bv_offset, v.bv_len, 16867ff50620SDavid Howells sum, off); 16877ff50620SDavid Howells kunmap_atomic(p); 16887ff50620SDavid Howells off += v.bv_len; 1689d879cb83SAl Viro }) 1690d879cb83SAl Viro ) 1691d879cb83SAl Viro *csum = sum; 1692d879cb83SAl Viro return bytes; 1693d879cb83SAl Viro } 1694d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter); 1695d879cb83SAl Viro 169652cbd23aSWillem de Bruijn size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 1697d879cb83SAl Viro struct iov_iter *i) 1698d879cb83SAl Viro { 169952cbd23aSWillem de Bruijn struct csum_state *csstate = _csstate; 170036f7a8a4SAl Viro const char *from = addr; 1701d879cb83SAl Viro __wsum sum, next; 170252cbd23aSWillem de Bruijn size_t off; 170378e1f386SAl Viro 170478e1f386SAl Viro if (unlikely(iov_iter_is_pipe(i))) 170552cbd23aSWillem de Bruijn return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); 170678e1f386SAl Viro 170752cbd23aSWillem de Bruijn sum = csstate->csum; 170852cbd23aSWillem de Bruijn off = csstate->off; 170978e1f386SAl Viro if (unlikely(iov_iter_is_discard(i))) { 1710241699cdSAl Viro WARN_ON(1); /* for now */ 1711241699cdSAl Viro return 0; 1712241699cdSAl Viro } 1713d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1714d879cb83SAl Viro next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, 1715d879cb83SAl Viro v.iov_base, 1716c693cc46SAl Viro v.iov_len); 1717c693cc46SAl Viro if (next) { 1718d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1719d879cb83SAl Viro off += v.iov_len; 1720d879cb83SAl Viro } 1721c693cc46SAl Viro next ? 0 : v.iov_len; 1722d879cb83SAl Viro }), ({ 1723d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1724f9152895SAl Viro sum = csum_and_memcpy(p + v.bv_offset, 1725f9152895SAl Viro (from += v.bv_len) - v.bv_len, 1726f9152895SAl Viro v.bv_len, sum, off); 1727d879cb83SAl Viro kunmap_atomic(p); 1728d879cb83SAl Viro off += v.bv_len; 1729d879cb83SAl Viro }),({ 1730f9152895SAl Viro sum = csum_and_memcpy(v.iov_base, 1731f9152895SAl Viro (from += v.iov_len) - v.iov_len, 1732f9152895SAl Viro v.iov_len, sum, off); 1733d879cb83SAl Viro off += v.iov_len; 17347ff50620SDavid Howells }), ({ 17357ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 17367ff50620SDavid Howells sum = csum_and_memcpy(p + v.bv_offset, 17377ff50620SDavid Howells (from += v.bv_len) - v.bv_len, 17387ff50620SDavid Howells v.bv_len, sum, off); 17397ff50620SDavid Howells kunmap_atomic(p); 17407ff50620SDavid Howells off += v.bv_len; 1741d879cb83SAl Viro }) 1742d879cb83SAl Viro ) 174352cbd23aSWillem de Bruijn csstate->csum = sum; 174452cbd23aSWillem de Bruijn csstate->off = off; 1745d879cb83SAl Viro return bytes; 1746d879cb83SAl Viro } 1747d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_to_iter); 1748d879cb83SAl Viro 1749d05f4435SSagi Grimberg size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, 1750d05f4435SSagi Grimberg struct iov_iter *i) 1751d05f4435SSagi Grimberg { 17527999096fSHerbert Xu #ifdef CONFIG_CRYPTO_HASH 1753d05f4435SSagi Grimberg struct ahash_request *hash = hashp; 1754d05f4435SSagi Grimberg struct scatterlist sg; 1755d05f4435SSagi Grimberg size_t copied; 1756d05f4435SSagi Grimberg 1757d05f4435SSagi Grimberg copied = copy_to_iter(addr, bytes, i); 1758d05f4435SSagi Grimberg sg_init_one(&sg, addr, copied); 1759d05f4435SSagi Grimberg ahash_request_set_crypt(hash, &sg, NULL, copied); 1760d05f4435SSagi Grimberg crypto_ahash_update(hash); 1761d05f4435SSagi Grimberg return copied; 176227fad74aSYueHaibing #else 176327fad74aSYueHaibing return 0; 176427fad74aSYueHaibing #endif 1765d05f4435SSagi Grimberg } 1766d05f4435SSagi Grimberg EXPORT_SYMBOL(hash_and_copy_to_iter); 1767d05f4435SSagi Grimberg 1768d879cb83SAl Viro int iov_iter_npages(const struct iov_iter *i, int maxpages) 1769d879cb83SAl Viro { 1770d879cb83SAl Viro size_t size = i->count; 1771d879cb83SAl Viro int npages = 0; 1772d879cb83SAl Viro 1773d879cb83SAl Viro if (!size) 1774d879cb83SAl Viro return 0; 17759ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 17769ea9ce04SDavid Howells return 0; 1777d879cb83SAl Viro 177800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 1779241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 17808cefc107SDavid Howells unsigned int iter_head; 1781241699cdSAl Viro size_t off; 1782241699cdSAl Viro 1783241699cdSAl Viro if (!sanity(i)) 1784241699cdSAl Viro return 0; 1785241699cdSAl Viro 17868cefc107SDavid Howells data_start(i, &iter_head, &off); 1787241699cdSAl Viro /* some of this one + all after this one */ 17888cefc107SDavid Howells npages = pipe_space_for_user(iter_head, pipe->tail, pipe); 1789241699cdSAl Viro if (npages >= maxpages) 1790241699cdSAl Viro return maxpages; 17917ff50620SDavid Howells } else if (unlikely(iov_iter_is_xarray(i))) { 17927ff50620SDavid Howells unsigned offset; 17937ff50620SDavid Howells 17947ff50620SDavid Howells offset = (i->xarray_start + i->iov_offset) & ~PAGE_MASK; 17957ff50620SDavid Howells 17967ff50620SDavid Howells npages = 1; 17977ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 17987ff50620SDavid Howells size -= PAGE_SIZE - offset; 17997ff50620SDavid Howells npages += size >> PAGE_SHIFT; 18007ff50620SDavid Howells size &= ~PAGE_MASK; 18017ff50620SDavid Howells if (size) 18027ff50620SDavid Howells npages++; 18037ff50620SDavid Howells } 18047ff50620SDavid Howells if (npages >= maxpages) 18057ff50620SDavid Howells return maxpages; 1806241699cdSAl Viro } else iterate_all_kinds(i, size, v, ({ 1807d879cb83SAl Viro unsigned long p = (unsigned long)v.iov_base; 1808d879cb83SAl Viro npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) 1809d879cb83SAl Viro - p / PAGE_SIZE; 1810d879cb83SAl Viro if (npages >= maxpages) 1811d879cb83SAl Viro return maxpages; 1812d879cb83SAl Viro 0;}),({ 1813d879cb83SAl Viro npages++; 1814d879cb83SAl Viro if (npages >= maxpages) 1815d879cb83SAl Viro return maxpages; 1816d879cb83SAl Viro }),({ 1817d879cb83SAl Viro unsigned long p = (unsigned long)v.iov_base; 1818d879cb83SAl Viro npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) 1819d879cb83SAl Viro - p / PAGE_SIZE; 1820d879cb83SAl Viro if (npages >= maxpages) 1821d879cb83SAl Viro return maxpages; 18227ff50620SDavid Howells }), 18237ff50620SDavid Howells 0 1824d879cb83SAl Viro ) 1825d879cb83SAl Viro return npages; 1826d879cb83SAl Viro } 1827d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_npages); 1828d879cb83SAl Viro 1829d879cb83SAl Viro const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) 1830d879cb83SAl Viro { 1831d879cb83SAl Viro *new = *old; 183200e23707SDavid Howells if (unlikely(iov_iter_is_pipe(new))) { 1833241699cdSAl Viro WARN_ON(1); 1834241699cdSAl Viro return NULL; 1835241699cdSAl Viro } 18367ff50620SDavid Howells if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) 18379ea9ce04SDavid Howells return NULL; 183800e23707SDavid Howells if (iov_iter_is_bvec(new)) 1839d879cb83SAl Viro return new->bvec = kmemdup(new->bvec, 1840d879cb83SAl Viro new->nr_segs * sizeof(struct bio_vec), 1841d879cb83SAl Viro flags); 1842d879cb83SAl Viro else 1843d879cb83SAl Viro /* iovec and kvec have identical layout */ 1844d879cb83SAl Viro return new->iov = kmemdup(new->iov, 1845d879cb83SAl Viro new->nr_segs * sizeof(struct iovec), 1846d879cb83SAl Viro flags); 1847d879cb83SAl Viro } 1848d879cb83SAl Viro EXPORT_SYMBOL(dup_iter); 1849bc917be8SAl Viro 1850bfdc5970SChristoph Hellwig static int copy_compat_iovec_from_user(struct iovec *iov, 1851bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1852bfdc5970SChristoph Hellwig { 1853bfdc5970SChristoph Hellwig const struct compat_iovec __user *uiov = 1854bfdc5970SChristoph Hellwig (const struct compat_iovec __user *)uvec; 1855bfdc5970SChristoph Hellwig int ret = -EFAULT, i; 1856bfdc5970SChristoph Hellwig 1857a959a978SChristoph Hellwig if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) 1858bfdc5970SChristoph Hellwig return -EFAULT; 1859bfdc5970SChristoph Hellwig 1860bfdc5970SChristoph Hellwig for (i = 0; i < nr_segs; i++) { 1861bfdc5970SChristoph Hellwig compat_uptr_t buf; 1862bfdc5970SChristoph Hellwig compat_ssize_t len; 1863bfdc5970SChristoph Hellwig 1864bfdc5970SChristoph Hellwig unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); 1865bfdc5970SChristoph Hellwig unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); 1866bfdc5970SChristoph Hellwig 1867bfdc5970SChristoph Hellwig /* check for compat_size_t not fitting in compat_ssize_t .. */ 1868bfdc5970SChristoph Hellwig if (len < 0) { 1869bfdc5970SChristoph Hellwig ret = -EINVAL; 1870bfdc5970SChristoph Hellwig goto uaccess_end; 1871bfdc5970SChristoph Hellwig } 1872bfdc5970SChristoph Hellwig iov[i].iov_base = compat_ptr(buf); 1873bfdc5970SChristoph Hellwig iov[i].iov_len = len; 1874bfdc5970SChristoph Hellwig } 1875bfdc5970SChristoph Hellwig 1876bfdc5970SChristoph Hellwig ret = 0; 1877bfdc5970SChristoph Hellwig uaccess_end: 1878bfdc5970SChristoph Hellwig user_access_end(); 1879bfdc5970SChristoph Hellwig return ret; 1880bfdc5970SChristoph Hellwig } 1881bfdc5970SChristoph Hellwig 1882bfdc5970SChristoph Hellwig static int copy_iovec_from_user(struct iovec *iov, 1883bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1884fb041b59SDavid Laight { 1885fb041b59SDavid Laight unsigned long seg; 1886bfdc5970SChristoph Hellwig 1887bfdc5970SChristoph Hellwig if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) 1888bfdc5970SChristoph Hellwig return -EFAULT; 1889bfdc5970SChristoph Hellwig for (seg = 0; seg < nr_segs; seg++) { 1890bfdc5970SChristoph Hellwig if ((ssize_t)iov[seg].iov_len < 0) 1891bfdc5970SChristoph Hellwig return -EINVAL; 1892bfdc5970SChristoph Hellwig } 1893bfdc5970SChristoph Hellwig 1894bfdc5970SChristoph Hellwig return 0; 1895bfdc5970SChristoph Hellwig } 1896bfdc5970SChristoph Hellwig 1897bfdc5970SChristoph Hellwig struct iovec *iovec_from_user(const struct iovec __user *uvec, 1898bfdc5970SChristoph Hellwig unsigned long nr_segs, unsigned long fast_segs, 1899bfdc5970SChristoph Hellwig struct iovec *fast_iov, bool compat) 1900bfdc5970SChristoph Hellwig { 1901bfdc5970SChristoph Hellwig struct iovec *iov = fast_iov; 1902bfdc5970SChristoph Hellwig int ret; 1903fb041b59SDavid Laight 1904fb041b59SDavid Laight /* 1905bfdc5970SChristoph Hellwig * SuS says "The readv() function *may* fail if the iovcnt argument was 1906bfdc5970SChristoph Hellwig * less than or equal to 0, or greater than {IOV_MAX}. Linux has 1907fb041b59SDavid Laight * traditionally returned zero for zero segments, so... 1908fb041b59SDavid Laight */ 1909bfdc5970SChristoph Hellwig if (nr_segs == 0) 1910bfdc5970SChristoph Hellwig return iov; 1911bfdc5970SChristoph Hellwig if (nr_segs > UIO_MAXIOV) 1912bfdc5970SChristoph Hellwig return ERR_PTR(-EINVAL); 1913fb041b59SDavid Laight if (nr_segs > fast_segs) { 1914fb041b59SDavid Laight iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); 1915bfdc5970SChristoph Hellwig if (!iov) 1916bfdc5970SChristoph Hellwig return ERR_PTR(-ENOMEM); 1917fb041b59SDavid Laight } 1918bfdc5970SChristoph Hellwig 1919bfdc5970SChristoph Hellwig if (compat) 1920bfdc5970SChristoph Hellwig ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); 1921bfdc5970SChristoph Hellwig else 1922bfdc5970SChristoph Hellwig ret = copy_iovec_from_user(iov, uvec, nr_segs); 1923bfdc5970SChristoph Hellwig if (ret) { 1924bfdc5970SChristoph Hellwig if (iov != fast_iov) 1925bfdc5970SChristoph Hellwig kfree(iov); 1926bfdc5970SChristoph Hellwig return ERR_PTR(ret); 1927fb041b59SDavid Laight } 1928bfdc5970SChristoph Hellwig 1929bfdc5970SChristoph Hellwig return iov; 1930bfdc5970SChristoph Hellwig } 1931bfdc5970SChristoph Hellwig 1932bfdc5970SChristoph Hellwig ssize_t __import_iovec(int type, const struct iovec __user *uvec, 1933bfdc5970SChristoph Hellwig unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, 1934bfdc5970SChristoph Hellwig struct iov_iter *i, bool compat) 1935bfdc5970SChristoph Hellwig { 1936bfdc5970SChristoph Hellwig ssize_t total_len = 0; 1937bfdc5970SChristoph Hellwig unsigned long seg; 1938bfdc5970SChristoph Hellwig struct iovec *iov; 1939bfdc5970SChristoph Hellwig 1940bfdc5970SChristoph Hellwig iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); 1941bfdc5970SChristoph Hellwig if (IS_ERR(iov)) { 1942bfdc5970SChristoph Hellwig *iovp = NULL; 1943bfdc5970SChristoph Hellwig return PTR_ERR(iov); 1944fb041b59SDavid Laight } 1945fb041b59SDavid Laight 1946fb041b59SDavid Laight /* 1947bfdc5970SChristoph Hellwig * According to the Single Unix Specification we should return EINVAL if 1948bfdc5970SChristoph Hellwig * an element length is < 0 when cast to ssize_t or if the total length 1949bfdc5970SChristoph Hellwig * would overflow the ssize_t return value of the system call. 1950fb041b59SDavid Laight * 1951fb041b59SDavid Laight * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the 1952fb041b59SDavid Laight * overflow case. 1953fb041b59SDavid Laight */ 1954fb041b59SDavid Laight for (seg = 0; seg < nr_segs; seg++) { 1955fb041b59SDavid Laight ssize_t len = (ssize_t)iov[seg].iov_len; 1956fb041b59SDavid Laight 1957bfdc5970SChristoph Hellwig if (!access_ok(iov[seg].iov_base, len)) { 1958bfdc5970SChristoph Hellwig if (iov != *iovp) 1959bfdc5970SChristoph Hellwig kfree(iov); 1960bfdc5970SChristoph Hellwig *iovp = NULL; 1961bfdc5970SChristoph Hellwig return -EFAULT; 1962fb041b59SDavid Laight } 1963bfdc5970SChristoph Hellwig 1964bfdc5970SChristoph Hellwig if (len > MAX_RW_COUNT - total_len) { 1965bfdc5970SChristoph Hellwig len = MAX_RW_COUNT - total_len; 1966fb041b59SDavid Laight iov[seg].iov_len = len; 1967fb041b59SDavid Laight } 1968bfdc5970SChristoph Hellwig total_len += len; 1969fb041b59SDavid Laight } 1970bfdc5970SChristoph Hellwig 1971bfdc5970SChristoph Hellwig iov_iter_init(i, type, iov, nr_segs, total_len); 1972bfdc5970SChristoph Hellwig if (iov == *iovp) 1973bfdc5970SChristoph Hellwig *iovp = NULL; 1974bfdc5970SChristoph Hellwig else 1975bfdc5970SChristoph Hellwig *iovp = iov; 1976bfdc5970SChristoph Hellwig return total_len; 1977fb041b59SDavid Laight } 1978fb041b59SDavid Laight 1979ffecee4fSVegard Nossum /** 1980ffecee4fSVegard Nossum * import_iovec() - Copy an array of &struct iovec from userspace 1981ffecee4fSVegard Nossum * into the kernel, check that it is valid, and initialize a new 1982ffecee4fSVegard Nossum * &struct iov_iter iterator to access it. 1983ffecee4fSVegard Nossum * 1984ffecee4fSVegard Nossum * @type: One of %READ or %WRITE. 1985bfdc5970SChristoph Hellwig * @uvec: Pointer to the userspace array. 1986ffecee4fSVegard Nossum * @nr_segs: Number of elements in userspace array. 1987ffecee4fSVegard Nossum * @fast_segs: Number of elements in @iov. 1988bfdc5970SChristoph Hellwig * @iovp: (input and output parameter) Pointer to pointer to (usually small 1989ffecee4fSVegard Nossum * on-stack) kernel array. 1990ffecee4fSVegard Nossum * @i: Pointer to iterator that will be initialized on success. 1991ffecee4fSVegard Nossum * 1992ffecee4fSVegard Nossum * If the array pointed to by *@iov is large enough to hold all @nr_segs, 1993ffecee4fSVegard Nossum * then this function places %NULL in *@iov on return. Otherwise, a new 1994ffecee4fSVegard Nossum * array will be allocated and the result placed in *@iov. This means that 1995ffecee4fSVegard Nossum * the caller may call kfree() on *@iov regardless of whether the small 1996ffecee4fSVegard Nossum * on-stack array was used or not (and regardless of whether this function 1997ffecee4fSVegard Nossum * returns an error or not). 1998ffecee4fSVegard Nossum * 199987e5e6daSJens Axboe * Return: Negative error code on error, bytes imported on success 2000ffecee4fSVegard Nossum */ 2001bfdc5970SChristoph Hellwig ssize_t import_iovec(int type, const struct iovec __user *uvec, 2002bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 2003bfdc5970SChristoph Hellwig struct iovec **iovp, struct iov_iter *i) 2004bc917be8SAl Viro { 200589cd35c5SChristoph Hellwig return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, 200689cd35c5SChristoph Hellwig in_compat_syscall()); 2007bc917be8SAl Viro } 2008bc917be8SAl Viro EXPORT_SYMBOL(import_iovec); 2009bc917be8SAl Viro 2010bc917be8SAl Viro int import_single_range(int rw, void __user *buf, size_t len, 2011bc917be8SAl Viro struct iovec *iov, struct iov_iter *i) 2012bc917be8SAl Viro { 2013bc917be8SAl Viro if (len > MAX_RW_COUNT) 2014bc917be8SAl Viro len = MAX_RW_COUNT; 201596d4f267SLinus Torvalds if (unlikely(!access_ok(buf, len))) 2016bc917be8SAl Viro return -EFAULT; 2017bc917be8SAl Viro 2018bc917be8SAl Viro iov->iov_base = buf; 2019bc917be8SAl Viro iov->iov_len = len; 2020bc917be8SAl Viro iov_iter_init(i, rw, iov, 1, len); 2021bc917be8SAl Viro return 0; 2022bc917be8SAl Viro } 2023e1267585SAl Viro EXPORT_SYMBOL(import_single_range); 2024