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_and_advance(i, n, v, I, B, K, X) { \ 118dd254f5aSAl Viro if (unlikely(i->count < n)) \ 119dd254f5aSAl Viro n = i->count; \ 120*f5da8354SAl Viro if (likely(n)) { \ 121d879cb83SAl Viro size_t skip = i->iov_offset; \ 12228f38db7SAl Viro if (likely(iter_is_iovec(i))) { \ 123d879cb83SAl Viro const struct iovec *iov; \ 124d879cb83SAl Viro struct iovec v; \ 125d879cb83SAl Viro iterate_iovec(i, n, v, iov, skip, (I)) \ 126d879cb83SAl Viro if (skip == iov->iov_len) { \ 127d879cb83SAl Viro iov++; \ 128d879cb83SAl Viro skip = 0; \ 129d879cb83SAl Viro } \ 130d879cb83SAl Viro i->nr_segs -= iov - i->iov; \ 131d879cb83SAl Viro i->iov = iov; \ 13228f38db7SAl Viro } else if (iov_iter_is_bvec(i)) { \ 13328f38db7SAl Viro const struct bio_vec *bvec = i->bvec; \ 13428f38db7SAl Viro struct bio_vec v; \ 13528f38db7SAl Viro struct bvec_iter __bi; \ 13628f38db7SAl Viro iterate_bvec(i, n, v, __bi, skip, (B)) \ 13728f38db7SAl Viro i->bvec = __bvec_iter_bvec(i->bvec, __bi); \ 13828f38db7SAl Viro i->nr_segs -= i->bvec - bvec; \ 13928f38db7SAl Viro skip = __bi.bi_bvec_done; \ 14028f38db7SAl Viro } else if (iov_iter_is_kvec(i)) { \ 14128f38db7SAl Viro const struct kvec *kvec; \ 14228f38db7SAl Viro struct kvec v; \ 14328f38db7SAl Viro iterate_kvec(i, n, v, kvec, skip, (K)) \ 14428f38db7SAl Viro if (skip == kvec->iov_len) { \ 14528f38db7SAl Viro kvec++; \ 14628f38db7SAl Viro skip = 0; \ 14728f38db7SAl Viro } \ 14828f38db7SAl Viro i->nr_segs -= kvec - i->kvec; \ 14928f38db7SAl Viro i->kvec = kvec; \ 15028f38db7SAl Viro } else if (iov_iter_is_xarray(i)) { \ 15128f38db7SAl Viro struct bio_vec v; \ 15228f38db7SAl Viro iterate_xarray(i, n, v, skip, (X)) \ 153d879cb83SAl Viro } \ 154d879cb83SAl Viro i->count -= n; \ 155d879cb83SAl Viro i->iov_offset = skip; \ 156dd254f5aSAl Viro } \ 157d879cb83SAl Viro } 158d879cb83SAl Viro 15909fc68dcSAl Viro static int copyout(void __user *to, const void *from, size_t n) 16009fc68dcSAl Viro { 1614d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1624d0e9df5SAlbert van der Linde return n; 16396d4f267SLinus Torvalds if (access_ok(to, n)) { 164d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 16509fc68dcSAl Viro n = raw_copy_to_user(to, from, n); 16609fc68dcSAl Viro } 16709fc68dcSAl Viro return n; 16809fc68dcSAl Viro } 16909fc68dcSAl Viro 17009fc68dcSAl Viro static int copyin(void *to, const void __user *from, size_t n) 17109fc68dcSAl Viro { 1724d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1734d0e9df5SAlbert van der Linde return n; 17496d4f267SLinus Torvalds if (access_ok(from, n)) { 175d0ef4c36SMarco Elver instrument_copy_from_user(to, from, n); 17609fc68dcSAl Viro n = raw_copy_from_user(to, from, n); 17709fc68dcSAl Viro } 17809fc68dcSAl Viro return n; 17909fc68dcSAl Viro } 18009fc68dcSAl Viro 181d879cb83SAl Viro static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, 182d879cb83SAl Viro struct iov_iter *i) 183d879cb83SAl Viro { 184d879cb83SAl Viro size_t skip, copy, left, wanted; 185d879cb83SAl Viro const struct iovec *iov; 186d879cb83SAl Viro char __user *buf; 187d879cb83SAl Viro void *kaddr, *from; 188d879cb83SAl Viro 189d879cb83SAl Viro if (unlikely(bytes > i->count)) 190d879cb83SAl Viro bytes = i->count; 191d879cb83SAl Viro 192d879cb83SAl Viro if (unlikely(!bytes)) 193d879cb83SAl Viro return 0; 194d879cb83SAl Viro 19509fc68dcSAl Viro might_fault(); 196d879cb83SAl Viro wanted = bytes; 197d879cb83SAl Viro iov = i->iov; 198d879cb83SAl Viro skip = i->iov_offset; 199d879cb83SAl Viro buf = iov->iov_base + skip; 200d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 201d879cb83SAl Viro 2023fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { 203d879cb83SAl Viro kaddr = kmap_atomic(page); 204d879cb83SAl Viro from = kaddr + offset; 205d879cb83SAl Viro 206d879cb83SAl Viro /* first chunk, usually the only one */ 20709fc68dcSAl Viro left = copyout(buf, from, copy); 208d879cb83SAl Viro copy -= left; 209d879cb83SAl Viro skip += copy; 210d879cb83SAl Viro from += copy; 211d879cb83SAl Viro bytes -= copy; 212d879cb83SAl Viro 213d879cb83SAl Viro while (unlikely(!left && bytes)) { 214d879cb83SAl Viro iov++; 215d879cb83SAl Viro buf = iov->iov_base; 216d879cb83SAl Viro copy = min(bytes, iov->iov_len); 21709fc68dcSAl Viro left = copyout(buf, from, copy); 218d879cb83SAl Viro copy -= left; 219d879cb83SAl Viro skip = copy; 220d879cb83SAl Viro from += copy; 221d879cb83SAl Viro bytes -= copy; 222d879cb83SAl Viro } 223d879cb83SAl Viro if (likely(!bytes)) { 224d879cb83SAl Viro kunmap_atomic(kaddr); 225d879cb83SAl Viro goto done; 226d879cb83SAl Viro } 227d879cb83SAl Viro offset = from - kaddr; 228d879cb83SAl Viro buf += copy; 229d879cb83SAl Viro kunmap_atomic(kaddr); 230d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 231d879cb83SAl Viro } 232d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 2333fa6c507SMikulas Patocka 234d879cb83SAl Viro kaddr = kmap(page); 235d879cb83SAl Viro from = kaddr + offset; 23609fc68dcSAl Viro left = copyout(buf, from, copy); 237d879cb83SAl Viro copy -= left; 238d879cb83SAl Viro skip += copy; 239d879cb83SAl Viro from += copy; 240d879cb83SAl Viro bytes -= copy; 241d879cb83SAl Viro while (unlikely(!left && bytes)) { 242d879cb83SAl Viro iov++; 243d879cb83SAl Viro buf = iov->iov_base; 244d879cb83SAl Viro copy = min(bytes, iov->iov_len); 24509fc68dcSAl Viro left = copyout(buf, from, copy); 246d879cb83SAl Viro copy -= left; 247d879cb83SAl Viro skip = copy; 248d879cb83SAl Viro from += copy; 249d879cb83SAl Viro bytes -= copy; 250d879cb83SAl Viro } 251d879cb83SAl Viro kunmap(page); 2523fa6c507SMikulas Patocka 253d879cb83SAl Viro done: 254d879cb83SAl Viro if (skip == iov->iov_len) { 255d879cb83SAl Viro iov++; 256d879cb83SAl Viro skip = 0; 257d879cb83SAl Viro } 258d879cb83SAl Viro i->count -= wanted - bytes; 259d879cb83SAl Viro i->nr_segs -= iov - i->iov; 260d879cb83SAl Viro i->iov = iov; 261d879cb83SAl Viro i->iov_offset = skip; 262d879cb83SAl Viro return wanted - bytes; 263d879cb83SAl Viro } 264d879cb83SAl Viro 265d879cb83SAl Viro static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, 266d879cb83SAl Viro struct iov_iter *i) 267d879cb83SAl Viro { 268d879cb83SAl Viro size_t skip, copy, left, wanted; 269d879cb83SAl Viro const struct iovec *iov; 270d879cb83SAl Viro char __user *buf; 271d879cb83SAl Viro void *kaddr, *to; 272d879cb83SAl Viro 273d879cb83SAl Viro if (unlikely(bytes > i->count)) 274d879cb83SAl Viro bytes = i->count; 275d879cb83SAl Viro 276d879cb83SAl Viro if (unlikely(!bytes)) 277d879cb83SAl Viro return 0; 278d879cb83SAl Viro 27909fc68dcSAl Viro might_fault(); 280d879cb83SAl Viro wanted = bytes; 281d879cb83SAl Viro iov = i->iov; 282d879cb83SAl Viro skip = i->iov_offset; 283d879cb83SAl Viro buf = iov->iov_base + skip; 284d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 285d879cb83SAl Viro 2863fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { 287d879cb83SAl Viro kaddr = kmap_atomic(page); 288d879cb83SAl Viro to = kaddr + offset; 289d879cb83SAl Viro 290d879cb83SAl Viro /* first chunk, usually the only one */ 29109fc68dcSAl Viro left = copyin(to, buf, copy); 292d879cb83SAl Viro copy -= left; 293d879cb83SAl Viro skip += copy; 294d879cb83SAl Viro to += copy; 295d879cb83SAl Viro bytes -= copy; 296d879cb83SAl Viro 297d879cb83SAl Viro while (unlikely(!left && bytes)) { 298d879cb83SAl Viro iov++; 299d879cb83SAl Viro buf = iov->iov_base; 300d879cb83SAl Viro copy = min(bytes, iov->iov_len); 30109fc68dcSAl Viro left = copyin(to, buf, copy); 302d879cb83SAl Viro copy -= left; 303d879cb83SAl Viro skip = copy; 304d879cb83SAl Viro to += copy; 305d879cb83SAl Viro bytes -= copy; 306d879cb83SAl Viro } 307d879cb83SAl Viro if (likely(!bytes)) { 308d879cb83SAl Viro kunmap_atomic(kaddr); 309d879cb83SAl Viro goto done; 310d879cb83SAl Viro } 311d879cb83SAl Viro offset = to - kaddr; 312d879cb83SAl Viro buf += copy; 313d879cb83SAl Viro kunmap_atomic(kaddr); 314d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 315d879cb83SAl Viro } 316d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 3173fa6c507SMikulas Patocka 318d879cb83SAl Viro kaddr = kmap(page); 319d879cb83SAl Viro to = kaddr + offset; 32009fc68dcSAl Viro left = copyin(to, buf, copy); 321d879cb83SAl Viro copy -= left; 322d879cb83SAl Viro skip += copy; 323d879cb83SAl Viro to += copy; 324d879cb83SAl Viro bytes -= copy; 325d879cb83SAl Viro while (unlikely(!left && bytes)) { 326d879cb83SAl Viro iov++; 327d879cb83SAl Viro buf = iov->iov_base; 328d879cb83SAl Viro copy = min(bytes, iov->iov_len); 32909fc68dcSAl Viro left = copyin(to, buf, copy); 330d879cb83SAl Viro copy -= left; 331d879cb83SAl Viro skip = copy; 332d879cb83SAl Viro to += copy; 333d879cb83SAl Viro bytes -= copy; 334d879cb83SAl Viro } 335d879cb83SAl Viro kunmap(page); 3363fa6c507SMikulas Patocka 337d879cb83SAl Viro done: 338d879cb83SAl Viro if (skip == iov->iov_len) { 339d879cb83SAl Viro iov++; 340d879cb83SAl Viro skip = 0; 341d879cb83SAl Viro } 342d879cb83SAl Viro i->count -= wanted - bytes; 343d879cb83SAl Viro i->nr_segs -= iov - i->iov; 344d879cb83SAl Viro i->iov = iov; 345d879cb83SAl Viro i->iov_offset = skip; 346d879cb83SAl Viro return wanted - bytes; 347d879cb83SAl Viro } 348d879cb83SAl Viro 349241699cdSAl Viro #ifdef PIPE_PARANOIA 350241699cdSAl Viro static bool sanity(const struct iov_iter *i) 351241699cdSAl Viro { 352241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 3538cefc107SDavid Howells unsigned int p_head = pipe->head; 3548cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3558cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3568cefc107SDavid Howells unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); 3578cefc107SDavid Howells unsigned int i_head = i->head; 3588cefc107SDavid Howells unsigned int idx; 3598cefc107SDavid Howells 360241699cdSAl Viro if (i->iov_offset) { 361241699cdSAl Viro struct pipe_buffer *p; 3628cefc107SDavid Howells if (unlikely(p_occupancy == 0)) 363241699cdSAl Viro goto Bad; // pipe must be non-empty 3648cefc107SDavid Howells if (unlikely(i_head != p_head - 1)) 365241699cdSAl Viro goto Bad; // must be at the last buffer... 366241699cdSAl Viro 3678cefc107SDavid Howells p = &pipe->bufs[i_head & p_mask]; 368241699cdSAl Viro if (unlikely(p->offset + p->len != i->iov_offset)) 369241699cdSAl Viro goto Bad; // ... at the end of segment 370241699cdSAl Viro } else { 3718cefc107SDavid Howells if (i_head != p_head) 372241699cdSAl Viro goto Bad; // must be right after the last buffer 373241699cdSAl Viro } 374241699cdSAl Viro return true; 375241699cdSAl Viro Bad: 3768cefc107SDavid Howells printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); 3778cefc107SDavid Howells printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", 3788cefc107SDavid Howells p_head, p_tail, pipe->ring_size); 3798cefc107SDavid Howells for (idx = 0; idx < pipe->ring_size; idx++) 380241699cdSAl Viro printk(KERN_ERR "[%p %p %d %d]\n", 381241699cdSAl Viro pipe->bufs[idx].ops, 382241699cdSAl Viro pipe->bufs[idx].page, 383241699cdSAl Viro pipe->bufs[idx].offset, 384241699cdSAl Viro pipe->bufs[idx].len); 385241699cdSAl Viro WARN_ON(1); 386241699cdSAl Viro return false; 387241699cdSAl Viro } 388241699cdSAl Viro #else 389241699cdSAl Viro #define sanity(i) true 390241699cdSAl Viro #endif 391241699cdSAl Viro 392241699cdSAl Viro static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, 393241699cdSAl Viro struct iov_iter *i) 394241699cdSAl Viro { 395241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 396241699cdSAl Viro struct pipe_buffer *buf; 3978cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3988cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3998cefc107SDavid Howells unsigned int i_head = i->head; 400241699cdSAl Viro size_t off; 401241699cdSAl Viro 402241699cdSAl Viro if (unlikely(bytes > i->count)) 403241699cdSAl Viro bytes = i->count; 404241699cdSAl Viro 405241699cdSAl Viro if (unlikely(!bytes)) 406241699cdSAl Viro return 0; 407241699cdSAl Viro 408241699cdSAl Viro if (!sanity(i)) 409241699cdSAl Viro return 0; 410241699cdSAl Viro 411241699cdSAl Viro off = i->iov_offset; 4128cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 413241699cdSAl Viro if (off) { 414241699cdSAl Viro if (offset == off && buf->page == page) { 415241699cdSAl Viro /* merge with the last one */ 416241699cdSAl Viro buf->len += bytes; 417241699cdSAl Viro i->iov_offset += bytes; 418241699cdSAl Viro goto out; 419241699cdSAl Viro } 4208cefc107SDavid Howells i_head++; 4218cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 422241699cdSAl Viro } 4236718b6f8SDavid Howells if (pipe_full(i_head, p_tail, pipe->max_usage)) 424241699cdSAl Viro return 0; 4258cefc107SDavid Howells 426241699cdSAl Viro buf->ops = &page_cache_pipe_buf_ops; 4278cefc107SDavid Howells get_page(page); 4288cefc107SDavid Howells buf->page = page; 429241699cdSAl Viro buf->offset = offset; 430241699cdSAl Viro buf->len = bytes; 4318cefc107SDavid Howells 4328cefc107SDavid Howells pipe->head = i_head + 1; 433241699cdSAl Viro i->iov_offset = offset + bytes; 4348cefc107SDavid Howells i->head = i_head; 435241699cdSAl Viro out: 436241699cdSAl Viro i->count -= bytes; 437241699cdSAl Viro return bytes; 438241699cdSAl Viro } 439241699cdSAl Viro 440d879cb83SAl Viro /* 441171a0203SAnton Altaparmakov * Fault in one or more iovecs of the given iov_iter, to a maximum length of 442171a0203SAnton Altaparmakov * bytes. For each iovec, fault in each page that constitutes the iovec. 443171a0203SAnton Altaparmakov * 444171a0203SAnton Altaparmakov * Return 0 on success, or non-zero if the memory could not be accessed (i.e. 445171a0203SAnton Altaparmakov * because it is an invalid address). 446171a0203SAnton Altaparmakov */ 4478409a0d2SAl Viro int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes) 448171a0203SAnton Altaparmakov { 4490e8f0d67SAl Viro if (iter_is_iovec(i)) { 4508409a0d2SAl Viro const struct iovec *p; 4518409a0d2SAl Viro size_t skip; 4528409a0d2SAl Viro 4538409a0d2SAl Viro if (bytes > i->count) 4548409a0d2SAl Viro bytes = i->count; 4558409a0d2SAl Viro for (p = i->iov, skip = i->iov_offset; bytes; p++, skip = 0) { 4568409a0d2SAl Viro size_t len = min(bytes, p->iov_len - skip); 4578409a0d2SAl Viro int err; 4588409a0d2SAl Viro 4598409a0d2SAl Viro if (unlikely(!len)) 4608409a0d2SAl Viro continue; 4618409a0d2SAl Viro err = fault_in_pages_readable(p->iov_base + skip, len); 462171a0203SAnton Altaparmakov if (unlikely(err)) 463171a0203SAnton Altaparmakov return err; 4648409a0d2SAl Viro bytes -= len; 4658409a0d2SAl Viro } 466171a0203SAnton Altaparmakov } 467171a0203SAnton Altaparmakov return 0; 468171a0203SAnton Altaparmakov } 469d4690f1eSAl Viro EXPORT_SYMBOL(iov_iter_fault_in_readable); 470171a0203SAnton Altaparmakov 471aa563d7bSDavid Howells void iov_iter_init(struct iov_iter *i, unsigned int direction, 472d879cb83SAl Viro const struct iovec *iov, unsigned long nr_segs, 473d879cb83SAl Viro size_t count) 474d879cb83SAl Viro { 475aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 4768cd54c1cSAl Viro WARN_ON_ONCE(uaccess_kernel()); 4778cd54c1cSAl Viro *i = (struct iov_iter) { 4788cd54c1cSAl Viro .iter_type = ITER_IOVEC, 4798cd54c1cSAl Viro .data_source = direction, 4808cd54c1cSAl Viro .iov = iov, 4818cd54c1cSAl Viro .nr_segs = nr_segs, 4828cd54c1cSAl Viro .iov_offset = 0, 4838cd54c1cSAl Viro .count = count 4848cd54c1cSAl Viro }; 485d879cb83SAl Viro } 486d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_init); 487d879cb83SAl Viro 488241699cdSAl Viro static inline bool allocated(struct pipe_buffer *buf) 489241699cdSAl Viro { 490241699cdSAl Viro return buf->ops == &default_pipe_buf_ops; 491241699cdSAl Viro } 492241699cdSAl Viro 4938cefc107SDavid Howells static inline void data_start(const struct iov_iter *i, 4948cefc107SDavid Howells unsigned int *iter_headp, size_t *offp) 495241699cdSAl Viro { 4968cefc107SDavid Howells unsigned int p_mask = i->pipe->ring_size - 1; 4978cefc107SDavid Howells unsigned int iter_head = i->head; 498241699cdSAl Viro size_t off = i->iov_offset; 4998cefc107SDavid Howells 5008cefc107SDavid Howells if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || 5018cefc107SDavid Howells off == PAGE_SIZE)) { 5028cefc107SDavid Howells iter_head++; 503241699cdSAl Viro off = 0; 504241699cdSAl Viro } 5058cefc107SDavid Howells *iter_headp = iter_head; 506241699cdSAl Viro *offp = off; 507241699cdSAl Viro } 508241699cdSAl Viro 509241699cdSAl Viro static size_t push_pipe(struct iov_iter *i, size_t size, 5108cefc107SDavid Howells int *iter_headp, size_t *offp) 511241699cdSAl Viro { 512241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5138cefc107SDavid Howells unsigned int p_tail = pipe->tail; 5148cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5158cefc107SDavid Howells unsigned int iter_head; 516241699cdSAl Viro size_t off; 517241699cdSAl Viro ssize_t left; 518241699cdSAl Viro 519241699cdSAl Viro if (unlikely(size > i->count)) 520241699cdSAl Viro size = i->count; 521241699cdSAl Viro if (unlikely(!size)) 522241699cdSAl Viro return 0; 523241699cdSAl Viro 524241699cdSAl Viro left = size; 5258cefc107SDavid Howells data_start(i, &iter_head, &off); 5268cefc107SDavid Howells *iter_headp = iter_head; 527241699cdSAl Viro *offp = off; 528241699cdSAl Viro if (off) { 529241699cdSAl Viro left -= PAGE_SIZE - off; 530241699cdSAl Viro if (left <= 0) { 5318cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len += size; 532241699cdSAl Viro return size; 533241699cdSAl Viro } 5348cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; 5358cefc107SDavid Howells iter_head++; 536241699cdSAl Viro } 5376718b6f8SDavid Howells while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { 5388cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; 539241699cdSAl Viro struct page *page = alloc_page(GFP_USER); 540241699cdSAl Viro if (!page) 541241699cdSAl Viro break; 5428cefc107SDavid Howells 5438cefc107SDavid Howells buf->ops = &default_pipe_buf_ops; 5448cefc107SDavid Howells buf->page = page; 5458cefc107SDavid Howells buf->offset = 0; 5468cefc107SDavid Howells buf->len = min_t(ssize_t, left, PAGE_SIZE); 5478cefc107SDavid Howells left -= buf->len; 5488cefc107SDavid Howells iter_head++; 5498cefc107SDavid Howells pipe->head = iter_head; 5508cefc107SDavid Howells 5518cefc107SDavid Howells if (left == 0) 552241699cdSAl Viro return size; 553241699cdSAl Viro } 554241699cdSAl Viro return size - left; 555241699cdSAl Viro } 556241699cdSAl Viro 557241699cdSAl Viro static size_t copy_pipe_to_iter(const void *addr, size_t bytes, 558241699cdSAl Viro struct iov_iter *i) 559241699cdSAl Viro { 560241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5618cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5628cefc107SDavid Howells unsigned int i_head; 563241699cdSAl Viro size_t n, off; 564241699cdSAl Viro 565241699cdSAl Viro if (!sanity(i)) 566241699cdSAl Viro return 0; 567241699cdSAl Viro 5688cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 569241699cdSAl Viro if (unlikely(!n)) 570241699cdSAl Viro return 0; 5718cefc107SDavid Howells do { 572241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 5738cefc107SDavid Howells memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); 5748cefc107SDavid Howells i->head = i_head; 575241699cdSAl Viro i->iov_offset = off + chunk; 576241699cdSAl Viro n -= chunk; 577241699cdSAl Viro addr += chunk; 5788cefc107SDavid Howells off = 0; 5798cefc107SDavid Howells i_head++; 5808cefc107SDavid Howells } while (n); 581241699cdSAl Viro i->count -= bytes; 582241699cdSAl Viro return bytes; 583241699cdSAl Viro } 584241699cdSAl Viro 585f9152895SAl Viro static __wsum csum_and_memcpy(void *to, const void *from, size_t len, 586f9152895SAl Viro __wsum sum, size_t off) 587f9152895SAl Viro { 588cc44c17bSAl Viro __wsum next = csum_partial_copy_nocheck(from, to, len); 589f9152895SAl Viro return csum_block_add(sum, next, off); 590f9152895SAl Viro } 591f9152895SAl Viro 59278e1f386SAl Viro static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, 59352cbd23aSWillem de Bruijn struct csum_state *csstate, 59452cbd23aSWillem de Bruijn struct iov_iter *i) 59578e1f386SAl Viro { 59678e1f386SAl Viro struct pipe_inode_info *pipe = i->pipe; 5978cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 59852cbd23aSWillem de Bruijn __wsum sum = csstate->csum; 59952cbd23aSWillem de Bruijn size_t off = csstate->off; 6008cefc107SDavid Howells unsigned int i_head; 60178e1f386SAl Viro size_t n, r; 60278e1f386SAl Viro 60378e1f386SAl Viro if (!sanity(i)) 60478e1f386SAl Viro return 0; 60578e1f386SAl Viro 6068cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &r); 60778e1f386SAl Viro if (unlikely(!n)) 60878e1f386SAl Viro return 0; 6098cefc107SDavid Howells do { 61078e1f386SAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - r); 6118cefc107SDavid Howells char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); 612f9152895SAl Viro sum = csum_and_memcpy(p + r, addr, chunk, sum, off); 61378e1f386SAl Viro kunmap_atomic(p); 6148cefc107SDavid Howells i->head = i_head; 61578e1f386SAl Viro i->iov_offset = r + chunk; 61678e1f386SAl Viro n -= chunk; 61778e1f386SAl Viro off += chunk; 61878e1f386SAl Viro addr += chunk; 6198cefc107SDavid Howells r = 0; 6208cefc107SDavid Howells i_head++; 6218cefc107SDavid Howells } while (n); 62278e1f386SAl Viro i->count -= bytes; 62352cbd23aSWillem de Bruijn csstate->csum = sum; 62452cbd23aSWillem de Bruijn csstate->off = off; 62578e1f386SAl Viro return bytes; 62678e1f386SAl Viro } 62778e1f386SAl Viro 628aa28de27SAl Viro size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 629d879cb83SAl Viro { 63036f7a8a4SAl Viro const char *from = addr; 63100e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 632241699cdSAl Viro return copy_pipe_to_iter(addr, bytes, i); 63309fc68dcSAl Viro if (iter_is_iovec(i)) 63409fc68dcSAl Viro might_fault(); 635d879cb83SAl Viro iterate_and_advance(i, bytes, v, 63609fc68dcSAl Viro copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 637d879cb83SAl Viro memcpy_to_page(v.bv_page, v.bv_offset, 638d879cb83SAl Viro (from += v.bv_len) - v.bv_len, v.bv_len), 6397ff50620SDavid Howells memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 6407ff50620SDavid Howells memcpy_to_page(v.bv_page, v.bv_offset, 6417ff50620SDavid Howells (from += v.bv_len) - v.bv_len, v.bv_len) 642d879cb83SAl Viro ) 643d879cb83SAl Viro 644d879cb83SAl Viro return bytes; 645d879cb83SAl Viro } 646aa28de27SAl Viro EXPORT_SYMBOL(_copy_to_iter); 647d879cb83SAl Viro 648ec6347bbSDan Williams #ifdef CONFIG_ARCH_HAS_COPY_MC 649ec6347bbSDan Williams static int copyout_mc(void __user *to, const void *from, size_t n) 6508780356eSDan Williams { 65196d4f267SLinus Torvalds if (access_ok(to, n)) { 652d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 653ec6347bbSDan Williams n = copy_mc_to_user((__force void *) to, from, n); 6548780356eSDan Williams } 6558780356eSDan Williams return n; 6568780356eSDan Williams } 6578780356eSDan Williams 658ec6347bbSDan Williams static unsigned long copy_mc_to_page(struct page *page, size_t offset, 6598780356eSDan Williams const char *from, size_t len) 6608780356eSDan Williams { 6618780356eSDan Williams unsigned long ret; 6628780356eSDan Williams char *to; 6638780356eSDan Williams 6648780356eSDan Williams to = kmap_atomic(page); 665ec6347bbSDan Williams ret = copy_mc_to_kernel(to + offset, from, len); 6668780356eSDan Williams kunmap_atomic(to); 6678780356eSDan Williams 6688780356eSDan Williams return ret; 6698780356eSDan Williams } 6708780356eSDan Williams 671ec6347bbSDan Williams static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, 672ca146f6fSDan Williams struct iov_iter *i) 673ca146f6fSDan Williams { 674ca146f6fSDan Williams struct pipe_inode_info *pipe = i->pipe; 6758cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 6768cefc107SDavid Howells unsigned int i_head; 677ca146f6fSDan Williams size_t n, off, xfer = 0; 678ca146f6fSDan Williams 679ca146f6fSDan Williams if (!sanity(i)) 680ca146f6fSDan Williams return 0; 681ca146f6fSDan Williams 6828cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 683ca146f6fSDan Williams if (unlikely(!n)) 684ca146f6fSDan Williams return 0; 6858cefc107SDavid Howells do { 686ca146f6fSDan Williams size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 687ca146f6fSDan Williams unsigned long rem; 688ca146f6fSDan Williams 689ec6347bbSDan Williams rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, 6908cefc107SDavid Howells off, addr, chunk); 6918cefc107SDavid Howells i->head = i_head; 692ca146f6fSDan Williams i->iov_offset = off + chunk - rem; 693ca146f6fSDan Williams xfer += chunk - rem; 694ca146f6fSDan Williams if (rem) 695ca146f6fSDan Williams break; 696ca146f6fSDan Williams n -= chunk; 697ca146f6fSDan Williams addr += chunk; 6988cefc107SDavid Howells off = 0; 6998cefc107SDavid Howells i_head++; 7008cefc107SDavid Howells } while (n); 701ca146f6fSDan Williams i->count -= xfer; 702ca146f6fSDan Williams return xfer; 703ca146f6fSDan Williams } 704ca146f6fSDan Williams 705bf3eeb9bSDan Williams /** 706ec6347bbSDan Williams * _copy_mc_to_iter - copy to iter with source memory error exception handling 707bf3eeb9bSDan Williams * @addr: source kernel address 708bf3eeb9bSDan Williams * @bytes: total transfer length 709bf3eeb9bSDan Williams * @iter: destination iterator 710bf3eeb9bSDan Williams * 711ec6347bbSDan Williams * The pmem driver deploys this for the dax operation 712ec6347bbSDan Williams * (dax_copy_to_iter()) for dax reads (bypass page-cache and the 713ec6347bbSDan Williams * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes 714ec6347bbSDan Williams * successfully copied. 715bf3eeb9bSDan Williams * 716ec6347bbSDan Williams * The main differences between this and typical _copy_to_iter(). 717bf3eeb9bSDan Williams * 718bf3eeb9bSDan Williams * * Typical tail/residue handling after a fault retries the copy 719bf3eeb9bSDan Williams * byte-by-byte until the fault happens again. Re-triggering machine 720bf3eeb9bSDan Williams * checks is potentially fatal so the implementation uses source 721bf3eeb9bSDan Williams * alignment and poison alignment assumptions to avoid re-triggering 722bf3eeb9bSDan Williams * hardware exceptions. 723bf3eeb9bSDan Williams * 724bf3eeb9bSDan Williams * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. 725bf3eeb9bSDan Williams * Compare to copy_to_iter() where only ITER_IOVEC attempts might return 726bf3eeb9bSDan Williams * a short copy. 727bf3eeb9bSDan Williams */ 728ec6347bbSDan Williams size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 7298780356eSDan Williams { 7308780356eSDan Williams const char *from = addr; 7318780356eSDan Williams unsigned long rem, curr_addr, s_addr = (unsigned long) addr; 7328780356eSDan Williams 73300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 734ec6347bbSDan Williams return copy_mc_pipe_to_iter(addr, bytes, i); 7358780356eSDan Williams if (iter_is_iovec(i)) 7368780356eSDan Williams might_fault(); 7378780356eSDan Williams iterate_and_advance(i, bytes, v, 738ec6347bbSDan Williams copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len, 739ec6347bbSDan Williams v.iov_len), 7408780356eSDan Williams ({ 741ec6347bbSDan Williams rem = copy_mc_to_page(v.bv_page, v.bv_offset, 7428780356eSDan Williams (from += v.bv_len) - v.bv_len, v.bv_len); 7438780356eSDan Williams if (rem) { 7448780356eSDan Williams curr_addr = (unsigned long) from; 7458780356eSDan Williams bytes = curr_addr - s_addr - rem; 7468780356eSDan Williams return bytes; 7478780356eSDan Williams } 7488780356eSDan Williams }), 7498780356eSDan Williams ({ 750ec6347bbSDan Williams rem = copy_mc_to_kernel(v.iov_base, (from += v.iov_len) 751ec6347bbSDan Williams - v.iov_len, v.iov_len); 7528780356eSDan Williams if (rem) { 7538780356eSDan Williams curr_addr = (unsigned long) from; 7548780356eSDan Williams bytes = curr_addr - s_addr - rem; 7558780356eSDan Williams return bytes; 7568780356eSDan Williams } 7577ff50620SDavid Howells }), 7587ff50620SDavid Howells ({ 7597ff50620SDavid Howells rem = copy_mc_to_page(v.bv_page, v.bv_offset, 7607ff50620SDavid Howells (from += v.bv_len) - v.bv_len, v.bv_len); 7617ff50620SDavid Howells if (rem) { 7627ff50620SDavid Howells curr_addr = (unsigned long) from; 7637ff50620SDavid Howells bytes = curr_addr - s_addr - rem; 7647ff50620SDavid Howells rcu_read_unlock(); 7653d14ec1fSDavid Howells i->iov_offset += bytes; 7663d14ec1fSDavid Howells i->count -= bytes; 7677ff50620SDavid Howells return bytes; 7687ff50620SDavid Howells } 7698780356eSDan Williams }) 7708780356eSDan Williams ) 7718780356eSDan Williams 7728780356eSDan Williams return bytes; 7738780356eSDan Williams } 774ec6347bbSDan Williams EXPORT_SYMBOL_GPL(_copy_mc_to_iter); 775ec6347bbSDan Williams #endif /* CONFIG_ARCH_HAS_COPY_MC */ 7768780356eSDan Williams 777aa28de27SAl Viro size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) 778d879cb83SAl Viro { 779d879cb83SAl Viro char *to = addr; 78000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 781241699cdSAl Viro WARN_ON(1); 782241699cdSAl Viro return 0; 783241699cdSAl Viro } 78409fc68dcSAl Viro if (iter_is_iovec(i)) 78509fc68dcSAl Viro might_fault(); 786d879cb83SAl Viro iterate_and_advance(i, bytes, v, 78709fc68dcSAl Viro copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 788d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 789d879cb83SAl Viro v.bv_offset, v.bv_len), 7907ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 7917ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 7927ff50620SDavid Howells v.bv_offset, v.bv_len) 793d879cb83SAl Viro ) 794d879cb83SAl Viro 795d879cb83SAl Viro return bytes; 796d879cb83SAl Viro } 797aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter); 798d879cb83SAl Viro 799aa28de27SAl Viro size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) 800d879cb83SAl Viro { 801d879cb83SAl Viro char *to = addr; 80200e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 803241699cdSAl Viro WARN_ON(1); 804241699cdSAl Viro return 0; 805241699cdSAl Viro } 806d879cb83SAl Viro iterate_and_advance(i, bytes, v, 8073f763453SAl Viro __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, 808d879cb83SAl Viro v.iov_base, v.iov_len), 809d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 810d879cb83SAl Viro v.bv_offset, v.bv_len), 8117ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 8127ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 8137ff50620SDavid Howells v.bv_offset, v.bv_len) 814d879cb83SAl Viro ) 815d879cb83SAl Viro 816d879cb83SAl Viro return bytes; 817d879cb83SAl Viro } 818aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_nocache); 819d879cb83SAl Viro 8200aed55afSDan Williams #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE 821abd08d7dSDan Williams /** 822abd08d7dSDan Williams * _copy_from_iter_flushcache - write destination through cpu cache 823abd08d7dSDan Williams * @addr: destination kernel address 824abd08d7dSDan Williams * @bytes: total transfer length 825abd08d7dSDan Williams * @iter: source iterator 826abd08d7dSDan Williams * 827abd08d7dSDan Williams * The pmem driver arranges for filesystem-dax to use this facility via 828abd08d7dSDan Williams * dax_copy_from_iter() for ensuring that writes to persistent memory 829abd08d7dSDan Williams * are flushed through the CPU cache. It is differentiated from 830abd08d7dSDan Williams * _copy_from_iter_nocache() in that guarantees all data is flushed for 831abd08d7dSDan Williams * all iterator types. The _copy_from_iter_nocache() only attempts to 832abd08d7dSDan Williams * bypass the cache for the ITER_IOVEC case, and on some archs may use 833abd08d7dSDan Williams * instructions that strand dirty-data in the cache. 834abd08d7dSDan Williams */ 8356a37e940SLinus Torvalds size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 8360aed55afSDan Williams { 8370aed55afSDan Williams char *to = addr; 83800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 8390aed55afSDan Williams WARN_ON(1); 8400aed55afSDan Williams return 0; 8410aed55afSDan Williams } 8420aed55afSDan Williams iterate_and_advance(i, bytes, v, 8430aed55afSDan Williams __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, 8440aed55afSDan Williams v.iov_base, v.iov_len), 8450aed55afSDan Williams memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 8460aed55afSDan Williams v.bv_offset, v.bv_len), 8470aed55afSDan Williams memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, 8487ff50620SDavid Howells v.iov_len), 8497ff50620SDavid Howells memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 8507ff50620SDavid Howells v.bv_offset, v.bv_len) 8510aed55afSDan Williams ) 8520aed55afSDan Williams 8530aed55afSDan Williams return bytes; 8540aed55afSDan Williams } 8556a37e940SLinus Torvalds EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); 8560aed55afSDan Williams #endif 8570aed55afSDan Williams 85872e809edSAl Viro static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) 85972e809edSAl Viro { 8606daef95bSEric Dumazet struct page *head; 8616daef95bSEric Dumazet size_t v = n + offset; 8626daef95bSEric Dumazet 8636daef95bSEric Dumazet /* 8646daef95bSEric Dumazet * The general case needs to access the page order in order 8656daef95bSEric Dumazet * to compute the page size. 8666daef95bSEric Dumazet * However, we mostly deal with order-0 pages and thus can 8676daef95bSEric Dumazet * avoid a possible cache line miss for requests that fit all 8686daef95bSEric Dumazet * page orders. 8696daef95bSEric Dumazet */ 8706daef95bSEric Dumazet if (n <= v && v <= PAGE_SIZE) 8716daef95bSEric Dumazet return true; 8726daef95bSEric Dumazet 8736daef95bSEric Dumazet head = compound_head(page); 8746daef95bSEric Dumazet v += (page - head) << PAGE_SHIFT; 875a90bcb86SPetar Penkov 876a50b854eSMatthew Wilcox (Oracle) if (likely(n <= v && v <= (page_size(head)))) 87772e809edSAl Viro return true; 87872e809edSAl Viro WARN_ON(1); 87972e809edSAl Viro return false; 88072e809edSAl Viro } 881cbbd26b8SAl Viro 88208aa6479SAl Viro static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 883d879cb83SAl Viro struct iov_iter *i) 884d879cb83SAl Viro { 88528f38db7SAl Viro if (likely(iter_is_iovec(i))) 88628f38db7SAl Viro return copy_page_to_iter_iovec(page, offset, bytes, i); 88728f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 888d879cb83SAl Viro void *kaddr = kmap_atomic(page); 889d879cb83SAl Viro size_t wanted = copy_to_iter(kaddr + offset, bytes, i); 890d879cb83SAl Viro kunmap_atomic(kaddr); 891d879cb83SAl Viro return wanted; 89228f38db7SAl Viro } 89328f38db7SAl Viro if (iov_iter_is_pipe(i)) 89428f38db7SAl Viro return copy_page_to_iter_pipe(page, offset, bytes, i); 89528f38db7SAl Viro if (unlikely(iov_iter_is_discard(i))) { 896a506abc7SAl Viro if (unlikely(i->count < bytes)) 897a506abc7SAl Viro bytes = i->count; 898a506abc7SAl Viro i->count -= bytes; 8999ea9ce04SDavid Howells return bytes; 90028f38db7SAl Viro } 90128f38db7SAl Viro WARN_ON(1); 90228f38db7SAl Viro return 0; 903d879cb83SAl Viro } 90408aa6479SAl Viro 90508aa6479SAl Viro size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 90608aa6479SAl Viro struct iov_iter *i) 90708aa6479SAl Viro { 90808aa6479SAl Viro size_t res = 0; 90908aa6479SAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 91008aa6479SAl Viro return 0; 91108aa6479SAl Viro page += offset / PAGE_SIZE; // first subpage 91208aa6479SAl Viro offset %= PAGE_SIZE; 91308aa6479SAl Viro while (1) { 91408aa6479SAl Viro size_t n = __copy_page_to_iter(page, offset, 91508aa6479SAl Viro min(bytes, (size_t)PAGE_SIZE - offset), i); 91608aa6479SAl Viro res += n; 91708aa6479SAl Viro bytes -= n; 91808aa6479SAl Viro if (!bytes || !n) 91908aa6479SAl Viro break; 92008aa6479SAl Viro offset += n; 92108aa6479SAl Viro if (offset == PAGE_SIZE) { 92208aa6479SAl Viro page++; 92308aa6479SAl Viro offset = 0; 92408aa6479SAl Viro } 92508aa6479SAl Viro } 92608aa6479SAl Viro return res; 92708aa6479SAl Viro } 928d879cb83SAl Viro EXPORT_SYMBOL(copy_page_to_iter); 929d879cb83SAl Viro 930d879cb83SAl Viro size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, 931d879cb83SAl Viro struct iov_iter *i) 932d879cb83SAl Viro { 93372e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 93472e809edSAl Viro return 0; 93528f38db7SAl Viro if (likely(iter_is_iovec(i))) 93628f38db7SAl Viro return copy_page_from_iter_iovec(page, offset, bytes, i); 93728f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 938d879cb83SAl Viro void *kaddr = kmap_atomic(page); 939aa28de27SAl Viro size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); 940d879cb83SAl Viro kunmap_atomic(kaddr); 941d879cb83SAl Viro return wanted; 94228f38db7SAl Viro } 94328f38db7SAl Viro WARN_ON(1); 94428f38db7SAl Viro return 0; 945d879cb83SAl Viro } 946d879cb83SAl Viro EXPORT_SYMBOL(copy_page_from_iter); 947d879cb83SAl Viro 948241699cdSAl Viro static size_t pipe_zero(size_t bytes, struct iov_iter *i) 949241699cdSAl Viro { 950241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 9518cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9528cefc107SDavid Howells unsigned int i_head; 953241699cdSAl Viro size_t n, off; 954241699cdSAl Viro 955241699cdSAl Viro if (!sanity(i)) 956241699cdSAl Viro return 0; 957241699cdSAl Viro 9588cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 959241699cdSAl Viro if (unlikely(!n)) 960241699cdSAl Viro return 0; 961241699cdSAl Viro 9628cefc107SDavid Howells do { 963241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 9648cefc107SDavid Howells memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); 9658cefc107SDavid Howells i->head = i_head; 966241699cdSAl Viro i->iov_offset = off + chunk; 967241699cdSAl Viro n -= chunk; 9688cefc107SDavid Howells off = 0; 9698cefc107SDavid Howells i_head++; 9708cefc107SDavid Howells } while (n); 971241699cdSAl Viro i->count -= bytes; 972241699cdSAl Viro return bytes; 973241699cdSAl Viro } 974241699cdSAl Viro 975d879cb83SAl Viro size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 976d879cb83SAl Viro { 97700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 978241699cdSAl Viro return pipe_zero(bytes, i); 979d879cb83SAl Viro iterate_and_advance(i, bytes, v, 98009fc68dcSAl Viro clear_user(v.iov_base, v.iov_len), 981d879cb83SAl Viro memzero_page(v.bv_page, v.bv_offset, v.bv_len), 9827ff50620SDavid Howells memset(v.iov_base, 0, v.iov_len), 9837ff50620SDavid Howells memzero_page(v.bv_page, v.bv_offset, v.bv_len) 984d879cb83SAl Viro ) 985d879cb83SAl Viro 986d879cb83SAl Viro return bytes; 987d879cb83SAl Viro } 988d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_zero); 989d879cb83SAl Viro 990f0b65f39SAl Viro size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, 991f0b65f39SAl Viro struct iov_iter *i) 992d879cb83SAl Viro { 993d879cb83SAl Viro char *kaddr = kmap_atomic(page), *p = kaddr + offset; 99472e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) { 99572e809edSAl Viro kunmap_atomic(kaddr); 99672e809edSAl Viro return 0; 99772e809edSAl Viro } 9989ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 999241699cdSAl Viro kunmap_atomic(kaddr); 1000241699cdSAl Viro WARN_ON(1); 1001241699cdSAl Viro return 0; 1002241699cdSAl Viro } 1003f0b65f39SAl Viro iterate_and_advance(i, bytes, v, 100409fc68dcSAl Viro copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 1005d879cb83SAl Viro memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 1006d879cb83SAl Viro v.bv_offset, v.bv_len), 10077ff50620SDavid Howells memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 10087ff50620SDavid Howells memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 10097ff50620SDavid Howells v.bv_offset, v.bv_len) 1010d879cb83SAl Viro ) 1011d879cb83SAl Viro kunmap_atomic(kaddr); 1012d879cb83SAl Viro return bytes; 1013d879cb83SAl Viro } 1014f0b65f39SAl Viro EXPORT_SYMBOL(copy_page_from_iter_atomic); 1015d879cb83SAl Viro 1016b9dc6f65SAl Viro static inline void pipe_truncate(struct iov_iter *i) 1017241699cdSAl Viro { 1018241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 10198cefc107SDavid Howells unsigned int p_tail = pipe->tail; 10208cefc107SDavid Howells unsigned int p_head = pipe->head; 10218cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10228cefc107SDavid Howells 10238cefc107SDavid Howells if (!pipe_empty(p_head, p_tail)) { 10248cefc107SDavid Howells struct pipe_buffer *buf; 10258cefc107SDavid Howells unsigned int i_head = i->head; 1026b9dc6f65SAl Viro size_t off = i->iov_offset; 10278cefc107SDavid Howells 1028b9dc6f65SAl Viro if (off) { 10298cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 10308cefc107SDavid Howells buf->len = off - buf->offset; 10318cefc107SDavid Howells i_head++; 1032b9dc6f65SAl Viro } 10338cefc107SDavid Howells while (p_head != i_head) { 10348cefc107SDavid Howells p_head--; 10358cefc107SDavid Howells pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); 1036241699cdSAl Viro } 10378cefc107SDavid Howells 10388cefc107SDavid Howells pipe->head = p_head; 1039241699cdSAl Viro } 1040b9dc6f65SAl Viro } 1041b9dc6f65SAl Viro 1042b9dc6f65SAl Viro static void pipe_advance(struct iov_iter *i, size_t size) 1043b9dc6f65SAl Viro { 1044b9dc6f65SAl Viro struct pipe_inode_info *pipe = i->pipe; 1045b9dc6f65SAl Viro if (size) { 1046b9dc6f65SAl Viro struct pipe_buffer *buf; 10478cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10488cefc107SDavid Howells unsigned int i_head = i->head; 1049b9dc6f65SAl Viro size_t off = i->iov_offset, left = size; 10508cefc107SDavid Howells 1051b9dc6f65SAl Viro if (off) /* make it relative to the beginning of buffer */ 10528cefc107SDavid Howells left += off - pipe->bufs[i_head & p_mask].offset; 1053b9dc6f65SAl Viro while (1) { 10548cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 1055b9dc6f65SAl Viro if (left <= buf->len) 1056b9dc6f65SAl Viro break; 1057b9dc6f65SAl Viro left -= buf->len; 10588cefc107SDavid Howells i_head++; 1059b9dc6f65SAl Viro } 10608cefc107SDavid Howells i->head = i_head; 1061b9dc6f65SAl Viro i->iov_offset = buf->offset + left; 1062b9dc6f65SAl Viro } 1063b9dc6f65SAl Viro i->count -= size; 1064b9dc6f65SAl Viro /* ... and discard everything past that point */ 1065b9dc6f65SAl Viro pipe_truncate(i); 1066241699cdSAl Viro } 1067241699cdSAl Viro 106854c8195bSPavel Begunkov static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) 106954c8195bSPavel Begunkov { 107054c8195bSPavel Begunkov struct bvec_iter bi; 107154c8195bSPavel Begunkov 107254c8195bSPavel Begunkov bi.bi_size = i->count; 107354c8195bSPavel Begunkov bi.bi_bvec_done = i->iov_offset; 107454c8195bSPavel Begunkov bi.bi_idx = 0; 107554c8195bSPavel Begunkov bvec_iter_advance(i->bvec, &bi, size); 107654c8195bSPavel Begunkov 107754c8195bSPavel Begunkov i->bvec += bi.bi_idx; 107854c8195bSPavel Begunkov i->nr_segs -= bi.bi_idx; 107954c8195bSPavel Begunkov i->count = bi.bi_size; 108054c8195bSPavel Begunkov i->iov_offset = bi.bi_bvec_done; 108154c8195bSPavel Begunkov } 108254c8195bSPavel Begunkov 1083185ac4d4SAl Viro static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) 1084185ac4d4SAl Viro { 1085185ac4d4SAl Viro const struct iovec *iov, *end; 1086185ac4d4SAl Viro 1087185ac4d4SAl Viro if (!i->count) 1088185ac4d4SAl Viro return; 1089185ac4d4SAl Viro i->count -= size; 1090185ac4d4SAl Viro 1091185ac4d4SAl Viro size += i->iov_offset; // from beginning of current segment 1092185ac4d4SAl Viro for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { 1093185ac4d4SAl Viro if (likely(size < iov->iov_len)) 1094185ac4d4SAl Viro break; 1095185ac4d4SAl Viro size -= iov->iov_len; 1096185ac4d4SAl Viro } 1097185ac4d4SAl Viro i->iov_offset = size; 1098185ac4d4SAl Viro i->nr_segs -= iov - i->iov; 1099185ac4d4SAl Viro i->iov = iov; 1100185ac4d4SAl Viro } 1101185ac4d4SAl Viro 1102d879cb83SAl Viro void iov_iter_advance(struct iov_iter *i, size_t size) 1103d879cb83SAl Viro { 11043b3fc051SAl Viro if (unlikely(i->count < size)) 11053b3fc051SAl Viro size = i->count; 1106185ac4d4SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { 1107185ac4d4SAl Viro /* iovec and kvec have identical layouts */ 1108185ac4d4SAl Viro iov_iter_iovec_advance(i, size); 1109185ac4d4SAl Viro } else if (iov_iter_is_bvec(i)) { 1110185ac4d4SAl Viro iov_iter_bvec_advance(i, size); 1111185ac4d4SAl Viro } else if (iov_iter_is_pipe(i)) { 1112241699cdSAl Viro pipe_advance(i, size); 1113185ac4d4SAl Viro } else if (unlikely(iov_iter_is_xarray(i))) { 11147ff50620SDavid Howells i->iov_offset += size; 11157ff50620SDavid Howells i->count -= size; 1116185ac4d4SAl Viro } else if (iov_iter_is_discard(i)) { 1117185ac4d4SAl Viro i->count -= size; 11187ff50620SDavid Howells } 1119d879cb83SAl Viro } 1120d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_advance); 1121d879cb83SAl Viro 112227c0e374SAl Viro void iov_iter_revert(struct iov_iter *i, size_t unroll) 112327c0e374SAl Viro { 112427c0e374SAl Viro if (!unroll) 112527c0e374SAl Viro return; 11265b47d59aSAl Viro if (WARN_ON(unroll > MAX_RW_COUNT)) 11275b47d59aSAl Viro return; 112827c0e374SAl Viro i->count += unroll; 112900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 113027c0e374SAl Viro struct pipe_inode_info *pipe = i->pipe; 11318cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 11328cefc107SDavid Howells unsigned int i_head = i->head; 113327c0e374SAl Viro size_t off = i->iov_offset; 113427c0e374SAl Viro while (1) { 11358cefc107SDavid Howells struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; 11368cefc107SDavid Howells size_t n = off - b->offset; 113727c0e374SAl Viro if (unroll < n) { 11384fa55cefSAl Viro off -= unroll; 113927c0e374SAl Viro break; 114027c0e374SAl Viro } 114127c0e374SAl Viro unroll -= n; 11428cefc107SDavid Howells if (!unroll && i_head == i->start_head) { 114327c0e374SAl Viro off = 0; 114427c0e374SAl Viro break; 114527c0e374SAl Viro } 11468cefc107SDavid Howells i_head--; 11478cefc107SDavid Howells b = &pipe->bufs[i_head & p_mask]; 11488cefc107SDavid Howells off = b->offset + b->len; 114927c0e374SAl Viro } 115027c0e374SAl Viro i->iov_offset = off; 11518cefc107SDavid Howells i->head = i_head; 115227c0e374SAl Viro pipe_truncate(i); 115327c0e374SAl Viro return; 115427c0e374SAl Viro } 11559ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 11569ea9ce04SDavid Howells return; 115727c0e374SAl Viro if (unroll <= i->iov_offset) { 115827c0e374SAl Viro i->iov_offset -= unroll; 115927c0e374SAl Viro return; 116027c0e374SAl Viro } 116127c0e374SAl Viro unroll -= i->iov_offset; 11627ff50620SDavid Howells if (iov_iter_is_xarray(i)) { 11637ff50620SDavid Howells BUG(); /* We should never go beyond the start of the specified 11647ff50620SDavid Howells * range since we might then be straying into pages that 11657ff50620SDavid Howells * aren't pinned. 11667ff50620SDavid Howells */ 11677ff50620SDavid Howells } else if (iov_iter_is_bvec(i)) { 116827c0e374SAl Viro const struct bio_vec *bvec = i->bvec; 116927c0e374SAl Viro while (1) { 117027c0e374SAl Viro size_t n = (--bvec)->bv_len; 117127c0e374SAl Viro i->nr_segs++; 117227c0e374SAl Viro if (unroll <= n) { 117327c0e374SAl Viro i->bvec = bvec; 117427c0e374SAl Viro i->iov_offset = n - unroll; 117527c0e374SAl Viro return; 117627c0e374SAl Viro } 117727c0e374SAl Viro unroll -= n; 117827c0e374SAl Viro } 117927c0e374SAl Viro } else { /* same logics for iovec and kvec */ 118027c0e374SAl Viro const struct iovec *iov = i->iov; 118127c0e374SAl Viro while (1) { 118227c0e374SAl Viro size_t n = (--iov)->iov_len; 118327c0e374SAl Viro i->nr_segs++; 118427c0e374SAl Viro if (unroll <= n) { 118527c0e374SAl Viro i->iov = iov; 118627c0e374SAl Viro i->iov_offset = n - unroll; 118727c0e374SAl Viro return; 118827c0e374SAl Viro } 118927c0e374SAl Viro unroll -= n; 119027c0e374SAl Viro } 119127c0e374SAl Viro } 119227c0e374SAl Viro } 119327c0e374SAl Viro EXPORT_SYMBOL(iov_iter_revert); 119427c0e374SAl Viro 1195d879cb83SAl Viro /* 1196d879cb83SAl Viro * Return the count of just the current iov_iter segment. 1197d879cb83SAl Viro */ 1198d879cb83SAl Viro size_t iov_iter_single_seg_count(const struct iov_iter *i) 1199d879cb83SAl Viro { 120028f38db7SAl Viro if (i->nr_segs > 1) { 120128f38db7SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 120228f38db7SAl Viro return min(i->count, i->iov->iov_len - i->iov_offset); 12037ff50620SDavid Howells if (iov_iter_is_bvec(i)) 1204d879cb83SAl Viro return min(i->count, i->bvec->bv_len - i->iov_offset); 120528f38db7SAl Viro } 120628f38db7SAl Viro return i->count; 1207d879cb83SAl Viro } 1208d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_single_seg_count); 1209d879cb83SAl Viro 1210aa563d7bSDavid Howells void iov_iter_kvec(struct iov_iter *i, unsigned int direction, 1211d879cb83SAl Viro const struct kvec *kvec, unsigned long nr_segs, 1212d879cb83SAl Viro size_t count) 1213d879cb83SAl Viro { 1214aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 12158cd54c1cSAl Viro *i = (struct iov_iter){ 12168cd54c1cSAl Viro .iter_type = ITER_KVEC, 12178cd54c1cSAl Viro .data_source = direction, 12188cd54c1cSAl Viro .kvec = kvec, 12198cd54c1cSAl Viro .nr_segs = nr_segs, 12208cd54c1cSAl Viro .iov_offset = 0, 12218cd54c1cSAl Viro .count = count 12228cd54c1cSAl Viro }; 1223d879cb83SAl Viro } 1224d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_kvec); 1225d879cb83SAl Viro 1226aa563d7bSDavid Howells void iov_iter_bvec(struct iov_iter *i, unsigned int direction, 1227d879cb83SAl Viro const struct bio_vec *bvec, unsigned long nr_segs, 1228d879cb83SAl Viro size_t count) 1229d879cb83SAl Viro { 1230aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 12318cd54c1cSAl Viro *i = (struct iov_iter){ 12328cd54c1cSAl Viro .iter_type = ITER_BVEC, 12338cd54c1cSAl Viro .data_source = direction, 12348cd54c1cSAl Viro .bvec = bvec, 12358cd54c1cSAl Viro .nr_segs = nr_segs, 12368cd54c1cSAl Viro .iov_offset = 0, 12378cd54c1cSAl Viro .count = count 12388cd54c1cSAl Viro }; 1239d879cb83SAl Viro } 1240d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_bvec); 1241d879cb83SAl Viro 1242aa563d7bSDavid Howells void iov_iter_pipe(struct iov_iter *i, unsigned int direction, 1243241699cdSAl Viro struct pipe_inode_info *pipe, 1244241699cdSAl Viro size_t count) 1245241699cdSAl Viro { 1246aa563d7bSDavid Howells BUG_ON(direction != READ); 12478cefc107SDavid Howells WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); 12488cd54c1cSAl Viro *i = (struct iov_iter){ 12498cd54c1cSAl Viro .iter_type = ITER_PIPE, 12508cd54c1cSAl Viro .data_source = false, 12518cd54c1cSAl Viro .pipe = pipe, 12528cd54c1cSAl Viro .head = pipe->head, 12538cd54c1cSAl Viro .start_head = pipe->head, 12548cd54c1cSAl Viro .iov_offset = 0, 12558cd54c1cSAl Viro .count = count 12568cd54c1cSAl Viro }; 1257241699cdSAl Viro } 1258241699cdSAl Viro EXPORT_SYMBOL(iov_iter_pipe); 1259241699cdSAl Viro 12609ea9ce04SDavid Howells /** 12617ff50620SDavid Howells * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray 12627ff50620SDavid Howells * @i: The iterator to initialise. 12637ff50620SDavid Howells * @direction: The direction of the transfer. 12647ff50620SDavid Howells * @xarray: The xarray to access. 12657ff50620SDavid Howells * @start: The start file position. 12667ff50620SDavid Howells * @count: The size of the I/O buffer in bytes. 12677ff50620SDavid Howells * 12687ff50620SDavid Howells * Set up an I/O iterator to either draw data out of the pages attached to an 12697ff50620SDavid Howells * inode or to inject data into those pages. The pages *must* be prevented 12707ff50620SDavid Howells * from evaporation, either by taking a ref on them or locking them by the 12717ff50620SDavid Howells * caller. 12727ff50620SDavid Howells */ 12737ff50620SDavid Howells void iov_iter_xarray(struct iov_iter *i, unsigned int direction, 12747ff50620SDavid Howells struct xarray *xarray, loff_t start, size_t count) 12757ff50620SDavid Howells { 12767ff50620SDavid Howells BUG_ON(direction & ~1); 12778cd54c1cSAl Viro *i = (struct iov_iter) { 12788cd54c1cSAl Viro .iter_type = ITER_XARRAY, 12798cd54c1cSAl Viro .data_source = direction, 12808cd54c1cSAl Viro .xarray = xarray, 12818cd54c1cSAl Viro .xarray_start = start, 12828cd54c1cSAl Viro .count = count, 12838cd54c1cSAl Viro .iov_offset = 0 12848cd54c1cSAl Viro }; 12857ff50620SDavid Howells } 12867ff50620SDavid Howells EXPORT_SYMBOL(iov_iter_xarray); 12877ff50620SDavid Howells 12887ff50620SDavid Howells /** 12899ea9ce04SDavid Howells * iov_iter_discard - Initialise an I/O iterator that discards data 12909ea9ce04SDavid Howells * @i: The iterator to initialise. 12919ea9ce04SDavid Howells * @direction: The direction of the transfer. 12929ea9ce04SDavid Howells * @count: The size of the I/O buffer in bytes. 12939ea9ce04SDavid Howells * 12949ea9ce04SDavid Howells * Set up an I/O iterator that just discards everything that's written to it. 12959ea9ce04SDavid Howells * It's only available as a READ iterator. 12969ea9ce04SDavid Howells */ 12979ea9ce04SDavid Howells void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) 12989ea9ce04SDavid Howells { 12999ea9ce04SDavid Howells BUG_ON(direction != READ); 13008cd54c1cSAl Viro *i = (struct iov_iter){ 13018cd54c1cSAl Viro .iter_type = ITER_DISCARD, 13028cd54c1cSAl Viro .data_source = false, 13038cd54c1cSAl Viro .count = count, 13048cd54c1cSAl Viro .iov_offset = 0 13058cd54c1cSAl Viro }; 13069ea9ce04SDavid Howells } 13079ea9ce04SDavid Howells EXPORT_SYMBOL(iov_iter_discard); 13089ea9ce04SDavid Howells 13099221d2e3SAl Viro static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) 1310d879cb83SAl Viro { 1311d879cb83SAl Viro unsigned long res = 0; 1312d879cb83SAl Viro size_t size = i->count; 13139221d2e3SAl Viro size_t skip = i->iov_offset; 13149221d2e3SAl Viro unsigned k; 1315d879cb83SAl Viro 13169221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 13179221d2e3SAl Viro size_t len = i->iov[k].iov_len - skip; 13189221d2e3SAl Viro if (len) { 13199221d2e3SAl Viro res |= (unsigned long)i->iov[k].iov_base + skip; 13209221d2e3SAl Viro if (len > size) 13219221d2e3SAl Viro len = size; 13229221d2e3SAl Viro res |= len; 13239221d2e3SAl Viro size -= len; 13249221d2e3SAl Viro if (!size) 13259221d2e3SAl Viro break; 13269221d2e3SAl Viro } 13279221d2e3SAl Viro } 13289221d2e3SAl Viro return res; 13299221d2e3SAl Viro } 13309221d2e3SAl Viro 13319221d2e3SAl Viro static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) 13329221d2e3SAl Viro { 13339221d2e3SAl Viro unsigned res = 0; 13349221d2e3SAl Viro size_t size = i->count; 13359221d2e3SAl Viro unsigned skip = i->iov_offset; 13369221d2e3SAl Viro unsigned k; 13379221d2e3SAl Viro 13389221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 13399221d2e3SAl Viro size_t len = i->bvec[k].bv_len - skip; 13409221d2e3SAl Viro res |= (unsigned long)i->bvec[k].bv_offset + skip; 13419221d2e3SAl Viro if (len > size) 13429221d2e3SAl Viro len = size; 13439221d2e3SAl Viro res |= len; 13449221d2e3SAl Viro size -= len; 13459221d2e3SAl Viro if (!size) 13469221d2e3SAl Viro break; 13479221d2e3SAl Viro } 13489221d2e3SAl Viro return res; 13499221d2e3SAl Viro } 13509221d2e3SAl Viro 13519221d2e3SAl Viro unsigned long iov_iter_alignment(const struct iov_iter *i) 13529221d2e3SAl Viro { 13539221d2e3SAl Viro /* iovec and kvec have identical layouts */ 13549221d2e3SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 13559221d2e3SAl Viro return iov_iter_alignment_iovec(i); 13569221d2e3SAl Viro 13579221d2e3SAl Viro if (iov_iter_is_bvec(i)) 13589221d2e3SAl Viro return iov_iter_alignment_bvec(i); 13599221d2e3SAl Viro 13609221d2e3SAl Viro if (iov_iter_is_pipe(i)) { 1361e0ff126eSJan Kara unsigned int p_mask = i->pipe->ring_size - 1; 13629221d2e3SAl Viro size_t size = i->count; 1363e0ff126eSJan Kara 13648cefc107SDavid Howells if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) 1365241699cdSAl Viro return size | i->iov_offset; 1366241699cdSAl Viro return size; 1367241699cdSAl Viro } 13689221d2e3SAl Viro 13699221d2e3SAl Viro if (iov_iter_is_xarray(i)) 13703d14ec1fSDavid Howells return (i->xarray_start + i->iov_offset) | i->count; 13719221d2e3SAl Viro 13729221d2e3SAl Viro return 0; 1373d879cb83SAl Viro } 1374d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_alignment); 1375d879cb83SAl Viro 1376357f435dSAl Viro unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 1377357f435dSAl Viro { 1378357f435dSAl Viro unsigned long res = 0; 1379610c7a71SAl Viro unsigned long v = 0; 1380357f435dSAl Viro size_t size = i->count; 1381610c7a71SAl Viro unsigned k; 1382357f435dSAl Viro 1383610c7a71SAl Viro if (WARN_ON(!iter_is_iovec(i))) 1384241699cdSAl Viro return ~0U; 1385241699cdSAl Viro 1386610c7a71SAl Viro for (k = 0; k < i->nr_segs; k++) { 1387610c7a71SAl Viro if (i->iov[k].iov_len) { 1388610c7a71SAl Viro unsigned long base = (unsigned long)i->iov[k].iov_base; 1389610c7a71SAl Viro if (v) // if not the first one 1390610c7a71SAl Viro res |= base | v; // this start | previous end 1391610c7a71SAl Viro v = base + i->iov[k].iov_len; 1392610c7a71SAl Viro if (size <= i->iov[k].iov_len) 1393610c7a71SAl Viro break; 1394610c7a71SAl Viro size -= i->iov[k].iov_len; 1395610c7a71SAl Viro } 1396610c7a71SAl Viro } 1397357f435dSAl Viro return res; 1398357f435dSAl Viro } 1399357f435dSAl Viro EXPORT_SYMBOL(iov_iter_gap_alignment); 1400357f435dSAl Viro 1401e76b6312SIlya Dryomov static inline ssize_t __pipe_get_pages(struct iov_iter *i, 1402241699cdSAl Viro size_t maxsize, 1403241699cdSAl Viro struct page **pages, 14048cefc107SDavid Howells int iter_head, 1405241699cdSAl Viro size_t *start) 1406241699cdSAl Viro { 1407241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 14088cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 14098cefc107SDavid Howells ssize_t n = push_pipe(i, maxsize, &iter_head, start); 1410241699cdSAl Viro if (!n) 1411241699cdSAl Viro return -EFAULT; 1412241699cdSAl Viro 1413241699cdSAl Viro maxsize = n; 1414241699cdSAl Viro n += *start; 14151689c73aSAl Viro while (n > 0) { 14168cefc107SDavid Howells get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); 14178cefc107SDavid Howells iter_head++; 1418241699cdSAl Viro n -= PAGE_SIZE; 1419241699cdSAl Viro } 1420241699cdSAl Viro 1421241699cdSAl Viro return maxsize; 1422241699cdSAl Viro } 1423241699cdSAl Viro 1424241699cdSAl Viro static ssize_t pipe_get_pages(struct iov_iter *i, 1425241699cdSAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1426241699cdSAl Viro size_t *start) 1427241699cdSAl Viro { 14288cefc107SDavid Howells unsigned int iter_head, npages; 1429241699cdSAl Viro size_t capacity; 1430241699cdSAl Viro 1431241699cdSAl Viro if (!sanity(i)) 1432241699cdSAl Viro return -EFAULT; 1433241699cdSAl Viro 14348cefc107SDavid Howells data_start(i, &iter_head, start); 14358cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 14368cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1437241699cdSAl Viro capacity = min(npages, maxpages) * PAGE_SIZE - *start; 1438241699cdSAl Viro 14398cefc107SDavid Howells return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); 1440241699cdSAl Viro } 1441241699cdSAl Viro 14427ff50620SDavid Howells static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, 14437ff50620SDavid Howells pgoff_t index, unsigned int nr_pages) 14447ff50620SDavid Howells { 14457ff50620SDavid Howells XA_STATE(xas, xa, index); 14467ff50620SDavid Howells struct page *page; 14477ff50620SDavid Howells unsigned int ret = 0; 14487ff50620SDavid Howells 14497ff50620SDavid Howells rcu_read_lock(); 14507ff50620SDavid Howells for (page = xas_load(&xas); page; page = xas_next(&xas)) { 14517ff50620SDavid Howells if (xas_retry(&xas, page)) 14527ff50620SDavid Howells continue; 14537ff50620SDavid Howells 14547ff50620SDavid Howells /* Has the page moved or been split? */ 14557ff50620SDavid Howells if (unlikely(page != xas_reload(&xas))) { 14567ff50620SDavid Howells xas_reset(&xas); 14577ff50620SDavid Howells continue; 14587ff50620SDavid Howells } 14597ff50620SDavid Howells 14607ff50620SDavid Howells pages[ret] = find_subpage(page, xas.xa_index); 14617ff50620SDavid Howells get_page(pages[ret]); 14627ff50620SDavid Howells if (++ret == nr_pages) 14637ff50620SDavid Howells break; 14647ff50620SDavid Howells } 14657ff50620SDavid Howells rcu_read_unlock(); 14667ff50620SDavid Howells return ret; 14677ff50620SDavid Howells } 14687ff50620SDavid Howells 14697ff50620SDavid Howells static ssize_t iter_xarray_get_pages(struct iov_iter *i, 14707ff50620SDavid Howells struct page **pages, size_t maxsize, 14717ff50620SDavid Howells unsigned maxpages, size_t *_start_offset) 14727ff50620SDavid Howells { 14737ff50620SDavid Howells unsigned nr, offset; 14747ff50620SDavid Howells pgoff_t index, count; 14757ff50620SDavid Howells size_t size = maxsize, actual; 14767ff50620SDavid Howells loff_t pos; 14777ff50620SDavid Howells 14787ff50620SDavid Howells if (!size || !maxpages) 14797ff50620SDavid Howells return 0; 14807ff50620SDavid Howells 14817ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 14827ff50620SDavid Howells index = pos >> PAGE_SHIFT; 14837ff50620SDavid Howells offset = pos & ~PAGE_MASK; 14847ff50620SDavid Howells *_start_offset = offset; 14857ff50620SDavid Howells 14867ff50620SDavid Howells count = 1; 14877ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 14887ff50620SDavid Howells size -= PAGE_SIZE - offset; 14897ff50620SDavid Howells count += size >> PAGE_SHIFT; 14907ff50620SDavid Howells size &= ~PAGE_MASK; 14917ff50620SDavid Howells if (size) 14927ff50620SDavid Howells count++; 14937ff50620SDavid Howells } 14947ff50620SDavid Howells 14957ff50620SDavid Howells if (count > maxpages) 14967ff50620SDavid Howells count = maxpages; 14977ff50620SDavid Howells 14987ff50620SDavid Howells nr = iter_xarray_populate_pages(pages, i->xarray, index, count); 14997ff50620SDavid Howells if (nr == 0) 15007ff50620SDavid Howells return 0; 15017ff50620SDavid Howells 15027ff50620SDavid Howells actual = PAGE_SIZE * nr; 15037ff50620SDavid Howells actual -= offset; 15047ff50620SDavid Howells if (nr == count && size > 0) { 15057ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 15067ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 15077ff50620SDavid Howells } 15087ff50620SDavid Howells return actual; 15097ff50620SDavid Howells } 15107ff50620SDavid Howells 15113d671ca6SAl Viro /* must be done on non-empty ITER_IOVEC one */ 15123d671ca6SAl Viro static unsigned long first_iovec_segment(const struct iov_iter *i, 15133d671ca6SAl Viro size_t *size, size_t *start, 15143d671ca6SAl Viro size_t maxsize, unsigned maxpages) 15153d671ca6SAl Viro { 15163d671ca6SAl Viro size_t skip; 15173d671ca6SAl Viro long k; 15183d671ca6SAl Viro 15193d671ca6SAl Viro for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { 15203d671ca6SAl Viro unsigned long addr = (unsigned long)i->iov[k].iov_base + skip; 15213d671ca6SAl Viro size_t len = i->iov[k].iov_len - skip; 15223d671ca6SAl Viro 15233d671ca6SAl Viro if (unlikely(!len)) 15243d671ca6SAl Viro continue; 15253d671ca6SAl Viro if (len > maxsize) 15263d671ca6SAl Viro len = maxsize; 15273d671ca6SAl Viro len += (*start = addr % PAGE_SIZE); 15283d671ca6SAl Viro if (len > maxpages * PAGE_SIZE) 15293d671ca6SAl Viro len = maxpages * PAGE_SIZE; 15303d671ca6SAl Viro *size = len; 15313d671ca6SAl Viro return addr & PAGE_MASK; 15323d671ca6SAl Viro } 15333d671ca6SAl Viro BUG(); // if it had been empty, we wouldn't get called 15343d671ca6SAl Viro } 15353d671ca6SAl Viro 15363d671ca6SAl Viro /* must be done on non-empty ITER_BVEC one */ 15373d671ca6SAl Viro static struct page *first_bvec_segment(const struct iov_iter *i, 15383d671ca6SAl Viro size_t *size, size_t *start, 15393d671ca6SAl Viro size_t maxsize, unsigned maxpages) 15403d671ca6SAl Viro { 15413d671ca6SAl Viro struct page *page; 15423d671ca6SAl Viro size_t skip = i->iov_offset, len; 15433d671ca6SAl Viro 15443d671ca6SAl Viro len = i->bvec->bv_len - skip; 15453d671ca6SAl Viro if (len > maxsize) 15463d671ca6SAl Viro len = maxsize; 15473d671ca6SAl Viro skip += i->bvec->bv_offset; 15483d671ca6SAl Viro page = i->bvec->bv_page + skip / PAGE_SIZE; 15493d671ca6SAl Viro len += (*start = skip % PAGE_SIZE); 15503d671ca6SAl Viro if (len > maxpages * PAGE_SIZE) 15513d671ca6SAl Viro len = maxpages * PAGE_SIZE; 15523d671ca6SAl Viro *size = len; 15533d671ca6SAl Viro return page; 15543d671ca6SAl Viro } 15553d671ca6SAl Viro 1556d879cb83SAl Viro ssize_t iov_iter_get_pages(struct iov_iter *i, 1557d879cb83SAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1558d879cb83SAl Viro size_t *start) 1559d879cb83SAl Viro { 15603d671ca6SAl Viro size_t len; 15613d671ca6SAl Viro int n, res; 15623d671ca6SAl Viro 1563d879cb83SAl Viro if (maxsize > i->count) 1564d879cb83SAl Viro maxsize = i->count; 15653d671ca6SAl Viro if (!maxsize) 15663d671ca6SAl Viro return 0; 1567d879cb83SAl Viro 15683d671ca6SAl Viro if (likely(iter_is_iovec(i))) { 15693d671ca6SAl Viro unsigned long addr; 15709ea9ce04SDavid Howells 15713d671ca6SAl Viro addr = first_iovec_segment(i, &len, start, maxsize, maxpages); 1572d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 157373b0140bSIra Weiny res = get_user_pages_fast(addr, n, 157473b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, 157573b0140bSIra Weiny pages); 1576d879cb83SAl Viro if (unlikely(res < 0)) 1577d879cb83SAl Viro return res; 1578d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 15793d671ca6SAl Viro } 15803d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 15813d671ca6SAl Viro struct page *page; 15823d671ca6SAl Viro 15833d671ca6SAl Viro page = first_bvec_segment(i, &len, start, maxsize, maxpages); 15843d671ca6SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 15853d671ca6SAl Viro while (n--) 15863d671ca6SAl Viro get_page(*pages++ = page++); 15873d671ca6SAl Viro return len - *start; 15883d671ca6SAl Viro } 15893d671ca6SAl Viro if (iov_iter_is_pipe(i)) 15903d671ca6SAl Viro return pipe_get_pages(i, pages, maxsize, maxpages, start); 15913d671ca6SAl Viro if (iov_iter_is_xarray(i)) 15923d671ca6SAl Viro return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); 1593d879cb83SAl Viro return -EFAULT; 1594d879cb83SAl Viro } 1595d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages); 1596d879cb83SAl Viro 1597d879cb83SAl Viro static struct page **get_pages_array(size_t n) 1598d879cb83SAl Viro { 1599752ade68SMichal Hocko return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); 1600d879cb83SAl Viro } 1601d879cb83SAl Viro 1602241699cdSAl Viro static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 1603241699cdSAl Viro struct page ***pages, size_t maxsize, 1604241699cdSAl Viro size_t *start) 1605241699cdSAl Viro { 1606241699cdSAl Viro struct page **p; 16078cefc107SDavid Howells unsigned int iter_head, npages; 1608d7760d63SIlya Dryomov ssize_t n; 1609241699cdSAl Viro 1610241699cdSAl Viro if (!sanity(i)) 1611241699cdSAl Viro return -EFAULT; 1612241699cdSAl Viro 16138cefc107SDavid Howells data_start(i, &iter_head, start); 16148cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 16158cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1616241699cdSAl Viro n = npages * PAGE_SIZE - *start; 1617241699cdSAl Viro if (maxsize > n) 1618241699cdSAl Viro maxsize = n; 1619241699cdSAl Viro else 1620241699cdSAl Viro npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1621241699cdSAl Viro p = get_pages_array(npages); 1622241699cdSAl Viro if (!p) 1623241699cdSAl Viro return -ENOMEM; 16248cefc107SDavid Howells n = __pipe_get_pages(i, maxsize, p, iter_head, start); 1625241699cdSAl Viro if (n > 0) 1626241699cdSAl Viro *pages = p; 1627241699cdSAl Viro else 1628241699cdSAl Viro kvfree(p); 1629241699cdSAl Viro return n; 1630241699cdSAl Viro } 1631241699cdSAl Viro 16327ff50620SDavid Howells static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, 16337ff50620SDavid Howells struct page ***pages, size_t maxsize, 16347ff50620SDavid Howells size_t *_start_offset) 16357ff50620SDavid Howells { 16367ff50620SDavid Howells struct page **p; 16377ff50620SDavid Howells unsigned nr, offset; 16387ff50620SDavid Howells pgoff_t index, count; 16397ff50620SDavid Howells size_t size = maxsize, actual; 16407ff50620SDavid Howells loff_t pos; 16417ff50620SDavid Howells 16427ff50620SDavid Howells if (!size) 16437ff50620SDavid Howells return 0; 16447ff50620SDavid Howells 16457ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 16467ff50620SDavid Howells index = pos >> PAGE_SHIFT; 16477ff50620SDavid Howells offset = pos & ~PAGE_MASK; 16487ff50620SDavid Howells *_start_offset = offset; 16497ff50620SDavid Howells 16507ff50620SDavid Howells count = 1; 16517ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 16527ff50620SDavid Howells size -= PAGE_SIZE - offset; 16537ff50620SDavid Howells count += size >> PAGE_SHIFT; 16547ff50620SDavid Howells size &= ~PAGE_MASK; 16557ff50620SDavid Howells if (size) 16567ff50620SDavid Howells count++; 16577ff50620SDavid Howells } 16587ff50620SDavid Howells 16597ff50620SDavid Howells p = get_pages_array(count); 16607ff50620SDavid Howells if (!p) 16617ff50620SDavid Howells return -ENOMEM; 16627ff50620SDavid Howells *pages = p; 16637ff50620SDavid Howells 16647ff50620SDavid Howells nr = iter_xarray_populate_pages(p, i->xarray, index, count); 16657ff50620SDavid Howells if (nr == 0) 16667ff50620SDavid Howells return 0; 16677ff50620SDavid Howells 16687ff50620SDavid Howells actual = PAGE_SIZE * nr; 16697ff50620SDavid Howells actual -= offset; 16707ff50620SDavid Howells if (nr == count && size > 0) { 16717ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 16727ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 16737ff50620SDavid Howells } 16747ff50620SDavid Howells return actual; 16757ff50620SDavid Howells } 16767ff50620SDavid Howells 1677d879cb83SAl Viro ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 1678d879cb83SAl Viro struct page ***pages, size_t maxsize, 1679d879cb83SAl Viro size_t *start) 1680d879cb83SAl Viro { 1681d879cb83SAl Viro struct page **p; 16823d671ca6SAl Viro size_t len; 16833d671ca6SAl Viro int n, res; 1684d879cb83SAl Viro 1685d879cb83SAl Viro if (maxsize > i->count) 1686d879cb83SAl Viro maxsize = i->count; 16873d671ca6SAl Viro if (!maxsize) 16883d671ca6SAl Viro return 0; 1689d879cb83SAl Viro 16903d671ca6SAl Viro if (likely(iter_is_iovec(i))) { 16913d671ca6SAl Viro unsigned long addr; 16929ea9ce04SDavid Howells 16933d671ca6SAl Viro addr = first_iovec_segment(i, &len, start, maxsize, ~0U); 1694d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 1695d879cb83SAl Viro p = get_pages_array(n); 1696d879cb83SAl Viro if (!p) 1697d879cb83SAl Viro return -ENOMEM; 169873b0140bSIra Weiny res = get_user_pages_fast(addr, n, 169973b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); 1700d879cb83SAl Viro if (unlikely(res < 0)) { 1701d879cb83SAl Viro kvfree(p); 1702d879cb83SAl Viro return res; 1703d879cb83SAl Viro } 1704d879cb83SAl Viro *pages = p; 1705d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 17063d671ca6SAl Viro } 17073d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 17083d671ca6SAl Viro struct page *page; 17093d671ca6SAl Viro 17103d671ca6SAl Viro page = first_bvec_segment(i, &len, start, maxsize, ~0U); 17113d671ca6SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 17123d671ca6SAl Viro *pages = p = get_pages_array(n); 1713d879cb83SAl Viro if (!p) 1714d879cb83SAl Viro return -ENOMEM; 17153d671ca6SAl Viro while (n--) 17163d671ca6SAl Viro get_page(*p++ = page++); 17173d671ca6SAl Viro return len - *start; 17183d671ca6SAl Viro } 17193d671ca6SAl Viro if (iov_iter_is_pipe(i)) 17203d671ca6SAl Viro return pipe_get_pages_alloc(i, pages, maxsize, start); 17213d671ca6SAl Viro if (iov_iter_is_xarray(i)) 17223d671ca6SAl Viro return iter_xarray_get_pages_alloc(i, pages, maxsize, start); 1723d879cb83SAl Viro return -EFAULT; 1724d879cb83SAl Viro } 1725d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages_alloc); 1726d879cb83SAl Viro 1727d879cb83SAl Viro size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 1728d879cb83SAl Viro struct iov_iter *i) 1729d879cb83SAl Viro { 1730d879cb83SAl Viro char *to = addr; 1731d879cb83SAl Viro __wsum sum, next; 1732d879cb83SAl Viro size_t off = 0; 1733d879cb83SAl Viro sum = *csum; 17349ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1735241699cdSAl Viro WARN_ON(1); 1736241699cdSAl Viro return 0; 1737241699cdSAl Viro } 1738d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1739d879cb83SAl Viro next = csum_and_copy_from_user(v.iov_base, 1740d879cb83SAl Viro (to += v.iov_len) - v.iov_len, 1741c693cc46SAl Viro v.iov_len); 1742c693cc46SAl Viro if (next) { 1743d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1744d879cb83SAl Viro off += v.iov_len; 1745d879cb83SAl Viro } 1746c693cc46SAl Viro next ? 0 : v.iov_len; 1747d879cb83SAl Viro }), ({ 1748d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1749f9152895SAl Viro sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 1750f9152895SAl Viro p + v.bv_offset, v.bv_len, 1751f9152895SAl Viro sum, off); 1752d879cb83SAl Viro kunmap_atomic(p); 1753d879cb83SAl Viro off += v.bv_len; 1754d879cb83SAl Viro }),({ 1755f9152895SAl Viro sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, 1756f9152895SAl Viro v.iov_base, v.iov_len, 1757f9152895SAl Viro sum, off); 1758d879cb83SAl Viro off += v.iov_len; 17597ff50620SDavid Howells }), ({ 17607ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 17617ff50620SDavid Howells sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 17627ff50620SDavid Howells p + v.bv_offset, v.bv_len, 17637ff50620SDavid Howells sum, off); 17647ff50620SDavid Howells kunmap_atomic(p); 17657ff50620SDavid Howells off += v.bv_len; 1766d879cb83SAl Viro }) 1767d879cb83SAl Viro ) 1768d879cb83SAl Viro *csum = sum; 1769d879cb83SAl Viro return bytes; 1770d879cb83SAl Viro } 1771d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter); 1772d879cb83SAl Viro 177352cbd23aSWillem de Bruijn size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 1774d879cb83SAl Viro struct iov_iter *i) 1775d879cb83SAl Viro { 177652cbd23aSWillem de Bruijn struct csum_state *csstate = _csstate; 177736f7a8a4SAl Viro const char *from = addr; 1778d879cb83SAl Viro __wsum sum, next; 177952cbd23aSWillem de Bruijn size_t off; 178078e1f386SAl Viro 178178e1f386SAl Viro if (unlikely(iov_iter_is_pipe(i))) 178252cbd23aSWillem de Bruijn return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); 178378e1f386SAl Viro 1784594e450bSAl Viro sum = csum_shift(csstate->csum, csstate->off); 1785594e450bSAl Viro off = 0; 178678e1f386SAl Viro if (unlikely(iov_iter_is_discard(i))) { 1787241699cdSAl Viro WARN_ON(1); /* for now */ 1788241699cdSAl Viro return 0; 1789241699cdSAl Viro } 1790d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1791d879cb83SAl Viro next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, 1792d879cb83SAl Viro v.iov_base, 1793c693cc46SAl Viro v.iov_len); 1794c693cc46SAl Viro if (next) { 1795d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1796d879cb83SAl Viro off += v.iov_len; 1797d879cb83SAl Viro } 1798c693cc46SAl Viro next ? 0 : v.iov_len; 1799d879cb83SAl Viro }), ({ 1800d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1801f9152895SAl Viro sum = csum_and_memcpy(p + v.bv_offset, 1802f9152895SAl Viro (from += v.bv_len) - v.bv_len, 1803f9152895SAl Viro v.bv_len, sum, off); 1804d879cb83SAl Viro kunmap_atomic(p); 1805d879cb83SAl Viro off += v.bv_len; 1806d879cb83SAl Viro }),({ 1807f9152895SAl Viro sum = csum_and_memcpy(v.iov_base, 1808f9152895SAl Viro (from += v.iov_len) - v.iov_len, 1809f9152895SAl Viro v.iov_len, sum, off); 1810d879cb83SAl Viro off += v.iov_len; 18117ff50620SDavid Howells }), ({ 18127ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 18137ff50620SDavid Howells sum = csum_and_memcpy(p + v.bv_offset, 18147ff50620SDavid Howells (from += v.bv_len) - v.bv_len, 18157ff50620SDavid Howells v.bv_len, sum, off); 18167ff50620SDavid Howells kunmap_atomic(p); 18177ff50620SDavid Howells off += v.bv_len; 1818d879cb83SAl Viro }) 1819d879cb83SAl Viro ) 1820594e450bSAl Viro csstate->csum = csum_shift(sum, csstate->off); 1821594e450bSAl Viro csstate->off += bytes; 1822d879cb83SAl Viro return bytes; 1823d879cb83SAl Viro } 1824d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_to_iter); 1825d879cb83SAl Viro 1826d05f4435SSagi Grimberg size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, 1827d05f4435SSagi Grimberg struct iov_iter *i) 1828d05f4435SSagi Grimberg { 18297999096fSHerbert Xu #ifdef CONFIG_CRYPTO_HASH 1830d05f4435SSagi Grimberg struct ahash_request *hash = hashp; 1831d05f4435SSagi Grimberg struct scatterlist sg; 1832d05f4435SSagi Grimberg size_t copied; 1833d05f4435SSagi Grimberg 1834d05f4435SSagi Grimberg copied = copy_to_iter(addr, bytes, i); 1835d05f4435SSagi Grimberg sg_init_one(&sg, addr, copied); 1836d05f4435SSagi Grimberg ahash_request_set_crypt(hash, &sg, NULL, copied); 1837d05f4435SSagi Grimberg crypto_ahash_update(hash); 1838d05f4435SSagi Grimberg return copied; 183927fad74aSYueHaibing #else 184027fad74aSYueHaibing return 0; 184127fad74aSYueHaibing #endif 1842d05f4435SSagi Grimberg } 1843d05f4435SSagi Grimberg EXPORT_SYMBOL(hash_and_copy_to_iter); 1844d05f4435SSagi Grimberg 184566531c65SAl Viro static int iov_npages(const struct iov_iter *i, int maxpages) 1846d879cb83SAl Viro { 184766531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 184866531c65SAl Viro const struct iovec *p; 1849d879cb83SAl Viro int npages = 0; 1850d879cb83SAl Viro 185166531c65SAl Viro for (p = i->iov; size; skip = 0, p++) { 185266531c65SAl Viro unsigned offs = offset_in_page(p->iov_base + skip); 185366531c65SAl Viro size_t len = min(p->iov_len - skip, size); 1854d879cb83SAl Viro 185566531c65SAl Viro if (len) { 185666531c65SAl Viro size -= len; 185766531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 185866531c65SAl Viro if (unlikely(npages > maxpages)) 185966531c65SAl Viro return maxpages; 186066531c65SAl Viro } 186166531c65SAl Viro } 186266531c65SAl Viro return npages; 186366531c65SAl Viro } 186466531c65SAl Viro 186566531c65SAl Viro static int bvec_npages(const struct iov_iter *i, int maxpages) 186666531c65SAl Viro { 186766531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 186866531c65SAl Viro const struct bio_vec *p; 186966531c65SAl Viro int npages = 0; 187066531c65SAl Viro 187166531c65SAl Viro for (p = i->bvec; size; skip = 0, p++) { 187266531c65SAl Viro unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; 187366531c65SAl Viro size_t len = min(p->bv_len - skip, size); 187466531c65SAl Viro 187566531c65SAl Viro size -= len; 187666531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 187766531c65SAl Viro if (unlikely(npages > maxpages)) 187866531c65SAl Viro return maxpages; 187966531c65SAl Viro } 188066531c65SAl Viro return npages; 188166531c65SAl Viro } 188266531c65SAl Viro 188366531c65SAl Viro int iov_iter_npages(const struct iov_iter *i, int maxpages) 188466531c65SAl Viro { 188566531c65SAl Viro if (unlikely(!i->count)) 188666531c65SAl Viro return 0; 188766531c65SAl Viro /* iovec and kvec have identical layouts */ 188866531c65SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 188966531c65SAl Viro return iov_npages(i, maxpages); 189066531c65SAl Viro if (iov_iter_is_bvec(i)) 189166531c65SAl Viro return bvec_npages(i, maxpages); 189266531c65SAl Viro if (iov_iter_is_pipe(i)) { 18938cefc107SDavid Howells unsigned int iter_head; 189466531c65SAl Viro int npages; 1895241699cdSAl Viro size_t off; 1896241699cdSAl Viro 1897241699cdSAl Viro if (!sanity(i)) 1898241699cdSAl Viro return 0; 1899241699cdSAl Viro 19008cefc107SDavid Howells data_start(i, &iter_head, &off); 1901241699cdSAl Viro /* some of this one + all after this one */ 190266531c65SAl Viro npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 190366531c65SAl Viro return min(npages, maxpages); 190466531c65SAl Viro } 190566531c65SAl Viro if (iov_iter_is_xarray(i)) { 1906e4f8df86SAl Viro unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; 1907e4f8df86SAl Viro int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); 190866531c65SAl Viro return min(npages, maxpages); 190966531c65SAl Viro } 191066531c65SAl Viro return 0; 1911d879cb83SAl Viro } 1912d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_npages); 1913d879cb83SAl Viro 1914d879cb83SAl Viro const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) 1915d879cb83SAl Viro { 1916d879cb83SAl Viro *new = *old; 191700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(new))) { 1918241699cdSAl Viro WARN_ON(1); 1919241699cdSAl Viro return NULL; 1920241699cdSAl Viro } 19217ff50620SDavid Howells if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) 19229ea9ce04SDavid Howells return NULL; 192300e23707SDavid Howells if (iov_iter_is_bvec(new)) 1924d879cb83SAl Viro return new->bvec = kmemdup(new->bvec, 1925d879cb83SAl Viro new->nr_segs * sizeof(struct bio_vec), 1926d879cb83SAl Viro flags); 1927d879cb83SAl Viro else 1928d879cb83SAl Viro /* iovec and kvec have identical layout */ 1929d879cb83SAl Viro return new->iov = kmemdup(new->iov, 1930d879cb83SAl Viro new->nr_segs * sizeof(struct iovec), 1931d879cb83SAl Viro flags); 1932d879cb83SAl Viro } 1933d879cb83SAl Viro EXPORT_SYMBOL(dup_iter); 1934bc917be8SAl Viro 1935bfdc5970SChristoph Hellwig static int copy_compat_iovec_from_user(struct iovec *iov, 1936bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1937bfdc5970SChristoph Hellwig { 1938bfdc5970SChristoph Hellwig const struct compat_iovec __user *uiov = 1939bfdc5970SChristoph Hellwig (const struct compat_iovec __user *)uvec; 1940bfdc5970SChristoph Hellwig int ret = -EFAULT, i; 1941bfdc5970SChristoph Hellwig 1942a959a978SChristoph Hellwig if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) 1943bfdc5970SChristoph Hellwig return -EFAULT; 1944bfdc5970SChristoph Hellwig 1945bfdc5970SChristoph Hellwig for (i = 0; i < nr_segs; i++) { 1946bfdc5970SChristoph Hellwig compat_uptr_t buf; 1947bfdc5970SChristoph Hellwig compat_ssize_t len; 1948bfdc5970SChristoph Hellwig 1949bfdc5970SChristoph Hellwig unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); 1950bfdc5970SChristoph Hellwig unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); 1951bfdc5970SChristoph Hellwig 1952bfdc5970SChristoph Hellwig /* check for compat_size_t not fitting in compat_ssize_t .. */ 1953bfdc5970SChristoph Hellwig if (len < 0) { 1954bfdc5970SChristoph Hellwig ret = -EINVAL; 1955bfdc5970SChristoph Hellwig goto uaccess_end; 1956bfdc5970SChristoph Hellwig } 1957bfdc5970SChristoph Hellwig iov[i].iov_base = compat_ptr(buf); 1958bfdc5970SChristoph Hellwig iov[i].iov_len = len; 1959bfdc5970SChristoph Hellwig } 1960bfdc5970SChristoph Hellwig 1961bfdc5970SChristoph Hellwig ret = 0; 1962bfdc5970SChristoph Hellwig uaccess_end: 1963bfdc5970SChristoph Hellwig user_access_end(); 1964bfdc5970SChristoph Hellwig return ret; 1965bfdc5970SChristoph Hellwig } 1966bfdc5970SChristoph Hellwig 1967bfdc5970SChristoph Hellwig static int copy_iovec_from_user(struct iovec *iov, 1968bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1969fb041b59SDavid Laight { 1970fb041b59SDavid Laight unsigned long seg; 1971bfdc5970SChristoph Hellwig 1972bfdc5970SChristoph Hellwig if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) 1973bfdc5970SChristoph Hellwig return -EFAULT; 1974bfdc5970SChristoph Hellwig for (seg = 0; seg < nr_segs; seg++) { 1975bfdc5970SChristoph Hellwig if ((ssize_t)iov[seg].iov_len < 0) 1976bfdc5970SChristoph Hellwig return -EINVAL; 1977bfdc5970SChristoph Hellwig } 1978bfdc5970SChristoph Hellwig 1979bfdc5970SChristoph Hellwig return 0; 1980bfdc5970SChristoph Hellwig } 1981bfdc5970SChristoph Hellwig 1982bfdc5970SChristoph Hellwig struct iovec *iovec_from_user(const struct iovec __user *uvec, 1983bfdc5970SChristoph Hellwig unsigned long nr_segs, unsigned long fast_segs, 1984bfdc5970SChristoph Hellwig struct iovec *fast_iov, bool compat) 1985bfdc5970SChristoph Hellwig { 1986bfdc5970SChristoph Hellwig struct iovec *iov = fast_iov; 1987bfdc5970SChristoph Hellwig int ret; 1988fb041b59SDavid Laight 1989fb041b59SDavid Laight /* 1990bfdc5970SChristoph Hellwig * SuS says "The readv() function *may* fail if the iovcnt argument was 1991bfdc5970SChristoph Hellwig * less than or equal to 0, or greater than {IOV_MAX}. Linux has 1992fb041b59SDavid Laight * traditionally returned zero for zero segments, so... 1993fb041b59SDavid Laight */ 1994bfdc5970SChristoph Hellwig if (nr_segs == 0) 1995bfdc5970SChristoph Hellwig return iov; 1996bfdc5970SChristoph Hellwig if (nr_segs > UIO_MAXIOV) 1997bfdc5970SChristoph Hellwig return ERR_PTR(-EINVAL); 1998fb041b59SDavid Laight if (nr_segs > fast_segs) { 1999fb041b59SDavid Laight iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); 2000bfdc5970SChristoph Hellwig if (!iov) 2001bfdc5970SChristoph Hellwig return ERR_PTR(-ENOMEM); 2002fb041b59SDavid Laight } 2003bfdc5970SChristoph Hellwig 2004bfdc5970SChristoph Hellwig if (compat) 2005bfdc5970SChristoph Hellwig ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); 2006bfdc5970SChristoph Hellwig else 2007bfdc5970SChristoph Hellwig ret = copy_iovec_from_user(iov, uvec, nr_segs); 2008bfdc5970SChristoph Hellwig if (ret) { 2009bfdc5970SChristoph Hellwig if (iov != fast_iov) 2010bfdc5970SChristoph Hellwig kfree(iov); 2011bfdc5970SChristoph Hellwig return ERR_PTR(ret); 2012fb041b59SDavid Laight } 2013bfdc5970SChristoph Hellwig 2014bfdc5970SChristoph Hellwig return iov; 2015bfdc5970SChristoph Hellwig } 2016bfdc5970SChristoph Hellwig 2017bfdc5970SChristoph Hellwig ssize_t __import_iovec(int type, const struct iovec __user *uvec, 2018bfdc5970SChristoph Hellwig unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, 2019bfdc5970SChristoph Hellwig struct iov_iter *i, bool compat) 2020bfdc5970SChristoph Hellwig { 2021bfdc5970SChristoph Hellwig ssize_t total_len = 0; 2022bfdc5970SChristoph Hellwig unsigned long seg; 2023bfdc5970SChristoph Hellwig struct iovec *iov; 2024bfdc5970SChristoph Hellwig 2025bfdc5970SChristoph Hellwig iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); 2026bfdc5970SChristoph Hellwig if (IS_ERR(iov)) { 2027bfdc5970SChristoph Hellwig *iovp = NULL; 2028bfdc5970SChristoph Hellwig return PTR_ERR(iov); 2029fb041b59SDavid Laight } 2030fb041b59SDavid Laight 2031fb041b59SDavid Laight /* 2032bfdc5970SChristoph Hellwig * According to the Single Unix Specification we should return EINVAL if 2033bfdc5970SChristoph Hellwig * an element length is < 0 when cast to ssize_t or if the total length 2034bfdc5970SChristoph Hellwig * would overflow the ssize_t return value of the system call. 2035fb041b59SDavid Laight * 2036fb041b59SDavid Laight * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the 2037fb041b59SDavid Laight * overflow case. 2038fb041b59SDavid Laight */ 2039fb041b59SDavid Laight for (seg = 0; seg < nr_segs; seg++) { 2040fb041b59SDavid Laight ssize_t len = (ssize_t)iov[seg].iov_len; 2041fb041b59SDavid Laight 2042bfdc5970SChristoph Hellwig if (!access_ok(iov[seg].iov_base, len)) { 2043bfdc5970SChristoph Hellwig if (iov != *iovp) 2044bfdc5970SChristoph Hellwig kfree(iov); 2045bfdc5970SChristoph Hellwig *iovp = NULL; 2046bfdc5970SChristoph Hellwig return -EFAULT; 2047fb041b59SDavid Laight } 2048bfdc5970SChristoph Hellwig 2049bfdc5970SChristoph Hellwig if (len > MAX_RW_COUNT - total_len) { 2050bfdc5970SChristoph Hellwig len = MAX_RW_COUNT - total_len; 2051fb041b59SDavid Laight iov[seg].iov_len = len; 2052fb041b59SDavid Laight } 2053bfdc5970SChristoph Hellwig total_len += len; 2054fb041b59SDavid Laight } 2055bfdc5970SChristoph Hellwig 2056bfdc5970SChristoph Hellwig iov_iter_init(i, type, iov, nr_segs, total_len); 2057bfdc5970SChristoph Hellwig if (iov == *iovp) 2058bfdc5970SChristoph Hellwig *iovp = NULL; 2059bfdc5970SChristoph Hellwig else 2060bfdc5970SChristoph Hellwig *iovp = iov; 2061bfdc5970SChristoph Hellwig return total_len; 2062fb041b59SDavid Laight } 2063fb041b59SDavid Laight 2064ffecee4fSVegard Nossum /** 2065ffecee4fSVegard Nossum * import_iovec() - Copy an array of &struct iovec from userspace 2066ffecee4fSVegard Nossum * into the kernel, check that it is valid, and initialize a new 2067ffecee4fSVegard Nossum * &struct iov_iter iterator to access it. 2068ffecee4fSVegard Nossum * 2069ffecee4fSVegard Nossum * @type: One of %READ or %WRITE. 2070bfdc5970SChristoph Hellwig * @uvec: Pointer to the userspace array. 2071ffecee4fSVegard Nossum * @nr_segs: Number of elements in userspace array. 2072ffecee4fSVegard Nossum * @fast_segs: Number of elements in @iov. 2073bfdc5970SChristoph Hellwig * @iovp: (input and output parameter) Pointer to pointer to (usually small 2074ffecee4fSVegard Nossum * on-stack) kernel array. 2075ffecee4fSVegard Nossum * @i: Pointer to iterator that will be initialized on success. 2076ffecee4fSVegard Nossum * 2077ffecee4fSVegard Nossum * If the array pointed to by *@iov is large enough to hold all @nr_segs, 2078ffecee4fSVegard Nossum * then this function places %NULL in *@iov on return. Otherwise, a new 2079ffecee4fSVegard Nossum * array will be allocated and the result placed in *@iov. This means that 2080ffecee4fSVegard Nossum * the caller may call kfree() on *@iov regardless of whether the small 2081ffecee4fSVegard Nossum * on-stack array was used or not (and regardless of whether this function 2082ffecee4fSVegard Nossum * returns an error or not). 2083ffecee4fSVegard Nossum * 208487e5e6daSJens Axboe * Return: Negative error code on error, bytes imported on success 2085ffecee4fSVegard Nossum */ 2086bfdc5970SChristoph Hellwig ssize_t import_iovec(int type, const struct iovec __user *uvec, 2087bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 2088bfdc5970SChristoph Hellwig struct iovec **iovp, struct iov_iter *i) 2089bc917be8SAl Viro { 209089cd35c5SChristoph Hellwig return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, 209189cd35c5SChristoph Hellwig in_compat_syscall()); 2092bc917be8SAl Viro } 2093bc917be8SAl Viro EXPORT_SYMBOL(import_iovec); 2094bc917be8SAl Viro 2095bc917be8SAl Viro int import_single_range(int rw, void __user *buf, size_t len, 2096bc917be8SAl Viro struct iovec *iov, struct iov_iter *i) 2097bc917be8SAl Viro { 2098bc917be8SAl Viro if (len > MAX_RW_COUNT) 2099bc917be8SAl Viro len = MAX_RW_COUNT; 210096d4f267SLinus Torvalds if (unlikely(!access_ok(buf, len))) 2101bc917be8SAl Viro return -EFAULT; 2102bc917be8SAl Viro 2103bc917be8SAl Viro iov->iov_base = buf; 2104bc917be8SAl Viro iov->iov_len = len; 2105bc917be8SAl Viro iov_iter_init(i, rw, iov, 1, len); 2106bc917be8SAl Viro return 0; 2107bc917be8SAl Viro } 2108e1267585SAl Viro EXPORT_SYMBOL(import_single_range); 2109