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 19*5c67aa90SAl Viro /* covers iovec and kvec alike */ 20d879cb83SAl Viro #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ 21d879cb83SAl Viro size_t left; \ 22d879cb83SAl Viro size_t wanted = n; \ 237a1bcb5dSAl Viro do { \ 24d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len - skip); \ 25d879cb83SAl Viro if (likely(__v.iov_len)) { \ 26d879cb83SAl Viro __v.iov_base = __p->iov_base + skip; \ 27d879cb83SAl Viro left = (STEP); \ 28d879cb83SAl Viro __v.iov_len -= left; \ 29d879cb83SAl Viro skip += __v.iov_len; \ 30d879cb83SAl Viro n -= __v.iov_len; \ 317a1bcb5dSAl Viro if (skip < __p->iov_len) \ 327a1bcb5dSAl Viro break; \ 33d879cb83SAl Viro } \ 34d879cb83SAl Viro __p++; \ 357a1bcb5dSAl Viro skip = 0; \ 367a1bcb5dSAl Viro } while (n); \ 37d879cb83SAl Viro n = wanted - n; \ 38d879cb83SAl Viro } 39d879cb83SAl Viro 401bdc76aeSMing Lei #define iterate_bvec(i, n, __v, __bi, skip, STEP) { \ 411bdc76aeSMing Lei struct bvec_iter __start; \ 421bdc76aeSMing Lei __start.bi_size = n; \ 431bdc76aeSMing Lei __start.bi_bvec_done = skip; \ 441bdc76aeSMing Lei __start.bi_idx = 0; \ 451bdc76aeSMing Lei for_each_bvec(__v, i->bvec, __bi, __start) { \ 46d879cb83SAl Viro (void)(STEP); \ 47d879cb83SAl Viro } \ 48d879cb83SAl Viro } 49d879cb83SAl Viro 507ff50620SDavid Howells #define iterate_xarray(i, n, __v, skip, STEP) { \ 517ff50620SDavid Howells struct page *head = NULL; \ 527ff50620SDavid Howells size_t wanted = n, seg, offset; \ 537ff50620SDavid Howells loff_t start = i->xarray_start + skip; \ 547ff50620SDavid Howells pgoff_t index = start >> PAGE_SHIFT; \ 557ff50620SDavid Howells int j; \ 567ff50620SDavid Howells \ 577ff50620SDavid Howells XA_STATE(xas, i->xarray, index); \ 587ff50620SDavid Howells \ 597ff50620SDavid Howells rcu_read_lock(); \ 607ff50620SDavid Howells xas_for_each(&xas, head, ULONG_MAX) { \ 617ff50620SDavid Howells if (xas_retry(&xas, head)) \ 627ff50620SDavid Howells continue; \ 637ff50620SDavid Howells if (WARN_ON(xa_is_value(head))) \ 647ff50620SDavid Howells break; \ 657ff50620SDavid Howells if (WARN_ON(PageHuge(head))) \ 667ff50620SDavid Howells break; \ 677ff50620SDavid Howells for (j = (head->index < index) ? index - head->index : 0; \ 687ff50620SDavid Howells j < thp_nr_pages(head); j++) { \ 697ff50620SDavid Howells __v.bv_page = head + j; \ 707ff50620SDavid Howells offset = (i->xarray_start + skip) & ~PAGE_MASK; \ 717ff50620SDavid Howells seg = PAGE_SIZE - offset; \ 727ff50620SDavid Howells __v.bv_offset = offset; \ 737ff50620SDavid Howells __v.bv_len = min(n, seg); \ 747ff50620SDavid Howells (void)(STEP); \ 757ff50620SDavid Howells n -= __v.bv_len; \ 767ff50620SDavid Howells skip += __v.bv_len; \ 777ff50620SDavid Howells if (n == 0) \ 787ff50620SDavid Howells break; \ 797ff50620SDavid Howells } \ 807ff50620SDavid Howells if (n == 0) \ 817ff50620SDavid Howells break; \ 827ff50620SDavid Howells } \ 837ff50620SDavid Howells rcu_read_unlock(); \ 847ff50620SDavid Howells n = wanted - n; \ 857ff50620SDavid Howells } 867ff50620SDavid Howells 877ff50620SDavid Howells #define iterate_and_advance(i, n, v, I, B, K, X) { \ 88dd254f5aSAl Viro if (unlikely(i->count < n)) \ 89dd254f5aSAl Viro n = i->count; \ 90f5da8354SAl Viro if (likely(n)) { \ 91d879cb83SAl Viro size_t skip = i->iov_offset; \ 9228f38db7SAl Viro if (likely(iter_is_iovec(i))) { \ 93*5c67aa90SAl Viro const struct iovec *iov = i->iov; \ 94d879cb83SAl Viro struct iovec v; \ 95d879cb83SAl Viro iterate_iovec(i, n, v, iov, skip, (I)) \ 96d879cb83SAl Viro i->nr_segs -= iov - i->iov; \ 97d879cb83SAl Viro i->iov = iov; \ 9828f38db7SAl Viro } else if (iov_iter_is_bvec(i)) { \ 9928f38db7SAl Viro const struct bio_vec *bvec = i->bvec; \ 10028f38db7SAl Viro struct bio_vec v; \ 10128f38db7SAl Viro struct bvec_iter __bi; \ 10228f38db7SAl Viro iterate_bvec(i, n, v, __bi, skip, (B)) \ 10328f38db7SAl Viro i->bvec = __bvec_iter_bvec(i->bvec, __bi); \ 10428f38db7SAl Viro i->nr_segs -= i->bvec - bvec; \ 10528f38db7SAl Viro skip = __bi.bi_bvec_done; \ 10628f38db7SAl Viro } else if (iov_iter_is_kvec(i)) { \ 107*5c67aa90SAl Viro const struct kvec *kvec = i->kvec; \ 10828f38db7SAl Viro struct kvec v; \ 109*5c67aa90SAl Viro iterate_iovec(i, n, v, kvec, skip, \ 110*5c67aa90SAl Viro ((void)(K),0)) \ 11128f38db7SAl Viro i->nr_segs -= kvec - i->kvec; \ 11228f38db7SAl Viro i->kvec = kvec; \ 11328f38db7SAl Viro } else if (iov_iter_is_xarray(i)) { \ 11428f38db7SAl Viro struct bio_vec v; \ 11528f38db7SAl Viro iterate_xarray(i, n, v, skip, (X)) \ 116d879cb83SAl Viro } \ 117d879cb83SAl Viro i->count -= n; \ 118d879cb83SAl Viro i->iov_offset = skip; \ 119dd254f5aSAl Viro } \ 120d879cb83SAl Viro } 121d879cb83SAl Viro 12209fc68dcSAl Viro static int copyout(void __user *to, const void *from, size_t n) 12309fc68dcSAl Viro { 1244d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1254d0e9df5SAlbert van der Linde return n; 12696d4f267SLinus Torvalds if (access_ok(to, n)) { 127d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 12809fc68dcSAl Viro n = raw_copy_to_user(to, from, n); 12909fc68dcSAl Viro } 13009fc68dcSAl Viro return n; 13109fc68dcSAl Viro } 13209fc68dcSAl Viro 13309fc68dcSAl Viro static int copyin(void *to, const void __user *from, size_t n) 13409fc68dcSAl Viro { 1354d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1364d0e9df5SAlbert van der Linde return n; 13796d4f267SLinus Torvalds if (access_ok(from, n)) { 138d0ef4c36SMarco Elver instrument_copy_from_user(to, from, n); 13909fc68dcSAl Viro n = raw_copy_from_user(to, from, n); 14009fc68dcSAl Viro } 14109fc68dcSAl Viro return n; 14209fc68dcSAl Viro } 14309fc68dcSAl Viro 144d879cb83SAl Viro static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, 145d879cb83SAl Viro struct iov_iter *i) 146d879cb83SAl Viro { 147d879cb83SAl Viro size_t skip, copy, left, wanted; 148d879cb83SAl Viro const struct iovec *iov; 149d879cb83SAl Viro char __user *buf; 150d879cb83SAl Viro void *kaddr, *from; 151d879cb83SAl Viro 152d879cb83SAl Viro if (unlikely(bytes > i->count)) 153d879cb83SAl Viro bytes = i->count; 154d879cb83SAl Viro 155d879cb83SAl Viro if (unlikely(!bytes)) 156d879cb83SAl Viro return 0; 157d879cb83SAl Viro 15809fc68dcSAl Viro might_fault(); 159d879cb83SAl Viro wanted = bytes; 160d879cb83SAl Viro iov = i->iov; 161d879cb83SAl Viro skip = i->iov_offset; 162d879cb83SAl Viro buf = iov->iov_base + skip; 163d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 164d879cb83SAl Viro 1653fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { 166d879cb83SAl Viro kaddr = kmap_atomic(page); 167d879cb83SAl Viro from = kaddr + offset; 168d879cb83SAl Viro 169d879cb83SAl Viro /* first chunk, usually the only one */ 17009fc68dcSAl Viro left = copyout(buf, from, copy); 171d879cb83SAl Viro copy -= left; 172d879cb83SAl Viro skip += copy; 173d879cb83SAl Viro from += copy; 174d879cb83SAl Viro bytes -= copy; 175d879cb83SAl Viro 176d879cb83SAl Viro while (unlikely(!left && bytes)) { 177d879cb83SAl Viro iov++; 178d879cb83SAl Viro buf = iov->iov_base; 179d879cb83SAl Viro copy = min(bytes, iov->iov_len); 18009fc68dcSAl Viro left = copyout(buf, from, copy); 181d879cb83SAl Viro copy -= left; 182d879cb83SAl Viro skip = copy; 183d879cb83SAl Viro from += copy; 184d879cb83SAl Viro bytes -= copy; 185d879cb83SAl Viro } 186d879cb83SAl Viro if (likely(!bytes)) { 187d879cb83SAl Viro kunmap_atomic(kaddr); 188d879cb83SAl Viro goto done; 189d879cb83SAl Viro } 190d879cb83SAl Viro offset = from - kaddr; 191d879cb83SAl Viro buf += copy; 192d879cb83SAl Viro kunmap_atomic(kaddr); 193d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 194d879cb83SAl Viro } 195d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 1963fa6c507SMikulas Patocka 197d879cb83SAl Viro kaddr = kmap(page); 198d879cb83SAl Viro from = kaddr + offset; 19909fc68dcSAl Viro left = copyout(buf, from, copy); 200d879cb83SAl Viro copy -= left; 201d879cb83SAl Viro skip += copy; 202d879cb83SAl Viro from += copy; 203d879cb83SAl Viro bytes -= copy; 204d879cb83SAl Viro while (unlikely(!left && bytes)) { 205d879cb83SAl Viro iov++; 206d879cb83SAl Viro buf = iov->iov_base; 207d879cb83SAl Viro copy = min(bytes, iov->iov_len); 20809fc68dcSAl Viro left = copyout(buf, from, copy); 209d879cb83SAl Viro copy -= left; 210d879cb83SAl Viro skip = copy; 211d879cb83SAl Viro from += copy; 212d879cb83SAl Viro bytes -= copy; 213d879cb83SAl Viro } 214d879cb83SAl Viro kunmap(page); 2153fa6c507SMikulas Patocka 216d879cb83SAl Viro done: 217d879cb83SAl Viro if (skip == iov->iov_len) { 218d879cb83SAl Viro iov++; 219d879cb83SAl Viro skip = 0; 220d879cb83SAl Viro } 221d879cb83SAl Viro i->count -= wanted - bytes; 222d879cb83SAl Viro i->nr_segs -= iov - i->iov; 223d879cb83SAl Viro i->iov = iov; 224d879cb83SAl Viro i->iov_offset = skip; 225d879cb83SAl Viro return wanted - bytes; 226d879cb83SAl Viro } 227d879cb83SAl Viro 228d879cb83SAl Viro static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, 229d879cb83SAl Viro struct iov_iter *i) 230d879cb83SAl Viro { 231d879cb83SAl Viro size_t skip, copy, left, wanted; 232d879cb83SAl Viro const struct iovec *iov; 233d879cb83SAl Viro char __user *buf; 234d879cb83SAl Viro void *kaddr, *to; 235d879cb83SAl Viro 236d879cb83SAl Viro if (unlikely(bytes > i->count)) 237d879cb83SAl Viro bytes = i->count; 238d879cb83SAl Viro 239d879cb83SAl Viro if (unlikely(!bytes)) 240d879cb83SAl Viro return 0; 241d879cb83SAl Viro 24209fc68dcSAl Viro might_fault(); 243d879cb83SAl Viro wanted = bytes; 244d879cb83SAl Viro iov = i->iov; 245d879cb83SAl Viro skip = i->iov_offset; 246d879cb83SAl Viro buf = iov->iov_base + skip; 247d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 248d879cb83SAl Viro 2493fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { 250d879cb83SAl Viro kaddr = kmap_atomic(page); 251d879cb83SAl Viro to = kaddr + offset; 252d879cb83SAl Viro 253d879cb83SAl Viro /* first chunk, usually the only one */ 25409fc68dcSAl Viro left = copyin(to, buf, copy); 255d879cb83SAl Viro copy -= left; 256d879cb83SAl Viro skip += copy; 257d879cb83SAl Viro to += copy; 258d879cb83SAl Viro bytes -= copy; 259d879cb83SAl Viro 260d879cb83SAl Viro while (unlikely(!left && bytes)) { 261d879cb83SAl Viro iov++; 262d879cb83SAl Viro buf = iov->iov_base; 263d879cb83SAl Viro copy = min(bytes, iov->iov_len); 26409fc68dcSAl Viro left = copyin(to, buf, copy); 265d879cb83SAl Viro copy -= left; 266d879cb83SAl Viro skip = copy; 267d879cb83SAl Viro to += copy; 268d879cb83SAl Viro bytes -= copy; 269d879cb83SAl Viro } 270d879cb83SAl Viro if (likely(!bytes)) { 271d879cb83SAl Viro kunmap_atomic(kaddr); 272d879cb83SAl Viro goto done; 273d879cb83SAl Viro } 274d879cb83SAl Viro offset = to - kaddr; 275d879cb83SAl Viro buf += copy; 276d879cb83SAl Viro kunmap_atomic(kaddr); 277d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 278d879cb83SAl Viro } 279d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 2803fa6c507SMikulas Patocka 281d879cb83SAl Viro kaddr = kmap(page); 282d879cb83SAl Viro to = kaddr + offset; 28309fc68dcSAl Viro left = copyin(to, buf, copy); 284d879cb83SAl Viro copy -= left; 285d879cb83SAl Viro skip += copy; 286d879cb83SAl Viro to += copy; 287d879cb83SAl Viro bytes -= copy; 288d879cb83SAl Viro while (unlikely(!left && bytes)) { 289d879cb83SAl Viro iov++; 290d879cb83SAl Viro buf = iov->iov_base; 291d879cb83SAl Viro copy = min(bytes, iov->iov_len); 29209fc68dcSAl Viro left = copyin(to, buf, copy); 293d879cb83SAl Viro copy -= left; 294d879cb83SAl Viro skip = copy; 295d879cb83SAl Viro to += copy; 296d879cb83SAl Viro bytes -= copy; 297d879cb83SAl Viro } 298d879cb83SAl Viro kunmap(page); 2993fa6c507SMikulas Patocka 300d879cb83SAl Viro done: 301d879cb83SAl Viro if (skip == iov->iov_len) { 302d879cb83SAl Viro iov++; 303d879cb83SAl Viro skip = 0; 304d879cb83SAl Viro } 305d879cb83SAl Viro i->count -= wanted - bytes; 306d879cb83SAl Viro i->nr_segs -= iov - i->iov; 307d879cb83SAl Viro i->iov = iov; 308d879cb83SAl Viro i->iov_offset = skip; 309d879cb83SAl Viro return wanted - bytes; 310d879cb83SAl Viro } 311d879cb83SAl Viro 312241699cdSAl Viro #ifdef PIPE_PARANOIA 313241699cdSAl Viro static bool sanity(const struct iov_iter *i) 314241699cdSAl Viro { 315241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 3168cefc107SDavid Howells unsigned int p_head = pipe->head; 3178cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3188cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3198cefc107SDavid Howells unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); 3208cefc107SDavid Howells unsigned int i_head = i->head; 3218cefc107SDavid Howells unsigned int idx; 3228cefc107SDavid Howells 323241699cdSAl Viro if (i->iov_offset) { 324241699cdSAl Viro struct pipe_buffer *p; 3258cefc107SDavid Howells if (unlikely(p_occupancy == 0)) 326241699cdSAl Viro goto Bad; // pipe must be non-empty 3278cefc107SDavid Howells if (unlikely(i_head != p_head - 1)) 328241699cdSAl Viro goto Bad; // must be at the last buffer... 329241699cdSAl Viro 3308cefc107SDavid Howells p = &pipe->bufs[i_head & p_mask]; 331241699cdSAl Viro if (unlikely(p->offset + p->len != i->iov_offset)) 332241699cdSAl Viro goto Bad; // ... at the end of segment 333241699cdSAl Viro } else { 3348cefc107SDavid Howells if (i_head != p_head) 335241699cdSAl Viro goto Bad; // must be right after the last buffer 336241699cdSAl Viro } 337241699cdSAl Viro return true; 338241699cdSAl Viro Bad: 3398cefc107SDavid Howells printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); 3408cefc107SDavid Howells printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", 3418cefc107SDavid Howells p_head, p_tail, pipe->ring_size); 3428cefc107SDavid Howells for (idx = 0; idx < pipe->ring_size; idx++) 343241699cdSAl Viro printk(KERN_ERR "[%p %p %d %d]\n", 344241699cdSAl Viro pipe->bufs[idx].ops, 345241699cdSAl Viro pipe->bufs[idx].page, 346241699cdSAl Viro pipe->bufs[idx].offset, 347241699cdSAl Viro pipe->bufs[idx].len); 348241699cdSAl Viro WARN_ON(1); 349241699cdSAl Viro return false; 350241699cdSAl Viro } 351241699cdSAl Viro #else 352241699cdSAl Viro #define sanity(i) true 353241699cdSAl Viro #endif 354241699cdSAl Viro 355241699cdSAl Viro static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, 356241699cdSAl Viro struct iov_iter *i) 357241699cdSAl Viro { 358241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 359241699cdSAl Viro struct pipe_buffer *buf; 3608cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3618cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3628cefc107SDavid Howells unsigned int i_head = i->head; 363241699cdSAl Viro size_t off; 364241699cdSAl Viro 365241699cdSAl Viro if (unlikely(bytes > i->count)) 366241699cdSAl Viro bytes = i->count; 367241699cdSAl Viro 368241699cdSAl Viro if (unlikely(!bytes)) 369241699cdSAl Viro return 0; 370241699cdSAl Viro 371241699cdSAl Viro if (!sanity(i)) 372241699cdSAl Viro return 0; 373241699cdSAl Viro 374241699cdSAl Viro off = i->iov_offset; 3758cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 376241699cdSAl Viro if (off) { 377241699cdSAl Viro if (offset == off && buf->page == page) { 378241699cdSAl Viro /* merge with the last one */ 379241699cdSAl Viro buf->len += bytes; 380241699cdSAl Viro i->iov_offset += bytes; 381241699cdSAl Viro goto out; 382241699cdSAl Viro } 3838cefc107SDavid Howells i_head++; 3848cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 385241699cdSAl Viro } 3866718b6f8SDavid Howells if (pipe_full(i_head, p_tail, pipe->max_usage)) 387241699cdSAl Viro return 0; 3888cefc107SDavid Howells 389241699cdSAl Viro buf->ops = &page_cache_pipe_buf_ops; 3908cefc107SDavid Howells get_page(page); 3918cefc107SDavid Howells buf->page = page; 392241699cdSAl Viro buf->offset = offset; 393241699cdSAl Viro buf->len = bytes; 3948cefc107SDavid Howells 3958cefc107SDavid Howells pipe->head = i_head + 1; 396241699cdSAl Viro i->iov_offset = offset + bytes; 3978cefc107SDavid Howells i->head = i_head; 398241699cdSAl Viro out: 399241699cdSAl Viro i->count -= bytes; 400241699cdSAl Viro return bytes; 401241699cdSAl Viro } 402241699cdSAl Viro 403d879cb83SAl Viro /* 404171a0203SAnton Altaparmakov * Fault in one or more iovecs of the given iov_iter, to a maximum length of 405171a0203SAnton Altaparmakov * bytes. For each iovec, fault in each page that constitutes the iovec. 406171a0203SAnton Altaparmakov * 407171a0203SAnton Altaparmakov * Return 0 on success, or non-zero if the memory could not be accessed (i.e. 408171a0203SAnton Altaparmakov * because it is an invalid address). 409171a0203SAnton Altaparmakov */ 4108409a0d2SAl Viro int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes) 411171a0203SAnton Altaparmakov { 4120e8f0d67SAl Viro if (iter_is_iovec(i)) { 4138409a0d2SAl Viro const struct iovec *p; 4148409a0d2SAl Viro size_t skip; 4158409a0d2SAl Viro 4168409a0d2SAl Viro if (bytes > i->count) 4178409a0d2SAl Viro bytes = i->count; 4188409a0d2SAl Viro for (p = i->iov, skip = i->iov_offset; bytes; p++, skip = 0) { 4198409a0d2SAl Viro size_t len = min(bytes, p->iov_len - skip); 4208409a0d2SAl Viro int err; 4218409a0d2SAl Viro 4228409a0d2SAl Viro if (unlikely(!len)) 4238409a0d2SAl Viro continue; 4248409a0d2SAl Viro err = fault_in_pages_readable(p->iov_base + skip, len); 425171a0203SAnton Altaparmakov if (unlikely(err)) 426171a0203SAnton Altaparmakov return err; 4278409a0d2SAl Viro bytes -= len; 4288409a0d2SAl Viro } 429171a0203SAnton Altaparmakov } 430171a0203SAnton Altaparmakov return 0; 431171a0203SAnton Altaparmakov } 432d4690f1eSAl Viro EXPORT_SYMBOL(iov_iter_fault_in_readable); 433171a0203SAnton Altaparmakov 434aa563d7bSDavid Howells void iov_iter_init(struct iov_iter *i, unsigned int direction, 435d879cb83SAl Viro const struct iovec *iov, unsigned long nr_segs, 436d879cb83SAl Viro size_t count) 437d879cb83SAl Viro { 438aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 4398cd54c1cSAl Viro WARN_ON_ONCE(uaccess_kernel()); 4408cd54c1cSAl Viro *i = (struct iov_iter) { 4418cd54c1cSAl Viro .iter_type = ITER_IOVEC, 4428cd54c1cSAl Viro .data_source = direction, 4438cd54c1cSAl Viro .iov = iov, 4448cd54c1cSAl Viro .nr_segs = nr_segs, 4458cd54c1cSAl Viro .iov_offset = 0, 4468cd54c1cSAl Viro .count = count 4478cd54c1cSAl Viro }; 448d879cb83SAl Viro } 449d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_init); 450d879cb83SAl Viro 451241699cdSAl Viro static inline bool allocated(struct pipe_buffer *buf) 452241699cdSAl Viro { 453241699cdSAl Viro return buf->ops == &default_pipe_buf_ops; 454241699cdSAl Viro } 455241699cdSAl Viro 4568cefc107SDavid Howells static inline void data_start(const struct iov_iter *i, 4578cefc107SDavid Howells unsigned int *iter_headp, size_t *offp) 458241699cdSAl Viro { 4598cefc107SDavid Howells unsigned int p_mask = i->pipe->ring_size - 1; 4608cefc107SDavid Howells unsigned int iter_head = i->head; 461241699cdSAl Viro size_t off = i->iov_offset; 4628cefc107SDavid Howells 4638cefc107SDavid Howells if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || 4648cefc107SDavid Howells off == PAGE_SIZE)) { 4658cefc107SDavid Howells iter_head++; 466241699cdSAl Viro off = 0; 467241699cdSAl Viro } 4688cefc107SDavid Howells *iter_headp = iter_head; 469241699cdSAl Viro *offp = off; 470241699cdSAl Viro } 471241699cdSAl Viro 472241699cdSAl Viro static size_t push_pipe(struct iov_iter *i, size_t size, 4738cefc107SDavid Howells int *iter_headp, size_t *offp) 474241699cdSAl Viro { 475241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 4768cefc107SDavid Howells unsigned int p_tail = pipe->tail; 4778cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 4788cefc107SDavid Howells unsigned int iter_head; 479241699cdSAl Viro size_t off; 480241699cdSAl Viro ssize_t left; 481241699cdSAl Viro 482241699cdSAl Viro if (unlikely(size > i->count)) 483241699cdSAl Viro size = i->count; 484241699cdSAl Viro if (unlikely(!size)) 485241699cdSAl Viro return 0; 486241699cdSAl Viro 487241699cdSAl Viro left = size; 4888cefc107SDavid Howells data_start(i, &iter_head, &off); 4898cefc107SDavid Howells *iter_headp = iter_head; 490241699cdSAl Viro *offp = off; 491241699cdSAl Viro if (off) { 492241699cdSAl Viro left -= PAGE_SIZE - off; 493241699cdSAl Viro if (left <= 0) { 4948cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len += size; 495241699cdSAl Viro return size; 496241699cdSAl Viro } 4978cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; 4988cefc107SDavid Howells iter_head++; 499241699cdSAl Viro } 5006718b6f8SDavid Howells while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { 5018cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; 502241699cdSAl Viro struct page *page = alloc_page(GFP_USER); 503241699cdSAl Viro if (!page) 504241699cdSAl Viro break; 5058cefc107SDavid Howells 5068cefc107SDavid Howells buf->ops = &default_pipe_buf_ops; 5078cefc107SDavid Howells buf->page = page; 5088cefc107SDavid Howells buf->offset = 0; 5098cefc107SDavid Howells buf->len = min_t(ssize_t, left, PAGE_SIZE); 5108cefc107SDavid Howells left -= buf->len; 5118cefc107SDavid Howells iter_head++; 5128cefc107SDavid Howells pipe->head = iter_head; 5138cefc107SDavid Howells 5148cefc107SDavid Howells if (left == 0) 515241699cdSAl Viro return size; 516241699cdSAl Viro } 517241699cdSAl Viro return size - left; 518241699cdSAl Viro } 519241699cdSAl Viro 520241699cdSAl Viro static size_t copy_pipe_to_iter(const void *addr, size_t bytes, 521241699cdSAl Viro struct iov_iter *i) 522241699cdSAl Viro { 523241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5248cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5258cefc107SDavid Howells unsigned int i_head; 526241699cdSAl Viro size_t n, off; 527241699cdSAl Viro 528241699cdSAl Viro if (!sanity(i)) 529241699cdSAl Viro return 0; 530241699cdSAl Viro 5318cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 532241699cdSAl Viro if (unlikely(!n)) 533241699cdSAl Viro return 0; 5348cefc107SDavid Howells do { 535241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 5368cefc107SDavid Howells memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); 5378cefc107SDavid Howells i->head = i_head; 538241699cdSAl Viro i->iov_offset = off + chunk; 539241699cdSAl Viro n -= chunk; 540241699cdSAl Viro addr += chunk; 5418cefc107SDavid Howells off = 0; 5428cefc107SDavid Howells i_head++; 5438cefc107SDavid Howells } while (n); 544241699cdSAl Viro i->count -= bytes; 545241699cdSAl Viro return bytes; 546241699cdSAl Viro } 547241699cdSAl Viro 548f9152895SAl Viro static __wsum csum_and_memcpy(void *to, const void *from, size_t len, 549f9152895SAl Viro __wsum sum, size_t off) 550f9152895SAl Viro { 551cc44c17bSAl Viro __wsum next = csum_partial_copy_nocheck(from, to, len); 552f9152895SAl Viro return csum_block_add(sum, next, off); 553f9152895SAl Viro } 554f9152895SAl Viro 55578e1f386SAl Viro static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, 55652cbd23aSWillem de Bruijn struct csum_state *csstate, 55752cbd23aSWillem de Bruijn struct iov_iter *i) 55878e1f386SAl Viro { 55978e1f386SAl Viro struct pipe_inode_info *pipe = i->pipe; 5608cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 56152cbd23aSWillem de Bruijn __wsum sum = csstate->csum; 56252cbd23aSWillem de Bruijn size_t off = csstate->off; 5638cefc107SDavid Howells unsigned int i_head; 56478e1f386SAl Viro size_t n, r; 56578e1f386SAl Viro 56678e1f386SAl Viro if (!sanity(i)) 56778e1f386SAl Viro return 0; 56878e1f386SAl Viro 5698cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &r); 57078e1f386SAl Viro if (unlikely(!n)) 57178e1f386SAl Viro return 0; 5728cefc107SDavid Howells do { 57378e1f386SAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - r); 5748cefc107SDavid Howells char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); 575f9152895SAl Viro sum = csum_and_memcpy(p + r, addr, chunk, sum, off); 57678e1f386SAl Viro kunmap_atomic(p); 5778cefc107SDavid Howells i->head = i_head; 57878e1f386SAl Viro i->iov_offset = r + chunk; 57978e1f386SAl Viro n -= chunk; 58078e1f386SAl Viro off += chunk; 58178e1f386SAl Viro addr += chunk; 5828cefc107SDavid Howells r = 0; 5838cefc107SDavid Howells i_head++; 5848cefc107SDavid Howells } while (n); 58578e1f386SAl Viro i->count -= bytes; 58652cbd23aSWillem de Bruijn csstate->csum = sum; 58752cbd23aSWillem de Bruijn csstate->off = off; 58878e1f386SAl Viro return bytes; 58978e1f386SAl Viro } 59078e1f386SAl Viro 591aa28de27SAl Viro size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 592d879cb83SAl Viro { 59336f7a8a4SAl Viro const char *from = addr; 59400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 595241699cdSAl Viro return copy_pipe_to_iter(addr, bytes, i); 59609fc68dcSAl Viro if (iter_is_iovec(i)) 59709fc68dcSAl Viro might_fault(); 598d879cb83SAl Viro iterate_and_advance(i, bytes, v, 59909fc68dcSAl Viro copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 600d879cb83SAl Viro memcpy_to_page(v.bv_page, v.bv_offset, 601d879cb83SAl Viro (from += v.bv_len) - v.bv_len, v.bv_len), 6027ff50620SDavid Howells memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 6037ff50620SDavid Howells memcpy_to_page(v.bv_page, v.bv_offset, 6047ff50620SDavid Howells (from += v.bv_len) - v.bv_len, v.bv_len) 605d879cb83SAl Viro ) 606d879cb83SAl Viro 607d879cb83SAl Viro return bytes; 608d879cb83SAl Viro } 609aa28de27SAl Viro EXPORT_SYMBOL(_copy_to_iter); 610d879cb83SAl Viro 611ec6347bbSDan Williams #ifdef CONFIG_ARCH_HAS_COPY_MC 612ec6347bbSDan Williams static int copyout_mc(void __user *to, const void *from, size_t n) 6138780356eSDan Williams { 61496d4f267SLinus Torvalds if (access_ok(to, n)) { 615d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 616ec6347bbSDan Williams n = copy_mc_to_user((__force void *) to, from, n); 6178780356eSDan Williams } 6188780356eSDan Williams return n; 6198780356eSDan Williams } 6208780356eSDan Williams 621ec6347bbSDan Williams static unsigned long copy_mc_to_page(struct page *page, size_t offset, 6228780356eSDan Williams const char *from, size_t len) 6238780356eSDan Williams { 6248780356eSDan Williams unsigned long ret; 6258780356eSDan Williams char *to; 6268780356eSDan Williams 6278780356eSDan Williams to = kmap_atomic(page); 628ec6347bbSDan Williams ret = copy_mc_to_kernel(to + offset, from, len); 6298780356eSDan Williams kunmap_atomic(to); 6308780356eSDan Williams 6318780356eSDan Williams return ret; 6328780356eSDan Williams } 6338780356eSDan Williams 634ec6347bbSDan Williams static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, 635ca146f6fSDan Williams struct iov_iter *i) 636ca146f6fSDan Williams { 637ca146f6fSDan Williams struct pipe_inode_info *pipe = i->pipe; 6388cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 6398cefc107SDavid Howells unsigned int i_head; 640ca146f6fSDan Williams size_t n, off, xfer = 0; 641ca146f6fSDan Williams 642ca146f6fSDan Williams if (!sanity(i)) 643ca146f6fSDan Williams return 0; 644ca146f6fSDan Williams 6458cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 646ca146f6fSDan Williams if (unlikely(!n)) 647ca146f6fSDan Williams return 0; 6488cefc107SDavid Howells do { 649ca146f6fSDan Williams size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 650ca146f6fSDan Williams unsigned long rem; 651ca146f6fSDan Williams 652ec6347bbSDan Williams rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, 6538cefc107SDavid Howells off, addr, chunk); 6548cefc107SDavid Howells i->head = i_head; 655ca146f6fSDan Williams i->iov_offset = off + chunk - rem; 656ca146f6fSDan Williams xfer += chunk - rem; 657ca146f6fSDan Williams if (rem) 658ca146f6fSDan Williams break; 659ca146f6fSDan Williams n -= chunk; 660ca146f6fSDan Williams addr += chunk; 6618cefc107SDavid Howells off = 0; 6628cefc107SDavid Howells i_head++; 6638cefc107SDavid Howells } while (n); 664ca146f6fSDan Williams i->count -= xfer; 665ca146f6fSDan Williams return xfer; 666ca146f6fSDan Williams } 667ca146f6fSDan Williams 668bf3eeb9bSDan Williams /** 669ec6347bbSDan Williams * _copy_mc_to_iter - copy to iter with source memory error exception handling 670bf3eeb9bSDan Williams * @addr: source kernel address 671bf3eeb9bSDan Williams * @bytes: total transfer length 672bf3eeb9bSDan Williams * @iter: destination iterator 673bf3eeb9bSDan Williams * 674ec6347bbSDan Williams * The pmem driver deploys this for the dax operation 675ec6347bbSDan Williams * (dax_copy_to_iter()) for dax reads (bypass page-cache and the 676ec6347bbSDan Williams * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes 677ec6347bbSDan Williams * successfully copied. 678bf3eeb9bSDan Williams * 679ec6347bbSDan Williams * The main differences between this and typical _copy_to_iter(). 680bf3eeb9bSDan Williams * 681bf3eeb9bSDan Williams * * Typical tail/residue handling after a fault retries the copy 682bf3eeb9bSDan Williams * byte-by-byte until the fault happens again. Re-triggering machine 683bf3eeb9bSDan Williams * checks is potentially fatal so the implementation uses source 684bf3eeb9bSDan Williams * alignment and poison alignment assumptions to avoid re-triggering 685bf3eeb9bSDan Williams * hardware exceptions. 686bf3eeb9bSDan Williams * 687bf3eeb9bSDan Williams * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. 688bf3eeb9bSDan Williams * Compare to copy_to_iter() where only ITER_IOVEC attempts might return 689bf3eeb9bSDan Williams * a short copy. 690bf3eeb9bSDan Williams */ 691ec6347bbSDan Williams size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 6928780356eSDan Williams { 6938780356eSDan Williams const char *from = addr; 6948780356eSDan Williams unsigned long rem, curr_addr, s_addr = (unsigned long) addr; 6958780356eSDan Williams 69600e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 697ec6347bbSDan Williams return copy_mc_pipe_to_iter(addr, bytes, i); 6988780356eSDan Williams if (iter_is_iovec(i)) 6998780356eSDan Williams might_fault(); 7008780356eSDan Williams iterate_and_advance(i, bytes, v, 701ec6347bbSDan Williams copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len, 702ec6347bbSDan Williams v.iov_len), 7038780356eSDan Williams ({ 704ec6347bbSDan Williams rem = copy_mc_to_page(v.bv_page, v.bv_offset, 7058780356eSDan Williams (from += v.bv_len) - v.bv_len, v.bv_len); 7068780356eSDan Williams if (rem) { 7078780356eSDan Williams curr_addr = (unsigned long) from; 7088780356eSDan Williams bytes = curr_addr - s_addr - rem; 7098780356eSDan Williams return bytes; 7108780356eSDan Williams } 7118780356eSDan Williams }), 7128780356eSDan Williams ({ 713ec6347bbSDan Williams rem = copy_mc_to_kernel(v.iov_base, (from += v.iov_len) 714ec6347bbSDan Williams - v.iov_len, v.iov_len); 7158780356eSDan Williams if (rem) { 7168780356eSDan Williams curr_addr = (unsigned long) from; 7178780356eSDan Williams bytes = curr_addr - s_addr - rem; 7188780356eSDan Williams return bytes; 7198780356eSDan Williams } 7207ff50620SDavid Howells }), 7217ff50620SDavid Howells ({ 7227ff50620SDavid Howells rem = copy_mc_to_page(v.bv_page, v.bv_offset, 7237ff50620SDavid Howells (from += v.bv_len) - v.bv_len, v.bv_len); 7247ff50620SDavid Howells if (rem) { 7257ff50620SDavid Howells curr_addr = (unsigned long) from; 7267ff50620SDavid Howells bytes = curr_addr - s_addr - rem; 7277ff50620SDavid Howells rcu_read_unlock(); 7283d14ec1fSDavid Howells i->iov_offset += bytes; 7293d14ec1fSDavid Howells i->count -= bytes; 7307ff50620SDavid Howells return bytes; 7317ff50620SDavid Howells } 7328780356eSDan Williams }) 7338780356eSDan Williams ) 7348780356eSDan Williams 7358780356eSDan Williams return bytes; 7368780356eSDan Williams } 737ec6347bbSDan Williams EXPORT_SYMBOL_GPL(_copy_mc_to_iter); 738ec6347bbSDan Williams #endif /* CONFIG_ARCH_HAS_COPY_MC */ 7398780356eSDan Williams 740aa28de27SAl Viro size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) 741d879cb83SAl Viro { 742d879cb83SAl Viro char *to = addr; 74300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 744241699cdSAl Viro WARN_ON(1); 745241699cdSAl Viro return 0; 746241699cdSAl Viro } 74709fc68dcSAl Viro if (iter_is_iovec(i)) 74809fc68dcSAl Viro might_fault(); 749d879cb83SAl Viro iterate_and_advance(i, bytes, v, 75009fc68dcSAl Viro copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 751d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 752d879cb83SAl Viro v.bv_offset, v.bv_len), 7537ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 7547ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 7557ff50620SDavid Howells v.bv_offset, v.bv_len) 756d879cb83SAl Viro ) 757d879cb83SAl Viro 758d879cb83SAl Viro return bytes; 759d879cb83SAl Viro } 760aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter); 761d879cb83SAl Viro 762aa28de27SAl Viro size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) 763d879cb83SAl Viro { 764d879cb83SAl Viro char *to = addr; 76500e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 766241699cdSAl Viro WARN_ON(1); 767241699cdSAl Viro return 0; 768241699cdSAl Viro } 769d879cb83SAl Viro iterate_and_advance(i, bytes, v, 7703f763453SAl Viro __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, 771d879cb83SAl Viro v.iov_base, v.iov_len), 772d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 773d879cb83SAl Viro v.bv_offset, v.bv_len), 7747ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 7757ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 7767ff50620SDavid Howells v.bv_offset, v.bv_len) 777d879cb83SAl Viro ) 778d879cb83SAl Viro 779d879cb83SAl Viro return bytes; 780d879cb83SAl Viro } 781aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_nocache); 782d879cb83SAl Viro 7830aed55afSDan Williams #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE 784abd08d7dSDan Williams /** 785abd08d7dSDan Williams * _copy_from_iter_flushcache - write destination through cpu cache 786abd08d7dSDan Williams * @addr: destination kernel address 787abd08d7dSDan Williams * @bytes: total transfer length 788abd08d7dSDan Williams * @iter: source iterator 789abd08d7dSDan Williams * 790abd08d7dSDan Williams * The pmem driver arranges for filesystem-dax to use this facility via 791abd08d7dSDan Williams * dax_copy_from_iter() for ensuring that writes to persistent memory 792abd08d7dSDan Williams * are flushed through the CPU cache. It is differentiated from 793abd08d7dSDan Williams * _copy_from_iter_nocache() in that guarantees all data is flushed for 794abd08d7dSDan Williams * all iterator types. The _copy_from_iter_nocache() only attempts to 795abd08d7dSDan Williams * bypass the cache for the ITER_IOVEC case, and on some archs may use 796abd08d7dSDan Williams * instructions that strand dirty-data in the cache. 797abd08d7dSDan Williams */ 7986a37e940SLinus Torvalds size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 7990aed55afSDan Williams { 8000aed55afSDan Williams char *to = addr; 80100e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 8020aed55afSDan Williams WARN_ON(1); 8030aed55afSDan Williams return 0; 8040aed55afSDan Williams } 8050aed55afSDan Williams iterate_and_advance(i, bytes, v, 8060aed55afSDan Williams __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, 8070aed55afSDan Williams v.iov_base, v.iov_len), 8080aed55afSDan Williams memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 8090aed55afSDan Williams v.bv_offset, v.bv_len), 8100aed55afSDan Williams memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, 8117ff50620SDavid Howells v.iov_len), 8127ff50620SDavid Howells memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 8137ff50620SDavid Howells v.bv_offset, v.bv_len) 8140aed55afSDan Williams ) 8150aed55afSDan Williams 8160aed55afSDan Williams return bytes; 8170aed55afSDan Williams } 8186a37e940SLinus Torvalds EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); 8190aed55afSDan Williams #endif 8200aed55afSDan Williams 82172e809edSAl Viro static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) 82272e809edSAl Viro { 8236daef95bSEric Dumazet struct page *head; 8246daef95bSEric Dumazet size_t v = n + offset; 8256daef95bSEric Dumazet 8266daef95bSEric Dumazet /* 8276daef95bSEric Dumazet * The general case needs to access the page order in order 8286daef95bSEric Dumazet * to compute the page size. 8296daef95bSEric Dumazet * However, we mostly deal with order-0 pages and thus can 8306daef95bSEric Dumazet * avoid a possible cache line miss for requests that fit all 8316daef95bSEric Dumazet * page orders. 8326daef95bSEric Dumazet */ 8336daef95bSEric Dumazet if (n <= v && v <= PAGE_SIZE) 8346daef95bSEric Dumazet return true; 8356daef95bSEric Dumazet 8366daef95bSEric Dumazet head = compound_head(page); 8376daef95bSEric Dumazet v += (page - head) << PAGE_SHIFT; 838a90bcb86SPetar Penkov 839a50b854eSMatthew Wilcox (Oracle) if (likely(n <= v && v <= (page_size(head)))) 84072e809edSAl Viro return true; 84172e809edSAl Viro WARN_ON(1); 84272e809edSAl Viro return false; 84372e809edSAl Viro } 844cbbd26b8SAl Viro 84508aa6479SAl Viro static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 846d879cb83SAl Viro struct iov_iter *i) 847d879cb83SAl Viro { 84828f38db7SAl Viro if (likely(iter_is_iovec(i))) 84928f38db7SAl Viro return copy_page_to_iter_iovec(page, offset, bytes, i); 85028f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 851d879cb83SAl Viro void *kaddr = kmap_atomic(page); 852d879cb83SAl Viro size_t wanted = copy_to_iter(kaddr + offset, bytes, i); 853d879cb83SAl Viro kunmap_atomic(kaddr); 854d879cb83SAl Viro return wanted; 85528f38db7SAl Viro } 85628f38db7SAl Viro if (iov_iter_is_pipe(i)) 85728f38db7SAl Viro return copy_page_to_iter_pipe(page, offset, bytes, i); 85828f38db7SAl Viro if (unlikely(iov_iter_is_discard(i))) { 859a506abc7SAl Viro if (unlikely(i->count < bytes)) 860a506abc7SAl Viro bytes = i->count; 861a506abc7SAl Viro i->count -= bytes; 8629ea9ce04SDavid Howells return bytes; 86328f38db7SAl Viro } 86428f38db7SAl Viro WARN_ON(1); 86528f38db7SAl Viro return 0; 866d879cb83SAl Viro } 86708aa6479SAl Viro 86808aa6479SAl Viro size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 86908aa6479SAl Viro struct iov_iter *i) 87008aa6479SAl Viro { 87108aa6479SAl Viro size_t res = 0; 87208aa6479SAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 87308aa6479SAl Viro return 0; 87408aa6479SAl Viro page += offset / PAGE_SIZE; // first subpage 87508aa6479SAl Viro offset %= PAGE_SIZE; 87608aa6479SAl Viro while (1) { 87708aa6479SAl Viro size_t n = __copy_page_to_iter(page, offset, 87808aa6479SAl Viro min(bytes, (size_t)PAGE_SIZE - offset), i); 87908aa6479SAl Viro res += n; 88008aa6479SAl Viro bytes -= n; 88108aa6479SAl Viro if (!bytes || !n) 88208aa6479SAl Viro break; 88308aa6479SAl Viro offset += n; 88408aa6479SAl Viro if (offset == PAGE_SIZE) { 88508aa6479SAl Viro page++; 88608aa6479SAl Viro offset = 0; 88708aa6479SAl Viro } 88808aa6479SAl Viro } 88908aa6479SAl Viro return res; 89008aa6479SAl Viro } 891d879cb83SAl Viro EXPORT_SYMBOL(copy_page_to_iter); 892d879cb83SAl Viro 893d879cb83SAl Viro size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, 894d879cb83SAl Viro struct iov_iter *i) 895d879cb83SAl Viro { 89672e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 89772e809edSAl Viro return 0; 89828f38db7SAl Viro if (likely(iter_is_iovec(i))) 89928f38db7SAl Viro return copy_page_from_iter_iovec(page, offset, bytes, i); 90028f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 901d879cb83SAl Viro void *kaddr = kmap_atomic(page); 902aa28de27SAl Viro size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); 903d879cb83SAl Viro kunmap_atomic(kaddr); 904d879cb83SAl Viro return wanted; 90528f38db7SAl Viro } 90628f38db7SAl Viro WARN_ON(1); 90728f38db7SAl Viro return 0; 908d879cb83SAl Viro } 909d879cb83SAl Viro EXPORT_SYMBOL(copy_page_from_iter); 910d879cb83SAl Viro 911241699cdSAl Viro static size_t pipe_zero(size_t bytes, struct iov_iter *i) 912241699cdSAl Viro { 913241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 9148cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9158cefc107SDavid Howells unsigned int i_head; 916241699cdSAl Viro size_t n, off; 917241699cdSAl Viro 918241699cdSAl Viro if (!sanity(i)) 919241699cdSAl Viro return 0; 920241699cdSAl Viro 9218cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 922241699cdSAl Viro if (unlikely(!n)) 923241699cdSAl Viro return 0; 924241699cdSAl Viro 9258cefc107SDavid Howells do { 926241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 9278cefc107SDavid Howells memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); 9288cefc107SDavid Howells i->head = i_head; 929241699cdSAl Viro i->iov_offset = off + chunk; 930241699cdSAl Viro n -= chunk; 9318cefc107SDavid Howells off = 0; 9328cefc107SDavid Howells i_head++; 9338cefc107SDavid Howells } while (n); 934241699cdSAl Viro i->count -= bytes; 935241699cdSAl Viro return bytes; 936241699cdSAl Viro } 937241699cdSAl Viro 938d879cb83SAl Viro size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 939d879cb83SAl Viro { 94000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 941241699cdSAl Viro return pipe_zero(bytes, i); 942d879cb83SAl Viro iterate_and_advance(i, bytes, v, 94309fc68dcSAl Viro clear_user(v.iov_base, v.iov_len), 944d879cb83SAl Viro memzero_page(v.bv_page, v.bv_offset, v.bv_len), 9457ff50620SDavid Howells memset(v.iov_base, 0, v.iov_len), 9467ff50620SDavid Howells memzero_page(v.bv_page, v.bv_offset, v.bv_len) 947d879cb83SAl Viro ) 948d879cb83SAl Viro 949d879cb83SAl Viro return bytes; 950d879cb83SAl Viro } 951d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_zero); 952d879cb83SAl Viro 953f0b65f39SAl Viro size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, 954f0b65f39SAl Viro struct iov_iter *i) 955d879cb83SAl Viro { 956d879cb83SAl Viro char *kaddr = kmap_atomic(page), *p = kaddr + offset; 95772e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) { 95872e809edSAl Viro kunmap_atomic(kaddr); 95972e809edSAl Viro return 0; 96072e809edSAl Viro } 9619ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 962241699cdSAl Viro kunmap_atomic(kaddr); 963241699cdSAl Viro WARN_ON(1); 964241699cdSAl Viro return 0; 965241699cdSAl Viro } 966f0b65f39SAl Viro iterate_and_advance(i, bytes, v, 96709fc68dcSAl Viro copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 968d879cb83SAl Viro memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 969d879cb83SAl Viro v.bv_offset, v.bv_len), 9707ff50620SDavid Howells memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 9717ff50620SDavid Howells memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 9727ff50620SDavid Howells v.bv_offset, v.bv_len) 973d879cb83SAl Viro ) 974d879cb83SAl Viro kunmap_atomic(kaddr); 975d879cb83SAl Viro return bytes; 976d879cb83SAl Viro } 977f0b65f39SAl Viro EXPORT_SYMBOL(copy_page_from_iter_atomic); 978d879cb83SAl Viro 979b9dc6f65SAl Viro static inline void pipe_truncate(struct iov_iter *i) 980241699cdSAl Viro { 981241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 9828cefc107SDavid Howells unsigned int p_tail = pipe->tail; 9838cefc107SDavid Howells unsigned int p_head = pipe->head; 9848cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9858cefc107SDavid Howells 9868cefc107SDavid Howells if (!pipe_empty(p_head, p_tail)) { 9878cefc107SDavid Howells struct pipe_buffer *buf; 9888cefc107SDavid Howells unsigned int i_head = i->head; 989b9dc6f65SAl Viro size_t off = i->iov_offset; 9908cefc107SDavid Howells 991b9dc6f65SAl Viro if (off) { 9928cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 9938cefc107SDavid Howells buf->len = off - buf->offset; 9948cefc107SDavid Howells i_head++; 995b9dc6f65SAl Viro } 9968cefc107SDavid Howells while (p_head != i_head) { 9978cefc107SDavid Howells p_head--; 9988cefc107SDavid Howells pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); 999241699cdSAl Viro } 10008cefc107SDavid Howells 10018cefc107SDavid Howells pipe->head = p_head; 1002241699cdSAl Viro } 1003b9dc6f65SAl Viro } 1004b9dc6f65SAl Viro 1005b9dc6f65SAl Viro static void pipe_advance(struct iov_iter *i, size_t size) 1006b9dc6f65SAl Viro { 1007b9dc6f65SAl Viro struct pipe_inode_info *pipe = i->pipe; 1008b9dc6f65SAl Viro if (size) { 1009b9dc6f65SAl Viro struct pipe_buffer *buf; 10108cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10118cefc107SDavid Howells unsigned int i_head = i->head; 1012b9dc6f65SAl Viro size_t off = i->iov_offset, left = size; 10138cefc107SDavid Howells 1014b9dc6f65SAl Viro if (off) /* make it relative to the beginning of buffer */ 10158cefc107SDavid Howells left += off - pipe->bufs[i_head & p_mask].offset; 1016b9dc6f65SAl Viro while (1) { 10178cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 1018b9dc6f65SAl Viro if (left <= buf->len) 1019b9dc6f65SAl Viro break; 1020b9dc6f65SAl Viro left -= buf->len; 10218cefc107SDavid Howells i_head++; 1022b9dc6f65SAl Viro } 10238cefc107SDavid Howells i->head = i_head; 1024b9dc6f65SAl Viro i->iov_offset = buf->offset + left; 1025b9dc6f65SAl Viro } 1026b9dc6f65SAl Viro i->count -= size; 1027b9dc6f65SAl Viro /* ... and discard everything past that point */ 1028b9dc6f65SAl Viro pipe_truncate(i); 1029241699cdSAl Viro } 1030241699cdSAl Viro 103154c8195bSPavel Begunkov static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) 103254c8195bSPavel Begunkov { 103354c8195bSPavel Begunkov struct bvec_iter bi; 103454c8195bSPavel Begunkov 103554c8195bSPavel Begunkov bi.bi_size = i->count; 103654c8195bSPavel Begunkov bi.bi_bvec_done = i->iov_offset; 103754c8195bSPavel Begunkov bi.bi_idx = 0; 103854c8195bSPavel Begunkov bvec_iter_advance(i->bvec, &bi, size); 103954c8195bSPavel Begunkov 104054c8195bSPavel Begunkov i->bvec += bi.bi_idx; 104154c8195bSPavel Begunkov i->nr_segs -= bi.bi_idx; 104254c8195bSPavel Begunkov i->count = bi.bi_size; 104354c8195bSPavel Begunkov i->iov_offset = bi.bi_bvec_done; 104454c8195bSPavel Begunkov } 104554c8195bSPavel Begunkov 1046185ac4d4SAl Viro static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) 1047185ac4d4SAl Viro { 1048185ac4d4SAl Viro const struct iovec *iov, *end; 1049185ac4d4SAl Viro 1050185ac4d4SAl Viro if (!i->count) 1051185ac4d4SAl Viro return; 1052185ac4d4SAl Viro i->count -= size; 1053185ac4d4SAl Viro 1054185ac4d4SAl Viro size += i->iov_offset; // from beginning of current segment 1055185ac4d4SAl Viro for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { 1056185ac4d4SAl Viro if (likely(size < iov->iov_len)) 1057185ac4d4SAl Viro break; 1058185ac4d4SAl Viro size -= iov->iov_len; 1059185ac4d4SAl Viro } 1060185ac4d4SAl Viro i->iov_offset = size; 1061185ac4d4SAl Viro i->nr_segs -= iov - i->iov; 1062185ac4d4SAl Viro i->iov = iov; 1063185ac4d4SAl Viro } 1064185ac4d4SAl Viro 1065d879cb83SAl Viro void iov_iter_advance(struct iov_iter *i, size_t size) 1066d879cb83SAl Viro { 10673b3fc051SAl Viro if (unlikely(i->count < size)) 10683b3fc051SAl Viro size = i->count; 1069185ac4d4SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { 1070185ac4d4SAl Viro /* iovec and kvec have identical layouts */ 1071185ac4d4SAl Viro iov_iter_iovec_advance(i, size); 1072185ac4d4SAl Viro } else if (iov_iter_is_bvec(i)) { 1073185ac4d4SAl Viro iov_iter_bvec_advance(i, size); 1074185ac4d4SAl Viro } else if (iov_iter_is_pipe(i)) { 1075241699cdSAl Viro pipe_advance(i, size); 1076185ac4d4SAl Viro } else if (unlikely(iov_iter_is_xarray(i))) { 10777ff50620SDavid Howells i->iov_offset += size; 10787ff50620SDavid Howells i->count -= size; 1079185ac4d4SAl Viro } else if (iov_iter_is_discard(i)) { 1080185ac4d4SAl Viro i->count -= size; 10817ff50620SDavid Howells } 1082d879cb83SAl Viro } 1083d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_advance); 1084d879cb83SAl Viro 108527c0e374SAl Viro void iov_iter_revert(struct iov_iter *i, size_t unroll) 108627c0e374SAl Viro { 108727c0e374SAl Viro if (!unroll) 108827c0e374SAl Viro return; 10895b47d59aSAl Viro if (WARN_ON(unroll > MAX_RW_COUNT)) 10905b47d59aSAl Viro return; 109127c0e374SAl Viro i->count += unroll; 109200e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 109327c0e374SAl Viro struct pipe_inode_info *pipe = i->pipe; 10948cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10958cefc107SDavid Howells unsigned int i_head = i->head; 109627c0e374SAl Viro size_t off = i->iov_offset; 109727c0e374SAl Viro while (1) { 10988cefc107SDavid Howells struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; 10998cefc107SDavid Howells size_t n = off - b->offset; 110027c0e374SAl Viro if (unroll < n) { 11014fa55cefSAl Viro off -= unroll; 110227c0e374SAl Viro break; 110327c0e374SAl Viro } 110427c0e374SAl Viro unroll -= n; 11058cefc107SDavid Howells if (!unroll && i_head == i->start_head) { 110627c0e374SAl Viro off = 0; 110727c0e374SAl Viro break; 110827c0e374SAl Viro } 11098cefc107SDavid Howells i_head--; 11108cefc107SDavid Howells b = &pipe->bufs[i_head & p_mask]; 11118cefc107SDavid Howells off = b->offset + b->len; 111227c0e374SAl Viro } 111327c0e374SAl Viro i->iov_offset = off; 11148cefc107SDavid Howells i->head = i_head; 111527c0e374SAl Viro pipe_truncate(i); 111627c0e374SAl Viro return; 111727c0e374SAl Viro } 11189ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 11199ea9ce04SDavid Howells return; 112027c0e374SAl Viro if (unroll <= i->iov_offset) { 112127c0e374SAl Viro i->iov_offset -= unroll; 112227c0e374SAl Viro return; 112327c0e374SAl Viro } 112427c0e374SAl Viro unroll -= i->iov_offset; 11257ff50620SDavid Howells if (iov_iter_is_xarray(i)) { 11267ff50620SDavid Howells BUG(); /* We should never go beyond the start of the specified 11277ff50620SDavid Howells * range since we might then be straying into pages that 11287ff50620SDavid Howells * aren't pinned. 11297ff50620SDavid Howells */ 11307ff50620SDavid Howells } else if (iov_iter_is_bvec(i)) { 113127c0e374SAl Viro const struct bio_vec *bvec = i->bvec; 113227c0e374SAl Viro while (1) { 113327c0e374SAl Viro size_t n = (--bvec)->bv_len; 113427c0e374SAl Viro i->nr_segs++; 113527c0e374SAl Viro if (unroll <= n) { 113627c0e374SAl Viro i->bvec = bvec; 113727c0e374SAl Viro i->iov_offset = n - unroll; 113827c0e374SAl Viro return; 113927c0e374SAl Viro } 114027c0e374SAl Viro unroll -= n; 114127c0e374SAl Viro } 114227c0e374SAl Viro } else { /* same logics for iovec and kvec */ 114327c0e374SAl Viro const struct iovec *iov = i->iov; 114427c0e374SAl Viro while (1) { 114527c0e374SAl Viro size_t n = (--iov)->iov_len; 114627c0e374SAl Viro i->nr_segs++; 114727c0e374SAl Viro if (unroll <= n) { 114827c0e374SAl Viro i->iov = iov; 114927c0e374SAl Viro i->iov_offset = n - unroll; 115027c0e374SAl Viro return; 115127c0e374SAl Viro } 115227c0e374SAl Viro unroll -= n; 115327c0e374SAl Viro } 115427c0e374SAl Viro } 115527c0e374SAl Viro } 115627c0e374SAl Viro EXPORT_SYMBOL(iov_iter_revert); 115727c0e374SAl Viro 1158d879cb83SAl Viro /* 1159d879cb83SAl Viro * Return the count of just the current iov_iter segment. 1160d879cb83SAl Viro */ 1161d879cb83SAl Viro size_t iov_iter_single_seg_count(const struct iov_iter *i) 1162d879cb83SAl Viro { 116328f38db7SAl Viro if (i->nr_segs > 1) { 116428f38db7SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 116528f38db7SAl Viro return min(i->count, i->iov->iov_len - i->iov_offset); 11667ff50620SDavid Howells if (iov_iter_is_bvec(i)) 1167d879cb83SAl Viro return min(i->count, i->bvec->bv_len - i->iov_offset); 116828f38db7SAl Viro } 116928f38db7SAl Viro return i->count; 1170d879cb83SAl Viro } 1171d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_single_seg_count); 1172d879cb83SAl Viro 1173aa563d7bSDavid Howells void iov_iter_kvec(struct iov_iter *i, unsigned int direction, 1174d879cb83SAl Viro const struct kvec *kvec, unsigned long nr_segs, 1175d879cb83SAl Viro size_t count) 1176d879cb83SAl Viro { 1177aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 11788cd54c1cSAl Viro *i = (struct iov_iter){ 11798cd54c1cSAl Viro .iter_type = ITER_KVEC, 11808cd54c1cSAl Viro .data_source = direction, 11818cd54c1cSAl Viro .kvec = kvec, 11828cd54c1cSAl Viro .nr_segs = nr_segs, 11838cd54c1cSAl Viro .iov_offset = 0, 11848cd54c1cSAl Viro .count = count 11858cd54c1cSAl Viro }; 1186d879cb83SAl Viro } 1187d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_kvec); 1188d879cb83SAl Viro 1189aa563d7bSDavid Howells void iov_iter_bvec(struct iov_iter *i, unsigned int direction, 1190d879cb83SAl Viro const struct bio_vec *bvec, unsigned long nr_segs, 1191d879cb83SAl Viro size_t count) 1192d879cb83SAl Viro { 1193aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 11948cd54c1cSAl Viro *i = (struct iov_iter){ 11958cd54c1cSAl Viro .iter_type = ITER_BVEC, 11968cd54c1cSAl Viro .data_source = direction, 11978cd54c1cSAl Viro .bvec = bvec, 11988cd54c1cSAl Viro .nr_segs = nr_segs, 11998cd54c1cSAl Viro .iov_offset = 0, 12008cd54c1cSAl Viro .count = count 12018cd54c1cSAl Viro }; 1202d879cb83SAl Viro } 1203d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_bvec); 1204d879cb83SAl Viro 1205aa563d7bSDavid Howells void iov_iter_pipe(struct iov_iter *i, unsigned int direction, 1206241699cdSAl Viro struct pipe_inode_info *pipe, 1207241699cdSAl Viro size_t count) 1208241699cdSAl Viro { 1209aa563d7bSDavid Howells BUG_ON(direction != READ); 12108cefc107SDavid Howells WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); 12118cd54c1cSAl Viro *i = (struct iov_iter){ 12128cd54c1cSAl Viro .iter_type = ITER_PIPE, 12138cd54c1cSAl Viro .data_source = false, 12148cd54c1cSAl Viro .pipe = pipe, 12158cd54c1cSAl Viro .head = pipe->head, 12168cd54c1cSAl Viro .start_head = pipe->head, 12178cd54c1cSAl Viro .iov_offset = 0, 12188cd54c1cSAl Viro .count = count 12198cd54c1cSAl Viro }; 1220241699cdSAl Viro } 1221241699cdSAl Viro EXPORT_SYMBOL(iov_iter_pipe); 1222241699cdSAl Viro 12239ea9ce04SDavid Howells /** 12247ff50620SDavid Howells * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray 12257ff50620SDavid Howells * @i: The iterator to initialise. 12267ff50620SDavid Howells * @direction: The direction of the transfer. 12277ff50620SDavid Howells * @xarray: The xarray to access. 12287ff50620SDavid Howells * @start: The start file position. 12297ff50620SDavid Howells * @count: The size of the I/O buffer in bytes. 12307ff50620SDavid Howells * 12317ff50620SDavid Howells * Set up an I/O iterator to either draw data out of the pages attached to an 12327ff50620SDavid Howells * inode or to inject data into those pages. The pages *must* be prevented 12337ff50620SDavid Howells * from evaporation, either by taking a ref on them or locking them by the 12347ff50620SDavid Howells * caller. 12357ff50620SDavid Howells */ 12367ff50620SDavid Howells void iov_iter_xarray(struct iov_iter *i, unsigned int direction, 12377ff50620SDavid Howells struct xarray *xarray, loff_t start, size_t count) 12387ff50620SDavid Howells { 12397ff50620SDavid Howells BUG_ON(direction & ~1); 12408cd54c1cSAl Viro *i = (struct iov_iter) { 12418cd54c1cSAl Viro .iter_type = ITER_XARRAY, 12428cd54c1cSAl Viro .data_source = direction, 12438cd54c1cSAl Viro .xarray = xarray, 12448cd54c1cSAl Viro .xarray_start = start, 12458cd54c1cSAl Viro .count = count, 12468cd54c1cSAl Viro .iov_offset = 0 12478cd54c1cSAl Viro }; 12487ff50620SDavid Howells } 12497ff50620SDavid Howells EXPORT_SYMBOL(iov_iter_xarray); 12507ff50620SDavid Howells 12517ff50620SDavid Howells /** 12529ea9ce04SDavid Howells * iov_iter_discard - Initialise an I/O iterator that discards data 12539ea9ce04SDavid Howells * @i: The iterator to initialise. 12549ea9ce04SDavid Howells * @direction: The direction of the transfer. 12559ea9ce04SDavid Howells * @count: The size of the I/O buffer in bytes. 12569ea9ce04SDavid Howells * 12579ea9ce04SDavid Howells * Set up an I/O iterator that just discards everything that's written to it. 12589ea9ce04SDavid Howells * It's only available as a READ iterator. 12599ea9ce04SDavid Howells */ 12609ea9ce04SDavid Howells void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) 12619ea9ce04SDavid Howells { 12629ea9ce04SDavid Howells BUG_ON(direction != READ); 12638cd54c1cSAl Viro *i = (struct iov_iter){ 12648cd54c1cSAl Viro .iter_type = ITER_DISCARD, 12658cd54c1cSAl Viro .data_source = false, 12668cd54c1cSAl Viro .count = count, 12678cd54c1cSAl Viro .iov_offset = 0 12688cd54c1cSAl Viro }; 12699ea9ce04SDavid Howells } 12709ea9ce04SDavid Howells EXPORT_SYMBOL(iov_iter_discard); 12719ea9ce04SDavid Howells 12729221d2e3SAl Viro static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) 1273d879cb83SAl Viro { 1274d879cb83SAl Viro unsigned long res = 0; 1275d879cb83SAl Viro size_t size = i->count; 12769221d2e3SAl Viro size_t skip = i->iov_offset; 12779221d2e3SAl Viro unsigned k; 1278d879cb83SAl Viro 12799221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 12809221d2e3SAl Viro size_t len = i->iov[k].iov_len - skip; 12819221d2e3SAl Viro if (len) { 12829221d2e3SAl Viro res |= (unsigned long)i->iov[k].iov_base + skip; 12839221d2e3SAl Viro if (len > size) 12849221d2e3SAl Viro len = size; 12859221d2e3SAl Viro res |= len; 12869221d2e3SAl Viro size -= len; 12879221d2e3SAl Viro if (!size) 12889221d2e3SAl Viro break; 12899221d2e3SAl Viro } 12909221d2e3SAl Viro } 12919221d2e3SAl Viro return res; 12929221d2e3SAl Viro } 12939221d2e3SAl Viro 12949221d2e3SAl Viro static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) 12959221d2e3SAl Viro { 12969221d2e3SAl Viro unsigned res = 0; 12979221d2e3SAl Viro size_t size = i->count; 12989221d2e3SAl Viro unsigned skip = i->iov_offset; 12999221d2e3SAl Viro unsigned k; 13009221d2e3SAl Viro 13019221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 13029221d2e3SAl Viro size_t len = i->bvec[k].bv_len - skip; 13039221d2e3SAl Viro res |= (unsigned long)i->bvec[k].bv_offset + skip; 13049221d2e3SAl Viro if (len > size) 13059221d2e3SAl Viro len = size; 13069221d2e3SAl Viro res |= len; 13079221d2e3SAl Viro size -= len; 13089221d2e3SAl Viro if (!size) 13099221d2e3SAl Viro break; 13109221d2e3SAl Viro } 13119221d2e3SAl Viro return res; 13129221d2e3SAl Viro } 13139221d2e3SAl Viro 13149221d2e3SAl Viro unsigned long iov_iter_alignment(const struct iov_iter *i) 13159221d2e3SAl Viro { 13169221d2e3SAl Viro /* iovec and kvec have identical layouts */ 13179221d2e3SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 13189221d2e3SAl Viro return iov_iter_alignment_iovec(i); 13199221d2e3SAl Viro 13209221d2e3SAl Viro if (iov_iter_is_bvec(i)) 13219221d2e3SAl Viro return iov_iter_alignment_bvec(i); 13229221d2e3SAl Viro 13239221d2e3SAl Viro if (iov_iter_is_pipe(i)) { 1324e0ff126eSJan Kara unsigned int p_mask = i->pipe->ring_size - 1; 13259221d2e3SAl Viro size_t size = i->count; 1326e0ff126eSJan Kara 13278cefc107SDavid Howells if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) 1328241699cdSAl Viro return size | i->iov_offset; 1329241699cdSAl Viro return size; 1330241699cdSAl Viro } 13319221d2e3SAl Viro 13329221d2e3SAl Viro if (iov_iter_is_xarray(i)) 13333d14ec1fSDavid Howells return (i->xarray_start + i->iov_offset) | i->count; 13349221d2e3SAl Viro 13359221d2e3SAl Viro return 0; 1336d879cb83SAl Viro } 1337d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_alignment); 1338d879cb83SAl Viro 1339357f435dSAl Viro unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 1340357f435dSAl Viro { 1341357f435dSAl Viro unsigned long res = 0; 1342610c7a71SAl Viro unsigned long v = 0; 1343357f435dSAl Viro size_t size = i->count; 1344610c7a71SAl Viro unsigned k; 1345357f435dSAl Viro 1346610c7a71SAl Viro if (WARN_ON(!iter_is_iovec(i))) 1347241699cdSAl Viro return ~0U; 1348241699cdSAl Viro 1349610c7a71SAl Viro for (k = 0; k < i->nr_segs; k++) { 1350610c7a71SAl Viro if (i->iov[k].iov_len) { 1351610c7a71SAl Viro unsigned long base = (unsigned long)i->iov[k].iov_base; 1352610c7a71SAl Viro if (v) // if not the first one 1353610c7a71SAl Viro res |= base | v; // this start | previous end 1354610c7a71SAl Viro v = base + i->iov[k].iov_len; 1355610c7a71SAl Viro if (size <= i->iov[k].iov_len) 1356610c7a71SAl Viro break; 1357610c7a71SAl Viro size -= i->iov[k].iov_len; 1358610c7a71SAl Viro } 1359610c7a71SAl Viro } 1360357f435dSAl Viro return res; 1361357f435dSAl Viro } 1362357f435dSAl Viro EXPORT_SYMBOL(iov_iter_gap_alignment); 1363357f435dSAl Viro 1364e76b6312SIlya Dryomov static inline ssize_t __pipe_get_pages(struct iov_iter *i, 1365241699cdSAl Viro size_t maxsize, 1366241699cdSAl Viro struct page **pages, 13678cefc107SDavid Howells int iter_head, 1368241699cdSAl Viro size_t *start) 1369241699cdSAl Viro { 1370241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 13718cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 13728cefc107SDavid Howells ssize_t n = push_pipe(i, maxsize, &iter_head, start); 1373241699cdSAl Viro if (!n) 1374241699cdSAl Viro return -EFAULT; 1375241699cdSAl Viro 1376241699cdSAl Viro maxsize = n; 1377241699cdSAl Viro n += *start; 13781689c73aSAl Viro while (n > 0) { 13798cefc107SDavid Howells get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); 13808cefc107SDavid Howells iter_head++; 1381241699cdSAl Viro n -= PAGE_SIZE; 1382241699cdSAl Viro } 1383241699cdSAl Viro 1384241699cdSAl Viro return maxsize; 1385241699cdSAl Viro } 1386241699cdSAl Viro 1387241699cdSAl Viro static ssize_t pipe_get_pages(struct iov_iter *i, 1388241699cdSAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1389241699cdSAl Viro size_t *start) 1390241699cdSAl Viro { 13918cefc107SDavid Howells unsigned int iter_head, npages; 1392241699cdSAl Viro size_t capacity; 1393241699cdSAl Viro 1394241699cdSAl Viro if (!sanity(i)) 1395241699cdSAl Viro return -EFAULT; 1396241699cdSAl Viro 13978cefc107SDavid Howells data_start(i, &iter_head, start); 13988cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 13998cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1400241699cdSAl Viro capacity = min(npages, maxpages) * PAGE_SIZE - *start; 1401241699cdSAl Viro 14028cefc107SDavid Howells return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); 1403241699cdSAl Viro } 1404241699cdSAl Viro 14057ff50620SDavid Howells static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, 14067ff50620SDavid Howells pgoff_t index, unsigned int nr_pages) 14077ff50620SDavid Howells { 14087ff50620SDavid Howells XA_STATE(xas, xa, index); 14097ff50620SDavid Howells struct page *page; 14107ff50620SDavid Howells unsigned int ret = 0; 14117ff50620SDavid Howells 14127ff50620SDavid Howells rcu_read_lock(); 14137ff50620SDavid Howells for (page = xas_load(&xas); page; page = xas_next(&xas)) { 14147ff50620SDavid Howells if (xas_retry(&xas, page)) 14157ff50620SDavid Howells continue; 14167ff50620SDavid Howells 14177ff50620SDavid Howells /* Has the page moved or been split? */ 14187ff50620SDavid Howells if (unlikely(page != xas_reload(&xas))) { 14197ff50620SDavid Howells xas_reset(&xas); 14207ff50620SDavid Howells continue; 14217ff50620SDavid Howells } 14227ff50620SDavid Howells 14237ff50620SDavid Howells pages[ret] = find_subpage(page, xas.xa_index); 14247ff50620SDavid Howells get_page(pages[ret]); 14257ff50620SDavid Howells if (++ret == nr_pages) 14267ff50620SDavid Howells break; 14277ff50620SDavid Howells } 14287ff50620SDavid Howells rcu_read_unlock(); 14297ff50620SDavid Howells return ret; 14307ff50620SDavid Howells } 14317ff50620SDavid Howells 14327ff50620SDavid Howells static ssize_t iter_xarray_get_pages(struct iov_iter *i, 14337ff50620SDavid Howells struct page **pages, size_t maxsize, 14347ff50620SDavid Howells unsigned maxpages, size_t *_start_offset) 14357ff50620SDavid Howells { 14367ff50620SDavid Howells unsigned nr, offset; 14377ff50620SDavid Howells pgoff_t index, count; 14387ff50620SDavid Howells size_t size = maxsize, actual; 14397ff50620SDavid Howells loff_t pos; 14407ff50620SDavid Howells 14417ff50620SDavid Howells if (!size || !maxpages) 14427ff50620SDavid Howells return 0; 14437ff50620SDavid Howells 14447ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 14457ff50620SDavid Howells index = pos >> PAGE_SHIFT; 14467ff50620SDavid Howells offset = pos & ~PAGE_MASK; 14477ff50620SDavid Howells *_start_offset = offset; 14487ff50620SDavid Howells 14497ff50620SDavid Howells count = 1; 14507ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 14517ff50620SDavid Howells size -= PAGE_SIZE - offset; 14527ff50620SDavid Howells count += size >> PAGE_SHIFT; 14537ff50620SDavid Howells size &= ~PAGE_MASK; 14547ff50620SDavid Howells if (size) 14557ff50620SDavid Howells count++; 14567ff50620SDavid Howells } 14577ff50620SDavid Howells 14587ff50620SDavid Howells if (count > maxpages) 14597ff50620SDavid Howells count = maxpages; 14607ff50620SDavid Howells 14617ff50620SDavid Howells nr = iter_xarray_populate_pages(pages, i->xarray, index, count); 14627ff50620SDavid Howells if (nr == 0) 14637ff50620SDavid Howells return 0; 14647ff50620SDavid Howells 14657ff50620SDavid Howells actual = PAGE_SIZE * nr; 14667ff50620SDavid Howells actual -= offset; 14677ff50620SDavid Howells if (nr == count && size > 0) { 14687ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 14697ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 14707ff50620SDavid Howells } 14717ff50620SDavid Howells return actual; 14727ff50620SDavid Howells } 14737ff50620SDavid Howells 14743d671ca6SAl Viro /* must be done on non-empty ITER_IOVEC one */ 14753d671ca6SAl Viro static unsigned long first_iovec_segment(const struct iov_iter *i, 14763d671ca6SAl Viro size_t *size, size_t *start, 14773d671ca6SAl Viro size_t maxsize, unsigned maxpages) 14783d671ca6SAl Viro { 14793d671ca6SAl Viro size_t skip; 14803d671ca6SAl Viro long k; 14813d671ca6SAl Viro 14823d671ca6SAl Viro for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { 14833d671ca6SAl Viro unsigned long addr = (unsigned long)i->iov[k].iov_base + skip; 14843d671ca6SAl Viro size_t len = i->iov[k].iov_len - skip; 14853d671ca6SAl Viro 14863d671ca6SAl Viro if (unlikely(!len)) 14873d671ca6SAl Viro continue; 14883d671ca6SAl Viro if (len > maxsize) 14893d671ca6SAl Viro len = maxsize; 14903d671ca6SAl Viro len += (*start = addr % PAGE_SIZE); 14913d671ca6SAl Viro if (len > maxpages * PAGE_SIZE) 14923d671ca6SAl Viro len = maxpages * PAGE_SIZE; 14933d671ca6SAl Viro *size = len; 14943d671ca6SAl Viro return addr & PAGE_MASK; 14953d671ca6SAl Viro } 14963d671ca6SAl Viro BUG(); // if it had been empty, we wouldn't get called 14973d671ca6SAl Viro } 14983d671ca6SAl Viro 14993d671ca6SAl Viro /* must be done on non-empty ITER_BVEC one */ 15003d671ca6SAl Viro static struct page *first_bvec_segment(const struct iov_iter *i, 15013d671ca6SAl Viro size_t *size, size_t *start, 15023d671ca6SAl Viro size_t maxsize, unsigned maxpages) 15033d671ca6SAl Viro { 15043d671ca6SAl Viro struct page *page; 15053d671ca6SAl Viro size_t skip = i->iov_offset, len; 15063d671ca6SAl Viro 15073d671ca6SAl Viro len = i->bvec->bv_len - skip; 15083d671ca6SAl Viro if (len > maxsize) 15093d671ca6SAl Viro len = maxsize; 15103d671ca6SAl Viro skip += i->bvec->bv_offset; 15113d671ca6SAl Viro page = i->bvec->bv_page + skip / PAGE_SIZE; 15123d671ca6SAl Viro len += (*start = skip % PAGE_SIZE); 15133d671ca6SAl Viro if (len > maxpages * PAGE_SIZE) 15143d671ca6SAl Viro len = maxpages * PAGE_SIZE; 15153d671ca6SAl Viro *size = len; 15163d671ca6SAl Viro return page; 15173d671ca6SAl Viro } 15183d671ca6SAl Viro 1519d879cb83SAl Viro ssize_t iov_iter_get_pages(struct iov_iter *i, 1520d879cb83SAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1521d879cb83SAl Viro size_t *start) 1522d879cb83SAl Viro { 15233d671ca6SAl Viro size_t len; 15243d671ca6SAl Viro int n, res; 15253d671ca6SAl Viro 1526d879cb83SAl Viro if (maxsize > i->count) 1527d879cb83SAl Viro maxsize = i->count; 15283d671ca6SAl Viro if (!maxsize) 15293d671ca6SAl Viro return 0; 1530d879cb83SAl Viro 15313d671ca6SAl Viro if (likely(iter_is_iovec(i))) { 15323d671ca6SAl Viro unsigned long addr; 15339ea9ce04SDavid Howells 15343d671ca6SAl Viro addr = first_iovec_segment(i, &len, start, maxsize, maxpages); 1535d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 153673b0140bSIra Weiny res = get_user_pages_fast(addr, n, 153773b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, 153873b0140bSIra Weiny pages); 1539d879cb83SAl Viro if (unlikely(res < 0)) 1540d879cb83SAl Viro return res; 1541d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 15423d671ca6SAl Viro } 15433d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 15443d671ca6SAl Viro struct page *page; 15453d671ca6SAl Viro 15463d671ca6SAl Viro page = first_bvec_segment(i, &len, start, maxsize, maxpages); 15473d671ca6SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 15483d671ca6SAl Viro while (n--) 15493d671ca6SAl Viro get_page(*pages++ = page++); 15503d671ca6SAl Viro return len - *start; 15513d671ca6SAl Viro } 15523d671ca6SAl Viro if (iov_iter_is_pipe(i)) 15533d671ca6SAl Viro return pipe_get_pages(i, pages, maxsize, maxpages, start); 15543d671ca6SAl Viro if (iov_iter_is_xarray(i)) 15553d671ca6SAl Viro return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); 1556d879cb83SAl Viro return -EFAULT; 1557d879cb83SAl Viro } 1558d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages); 1559d879cb83SAl Viro 1560d879cb83SAl Viro static struct page **get_pages_array(size_t n) 1561d879cb83SAl Viro { 1562752ade68SMichal Hocko return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); 1563d879cb83SAl Viro } 1564d879cb83SAl Viro 1565241699cdSAl Viro static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 1566241699cdSAl Viro struct page ***pages, size_t maxsize, 1567241699cdSAl Viro size_t *start) 1568241699cdSAl Viro { 1569241699cdSAl Viro struct page **p; 15708cefc107SDavid Howells unsigned int iter_head, npages; 1571d7760d63SIlya Dryomov ssize_t n; 1572241699cdSAl Viro 1573241699cdSAl Viro if (!sanity(i)) 1574241699cdSAl Viro return -EFAULT; 1575241699cdSAl Viro 15768cefc107SDavid Howells data_start(i, &iter_head, start); 15778cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 15788cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1579241699cdSAl Viro n = npages * PAGE_SIZE - *start; 1580241699cdSAl Viro if (maxsize > n) 1581241699cdSAl Viro maxsize = n; 1582241699cdSAl Viro else 1583241699cdSAl Viro npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1584241699cdSAl Viro p = get_pages_array(npages); 1585241699cdSAl Viro if (!p) 1586241699cdSAl Viro return -ENOMEM; 15878cefc107SDavid Howells n = __pipe_get_pages(i, maxsize, p, iter_head, start); 1588241699cdSAl Viro if (n > 0) 1589241699cdSAl Viro *pages = p; 1590241699cdSAl Viro else 1591241699cdSAl Viro kvfree(p); 1592241699cdSAl Viro return n; 1593241699cdSAl Viro } 1594241699cdSAl Viro 15957ff50620SDavid Howells static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, 15967ff50620SDavid Howells struct page ***pages, size_t maxsize, 15977ff50620SDavid Howells size_t *_start_offset) 15987ff50620SDavid Howells { 15997ff50620SDavid Howells struct page **p; 16007ff50620SDavid Howells unsigned nr, offset; 16017ff50620SDavid Howells pgoff_t index, count; 16027ff50620SDavid Howells size_t size = maxsize, actual; 16037ff50620SDavid Howells loff_t pos; 16047ff50620SDavid Howells 16057ff50620SDavid Howells if (!size) 16067ff50620SDavid Howells return 0; 16077ff50620SDavid Howells 16087ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 16097ff50620SDavid Howells index = pos >> PAGE_SHIFT; 16107ff50620SDavid Howells offset = pos & ~PAGE_MASK; 16117ff50620SDavid Howells *_start_offset = offset; 16127ff50620SDavid Howells 16137ff50620SDavid Howells count = 1; 16147ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 16157ff50620SDavid Howells size -= PAGE_SIZE - offset; 16167ff50620SDavid Howells count += size >> PAGE_SHIFT; 16177ff50620SDavid Howells size &= ~PAGE_MASK; 16187ff50620SDavid Howells if (size) 16197ff50620SDavid Howells count++; 16207ff50620SDavid Howells } 16217ff50620SDavid Howells 16227ff50620SDavid Howells p = get_pages_array(count); 16237ff50620SDavid Howells if (!p) 16247ff50620SDavid Howells return -ENOMEM; 16257ff50620SDavid Howells *pages = p; 16267ff50620SDavid Howells 16277ff50620SDavid Howells nr = iter_xarray_populate_pages(p, i->xarray, index, count); 16287ff50620SDavid Howells if (nr == 0) 16297ff50620SDavid Howells return 0; 16307ff50620SDavid Howells 16317ff50620SDavid Howells actual = PAGE_SIZE * nr; 16327ff50620SDavid Howells actual -= offset; 16337ff50620SDavid Howells if (nr == count && size > 0) { 16347ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 16357ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 16367ff50620SDavid Howells } 16377ff50620SDavid Howells return actual; 16387ff50620SDavid Howells } 16397ff50620SDavid Howells 1640d879cb83SAl Viro ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 1641d879cb83SAl Viro struct page ***pages, size_t maxsize, 1642d879cb83SAl Viro size_t *start) 1643d879cb83SAl Viro { 1644d879cb83SAl Viro struct page **p; 16453d671ca6SAl Viro size_t len; 16463d671ca6SAl Viro int n, res; 1647d879cb83SAl Viro 1648d879cb83SAl Viro if (maxsize > i->count) 1649d879cb83SAl Viro maxsize = i->count; 16503d671ca6SAl Viro if (!maxsize) 16513d671ca6SAl Viro return 0; 1652d879cb83SAl Viro 16533d671ca6SAl Viro if (likely(iter_is_iovec(i))) { 16543d671ca6SAl Viro unsigned long addr; 16559ea9ce04SDavid Howells 16563d671ca6SAl Viro addr = first_iovec_segment(i, &len, start, maxsize, ~0U); 1657d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 1658d879cb83SAl Viro p = get_pages_array(n); 1659d879cb83SAl Viro if (!p) 1660d879cb83SAl Viro return -ENOMEM; 166173b0140bSIra Weiny res = get_user_pages_fast(addr, n, 166273b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); 1663d879cb83SAl Viro if (unlikely(res < 0)) { 1664d879cb83SAl Viro kvfree(p); 1665d879cb83SAl Viro return res; 1666d879cb83SAl Viro } 1667d879cb83SAl Viro *pages = p; 1668d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 16693d671ca6SAl Viro } 16703d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 16713d671ca6SAl Viro struct page *page; 16723d671ca6SAl Viro 16733d671ca6SAl Viro page = first_bvec_segment(i, &len, start, maxsize, ~0U); 16743d671ca6SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 16753d671ca6SAl Viro *pages = p = get_pages_array(n); 1676d879cb83SAl Viro if (!p) 1677d879cb83SAl Viro return -ENOMEM; 16783d671ca6SAl Viro while (n--) 16793d671ca6SAl Viro get_page(*p++ = page++); 16803d671ca6SAl Viro return len - *start; 16813d671ca6SAl Viro } 16823d671ca6SAl Viro if (iov_iter_is_pipe(i)) 16833d671ca6SAl Viro return pipe_get_pages_alloc(i, pages, maxsize, start); 16843d671ca6SAl Viro if (iov_iter_is_xarray(i)) 16853d671ca6SAl Viro return iter_xarray_get_pages_alloc(i, pages, maxsize, start); 1686d879cb83SAl Viro return -EFAULT; 1687d879cb83SAl Viro } 1688d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages_alloc); 1689d879cb83SAl Viro 1690d879cb83SAl Viro size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 1691d879cb83SAl Viro struct iov_iter *i) 1692d879cb83SAl Viro { 1693d879cb83SAl Viro char *to = addr; 1694d879cb83SAl Viro __wsum sum, next; 1695d879cb83SAl Viro size_t off = 0; 1696d879cb83SAl Viro sum = *csum; 16979ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1698241699cdSAl Viro WARN_ON(1); 1699241699cdSAl Viro return 0; 1700241699cdSAl Viro } 1701d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1702d879cb83SAl Viro next = csum_and_copy_from_user(v.iov_base, 1703d879cb83SAl Viro (to += v.iov_len) - v.iov_len, 1704c693cc46SAl Viro v.iov_len); 1705c693cc46SAl Viro if (next) { 1706d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1707d879cb83SAl Viro off += v.iov_len; 1708d879cb83SAl Viro } 1709c693cc46SAl Viro next ? 0 : v.iov_len; 1710d879cb83SAl Viro }), ({ 1711d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1712f9152895SAl Viro sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 1713f9152895SAl Viro p + v.bv_offset, v.bv_len, 1714f9152895SAl Viro sum, off); 1715d879cb83SAl Viro kunmap_atomic(p); 1716d879cb83SAl Viro off += v.bv_len; 1717d879cb83SAl Viro }),({ 1718f9152895SAl Viro sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, 1719f9152895SAl Viro v.iov_base, v.iov_len, 1720f9152895SAl Viro sum, off); 1721d879cb83SAl Viro off += v.iov_len; 17227ff50620SDavid Howells }), ({ 17237ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 17247ff50620SDavid Howells sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 17257ff50620SDavid Howells p + v.bv_offset, v.bv_len, 17267ff50620SDavid Howells sum, off); 17277ff50620SDavid Howells kunmap_atomic(p); 17287ff50620SDavid Howells off += v.bv_len; 1729d879cb83SAl Viro }) 1730d879cb83SAl Viro ) 1731d879cb83SAl Viro *csum = sum; 1732d879cb83SAl Viro return bytes; 1733d879cb83SAl Viro } 1734d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter); 1735d879cb83SAl Viro 173652cbd23aSWillem de Bruijn size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 1737d879cb83SAl Viro struct iov_iter *i) 1738d879cb83SAl Viro { 173952cbd23aSWillem de Bruijn struct csum_state *csstate = _csstate; 174036f7a8a4SAl Viro const char *from = addr; 1741d879cb83SAl Viro __wsum sum, next; 174252cbd23aSWillem de Bruijn size_t off; 174378e1f386SAl Viro 174478e1f386SAl Viro if (unlikely(iov_iter_is_pipe(i))) 174552cbd23aSWillem de Bruijn return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); 174678e1f386SAl Viro 1747594e450bSAl Viro sum = csum_shift(csstate->csum, csstate->off); 1748594e450bSAl Viro off = 0; 174978e1f386SAl Viro if (unlikely(iov_iter_is_discard(i))) { 1750241699cdSAl Viro WARN_ON(1); /* for now */ 1751241699cdSAl Viro return 0; 1752241699cdSAl Viro } 1753d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1754d879cb83SAl Viro next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, 1755d879cb83SAl Viro v.iov_base, 1756c693cc46SAl Viro v.iov_len); 1757c693cc46SAl Viro if (next) { 1758d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1759d879cb83SAl Viro off += v.iov_len; 1760d879cb83SAl Viro } 1761c693cc46SAl Viro next ? 0 : v.iov_len; 1762d879cb83SAl Viro }), ({ 1763d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1764f9152895SAl Viro sum = csum_and_memcpy(p + v.bv_offset, 1765f9152895SAl Viro (from += v.bv_len) - v.bv_len, 1766f9152895SAl Viro v.bv_len, sum, off); 1767d879cb83SAl Viro kunmap_atomic(p); 1768d879cb83SAl Viro off += v.bv_len; 1769d879cb83SAl Viro }),({ 1770f9152895SAl Viro sum = csum_and_memcpy(v.iov_base, 1771f9152895SAl Viro (from += v.iov_len) - v.iov_len, 1772f9152895SAl Viro v.iov_len, sum, off); 1773d879cb83SAl Viro off += v.iov_len; 17747ff50620SDavid Howells }), ({ 17757ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 17767ff50620SDavid Howells sum = csum_and_memcpy(p + v.bv_offset, 17777ff50620SDavid Howells (from += v.bv_len) - v.bv_len, 17787ff50620SDavid Howells v.bv_len, sum, off); 17797ff50620SDavid Howells kunmap_atomic(p); 17807ff50620SDavid Howells off += v.bv_len; 1781d879cb83SAl Viro }) 1782d879cb83SAl Viro ) 1783594e450bSAl Viro csstate->csum = csum_shift(sum, csstate->off); 1784594e450bSAl Viro csstate->off += bytes; 1785d879cb83SAl Viro return bytes; 1786d879cb83SAl Viro } 1787d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_to_iter); 1788d879cb83SAl Viro 1789d05f4435SSagi Grimberg size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, 1790d05f4435SSagi Grimberg struct iov_iter *i) 1791d05f4435SSagi Grimberg { 17927999096fSHerbert Xu #ifdef CONFIG_CRYPTO_HASH 1793d05f4435SSagi Grimberg struct ahash_request *hash = hashp; 1794d05f4435SSagi Grimberg struct scatterlist sg; 1795d05f4435SSagi Grimberg size_t copied; 1796d05f4435SSagi Grimberg 1797d05f4435SSagi Grimberg copied = copy_to_iter(addr, bytes, i); 1798d05f4435SSagi Grimberg sg_init_one(&sg, addr, copied); 1799d05f4435SSagi Grimberg ahash_request_set_crypt(hash, &sg, NULL, copied); 1800d05f4435SSagi Grimberg crypto_ahash_update(hash); 1801d05f4435SSagi Grimberg return copied; 180227fad74aSYueHaibing #else 180327fad74aSYueHaibing return 0; 180427fad74aSYueHaibing #endif 1805d05f4435SSagi Grimberg } 1806d05f4435SSagi Grimberg EXPORT_SYMBOL(hash_and_copy_to_iter); 1807d05f4435SSagi Grimberg 180866531c65SAl Viro static int iov_npages(const struct iov_iter *i, int maxpages) 1809d879cb83SAl Viro { 181066531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 181166531c65SAl Viro const struct iovec *p; 1812d879cb83SAl Viro int npages = 0; 1813d879cb83SAl Viro 181466531c65SAl Viro for (p = i->iov; size; skip = 0, p++) { 181566531c65SAl Viro unsigned offs = offset_in_page(p->iov_base + skip); 181666531c65SAl Viro size_t len = min(p->iov_len - skip, size); 1817d879cb83SAl Viro 181866531c65SAl Viro if (len) { 181966531c65SAl Viro size -= len; 182066531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 182166531c65SAl Viro if (unlikely(npages > maxpages)) 182266531c65SAl Viro return maxpages; 182366531c65SAl Viro } 182466531c65SAl Viro } 182566531c65SAl Viro return npages; 182666531c65SAl Viro } 182766531c65SAl Viro 182866531c65SAl Viro static int bvec_npages(const struct iov_iter *i, int maxpages) 182966531c65SAl Viro { 183066531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 183166531c65SAl Viro const struct bio_vec *p; 183266531c65SAl Viro int npages = 0; 183366531c65SAl Viro 183466531c65SAl Viro for (p = i->bvec; size; skip = 0, p++) { 183566531c65SAl Viro unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; 183666531c65SAl Viro size_t len = min(p->bv_len - skip, size); 183766531c65SAl Viro 183866531c65SAl Viro size -= len; 183966531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 184066531c65SAl Viro if (unlikely(npages > maxpages)) 184166531c65SAl Viro return maxpages; 184266531c65SAl Viro } 184366531c65SAl Viro return npages; 184466531c65SAl Viro } 184566531c65SAl Viro 184666531c65SAl Viro int iov_iter_npages(const struct iov_iter *i, int maxpages) 184766531c65SAl Viro { 184866531c65SAl Viro if (unlikely(!i->count)) 184966531c65SAl Viro return 0; 185066531c65SAl Viro /* iovec and kvec have identical layouts */ 185166531c65SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 185266531c65SAl Viro return iov_npages(i, maxpages); 185366531c65SAl Viro if (iov_iter_is_bvec(i)) 185466531c65SAl Viro return bvec_npages(i, maxpages); 185566531c65SAl Viro if (iov_iter_is_pipe(i)) { 18568cefc107SDavid Howells unsigned int iter_head; 185766531c65SAl Viro int npages; 1858241699cdSAl Viro size_t off; 1859241699cdSAl Viro 1860241699cdSAl Viro if (!sanity(i)) 1861241699cdSAl Viro return 0; 1862241699cdSAl Viro 18638cefc107SDavid Howells data_start(i, &iter_head, &off); 1864241699cdSAl Viro /* some of this one + all after this one */ 186566531c65SAl Viro npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 186666531c65SAl Viro return min(npages, maxpages); 186766531c65SAl Viro } 186866531c65SAl Viro if (iov_iter_is_xarray(i)) { 1869e4f8df86SAl Viro unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; 1870e4f8df86SAl Viro int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); 187166531c65SAl Viro return min(npages, maxpages); 187266531c65SAl Viro } 187366531c65SAl Viro return 0; 1874d879cb83SAl Viro } 1875d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_npages); 1876d879cb83SAl Viro 1877d879cb83SAl Viro const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) 1878d879cb83SAl Viro { 1879d879cb83SAl Viro *new = *old; 188000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(new))) { 1881241699cdSAl Viro WARN_ON(1); 1882241699cdSAl Viro return NULL; 1883241699cdSAl Viro } 18847ff50620SDavid Howells if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) 18859ea9ce04SDavid Howells return NULL; 188600e23707SDavid Howells if (iov_iter_is_bvec(new)) 1887d879cb83SAl Viro return new->bvec = kmemdup(new->bvec, 1888d879cb83SAl Viro new->nr_segs * sizeof(struct bio_vec), 1889d879cb83SAl Viro flags); 1890d879cb83SAl Viro else 1891d879cb83SAl Viro /* iovec and kvec have identical layout */ 1892d879cb83SAl Viro return new->iov = kmemdup(new->iov, 1893d879cb83SAl Viro new->nr_segs * sizeof(struct iovec), 1894d879cb83SAl Viro flags); 1895d879cb83SAl Viro } 1896d879cb83SAl Viro EXPORT_SYMBOL(dup_iter); 1897bc917be8SAl Viro 1898bfdc5970SChristoph Hellwig static int copy_compat_iovec_from_user(struct iovec *iov, 1899bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1900bfdc5970SChristoph Hellwig { 1901bfdc5970SChristoph Hellwig const struct compat_iovec __user *uiov = 1902bfdc5970SChristoph Hellwig (const struct compat_iovec __user *)uvec; 1903bfdc5970SChristoph Hellwig int ret = -EFAULT, i; 1904bfdc5970SChristoph Hellwig 1905a959a978SChristoph Hellwig if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) 1906bfdc5970SChristoph Hellwig return -EFAULT; 1907bfdc5970SChristoph Hellwig 1908bfdc5970SChristoph Hellwig for (i = 0; i < nr_segs; i++) { 1909bfdc5970SChristoph Hellwig compat_uptr_t buf; 1910bfdc5970SChristoph Hellwig compat_ssize_t len; 1911bfdc5970SChristoph Hellwig 1912bfdc5970SChristoph Hellwig unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); 1913bfdc5970SChristoph Hellwig unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); 1914bfdc5970SChristoph Hellwig 1915bfdc5970SChristoph Hellwig /* check for compat_size_t not fitting in compat_ssize_t .. */ 1916bfdc5970SChristoph Hellwig if (len < 0) { 1917bfdc5970SChristoph Hellwig ret = -EINVAL; 1918bfdc5970SChristoph Hellwig goto uaccess_end; 1919bfdc5970SChristoph Hellwig } 1920bfdc5970SChristoph Hellwig iov[i].iov_base = compat_ptr(buf); 1921bfdc5970SChristoph Hellwig iov[i].iov_len = len; 1922bfdc5970SChristoph Hellwig } 1923bfdc5970SChristoph Hellwig 1924bfdc5970SChristoph Hellwig ret = 0; 1925bfdc5970SChristoph Hellwig uaccess_end: 1926bfdc5970SChristoph Hellwig user_access_end(); 1927bfdc5970SChristoph Hellwig return ret; 1928bfdc5970SChristoph Hellwig } 1929bfdc5970SChristoph Hellwig 1930bfdc5970SChristoph Hellwig static int copy_iovec_from_user(struct iovec *iov, 1931bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1932fb041b59SDavid Laight { 1933fb041b59SDavid Laight unsigned long seg; 1934bfdc5970SChristoph Hellwig 1935bfdc5970SChristoph Hellwig if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) 1936bfdc5970SChristoph Hellwig return -EFAULT; 1937bfdc5970SChristoph Hellwig for (seg = 0; seg < nr_segs; seg++) { 1938bfdc5970SChristoph Hellwig if ((ssize_t)iov[seg].iov_len < 0) 1939bfdc5970SChristoph Hellwig return -EINVAL; 1940bfdc5970SChristoph Hellwig } 1941bfdc5970SChristoph Hellwig 1942bfdc5970SChristoph Hellwig return 0; 1943bfdc5970SChristoph Hellwig } 1944bfdc5970SChristoph Hellwig 1945bfdc5970SChristoph Hellwig struct iovec *iovec_from_user(const struct iovec __user *uvec, 1946bfdc5970SChristoph Hellwig unsigned long nr_segs, unsigned long fast_segs, 1947bfdc5970SChristoph Hellwig struct iovec *fast_iov, bool compat) 1948bfdc5970SChristoph Hellwig { 1949bfdc5970SChristoph Hellwig struct iovec *iov = fast_iov; 1950bfdc5970SChristoph Hellwig int ret; 1951fb041b59SDavid Laight 1952fb041b59SDavid Laight /* 1953bfdc5970SChristoph Hellwig * SuS says "The readv() function *may* fail if the iovcnt argument was 1954bfdc5970SChristoph Hellwig * less than or equal to 0, or greater than {IOV_MAX}. Linux has 1955fb041b59SDavid Laight * traditionally returned zero for zero segments, so... 1956fb041b59SDavid Laight */ 1957bfdc5970SChristoph Hellwig if (nr_segs == 0) 1958bfdc5970SChristoph Hellwig return iov; 1959bfdc5970SChristoph Hellwig if (nr_segs > UIO_MAXIOV) 1960bfdc5970SChristoph Hellwig return ERR_PTR(-EINVAL); 1961fb041b59SDavid Laight if (nr_segs > fast_segs) { 1962fb041b59SDavid Laight iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); 1963bfdc5970SChristoph Hellwig if (!iov) 1964bfdc5970SChristoph Hellwig return ERR_PTR(-ENOMEM); 1965fb041b59SDavid Laight } 1966bfdc5970SChristoph Hellwig 1967bfdc5970SChristoph Hellwig if (compat) 1968bfdc5970SChristoph Hellwig ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); 1969bfdc5970SChristoph Hellwig else 1970bfdc5970SChristoph Hellwig ret = copy_iovec_from_user(iov, uvec, nr_segs); 1971bfdc5970SChristoph Hellwig if (ret) { 1972bfdc5970SChristoph Hellwig if (iov != fast_iov) 1973bfdc5970SChristoph Hellwig kfree(iov); 1974bfdc5970SChristoph Hellwig return ERR_PTR(ret); 1975fb041b59SDavid Laight } 1976bfdc5970SChristoph Hellwig 1977bfdc5970SChristoph Hellwig return iov; 1978bfdc5970SChristoph Hellwig } 1979bfdc5970SChristoph Hellwig 1980bfdc5970SChristoph Hellwig ssize_t __import_iovec(int type, const struct iovec __user *uvec, 1981bfdc5970SChristoph Hellwig unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, 1982bfdc5970SChristoph Hellwig struct iov_iter *i, bool compat) 1983bfdc5970SChristoph Hellwig { 1984bfdc5970SChristoph Hellwig ssize_t total_len = 0; 1985bfdc5970SChristoph Hellwig unsigned long seg; 1986bfdc5970SChristoph Hellwig struct iovec *iov; 1987bfdc5970SChristoph Hellwig 1988bfdc5970SChristoph Hellwig iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); 1989bfdc5970SChristoph Hellwig if (IS_ERR(iov)) { 1990bfdc5970SChristoph Hellwig *iovp = NULL; 1991bfdc5970SChristoph Hellwig return PTR_ERR(iov); 1992fb041b59SDavid Laight } 1993fb041b59SDavid Laight 1994fb041b59SDavid Laight /* 1995bfdc5970SChristoph Hellwig * According to the Single Unix Specification we should return EINVAL if 1996bfdc5970SChristoph Hellwig * an element length is < 0 when cast to ssize_t or if the total length 1997bfdc5970SChristoph Hellwig * would overflow the ssize_t return value of the system call. 1998fb041b59SDavid Laight * 1999fb041b59SDavid Laight * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the 2000fb041b59SDavid Laight * overflow case. 2001fb041b59SDavid Laight */ 2002fb041b59SDavid Laight for (seg = 0; seg < nr_segs; seg++) { 2003fb041b59SDavid Laight ssize_t len = (ssize_t)iov[seg].iov_len; 2004fb041b59SDavid Laight 2005bfdc5970SChristoph Hellwig if (!access_ok(iov[seg].iov_base, len)) { 2006bfdc5970SChristoph Hellwig if (iov != *iovp) 2007bfdc5970SChristoph Hellwig kfree(iov); 2008bfdc5970SChristoph Hellwig *iovp = NULL; 2009bfdc5970SChristoph Hellwig return -EFAULT; 2010fb041b59SDavid Laight } 2011bfdc5970SChristoph Hellwig 2012bfdc5970SChristoph Hellwig if (len > MAX_RW_COUNT - total_len) { 2013bfdc5970SChristoph Hellwig len = MAX_RW_COUNT - total_len; 2014fb041b59SDavid Laight iov[seg].iov_len = len; 2015fb041b59SDavid Laight } 2016bfdc5970SChristoph Hellwig total_len += len; 2017fb041b59SDavid Laight } 2018bfdc5970SChristoph Hellwig 2019bfdc5970SChristoph Hellwig iov_iter_init(i, type, iov, nr_segs, total_len); 2020bfdc5970SChristoph Hellwig if (iov == *iovp) 2021bfdc5970SChristoph Hellwig *iovp = NULL; 2022bfdc5970SChristoph Hellwig else 2023bfdc5970SChristoph Hellwig *iovp = iov; 2024bfdc5970SChristoph Hellwig return total_len; 2025fb041b59SDavid Laight } 2026fb041b59SDavid Laight 2027ffecee4fSVegard Nossum /** 2028ffecee4fSVegard Nossum * import_iovec() - Copy an array of &struct iovec from userspace 2029ffecee4fSVegard Nossum * into the kernel, check that it is valid, and initialize a new 2030ffecee4fSVegard Nossum * &struct iov_iter iterator to access it. 2031ffecee4fSVegard Nossum * 2032ffecee4fSVegard Nossum * @type: One of %READ or %WRITE. 2033bfdc5970SChristoph Hellwig * @uvec: Pointer to the userspace array. 2034ffecee4fSVegard Nossum * @nr_segs: Number of elements in userspace array. 2035ffecee4fSVegard Nossum * @fast_segs: Number of elements in @iov. 2036bfdc5970SChristoph Hellwig * @iovp: (input and output parameter) Pointer to pointer to (usually small 2037ffecee4fSVegard Nossum * on-stack) kernel array. 2038ffecee4fSVegard Nossum * @i: Pointer to iterator that will be initialized on success. 2039ffecee4fSVegard Nossum * 2040ffecee4fSVegard Nossum * If the array pointed to by *@iov is large enough to hold all @nr_segs, 2041ffecee4fSVegard Nossum * then this function places %NULL in *@iov on return. Otherwise, a new 2042ffecee4fSVegard Nossum * array will be allocated and the result placed in *@iov. This means that 2043ffecee4fSVegard Nossum * the caller may call kfree() on *@iov regardless of whether the small 2044ffecee4fSVegard Nossum * on-stack array was used or not (and regardless of whether this function 2045ffecee4fSVegard Nossum * returns an error or not). 2046ffecee4fSVegard Nossum * 204787e5e6daSJens Axboe * Return: Negative error code on error, bytes imported on success 2048ffecee4fSVegard Nossum */ 2049bfdc5970SChristoph Hellwig ssize_t import_iovec(int type, const struct iovec __user *uvec, 2050bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 2051bfdc5970SChristoph Hellwig struct iovec **iovp, struct iov_iter *i) 2052bc917be8SAl Viro { 205389cd35c5SChristoph Hellwig return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, 205489cd35c5SChristoph Hellwig in_compat_syscall()); 2055bc917be8SAl Viro } 2056bc917be8SAl Viro EXPORT_SYMBOL(import_iovec); 2057bc917be8SAl Viro 2058bc917be8SAl Viro int import_single_range(int rw, void __user *buf, size_t len, 2059bc917be8SAl Viro struct iovec *iov, struct iov_iter *i) 2060bc917be8SAl Viro { 2061bc917be8SAl Viro if (len > MAX_RW_COUNT) 2062bc917be8SAl Viro len = MAX_RW_COUNT; 206396d4f267SLinus Torvalds if (unlikely(!access_ok(buf, len))) 2064bc917be8SAl Viro return -EFAULT; 2065bc917be8SAl Viro 2066bc917be8SAl Viro iov->iov_base = buf; 2067bc917be8SAl Viro iov->iov_len = len; 2068bc917be8SAl Viro iov_iter_init(i, rw, iov, 1, len); 2069bc917be8SAl Viro return 0; 2070bc917be8SAl Viro } 2071e1267585SAl Viro EXPORT_SYMBOL(import_single_range); 2072