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 19fcb14cb1SAl Viro /* covers ubuf and kbuf alike */ 20fcb14cb1SAl Viro #define iterate_buf(i, n, base, len, off, __p, STEP) { \ 21fcb14cb1SAl Viro size_t __maybe_unused off = 0; \ 22fcb14cb1SAl Viro len = n; \ 23fcb14cb1SAl Viro base = __p + i->iov_offset; \ 24fcb14cb1SAl Viro len -= (STEP); \ 25fcb14cb1SAl Viro i->iov_offset += len; \ 26fcb14cb1SAl Viro n = len; \ 27fcb14cb1SAl Viro } 28fcb14cb1SAl Viro 295c67aa90SAl Viro /* covers iovec and kvec alike */ 30a6e4ec7bSAl Viro #define iterate_iovec(i, n, base, len, off, __p, STEP) { \ 317baa5099SAl Viro size_t off = 0; \ 32a6e4ec7bSAl Viro size_t skip = i->iov_offset; \ 337a1bcb5dSAl Viro do { \ 347baa5099SAl Viro len = min(n, __p->iov_len - skip); \ 357baa5099SAl Viro if (likely(len)) { \ 367baa5099SAl Viro base = __p->iov_base + skip; \ 377baa5099SAl Viro len -= (STEP); \ 387baa5099SAl Viro off += len; \ 397baa5099SAl Viro skip += len; \ 407baa5099SAl Viro n -= len; \ 417a1bcb5dSAl Viro if (skip < __p->iov_len) \ 427a1bcb5dSAl Viro break; \ 43d879cb83SAl Viro } \ 44d879cb83SAl Viro __p++; \ 457a1bcb5dSAl Viro skip = 0; \ 467a1bcb5dSAl Viro } while (n); \ 47a6e4ec7bSAl Viro i->iov_offset = skip; \ 487baa5099SAl Viro n = off; \ 49d879cb83SAl Viro } 50d879cb83SAl Viro 51a6e4ec7bSAl Viro #define iterate_bvec(i, n, base, len, off, p, STEP) { \ 527baa5099SAl Viro size_t off = 0; \ 53a6e4ec7bSAl Viro unsigned skip = i->iov_offset; \ 547491a2bfSAl Viro while (n) { \ 557491a2bfSAl Viro unsigned offset = p->bv_offset + skip; \ 561b4fb5ffSAl Viro unsigned left; \ 5721b56c84SAl Viro void *kaddr = kmap_local_page(p->bv_page + \ 5821b56c84SAl Viro offset / PAGE_SIZE); \ 597baa5099SAl Viro base = kaddr + offset % PAGE_SIZE; \ 60a6e4ec7bSAl Viro len = min(min(n, (size_t)(p->bv_len - skip)), \ 617491a2bfSAl Viro (size_t)(PAGE_SIZE - offset % PAGE_SIZE)); \ 621b4fb5ffSAl Viro left = (STEP); \ 6321b56c84SAl Viro kunmap_local(kaddr); \ 647baa5099SAl Viro len -= left; \ 657baa5099SAl Viro off += len; \ 667baa5099SAl Viro skip += len; \ 677491a2bfSAl Viro if (skip == p->bv_len) { \ 687491a2bfSAl Viro skip = 0; \ 697491a2bfSAl Viro p++; \ 70d879cb83SAl Viro } \ 717baa5099SAl Viro n -= len; \ 721b4fb5ffSAl Viro if (left) \ 731b4fb5ffSAl Viro break; \ 747491a2bfSAl Viro } \ 75a6e4ec7bSAl Viro i->iov_offset = skip; \ 767baa5099SAl Viro n = off; \ 77d879cb83SAl Viro } 78d879cb83SAl Viro 79a6e4ec7bSAl Viro #define iterate_xarray(i, n, base, len, __off, STEP) { \ 801b4fb5ffSAl Viro __label__ __out; \ 81622838f3SAl Viro size_t __off = 0; \ 82821979f5SMatthew Wilcox (Oracle) struct folio *folio; \ 83a6e4ec7bSAl Viro loff_t start = i->xarray_start + i->iov_offset; \ 844b179e9aSAl Viro pgoff_t index = start / PAGE_SIZE; \ 857ff50620SDavid Howells XA_STATE(xas, i->xarray, index); \ 867ff50620SDavid Howells \ 87821979f5SMatthew Wilcox (Oracle) len = PAGE_SIZE - offset_in_page(start); \ 887ff50620SDavid Howells rcu_read_lock(); \ 89821979f5SMatthew Wilcox (Oracle) xas_for_each(&xas, folio, ULONG_MAX) { \ 901b4fb5ffSAl Viro unsigned left; \ 91821979f5SMatthew Wilcox (Oracle) size_t offset; \ 92821979f5SMatthew Wilcox (Oracle) if (xas_retry(&xas, folio)) \ 937ff50620SDavid Howells continue; \ 94821979f5SMatthew Wilcox (Oracle) if (WARN_ON(xa_is_value(folio))) \ 957ff50620SDavid Howells break; \ 96821979f5SMatthew Wilcox (Oracle) if (WARN_ON(folio_test_hugetlb(folio))) \ 977ff50620SDavid Howells break; \ 98821979f5SMatthew Wilcox (Oracle) offset = offset_in_folio(folio, start + __off); \ 99821979f5SMatthew Wilcox (Oracle) while (offset < folio_size(folio)) { \ 100821979f5SMatthew Wilcox (Oracle) base = kmap_local_folio(folio, offset); \ 1017baa5099SAl Viro len = min(n, len); \ 1021b4fb5ffSAl Viro left = (STEP); \ 103821979f5SMatthew Wilcox (Oracle) kunmap_local(base); \ 1047baa5099SAl Viro len -= left; \ 1057baa5099SAl Viro __off += len; \ 1067baa5099SAl Viro n -= len; \ 1071b4fb5ffSAl Viro if (left || n == 0) \ 1081b4fb5ffSAl Viro goto __out; \ 109821979f5SMatthew Wilcox (Oracle) offset += len; \ 110821979f5SMatthew Wilcox (Oracle) len = PAGE_SIZE; \ 1117ff50620SDavid Howells } \ 1127ff50620SDavid Howells } \ 1131b4fb5ffSAl Viro __out: \ 1147ff50620SDavid Howells rcu_read_unlock(); \ 115a6e4ec7bSAl Viro i->iov_offset += __off; \ 116622838f3SAl Viro n = __off; \ 1177ff50620SDavid Howells } 1187ff50620SDavid Howells 1197baa5099SAl Viro #define __iterate_and_advance(i, n, base, len, off, I, K) { \ 120dd254f5aSAl Viro if (unlikely(i->count < n)) \ 121dd254f5aSAl Viro n = i->count; \ 122f5da8354SAl Viro if (likely(n)) { \ 123fcb14cb1SAl Viro if (likely(iter_is_ubuf(i))) { \ 124fcb14cb1SAl Viro void __user *base; \ 125fcb14cb1SAl Viro size_t len; \ 126fcb14cb1SAl Viro iterate_buf(i, n, base, len, off, \ 127fcb14cb1SAl Viro i->ubuf, (I)) \ 128fcb14cb1SAl Viro } else if (likely(iter_is_iovec(i))) { \ 1295c67aa90SAl Viro const struct iovec *iov = i->iov; \ 1307baa5099SAl Viro void __user *base; \ 1317baa5099SAl Viro size_t len; \ 1327baa5099SAl Viro iterate_iovec(i, n, base, len, off, \ 133a6e4ec7bSAl Viro iov, (I)) \ 134d879cb83SAl Viro i->nr_segs -= iov - i->iov; \ 135d879cb83SAl Viro i->iov = iov; \ 13628f38db7SAl Viro } else if (iov_iter_is_bvec(i)) { \ 13728f38db7SAl Viro const struct bio_vec *bvec = i->bvec; \ 1387baa5099SAl Viro void *base; \ 1397baa5099SAl Viro size_t len; \ 1407baa5099SAl Viro iterate_bvec(i, n, base, len, off, \ 141a6e4ec7bSAl Viro bvec, (K)) \ 1427491a2bfSAl Viro i->nr_segs -= bvec - i->bvec; \ 1437491a2bfSAl Viro i->bvec = bvec; \ 14428f38db7SAl Viro } else if (iov_iter_is_kvec(i)) { \ 1455c67aa90SAl Viro const struct kvec *kvec = i->kvec; \ 1467baa5099SAl Viro void *base; \ 1477baa5099SAl Viro size_t len; \ 1487baa5099SAl Viro iterate_iovec(i, n, base, len, off, \ 149a6e4ec7bSAl Viro kvec, (K)) \ 15028f38db7SAl Viro i->nr_segs -= kvec - i->kvec; \ 15128f38db7SAl Viro i->kvec = kvec; \ 15228f38db7SAl Viro } else if (iov_iter_is_xarray(i)) { \ 1537baa5099SAl Viro void *base; \ 1547baa5099SAl Viro size_t len; \ 1557baa5099SAl Viro iterate_xarray(i, n, base, len, off, \ 156a6e4ec7bSAl Viro (K)) \ 157d879cb83SAl Viro } \ 158d879cb83SAl Viro i->count -= n; \ 159dd254f5aSAl Viro } \ 160d879cb83SAl Viro } 1617baa5099SAl Viro #define iterate_and_advance(i, n, base, len, off, I, K) \ 1627baa5099SAl Viro __iterate_and_advance(i, n, base, len, off, I, ((void)(K),0)) 163d879cb83SAl Viro 16409fc68dcSAl Viro static int copyout(void __user *to, const void *from, size_t n) 16509fc68dcSAl Viro { 1664d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1674d0e9df5SAlbert van der Linde return n; 16896d4f267SLinus Torvalds if (access_ok(to, n)) { 169d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 17009fc68dcSAl Viro n = raw_copy_to_user(to, from, n); 17109fc68dcSAl Viro } 17209fc68dcSAl Viro return n; 17309fc68dcSAl Viro } 17409fc68dcSAl Viro 17509fc68dcSAl Viro static int copyin(void *to, const void __user *from, size_t n) 17609fc68dcSAl Viro { 1774d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1784d0e9df5SAlbert van der Linde return n; 17996d4f267SLinus Torvalds if (access_ok(from, n)) { 180d0ef4c36SMarco Elver instrument_copy_from_user(to, from, n); 18109fc68dcSAl Viro n = raw_copy_from_user(to, from, n); 18209fc68dcSAl Viro } 18309fc68dcSAl Viro return n; 18409fc68dcSAl Viro } 18509fc68dcSAl Viro 1862dcedb2aSAl Viro static inline struct pipe_buffer *pipe_buf(const struct pipe_inode_info *pipe, 1872dcedb2aSAl Viro unsigned int slot) 1882dcedb2aSAl Viro { 1892dcedb2aSAl Viro return &pipe->bufs[slot & (pipe->ring_size - 1)]; 1902dcedb2aSAl Viro } 1912dcedb2aSAl Viro 192241699cdSAl Viro #ifdef PIPE_PARANOIA 193241699cdSAl Viro static bool sanity(const struct iov_iter *i) 194241699cdSAl Viro { 195241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 1968cefc107SDavid Howells unsigned int p_head = pipe->head; 1978cefc107SDavid Howells unsigned int p_tail = pipe->tail; 1988cefc107SDavid Howells unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); 1998cefc107SDavid Howells unsigned int i_head = i->head; 2008cefc107SDavid Howells unsigned int idx; 2018cefc107SDavid Howells 202241699cdSAl Viro if (i->iov_offset) { 203241699cdSAl Viro struct pipe_buffer *p; 2048cefc107SDavid Howells if (unlikely(p_occupancy == 0)) 205241699cdSAl Viro goto Bad; // pipe must be non-empty 2068cefc107SDavid Howells if (unlikely(i_head != p_head - 1)) 207241699cdSAl Viro goto Bad; // must be at the last buffer... 208241699cdSAl Viro 2092dcedb2aSAl Viro p = pipe_buf(pipe, i_head); 210241699cdSAl Viro if (unlikely(p->offset + p->len != i->iov_offset)) 211241699cdSAl Viro goto Bad; // ... at the end of segment 212241699cdSAl Viro } else { 2138cefc107SDavid Howells if (i_head != p_head) 214241699cdSAl Viro goto Bad; // must be right after the last buffer 215241699cdSAl Viro } 216241699cdSAl Viro return true; 217241699cdSAl Viro Bad: 2188cefc107SDavid Howells printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); 2198cefc107SDavid Howells printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", 2208cefc107SDavid Howells p_head, p_tail, pipe->ring_size); 2218cefc107SDavid Howells for (idx = 0; idx < pipe->ring_size; idx++) 222241699cdSAl Viro printk(KERN_ERR "[%p %p %d %d]\n", 223241699cdSAl Viro pipe->bufs[idx].ops, 224241699cdSAl Viro pipe->bufs[idx].page, 225241699cdSAl Viro pipe->bufs[idx].offset, 226241699cdSAl Viro pipe->bufs[idx].len); 227241699cdSAl Viro WARN_ON(1); 228241699cdSAl Viro return false; 229241699cdSAl Viro } 230241699cdSAl Viro #else 231241699cdSAl Viro #define sanity(i) true 232241699cdSAl Viro #endif 233241699cdSAl Viro 23447b7fcaeSAl Viro static struct page *push_anon(struct pipe_inode_info *pipe, unsigned size) 23547b7fcaeSAl Viro { 23647b7fcaeSAl Viro struct page *page = alloc_page(GFP_USER); 23747b7fcaeSAl Viro if (page) { 23847b7fcaeSAl Viro struct pipe_buffer *buf = pipe_buf(pipe, pipe->head++); 23947b7fcaeSAl Viro *buf = (struct pipe_buffer) { 24047b7fcaeSAl Viro .ops = &default_pipe_buf_ops, 24147b7fcaeSAl Viro .page = page, 24247b7fcaeSAl Viro .offset = 0, 24347b7fcaeSAl Viro .len = size 24447b7fcaeSAl Viro }; 24547b7fcaeSAl Viro } 24647b7fcaeSAl Viro return page; 24747b7fcaeSAl Viro } 24847b7fcaeSAl Viro 24947b7fcaeSAl Viro static void push_page(struct pipe_inode_info *pipe, struct page *page, 25047b7fcaeSAl Viro unsigned int offset, unsigned int size) 25147b7fcaeSAl Viro { 25247b7fcaeSAl Viro struct pipe_buffer *buf = pipe_buf(pipe, pipe->head++); 25347b7fcaeSAl Viro *buf = (struct pipe_buffer) { 25447b7fcaeSAl Viro .ops = &page_cache_pipe_buf_ops, 25547b7fcaeSAl Viro .page = page, 25647b7fcaeSAl Viro .offset = offset, 25747b7fcaeSAl Viro .len = size 25847b7fcaeSAl Viro }; 25947b7fcaeSAl Viro get_page(page); 26047b7fcaeSAl Viro } 26147b7fcaeSAl Viro 2628fad7767SAl Viro static inline bool allocated(struct pipe_buffer *buf) 2638fad7767SAl Viro { 2648fad7767SAl Viro return buf->ops == &default_pipe_buf_ops; 2658fad7767SAl Viro } 2668fad7767SAl Viro 2678fad7767SAl Viro static struct page *append_pipe(struct iov_iter *i, size_t size, 2688fad7767SAl Viro unsigned int *off) 2698fad7767SAl Viro { 2708fad7767SAl Viro struct pipe_inode_info *pipe = i->pipe; 2718fad7767SAl Viro size_t offset = i->iov_offset; 2728fad7767SAl Viro struct pipe_buffer *buf; 2738fad7767SAl Viro struct page *page; 2748fad7767SAl Viro 2758fad7767SAl Viro if (offset && offset < PAGE_SIZE) { 2768fad7767SAl Viro // some space in the last buffer; can we add to it? 2778fad7767SAl Viro buf = pipe_buf(pipe, pipe->head - 1); 2788fad7767SAl Viro if (allocated(buf)) { 2798fad7767SAl Viro size = min_t(size_t, size, PAGE_SIZE - offset); 2808fad7767SAl Viro buf->len += size; 2818fad7767SAl Viro i->iov_offset += size; 2828fad7767SAl Viro i->count -= size; 2838fad7767SAl Viro *off = offset; 2848fad7767SAl Viro return buf->page; 2858fad7767SAl Viro } 2868fad7767SAl Viro } 2878fad7767SAl Viro // OK, we need a new buffer 2888fad7767SAl Viro *off = 0; 2898fad7767SAl Viro size = min_t(size_t, size, PAGE_SIZE); 2908fad7767SAl Viro if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) 2918fad7767SAl Viro return NULL; 2928fad7767SAl Viro page = push_anon(pipe, size); 2938fad7767SAl Viro if (!page) 2948fad7767SAl Viro return NULL; 2958fad7767SAl Viro i->head = pipe->head - 1; 2968fad7767SAl Viro i->iov_offset = size; 2978fad7767SAl Viro i->count -= size; 2988fad7767SAl Viro return page; 2998fad7767SAl Viro } 3008fad7767SAl Viro 301241699cdSAl Viro static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, 302241699cdSAl Viro struct iov_iter *i) 303241699cdSAl Viro { 304241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 30547b7fcaeSAl Viro unsigned int head = pipe->head; 306241699cdSAl Viro 307241699cdSAl Viro if (unlikely(bytes > i->count)) 308241699cdSAl Viro bytes = i->count; 309241699cdSAl Viro 310241699cdSAl Viro if (unlikely(!bytes)) 311241699cdSAl Viro return 0; 312241699cdSAl Viro 313241699cdSAl Viro if (!sanity(i)) 314241699cdSAl Viro return 0; 315241699cdSAl Viro 31647b7fcaeSAl Viro if (offset && i->iov_offset == offset) { // could we merge it? 31747b7fcaeSAl Viro struct pipe_buffer *buf = pipe_buf(pipe, head - 1); 31847b7fcaeSAl Viro if (buf->page == page) { 319241699cdSAl Viro buf->len += bytes; 320241699cdSAl Viro i->iov_offset += bytes; 32147b7fcaeSAl Viro i->count -= bytes; 32247b7fcaeSAl Viro return bytes; 323241699cdSAl Viro } 324241699cdSAl Viro } 32547b7fcaeSAl Viro if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) 326241699cdSAl Viro return 0; 3278cefc107SDavid Howells 32847b7fcaeSAl Viro push_page(pipe, page, offset, bytes); 329241699cdSAl Viro i->iov_offset = offset + bytes; 33047b7fcaeSAl Viro i->head = head; 331241699cdSAl Viro i->count -= bytes; 332241699cdSAl Viro return bytes; 333241699cdSAl Viro } 334241699cdSAl Viro 335d879cb83SAl Viro /* 336a6294593SAndreas Gruenbacher * fault_in_iov_iter_readable - fault in iov iterator for reading 337a6294593SAndreas Gruenbacher * @i: iterator 338a6294593SAndreas Gruenbacher * @size: maximum length 339171a0203SAnton Altaparmakov * 340a6294593SAndreas Gruenbacher * Fault in one or more iovecs of the given iov_iter, to a maximum length of 341a6294593SAndreas Gruenbacher * @size. For each iovec, fault in each page that constitutes the iovec. 342a6294593SAndreas Gruenbacher * 343a6294593SAndreas Gruenbacher * Returns the number of bytes not faulted in (like copy_to_user() and 344a6294593SAndreas Gruenbacher * copy_from_user()). 345a6294593SAndreas Gruenbacher * 346a6294593SAndreas Gruenbacher * Always returns 0 for non-userspace iterators. 347171a0203SAnton Altaparmakov */ 348a6294593SAndreas Gruenbacher size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t size) 349171a0203SAnton Altaparmakov { 350fcb14cb1SAl Viro if (iter_is_ubuf(i)) { 351fcb14cb1SAl Viro size_t n = min(size, iov_iter_count(i)); 352fcb14cb1SAl Viro n -= fault_in_readable(i->ubuf + i->iov_offset, n); 353fcb14cb1SAl Viro return size - n; 354fcb14cb1SAl Viro } else if (iter_is_iovec(i)) { 355a6294593SAndreas Gruenbacher size_t count = min(size, iov_iter_count(i)); 3568409a0d2SAl Viro const struct iovec *p; 3578409a0d2SAl Viro size_t skip; 3588409a0d2SAl Viro 359a6294593SAndreas Gruenbacher size -= count; 360a6294593SAndreas Gruenbacher for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) { 361a6294593SAndreas Gruenbacher size_t len = min(count, p->iov_len - skip); 362a6294593SAndreas Gruenbacher size_t ret; 3638409a0d2SAl Viro 3648409a0d2SAl Viro if (unlikely(!len)) 3658409a0d2SAl Viro continue; 366a6294593SAndreas Gruenbacher ret = fault_in_readable(p->iov_base + skip, len); 367a6294593SAndreas Gruenbacher count -= len - ret; 368a6294593SAndreas Gruenbacher if (ret) 369a6294593SAndreas Gruenbacher break; 3708409a0d2SAl Viro } 371a6294593SAndreas Gruenbacher return count + size; 372171a0203SAnton Altaparmakov } 373171a0203SAnton Altaparmakov return 0; 374171a0203SAnton Altaparmakov } 375a6294593SAndreas Gruenbacher EXPORT_SYMBOL(fault_in_iov_iter_readable); 376171a0203SAnton Altaparmakov 377cdd591fcSAndreas Gruenbacher /* 378cdd591fcSAndreas Gruenbacher * fault_in_iov_iter_writeable - fault in iov iterator for writing 379cdd591fcSAndreas Gruenbacher * @i: iterator 380cdd591fcSAndreas Gruenbacher * @size: maximum length 381cdd591fcSAndreas Gruenbacher * 382cdd591fcSAndreas Gruenbacher * Faults in the iterator using get_user_pages(), i.e., without triggering 383cdd591fcSAndreas Gruenbacher * hardware page faults. This is primarily useful when we already know that 384cdd591fcSAndreas Gruenbacher * some or all of the pages in @i aren't in memory. 385cdd591fcSAndreas Gruenbacher * 386cdd591fcSAndreas Gruenbacher * Returns the number of bytes not faulted in, like copy_to_user() and 387cdd591fcSAndreas Gruenbacher * copy_from_user(). 388cdd591fcSAndreas Gruenbacher * 389cdd591fcSAndreas Gruenbacher * Always returns 0 for non-user-space iterators. 390cdd591fcSAndreas Gruenbacher */ 391cdd591fcSAndreas Gruenbacher size_t fault_in_iov_iter_writeable(const struct iov_iter *i, size_t size) 392cdd591fcSAndreas Gruenbacher { 393fcb14cb1SAl Viro if (iter_is_ubuf(i)) { 394fcb14cb1SAl Viro size_t n = min(size, iov_iter_count(i)); 395fcb14cb1SAl Viro n -= fault_in_safe_writeable(i->ubuf + i->iov_offset, n); 396fcb14cb1SAl Viro return size - n; 397fcb14cb1SAl Viro } else if (iter_is_iovec(i)) { 398cdd591fcSAndreas Gruenbacher size_t count = min(size, iov_iter_count(i)); 399cdd591fcSAndreas Gruenbacher const struct iovec *p; 400cdd591fcSAndreas Gruenbacher size_t skip; 401cdd591fcSAndreas Gruenbacher 402cdd591fcSAndreas Gruenbacher size -= count; 403cdd591fcSAndreas Gruenbacher for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) { 404cdd591fcSAndreas Gruenbacher size_t len = min(count, p->iov_len - skip); 405cdd591fcSAndreas Gruenbacher size_t ret; 406cdd591fcSAndreas Gruenbacher 407cdd591fcSAndreas Gruenbacher if (unlikely(!len)) 408cdd591fcSAndreas Gruenbacher continue; 409cdd591fcSAndreas Gruenbacher ret = fault_in_safe_writeable(p->iov_base + skip, len); 410cdd591fcSAndreas Gruenbacher count -= len - ret; 411cdd591fcSAndreas Gruenbacher if (ret) 412cdd591fcSAndreas Gruenbacher break; 413cdd591fcSAndreas Gruenbacher } 414cdd591fcSAndreas Gruenbacher return count + size; 415cdd591fcSAndreas Gruenbacher } 416cdd591fcSAndreas Gruenbacher return 0; 417cdd591fcSAndreas Gruenbacher } 418cdd591fcSAndreas Gruenbacher EXPORT_SYMBOL(fault_in_iov_iter_writeable); 419cdd591fcSAndreas Gruenbacher 420aa563d7bSDavid Howells void iov_iter_init(struct iov_iter *i, unsigned int direction, 421d879cb83SAl Viro const struct iovec *iov, unsigned long nr_segs, 422d879cb83SAl Viro size_t count) 423d879cb83SAl Viro { 424aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 4258cd54c1cSAl Viro *i = (struct iov_iter) { 4268cd54c1cSAl Viro .iter_type = ITER_IOVEC, 4273337ab08SAndreas Gruenbacher .nofault = false, 428fcb14cb1SAl Viro .user_backed = true, 4298cd54c1cSAl Viro .data_source = direction, 4308cd54c1cSAl Viro .iov = iov, 4318cd54c1cSAl Viro .nr_segs = nr_segs, 4328cd54c1cSAl Viro .iov_offset = 0, 4338cd54c1cSAl Viro .count = count 4348cd54c1cSAl Viro }; 435d879cb83SAl Viro } 436d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_init); 437d879cb83SAl Viro 4388cefc107SDavid Howells static inline void data_start(const struct iov_iter *i, 4398cefc107SDavid Howells unsigned int *iter_headp, size_t *offp) 440241699cdSAl Viro { 4418cefc107SDavid Howells unsigned int iter_head = i->head; 442241699cdSAl Viro size_t off = i->iov_offset; 4438cefc107SDavid Howells 4442dcedb2aSAl Viro if (off && (!allocated(pipe_buf(i->pipe, iter_head)) || 4458cefc107SDavid Howells off == PAGE_SIZE)) { 4468cefc107SDavid Howells iter_head++; 447241699cdSAl Viro off = 0; 448241699cdSAl Viro } 4498cefc107SDavid Howells *iter_headp = iter_head; 450241699cdSAl Viro *offp = off; 451241699cdSAl Viro } 452241699cdSAl Viro 453241699cdSAl Viro static size_t copy_pipe_to_iter(const void *addr, size_t bytes, 454241699cdSAl Viro struct iov_iter *i) 455241699cdSAl Viro { 4568fad7767SAl Viro unsigned int off, chunk; 4578fad7767SAl Viro 4588fad7767SAl Viro if (unlikely(bytes > i->count)) 4598fad7767SAl Viro bytes = i->count; 4608fad7767SAl Viro if (unlikely(!bytes)) 4618fad7767SAl Viro return 0; 462241699cdSAl Viro 463241699cdSAl Viro if (!sanity(i)) 464241699cdSAl Viro return 0; 465241699cdSAl Viro 4668fad7767SAl Viro for (size_t n = bytes; n; n -= chunk) { 4678fad7767SAl Viro struct page *page = append_pipe(i, n, &off); 4688fad7767SAl Viro chunk = min_t(size_t, n, PAGE_SIZE - off); 4698fad7767SAl Viro if (!page) 4708fad7767SAl Viro return bytes - n; 4718fad7767SAl Viro memcpy_to_page(page, off, addr, chunk); 472241699cdSAl Viro addr += chunk; 4738fad7767SAl Viro } 474241699cdSAl Viro return bytes; 475241699cdSAl Viro } 476241699cdSAl Viro 477f9152895SAl Viro static __wsum csum_and_memcpy(void *to, const void *from, size_t len, 478f9152895SAl Viro __wsum sum, size_t off) 479f9152895SAl Viro { 480cc44c17bSAl Viro __wsum next = csum_partial_copy_nocheck(from, to, len); 481f9152895SAl Viro return csum_block_add(sum, next, off); 482f9152895SAl Viro } 483f9152895SAl Viro 48478e1f386SAl Viro static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, 4856852df12SAl Viro struct iov_iter *i, __wsum *sump) 48678e1f386SAl Viro { 4876852df12SAl Viro __wsum sum = *sump; 4886852df12SAl Viro size_t off = 0; 4898fad7767SAl Viro unsigned int chunk, r; 4908fad7767SAl Viro 4918fad7767SAl Viro if (unlikely(bytes > i->count)) 4928fad7767SAl Viro bytes = i->count; 4938fad7767SAl Viro if (unlikely(!bytes)) 4948fad7767SAl Viro return 0; 49578e1f386SAl Viro 49678e1f386SAl Viro if (!sanity(i)) 49778e1f386SAl Viro return 0; 49878e1f386SAl Viro 4996852df12SAl Viro while (bytes) { 5008fad7767SAl Viro struct page *page = append_pipe(i, bytes, &r); 5018fad7767SAl Viro char *p; 5028fad7767SAl Viro 5038fad7767SAl Viro if (!page) 5048fad7767SAl Viro break; 5058fad7767SAl Viro chunk = min_t(size_t, bytes, PAGE_SIZE - r); 5068fad7767SAl Viro p = kmap_local_page(page); 5076852df12SAl Viro sum = csum_and_memcpy(p + r, addr + off, chunk, sum, off); 5082495bdccSAl Viro kunmap_local(p); 50978e1f386SAl Viro off += chunk; 5108fad7767SAl Viro bytes -= chunk; 5116852df12SAl Viro } 5126852df12SAl Viro *sump = sum; 5136852df12SAl Viro return off; 51478e1f386SAl Viro } 51578e1f386SAl Viro 516aa28de27SAl Viro size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 517d879cb83SAl Viro { 51800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 519241699cdSAl Viro return copy_pipe_to_iter(addr, bytes, i); 520fcb14cb1SAl Viro if (user_backed_iter(i)) 52109fc68dcSAl Viro might_fault(); 5227baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 5237baa5099SAl Viro copyout(base, addr + off, len), 5247baa5099SAl Viro memcpy(base, addr + off, len) 525d879cb83SAl Viro ) 526d879cb83SAl Viro 527d879cb83SAl Viro return bytes; 528d879cb83SAl Viro } 529aa28de27SAl Viro EXPORT_SYMBOL(_copy_to_iter); 530d879cb83SAl Viro 531ec6347bbSDan Williams #ifdef CONFIG_ARCH_HAS_COPY_MC 532ec6347bbSDan Williams static int copyout_mc(void __user *to, const void *from, size_t n) 5338780356eSDan Williams { 53496d4f267SLinus Torvalds if (access_ok(to, n)) { 535d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 536ec6347bbSDan Williams n = copy_mc_to_user((__force void *) to, from, n); 5378780356eSDan Williams } 5388780356eSDan Williams return n; 5398780356eSDan Williams } 5408780356eSDan Williams 541ec6347bbSDan Williams static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, 542ca146f6fSDan Williams struct iov_iter *i) 543ca146f6fSDan Williams { 5448fad7767SAl Viro size_t xfer = 0; 5458fad7767SAl Viro unsigned int off, chunk; 5468fad7767SAl Viro 5478fad7767SAl Viro if (unlikely(bytes > i->count)) 5488fad7767SAl Viro bytes = i->count; 5498fad7767SAl Viro if (unlikely(!bytes)) 5508fad7767SAl Viro return 0; 551ca146f6fSDan Williams 552ca146f6fSDan Williams if (!sanity(i)) 553ca146f6fSDan Williams return 0; 554ca146f6fSDan Williams 5558fad7767SAl Viro while (bytes) { 5568fad7767SAl Viro struct page *page = append_pipe(i, bytes, &off); 557ca146f6fSDan Williams unsigned long rem; 5588fad7767SAl Viro char *p; 5598fad7767SAl Viro 5608fad7767SAl Viro if (!page) 5618fad7767SAl Viro break; 5628fad7767SAl Viro chunk = min_t(size_t, bytes, PAGE_SIZE - off); 5638fad7767SAl Viro p = kmap_local_page(page); 5642a510a74SAl Viro rem = copy_mc_to_kernel(p + off, addr + xfer, chunk); 5652a510a74SAl Viro chunk -= rem; 5662a510a74SAl Viro kunmap_local(p); 5672a510a74SAl Viro xfer += chunk; 5688fad7767SAl Viro bytes -= chunk; 569c3497fd0SAl Viro if (rem) { 5708fad7767SAl Viro iov_iter_revert(i, rem); 571ca146f6fSDan Williams break; 572c3497fd0SAl Viro } 5732a510a74SAl Viro } 574ca146f6fSDan Williams return xfer; 575ca146f6fSDan Williams } 576ca146f6fSDan Williams 577bf3eeb9bSDan Williams /** 578ec6347bbSDan Williams * _copy_mc_to_iter - copy to iter with source memory error exception handling 579bf3eeb9bSDan Williams * @addr: source kernel address 580bf3eeb9bSDan Williams * @bytes: total transfer length 58144e55997SRandy Dunlap * @i: destination iterator 582bf3eeb9bSDan Williams * 583ec6347bbSDan Williams * The pmem driver deploys this for the dax operation 584ec6347bbSDan Williams * (dax_copy_to_iter()) for dax reads (bypass page-cache and the 585ec6347bbSDan Williams * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes 586ec6347bbSDan Williams * successfully copied. 587bf3eeb9bSDan Williams * 588ec6347bbSDan Williams * The main differences between this and typical _copy_to_iter(). 589bf3eeb9bSDan Williams * 590bf3eeb9bSDan Williams * * Typical tail/residue handling after a fault retries the copy 591bf3eeb9bSDan Williams * byte-by-byte until the fault happens again. Re-triggering machine 592bf3eeb9bSDan Williams * checks is potentially fatal so the implementation uses source 593bf3eeb9bSDan Williams * alignment and poison alignment assumptions to avoid re-triggering 594bf3eeb9bSDan Williams * hardware exceptions. 595bf3eeb9bSDan Williams * 596bf3eeb9bSDan Williams * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. 597bf3eeb9bSDan Williams * Compare to copy_to_iter() where only ITER_IOVEC attempts might return 598bf3eeb9bSDan Williams * a short copy. 59944e55997SRandy Dunlap * 60044e55997SRandy Dunlap * Return: number of bytes copied (may be %0) 601bf3eeb9bSDan Williams */ 602ec6347bbSDan Williams size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 6038780356eSDan Williams { 60400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 605ec6347bbSDan Williams return copy_mc_pipe_to_iter(addr, bytes, i); 606fcb14cb1SAl Viro if (user_backed_iter(i)) 6078780356eSDan Williams might_fault(); 6087baa5099SAl Viro __iterate_and_advance(i, bytes, base, len, off, 6097baa5099SAl Viro copyout_mc(base, addr + off, len), 6107baa5099SAl Viro copy_mc_to_kernel(base, addr + off, len) 6118780356eSDan Williams ) 6128780356eSDan Williams 6138780356eSDan Williams return bytes; 6148780356eSDan Williams } 615ec6347bbSDan Williams EXPORT_SYMBOL_GPL(_copy_mc_to_iter); 616ec6347bbSDan Williams #endif /* CONFIG_ARCH_HAS_COPY_MC */ 6178780356eSDan Williams 618aa28de27SAl Viro size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) 619d879cb83SAl Viro { 62000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 621241699cdSAl Viro WARN_ON(1); 622241699cdSAl Viro return 0; 623241699cdSAl Viro } 624fcb14cb1SAl Viro if (user_backed_iter(i)) 62509fc68dcSAl Viro might_fault(); 6267baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 6277baa5099SAl Viro copyin(addr + off, base, len), 6287baa5099SAl Viro memcpy(addr + off, base, len) 629d879cb83SAl Viro ) 630d879cb83SAl Viro 631d879cb83SAl Viro return bytes; 632d879cb83SAl Viro } 633aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter); 634d879cb83SAl Viro 635aa28de27SAl Viro size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) 636d879cb83SAl Viro { 63700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 638241699cdSAl Viro WARN_ON(1); 639241699cdSAl Viro return 0; 640241699cdSAl Viro } 6417baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 6427baa5099SAl Viro __copy_from_user_inatomic_nocache(addr + off, base, len), 6437baa5099SAl Viro memcpy(addr + off, base, len) 644d879cb83SAl Viro ) 645d879cb83SAl Viro 646d879cb83SAl Viro return bytes; 647d879cb83SAl Viro } 648aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_nocache); 649d879cb83SAl Viro 6500aed55afSDan Williams #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE 651abd08d7dSDan Williams /** 652abd08d7dSDan Williams * _copy_from_iter_flushcache - write destination through cpu cache 653abd08d7dSDan Williams * @addr: destination kernel address 654abd08d7dSDan Williams * @bytes: total transfer length 65544e55997SRandy Dunlap * @i: source iterator 656abd08d7dSDan Williams * 657abd08d7dSDan Williams * The pmem driver arranges for filesystem-dax to use this facility via 658abd08d7dSDan Williams * dax_copy_from_iter() for ensuring that writes to persistent memory 659abd08d7dSDan Williams * are flushed through the CPU cache. It is differentiated from 660abd08d7dSDan Williams * _copy_from_iter_nocache() in that guarantees all data is flushed for 661abd08d7dSDan Williams * all iterator types. The _copy_from_iter_nocache() only attempts to 662abd08d7dSDan Williams * bypass the cache for the ITER_IOVEC case, and on some archs may use 663abd08d7dSDan Williams * instructions that strand dirty-data in the cache. 66444e55997SRandy Dunlap * 66544e55997SRandy Dunlap * Return: number of bytes copied (may be %0) 666abd08d7dSDan Williams */ 6676a37e940SLinus Torvalds size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 6680aed55afSDan Williams { 66900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 6700aed55afSDan Williams WARN_ON(1); 6710aed55afSDan Williams return 0; 6720aed55afSDan Williams } 6737baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 6747baa5099SAl Viro __copy_from_user_flushcache(addr + off, base, len), 6757baa5099SAl Viro memcpy_flushcache(addr + off, base, len) 6760aed55afSDan Williams ) 6770aed55afSDan Williams 6780aed55afSDan Williams return bytes; 6790aed55afSDan Williams } 6806a37e940SLinus Torvalds EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); 6810aed55afSDan Williams #endif 6820aed55afSDan Williams 68372e809edSAl Viro static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) 68472e809edSAl Viro { 6856daef95bSEric Dumazet struct page *head; 6866daef95bSEric Dumazet size_t v = n + offset; 6876daef95bSEric Dumazet 6886daef95bSEric Dumazet /* 6896daef95bSEric Dumazet * The general case needs to access the page order in order 6906daef95bSEric Dumazet * to compute the page size. 6916daef95bSEric Dumazet * However, we mostly deal with order-0 pages and thus can 6926daef95bSEric Dumazet * avoid a possible cache line miss for requests that fit all 6936daef95bSEric Dumazet * page orders. 6946daef95bSEric Dumazet */ 6956daef95bSEric Dumazet if (n <= v && v <= PAGE_SIZE) 6966daef95bSEric Dumazet return true; 6976daef95bSEric Dumazet 6986daef95bSEric Dumazet head = compound_head(page); 6996daef95bSEric Dumazet v += (page - head) << PAGE_SHIFT; 700a90bcb86SPetar Penkov 701a50b854eSMatthew Wilcox (Oracle) if (likely(n <= v && v <= (page_size(head)))) 70272e809edSAl Viro return true; 70372e809edSAl Viro WARN_ON(1); 70472e809edSAl Viro return false; 70572e809edSAl Viro } 706cbbd26b8SAl Viro 70708aa6479SAl Viro static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 708d879cb83SAl Viro struct iov_iter *i) 709d879cb83SAl Viro { 71059bb69c6SAl Viro if (unlikely(iov_iter_is_pipe(i))) { 71159bb69c6SAl Viro return copy_page_to_iter_pipe(page, offset, bytes, i); 71259bb69c6SAl Viro } else { 713c1d4d6a9SAl Viro void *kaddr = kmap_local_page(page); 714c1d4d6a9SAl Viro size_t wanted = _copy_to_iter(kaddr + offset, bytes, i); 715c1d4d6a9SAl Viro kunmap_local(kaddr); 716d879cb83SAl Viro return wanted; 71728f38db7SAl Viro } 718d879cb83SAl Viro } 71908aa6479SAl Viro 72008aa6479SAl Viro size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 72108aa6479SAl Viro struct iov_iter *i) 72208aa6479SAl Viro { 72308aa6479SAl Viro size_t res = 0; 72408aa6479SAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 72508aa6479SAl Viro return 0; 72608aa6479SAl Viro page += offset / PAGE_SIZE; // first subpage 72708aa6479SAl Viro offset %= PAGE_SIZE; 72808aa6479SAl Viro while (1) { 72908aa6479SAl Viro size_t n = __copy_page_to_iter(page, offset, 73008aa6479SAl Viro min(bytes, (size_t)PAGE_SIZE - offset), i); 73108aa6479SAl Viro res += n; 73208aa6479SAl Viro bytes -= n; 73308aa6479SAl Viro if (!bytes || !n) 73408aa6479SAl Viro break; 73508aa6479SAl Viro offset += n; 73608aa6479SAl Viro if (offset == PAGE_SIZE) { 73708aa6479SAl Viro page++; 73808aa6479SAl Viro offset = 0; 73908aa6479SAl Viro } 74008aa6479SAl Viro } 74108aa6479SAl Viro return res; 74208aa6479SAl Viro } 743d879cb83SAl Viro EXPORT_SYMBOL(copy_page_to_iter); 744d879cb83SAl Viro 745d879cb83SAl Viro size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, 746d879cb83SAl Viro struct iov_iter *i) 747d879cb83SAl Viro { 74859bb69c6SAl Viro if (page_copy_sane(page, offset, bytes)) { 74955ca375cSAl Viro void *kaddr = kmap_local_page(page); 750aa28de27SAl Viro size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); 75155ca375cSAl Viro kunmap_local(kaddr); 752d879cb83SAl Viro return wanted; 75328f38db7SAl Viro } 75428f38db7SAl Viro return 0; 755d879cb83SAl Viro } 756d879cb83SAl Viro EXPORT_SYMBOL(copy_page_from_iter); 757d879cb83SAl Viro 758241699cdSAl Viro static size_t pipe_zero(size_t bytes, struct iov_iter *i) 759241699cdSAl Viro { 7608fad7767SAl Viro unsigned int chunk, off; 7618fad7767SAl Viro 7628fad7767SAl Viro if (unlikely(bytes > i->count)) 7638fad7767SAl Viro bytes = i->count; 7648fad7767SAl Viro if (unlikely(!bytes)) 7658fad7767SAl Viro return 0; 766241699cdSAl Viro 767241699cdSAl Viro if (!sanity(i)) 768241699cdSAl Viro return 0; 769241699cdSAl Viro 7708fad7767SAl Viro for (size_t n = bytes; n; n -= chunk) { 7718fad7767SAl Viro struct page *page = append_pipe(i, n, &off); 7728fad7767SAl Viro char *p; 773241699cdSAl Viro 7748fad7767SAl Viro if (!page) 7758fad7767SAl Viro return bytes - n; 7768fad7767SAl Viro chunk = min_t(size_t, n, PAGE_SIZE - off); 7778fad7767SAl Viro p = kmap_local_page(page); 778893839fdSAl Viro memset(p + off, 0, chunk); 779893839fdSAl Viro kunmap_local(p); 7808fad7767SAl Viro } 781241699cdSAl Viro return bytes; 782241699cdSAl Viro } 783241699cdSAl Viro 784d879cb83SAl Viro size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 785d879cb83SAl Viro { 78600e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 787241699cdSAl Viro return pipe_zero(bytes, i); 7887baa5099SAl Viro iterate_and_advance(i, bytes, base, len, count, 7897baa5099SAl Viro clear_user(base, len), 7907baa5099SAl Viro memset(base, 0, len) 791d879cb83SAl Viro ) 792d879cb83SAl Viro 793d879cb83SAl Viro return bytes; 794d879cb83SAl Viro } 795d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_zero); 796d879cb83SAl Viro 797f0b65f39SAl Viro size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, 798f0b65f39SAl Viro struct iov_iter *i) 799d879cb83SAl Viro { 800d879cb83SAl Viro char *kaddr = kmap_atomic(page), *p = kaddr + offset; 80172e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) { 80272e809edSAl Viro kunmap_atomic(kaddr); 80372e809edSAl Viro return 0; 80472e809edSAl Viro } 8059ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 806241699cdSAl Viro kunmap_atomic(kaddr); 807241699cdSAl Viro WARN_ON(1); 808241699cdSAl Viro return 0; 809241699cdSAl Viro } 8107baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 8117baa5099SAl Viro copyin(p + off, base, len), 8127baa5099SAl Viro memcpy(p + off, base, len) 813d879cb83SAl Viro ) 814d879cb83SAl Viro kunmap_atomic(kaddr); 815d879cb83SAl Viro return bytes; 816d879cb83SAl Viro } 817f0b65f39SAl Viro EXPORT_SYMBOL(copy_page_from_iter_atomic); 818d879cb83SAl Viro 819b9dc6f65SAl Viro static inline void pipe_truncate(struct iov_iter *i) 820241699cdSAl Viro { 821241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 8228cefc107SDavid Howells unsigned int p_tail = pipe->tail; 8238cefc107SDavid Howells unsigned int p_head = pipe->head; 8248cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 8258cefc107SDavid Howells 8268cefc107SDavid Howells if (!pipe_empty(p_head, p_tail)) { 8278cefc107SDavid Howells struct pipe_buffer *buf; 8288cefc107SDavid Howells unsigned int i_head = i->head; 829b9dc6f65SAl Viro size_t off = i->iov_offset; 8308cefc107SDavid Howells 831b9dc6f65SAl Viro if (off) { 8328cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 8338cefc107SDavid Howells buf->len = off - buf->offset; 8348cefc107SDavid Howells i_head++; 835b9dc6f65SAl Viro } 8368cefc107SDavid Howells while (p_head != i_head) { 8378cefc107SDavid Howells p_head--; 8388cefc107SDavid Howells pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); 839241699cdSAl Viro } 8408cefc107SDavid Howells 8418cefc107SDavid Howells pipe->head = p_head; 842241699cdSAl Viro } 843b9dc6f65SAl Viro } 844b9dc6f65SAl Viro 845b9dc6f65SAl Viro static void pipe_advance(struct iov_iter *i, size_t size) 846b9dc6f65SAl Viro { 847b9dc6f65SAl Viro struct pipe_inode_info *pipe = i->pipe; 848b9dc6f65SAl Viro if (size) { 849b9dc6f65SAl Viro struct pipe_buffer *buf; 8508cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 8518cefc107SDavid Howells unsigned int i_head = i->head; 852b9dc6f65SAl Viro size_t off = i->iov_offset, left = size; 8538cefc107SDavid Howells 854b9dc6f65SAl Viro if (off) /* make it relative to the beginning of buffer */ 8558cefc107SDavid Howells left += off - pipe->bufs[i_head & p_mask].offset; 856b9dc6f65SAl Viro while (1) { 8578cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 858b9dc6f65SAl Viro if (left <= buf->len) 859b9dc6f65SAl Viro break; 860b9dc6f65SAl Viro left -= buf->len; 8618cefc107SDavid Howells i_head++; 862b9dc6f65SAl Viro } 8638cefc107SDavid Howells i->head = i_head; 864b9dc6f65SAl Viro i->iov_offset = buf->offset + left; 865b9dc6f65SAl Viro } 866b9dc6f65SAl Viro i->count -= size; 867b9dc6f65SAl Viro /* ... and discard everything past that point */ 868b9dc6f65SAl Viro pipe_truncate(i); 869241699cdSAl Viro } 870241699cdSAl Viro 87154c8195bSPavel Begunkov static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) 87254c8195bSPavel Begunkov { 87318fa9af7SAl Viro const struct bio_vec *bvec, *end; 87454c8195bSPavel Begunkov 87518fa9af7SAl Viro if (!i->count) 87618fa9af7SAl Viro return; 87718fa9af7SAl Viro i->count -= size; 87854c8195bSPavel Begunkov 87918fa9af7SAl Viro size += i->iov_offset; 88018fa9af7SAl Viro 88118fa9af7SAl Viro for (bvec = i->bvec, end = bvec + i->nr_segs; bvec < end; bvec++) { 88218fa9af7SAl Viro if (likely(size < bvec->bv_len)) 88318fa9af7SAl Viro break; 88418fa9af7SAl Viro size -= bvec->bv_len; 88518fa9af7SAl Viro } 88618fa9af7SAl Viro i->iov_offset = size; 88718fa9af7SAl Viro i->nr_segs -= bvec - i->bvec; 88818fa9af7SAl Viro i->bvec = bvec; 88954c8195bSPavel Begunkov } 89054c8195bSPavel Begunkov 891185ac4d4SAl Viro static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) 892185ac4d4SAl Viro { 893185ac4d4SAl Viro const struct iovec *iov, *end; 894185ac4d4SAl Viro 895185ac4d4SAl Viro if (!i->count) 896185ac4d4SAl Viro return; 897185ac4d4SAl Viro i->count -= size; 898185ac4d4SAl Viro 899185ac4d4SAl Viro size += i->iov_offset; // from beginning of current segment 900185ac4d4SAl Viro for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { 901185ac4d4SAl Viro if (likely(size < iov->iov_len)) 902185ac4d4SAl Viro break; 903185ac4d4SAl Viro size -= iov->iov_len; 904185ac4d4SAl Viro } 905185ac4d4SAl Viro i->iov_offset = size; 906185ac4d4SAl Viro i->nr_segs -= iov - i->iov; 907185ac4d4SAl Viro i->iov = iov; 908185ac4d4SAl Viro } 909185ac4d4SAl Viro 910d879cb83SAl Viro void iov_iter_advance(struct iov_iter *i, size_t size) 911d879cb83SAl Viro { 9123b3fc051SAl Viro if (unlikely(i->count < size)) 9133b3fc051SAl Viro size = i->count; 914fcb14cb1SAl Viro if (likely(iter_is_ubuf(i)) || unlikely(iov_iter_is_xarray(i))) { 915fcb14cb1SAl Viro i->iov_offset += size; 916fcb14cb1SAl Viro i->count -= size; 917fcb14cb1SAl Viro } else if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { 918185ac4d4SAl Viro /* iovec and kvec have identical layouts */ 919185ac4d4SAl Viro iov_iter_iovec_advance(i, size); 920185ac4d4SAl Viro } else if (iov_iter_is_bvec(i)) { 921185ac4d4SAl Viro iov_iter_bvec_advance(i, size); 922185ac4d4SAl Viro } else if (iov_iter_is_pipe(i)) { 923241699cdSAl Viro pipe_advance(i, size); 924185ac4d4SAl Viro } else if (iov_iter_is_discard(i)) { 925185ac4d4SAl Viro i->count -= size; 9267ff50620SDavid Howells } 927d879cb83SAl Viro } 928d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_advance); 929d879cb83SAl Viro 93027c0e374SAl Viro void iov_iter_revert(struct iov_iter *i, size_t unroll) 93127c0e374SAl Viro { 93227c0e374SAl Viro if (!unroll) 93327c0e374SAl Viro return; 9345b47d59aSAl Viro if (WARN_ON(unroll > MAX_RW_COUNT)) 9355b47d59aSAl Viro return; 93627c0e374SAl Viro i->count += unroll; 93700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 93827c0e374SAl Viro struct pipe_inode_info *pipe = i->pipe; 9398cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9408cefc107SDavid Howells unsigned int i_head = i->head; 94127c0e374SAl Viro size_t off = i->iov_offset; 94227c0e374SAl Viro while (1) { 9438cefc107SDavid Howells struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; 9448cefc107SDavid Howells size_t n = off - b->offset; 94527c0e374SAl Viro if (unroll < n) { 9464fa55cefSAl Viro off -= unroll; 94727c0e374SAl Viro break; 94827c0e374SAl Viro } 94927c0e374SAl Viro unroll -= n; 9508cefc107SDavid Howells if (!unroll && i_head == i->start_head) { 95127c0e374SAl Viro off = 0; 95227c0e374SAl Viro break; 95327c0e374SAl Viro } 9548cefc107SDavid Howells i_head--; 9558cefc107SDavid Howells b = &pipe->bufs[i_head & p_mask]; 9568cefc107SDavid Howells off = b->offset + b->len; 95727c0e374SAl Viro } 95827c0e374SAl Viro i->iov_offset = off; 9598cefc107SDavid Howells i->head = i_head; 96027c0e374SAl Viro pipe_truncate(i); 96127c0e374SAl Viro return; 96227c0e374SAl Viro } 9639ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 9649ea9ce04SDavid Howells return; 96527c0e374SAl Viro if (unroll <= i->iov_offset) { 96627c0e374SAl Viro i->iov_offset -= unroll; 96727c0e374SAl Viro return; 96827c0e374SAl Viro } 96927c0e374SAl Viro unroll -= i->iov_offset; 970fcb14cb1SAl Viro if (iov_iter_is_xarray(i) || iter_is_ubuf(i)) { 9717ff50620SDavid Howells BUG(); /* We should never go beyond the start of the specified 9727ff50620SDavid Howells * range since we might then be straying into pages that 9737ff50620SDavid Howells * aren't pinned. 9747ff50620SDavid Howells */ 9757ff50620SDavid Howells } else if (iov_iter_is_bvec(i)) { 97627c0e374SAl Viro const struct bio_vec *bvec = i->bvec; 97727c0e374SAl Viro while (1) { 97827c0e374SAl Viro size_t n = (--bvec)->bv_len; 97927c0e374SAl Viro i->nr_segs++; 98027c0e374SAl Viro if (unroll <= n) { 98127c0e374SAl Viro i->bvec = bvec; 98227c0e374SAl Viro i->iov_offset = n - unroll; 98327c0e374SAl Viro return; 98427c0e374SAl Viro } 98527c0e374SAl Viro unroll -= n; 98627c0e374SAl Viro } 98727c0e374SAl Viro } else { /* same logics for iovec and kvec */ 98827c0e374SAl Viro const struct iovec *iov = i->iov; 98927c0e374SAl Viro while (1) { 99027c0e374SAl Viro size_t n = (--iov)->iov_len; 99127c0e374SAl Viro i->nr_segs++; 99227c0e374SAl Viro if (unroll <= n) { 99327c0e374SAl Viro i->iov = iov; 99427c0e374SAl Viro i->iov_offset = n - unroll; 99527c0e374SAl Viro return; 99627c0e374SAl Viro } 99727c0e374SAl Viro unroll -= n; 99827c0e374SAl Viro } 99927c0e374SAl Viro } 100027c0e374SAl Viro } 100127c0e374SAl Viro EXPORT_SYMBOL(iov_iter_revert); 100227c0e374SAl Viro 1003d879cb83SAl Viro /* 1004d879cb83SAl Viro * Return the count of just the current iov_iter segment. 1005d879cb83SAl Viro */ 1006d879cb83SAl Viro size_t iov_iter_single_seg_count(const struct iov_iter *i) 1007d879cb83SAl Viro { 100828f38db7SAl Viro if (i->nr_segs > 1) { 100928f38db7SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 101028f38db7SAl Viro return min(i->count, i->iov->iov_len - i->iov_offset); 10117ff50620SDavid Howells if (iov_iter_is_bvec(i)) 1012d879cb83SAl Viro return min(i->count, i->bvec->bv_len - i->iov_offset); 101328f38db7SAl Viro } 101428f38db7SAl Viro return i->count; 1015d879cb83SAl Viro } 1016d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_single_seg_count); 1017d879cb83SAl Viro 1018aa563d7bSDavid Howells void iov_iter_kvec(struct iov_iter *i, unsigned int direction, 1019d879cb83SAl Viro const struct kvec *kvec, unsigned long nr_segs, 1020d879cb83SAl Viro size_t count) 1021d879cb83SAl Viro { 1022aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 10238cd54c1cSAl Viro *i = (struct iov_iter){ 10248cd54c1cSAl Viro .iter_type = ITER_KVEC, 10258cd54c1cSAl Viro .data_source = direction, 10268cd54c1cSAl Viro .kvec = kvec, 10278cd54c1cSAl Viro .nr_segs = nr_segs, 10288cd54c1cSAl Viro .iov_offset = 0, 10298cd54c1cSAl Viro .count = count 10308cd54c1cSAl Viro }; 1031d879cb83SAl Viro } 1032d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_kvec); 1033d879cb83SAl Viro 1034aa563d7bSDavid Howells void iov_iter_bvec(struct iov_iter *i, unsigned int direction, 1035d879cb83SAl Viro const struct bio_vec *bvec, unsigned long nr_segs, 1036d879cb83SAl Viro size_t count) 1037d879cb83SAl Viro { 1038aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 10398cd54c1cSAl Viro *i = (struct iov_iter){ 10408cd54c1cSAl Viro .iter_type = ITER_BVEC, 10418cd54c1cSAl Viro .data_source = direction, 10428cd54c1cSAl Viro .bvec = bvec, 10438cd54c1cSAl Viro .nr_segs = nr_segs, 10448cd54c1cSAl Viro .iov_offset = 0, 10458cd54c1cSAl Viro .count = count 10468cd54c1cSAl Viro }; 1047d879cb83SAl Viro } 1048d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_bvec); 1049d879cb83SAl Viro 1050aa563d7bSDavid Howells void iov_iter_pipe(struct iov_iter *i, unsigned int direction, 1051241699cdSAl Viro struct pipe_inode_info *pipe, 1052241699cdSAl Viro size_t count) 1053241699cdSAl Viro { 1054aa563d7bSDavid Howells BUG_ON(direction != READ); 10558cefc107SDavid Howells WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); 10568cd54c1cSAl Viro *i = (struct iov_iter){ 10578cd54c1cSAl Viro .iter_type = ITER_PIPE, 10588cd54c1cSAl Viro .data_source = false, 10598cd54c1cSAl Viro .pipe = pipe, 10608cd54c1cSAl Viro .head = pipe->head, 10618cd54c1cSAl Viro .start_head = pipe->head, 10628cd54c1cSAl Viro .iov_offset = 0, 10638cd54c1cSAl Viro .count = count 10648cd54c1cSAl Viro }; 1065241699cdSAl Viro } 1066241699cdSAl Viro EXPORT_SYMBOL(iov_iter_pipe); 1067241699cdSAl Viro 10689ea9ce04SDavid Howells /** 10697ff50620SDavid Howells * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray 10707ff50620SDavid Howells * @i: The iterator to initialise. 10717ff50620SDavid Howells * @direction: The direction of the transfer. 10727ff50620SDavid Howells * @xarray: The xarray to access. 10737ff50620SDavid Howells * @start: The start file position. 10747ff50620SDavid Howells * @count: The size of the I/O buffer in bytes. 10757ff50620SDavid Howells * 10767ff50620SDavid Howells * Set up an I/O iterator to either draw data out of the pages attached to an 10777ff50620SDavid Howells * inode or to inject data into those pages. The pages *must* be prevented 10787ff50620SDavid Howells * from evaporation, either by taking a ref on them or locking them by the 10797ff50620SDavid Howells * caller. 10807ff50620SDavid Howells */ 10817ff50620SDavid Howells void iov_iter_xarray(struct iov_iter *i, unsigned int direction, 10827ff50620SDavid Howells struct xarray *xarray, loff_t start, size_t count) 10837ff50620SDavid Howells { 10847ff50620SDavid Howells BUG_ON(direction & ~1); 10858cd54c1cSAl Viro *i = (struct iov_iter) { 10868cd54c1cSAl Viro .iter_type = ITER_XARRAY, 10878cd54c1cSAl Viro .data_source = direction, 10888cd54c1cSAl Viro .xarray = xarray, 10898cd54c1cSAl Viro .xarray_start = start, 10908cd54c1cSAl Viro .count = count, 10918cd54c1cSAl Viro .iov_offset = 0 10928cd54c1cSAl Viro }; 10937ff50620SDavid Howells } 10947ff50620SDavid Howells EXPORT_SYMBOL(iov_iter_xarray); 10957ff50620SDavid Howells 10967ff50620SDavid Howells /** 10979ea9ce04SDavid Howells * iov_iter_discard - Initialise an I/O iterator that discards data 10989ea9ce04SDavid Howells * @i: The iterator to initialise. 10999ea9ce04SDavid Howells * @direction: The direction of the transfer. 11009ea9ce04SDavid Howells * @count: The size of the I/O buffer in bytes. 11019ea9ce04SDavid Howells * 11029ea9ce04SDavid Howells * Set up an I/O iterator that just discards everything that's written to it. 11039ea9ce04SDavid Howells * It's only available as a READ iterator. 11049ea9ce04SDavid Howells */ 11059ea9ce04SDavid Howells void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) 11069ea9ce04SDavid Howells { 11079ea9ce04SDavid Howells BUG_ON(direction != READ); 11088cd54c1cSAl Viro *i = (struct iov_iter){ 11098cd54c1cSAl Viro .iter_type = ITER_DISCARD, 11108cd54c1cSAl Viro .data_source = false, 11118cd54c1cSAl Viro .count = count, 11128cd54c1cSAl Viro .iov_offset = 0 11138cd54c1cSAl Viro }; 11149ea9ce04SDavid Howells } 11159ea9ce04SDavid Howells EXPORT_SYMBOL(iov_iter_discard); 11169ea9ce04SDavid Howells 1117cfa320f7SKeith Busch static bool iov_iter_aligned_iovec(const struct iov_iter *i, unsigned addr_mask, 1118cfa320f7SKeith Busch unsigned len_mask) 1119cfa320f7SKeith Busch { 1120cfa320f7SKeith Busch size_t size = i->count; 1121cfa320f7SKeith Busch size_t skip = i->iov_offset; 1122cfa320f7SKeith Busch unsigned k; 1123cfa320f7SKeith Busch 1124cfa320f7SKeith Busch for (k = 0; k < i->nr_segs; k++, skip = 0) { 1125cfa320f7SKeith Busch size_t len = i->iov[k].iov_len - skip; 1126cfa320f7SKeith Busch 1127cfa320f7SKeith Busch if (len > size) 1128cfa320f7SKeith Busch len = size; 1129cfa320f7SKeith Busch if (len & len_mask) 1130cfa320f7SKeith Busch return false; 1131cfa320f7SKeith Busch if ((unsigned long)(i->iov[k].iov_base + skip) & addr_mask) 1132cfa320f7SKeith Busch return false; 1133cfa320f7SKeith Busch 1134cfa320f7SKeith Busch size -= len; 1135cfa320f7SKeith Busch if (!size) 1136cfa320f7SKeith Busch break; 1137cfa320f7SKeith Busch } 1138cfa320f7SKeith Busch return true; 1139cfa320f7SKeith Busch } 1140cfa320f7SKeith Busch 1141cfa320f7SKeith Busch static bool iov_iter_aligned_bvec(const struct iov_iter *i, unsigned addr_mask, 1142cfa320f7SKeith Busch unsigned len_mask) 1143cfa320f7SKeith Busch { 1144cfa320f7SKeith Busch size_t size = i->count; 1145cfa320f7SKeith Busch unsigned skip = i->iov_offset; 1146cfa320f7SKeith Busch unsigned k; 1147cfa320f7SKeith Busch 1148cfa320f7SKeith Busch for (k = 0; k < i->nr_segs; k++, skip = 0) { 1149cfa320f7SKeith Busch size_t len = i->bvec[k].bv_len - skip; 1150cfa320f7SKeith Busch 1151cfa320f7SKeith Busch if (len > size) 1152cfa320f7SKeith Busch len = size; 1153cfa320f7SKeith Busch if (len & len_mask) 1154cfa320f7SKeith Busch return false; 1155cfa320f7SKeith Busch if ((unsigned long)(i->bvec[k].bv_offset + skip) & addr_mask) 1156cfa320f7SKeith Busch return false; 1157cfa320f7SKeith Busch 1158cfa320f7SKeith Busch size -= len; 1159cfa320f7SKeith Busch if (!size) 1160cfa320f7SKeith Busch break; 1161cfa320f7SKeith Busch } 1162cfa320f7SKeith Busch return true; 1163cfa320f7SKeith Busch } 1164cfa320f7SKeith Busch 1165cfa320f7SKeith Busch /** 1166cfa320f7SKeith Busch * iov_iter_is_aligned() - Check if the addresses and lengths of each segments 1167cfa320f7SKeith Busch * are aligned to the parameters. 1168cfa320f7SKeith Busch * 1169cfa320f7SKeith Busch * @i: &struct iov_iter to restore 1170cfa320f7SKeith Busch * @addr_mask: bit mask to check against the iov element's addresses 1171cfa320f7SKeith Busch * @len_mask: bit mask to check against the iov element's lengths 1172cfa320f7SKeith Busch * 1173cfa320f7SKeith Busch * Return: false if any addresses or lengths intersect with the provided masks 1174cfa320f7SKeith Busch */ 1175cfa320f7SKeith Busch bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask, 1176cfa320f7SKeith Busch unsigned len_mask) 1177cfa320f7SKeith Busch { 1178fcb14cb1SAl Viro if (likely(iter_is_ubuf(i))) { 1179fcb14cb1SAl Viro if (i->count & len_mask) 1180fcb14cb1SAl Viro return false; 1181fcb14cb1SAl Viro if ((unsigned long)(i->ubuf + i->iov_offset) & addr_mask) 1182fcb14cb1SAl Viro return false; 1183fcb14cb1SAl Viro return true; 1184fcb14cb1SAl Viro } 1185fcb14cb1SAl Viro 1186cfa320f7SKeith Busch if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 1187cfa320f7SKeith Busch return iov_iter_aligned_iovec(i, addr_mask, len_mask); 1188cfa320f7SKeith Busch 1189cfa320f7SKeith Busch if (iov_iter_is_bvec(i)) 1190cfa320f7SKeith Busch return iov_iter_aligned_bvec(i, addr_mask, len_mask); 1191cfa320f7SKeith Busch 1192cfa320f7SKeith Busch if (iov_iter_is_pipe(i)) { 1193cfa320f7SKeith Busch unsigned int p_mask = i->pipe->ring_size - 1; 1194cfa320f7SKeith Busch size_t size = i->count; 1195cfa320f7SKeith Busch 1196cfa320f7SKeith Busch if (size & len_mask) 1197cfa320f7SKeith Busch return false; 1198cfa320f7SKeith Busch if (size && allocated(&i->pipe->bufs[i->head & p_mask])) { 1199cfa320f7SKeith Busch if (i->iov_offset & addr_mask) 1200cfa320f7SKeith Busch return false; 1201cfa320f7SKeith Busch } 1202cfa320f7SKeith Busch 1203cfa320f7SKeith Busch return true; 1204cfa320f7SKeith Busch } 1205cfa320f7SKeith Busch 1206cfa320f7SKeith Busch if (iov_iter_is_xarray(i)) { 1207cfa320f7SKeith Busch if (i->count & len_mask) 1208cfa320f7SKeith Busch return false; 1209cfa320f7SKeith Busch if ((i->xarray_start + i->iov_offset) & addr_mask) 1210cfa320f7SKeith Busch return false; 1211cfa320f7SKeith Busch } 1212cfa320f7SKeith Busch 1213cfa320f7SKeith Busch return true; 1214cfa320f7SKeith Busch } 1215cfa320f7SKeith Busch EXPORT_SYMBOL_GPL(iov_iter_is_aligned); 1216cfa320f7SKeith Busch 12179221d2e3SAl Viro static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) 1218d879cb83SAl Viro { 1219d879cb83SAl Viro unsigned long res = 0; 1220d879cb83SAl Viro size_t size = i->count; 12219221d2e3SAl Viro size_t skip = i->iov_offset; 12229221d2e3SAl Viro unsigned k; 1223d879cb83SAl Viro 12249221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 12259221d2e3SAl Viro size_t len = i->iov[k].iov_len - skip; 12269221d2e3SAl Viro if (len) { 12279221d2e3SAl Viro res |= (unsigned long)i->iov[k].iov_base + skip; 12289221d2e3SAl Viro if (len > size) 12299221d2e3SAl Viro len = size; 12309221d2e3SAl Viro res |= len; 12319221d2e3SAl Viro size -= len; 12329221d2e3SAl Viro if (!size) 12339221d2e3SAl Viro break; 12349221d2e3SAl Viro } 12359221d2e3SAl Viro } 12369221d2e3SAl Viro return res; 12379221d2e3SAl Viro } 12389221d2e3SAl Viro 12399221d2e3SAl Viro static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) 12409221d2e3SAl Viro { 12419221d2e3SAl Viro unsigned res = 0; 12429221d2e3SAl Viro size_t size = i->count; 12439221d2e3SAl Viro unsigned skip = i->iov_offset; 12449221d2e3SAl Viro unsigned k; 12459221d2e3SAl Viro 12469221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 12479221d2e3SAl Viro size_t len = i->bvec[k].bv_len - skip; 12489221d2e3SAl Viro res |= (unsigned long)i->bvec[k].bv_offset + skip; 12499221d2e3SAl Viro if (len > size) 12509221d2e3SAl Viro len = size; 12519221d2e3SAl Viro res |= len; 12529221d2e3SAl Viro size -= len; 12539221d2e3SAl Viro if (!size) 12549221d2e3SAl Viro break; 12559221d2e3SAl Viro } 12569221d2e3SAl Viro return res; 12579221d2e3SAl Viro } 12589221d2e3SAl Viro 12599221d2e3SAl Viro unsigned long iov_iter_alignment(const struct iov_iter *i) 12609221d2e3SAl Viro { 1261fcb14cb1SAl Viro if (likely(iter_is_ubuf(i))) { 1262fcb14cb1SAl Viro size_t size = i->count; 1263fcb14cb1SAl Viro if (size) 1264fcb14cb1SAl Viro return ((unsigned long)i->ubuf + i->iov_offset) | size; 1265fcb14cb1SAl Viro return 0; 1266fcb14cb1SAl Viro } 1267fcb14cb1SAl Viro 12689221d2e3SAl Viro /* iovec and kvec have identical layouts */ 12699221d2e3SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 12709221d2e3SAl Viro return iov_iter_alignment_iovec(i); 12719221d2e3SAl Viro 12729221d2e3SAl Viro if (iov_iter_is_bvec(i)) 12739221d2e3SAl Viro return iov_iter_alignment_bvec(i); 12749221d2e3SAl Viro 12759221d2e3SAl Viro if (iov_iter_is_pipe(i)) { 12769221d2e3SAl Viro size_t size = i->count; 1277e0ff126eSJan Kara 12782dcedb2aSAl Viro if (size && i->iov_offset && allocated(pipe_buf(i->pipe, i->head))) 1279241699cdSAl Viro return size | i->iov_offset; 1280241699cdSAl Viro return size; 1281241699cdSAl Viro } 12829221d2e3SAl Viro 12839221d2e3SAl Viro if (iov_iter_is_xarray(i)) 12843d14ec1fSDavid Howells return (i->xarray_start + i->iov_offset) | i->count; 12859221d2e3SAl Viro 12869221d2e3SAl Viro return 0; 1287d879cb83SAl Viro } 1288d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_alignment); 1289d879cb83SAl Viro 1290357f435dSAl Viro unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 1291357f435dSAl Viro { 1292357f435dSAl Viro unsigned long res = 0; 1293610c7a71SAl Viro unsigned long v = 0; 1294357f435dSAl Viro size_t size = i->count; 1295610c7a71SAl Viro unsigned k; 1296357f435dSAl Viro 1297fcb14cb1SAl Viro if (iter_is_ubuf(i)) 1298fcb14cb1SAl Viro return 0; 1299fcb14cb1SAl Viro 1300610c7a71SAl Viro if (WARN_ON(!iter_is_iovec(i))) 1301241699cdSAl Viro return ~0U; 1302241699cdSAl Viro 1303610c7a71SAl Viro for (k = 0; k < i->nr_segs; k++) { 1304610c7a71SAl Viro if (i->iov[k].iov_len) { 1305610c7a71SAl Viro unsigned long base = (unsigned long)i->iov[k].iov_base; 1306610c7a71SAl Viro if (v) // if not the first one 1307610c7a71SAl Viro res |= base | v; // this start | previous end 1308610c7a71SAl Viro v = base + i->iov[k].iov_len; 1309610c7a71SAl Viro if (size <= i->iov[k].iov_len) 1310610c7a71SAl Viro break; 1311610c7a71SAl Viro size -= i->iov[k].iov_len; 1312610c7a71SAl Viro } 1313610c7a71SAl Viro } 1314357f435dSAl Viro return res; 1315357f435dSAl Viro } 1316357f435dSAl Viro EXPORT_SYMBOL(iov_iter_gap_alignment); 1317357f435dSAl Viro 1318e76b6312SIlya Dryomov static inline ssize_t __pipe_get_pages(struct iov_iter *i, 1319241699cdSAl Viro size_t maxsize, 1320241699cdSAl Viro struct page **pages, 13218cefc107SDavid Howells int iter_head, 1322*e3b42964SAl Viro size_t off) 1323241699cdSAl Viro { 1324241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 1325*e3b42964SAl Viro ssize_t left = maxsize; 1326241699cdSAl Viro 1327*e3b42964SAl Viro if (off) { 1328*e3b42964SAl Viro struct pipe_buffer *buf = pipe_buf(pipe, iter_head); 1329241699cdSAl Viro 1330*e3b42964SAl Viro get_page(*pages++ = buf->page); 1331*e3b42964SAl Viro left -= PAGE_SIZE - off; 1332*e3b42964SAl Viro if (left <= 0) { 1333*e3b42964SAl Viro buf->len += maxsize; 1334241699cdSAl Viro return maxsize; 1335241699cdSAl Viro } 1336*e3b42964SAl Viro buf->len = PAGE_SIZE; 1337*e3b42964SAl Viro } 1338*e3b42964SAl Viro while (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) { 1339*e3b42964SAl Viro struct page *page = push_anon(pipe, 1340*e3b42964SAl Viro min_t(ssize_t, left, PAGE_SIZE)); 1341*e3b42964SAl Viro if (!page) 1342*e3b42964SAl Viro break; 1343*e3b42964SAl Viro get_page(*pages++ = page); 1344*e3b42964SAl Viro left -= PAGE_SIZE; 1345*e3b42964SAl Viro if (left <= 0) 1346*e3b42964SAl Viro return maxsize; 1347*e3b42964SAl Viro } 1348*e3b42964SAl Viro return maxsize - left ? : -EFAULT; 1349*e3b42964SAl Viro } 1350241699cdSAl Viro 1351241699cdSAl Viro static ssize_t pipe_get_pages(struct iov_iter *i, 1352241699cdSAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1353241699cdSAl Viro size_t *start) 1354241699cdSAl Viro { 13558cefc107SDavid Howells unsigned int iter_head, npages; 1356241699cdSAl Viro size_t capacity; 1357241699cdSAl Viro 1358241699cdSAl Viro if (!sanity(i)) 1359241699cdSAl Viro return -EFAULT; 1360241699cdSAl Viro 13618cefc107SDavid Howells data_start(i, &iter_head, start); 13628cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 13638cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1364241699cdSAl Viro capacity = min(npages, maxpages) * PAGE_SIZE - *start; 1365241699cdSAl Viro 1366*e3b42964SAl Viro return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, *start); 1367241699cdSAl Viro } 1368241699cdSAl Viro 13697ff50620SDavid Howells static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, 13707ff50620SDavid Howells pgoff_t index, unsigned int nr_pages) 13717ff50620SDavid Howells { 13727ff50620SDavid Howells XA_STATE(xas, xa, index); 13737ff50620SDavid Howells struct page *page; 13747ff50620SDavid Howells unsigned int ret = 0; 13757ff50620SDavid Howells 13767ff50620SDavid Howells rcu_read_lock(); 13777ff50620SDavid Howells for (page = xas_load(&xas); page; page = xas_next(&xas)) { 13787ff50620SDavid Howells if (xas_retry(&xas, page)) 13797ff50620SDavid Howells continue; 13807ff50620SDavid Howells 13817ff50620SDavid Howells /* Has the page moved or been split? */ 13827ff50620SDavid Howells if (unlikely(page != xas_reload(&xas))) { 13837ff50620SDavid Howells xas_reset(&xas); 13847ff50620SDavid Howells continue; 13857ff50620SDavid Howells } 13867ff50620SDavid Howells 13877ff50620SDavid Howells pages[ret] = find_subpage(page, xas.xa_index); 13887ff50620SDavid Howells get_page(pages[ret]); 13897ff50620SDavid Howells if (++ret == nr_pages) 13907ff50620SDavid Howells break; 13917ff50620SDavid Howells } 13927ff50620SDavid Howells rcu_read_unlock(); 13937ff50620SDavid Howells return ret; 13947ff50620SDavid Howells } 13957ff50620SDavid Howells 13967ff50620SDavid Howells static ssize_t iter_xarray_get_pages(struct iov_iter *i, 13977ff50620SDavid Howells struct page **pages, size_t maxsize, 13987ff50620SDavid Howells unsigned maxpages, size_t *_start_offset) 13997ff50620SDavid Howells { 14007ff50620SDavid Howells unsigned nr, offset; 14017ff50620SDavid Howells pgoff_t index, count; 14026c776766SDavid Howells size_t size = maxsize; 14037ff50620SDavid Howells loff_t pos; 14047ff50620SDavid Howells 14057ff50620SDavid Howells if (!size || !maxpages) 14067ff50620SDavid Howells return 0; 14077ff50620SDavid Howells 14087ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 14097ff50620SDavid Howells index = pos >> PAGE_SHIFT; 14107ff50620SDavid Howells offset = pos & ~PAGE_MASK; 14117ff50620SDavid Howells *_start_offset = offset; 14127ff50620SDavid Howells 14137ff50620SDavid Howells count = 1; 14147ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 14157ff50620SDavid Howells size -= PAGE_SIZE - offset; 14167ff50620SDavid Howells count += size >> PAGE_SHIFT; 14177ff50620SDavid Howells size &= ~PAGE_MASK; 14187ff50620SDavid Howells if (size) 14197ff50620SDavid Howells count++; 14207ff50620SDavid Howells } 14217ff50620SDavid Howells 14227ff50620SDavid Howells if (count > maxpages) 14237ff50620SDavid Howells count = maxpages; 14247ff50620SDavid Howells 14257ff50620SDavid Howells nr = iter_xarray_populate_pages(pages, i->xarray, index, count); 14267ff50620SDavid Howells if (nr == 0) 14277ff50620SDavid Howells return 0; 14287ff50620SDavid Howells 14291c27f1fcSLinus Torvalds return min_t(size_t, nr * PAGE_SIZE - offset, maxsize); 14307ff50620SDavid Howells } 14317ff50620SDavid Howells 1432fcb14cb1SAl Viro /* must be done on non-empty ITER_UBUF or ITER_IOVEC one */ 1433dd45ab9dSAl Viro static unsigned long first_iovec_segment(const struct iov_iter *i, size_t *size) 14343d671ca6SAl Viro { 14353d671ca6SAl Viro size_t skip; 14363d671ca6SAl Viro long k; 14373d671ca6SAl Viro 1438fcb14cb1SAl Viro if (iter_is_ubuf(i)) 1439fcb14cb1SAl Viro return (unsigned long)i->ubuf + i->iov_offset; 1440fcb14cb1SAl Viro 14413d671ca6SAl Viro for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { 14423d671ca6SAl Viro size_t len = i->iov[k].iov_len - skip; 14433d671ca6SAl Viro 14443d671ca6SAl Viro if (unlikely(!len)) 14453d671ca6SAl Viro continue; 144659dbd7d0SAl Viro if (*size > len) 14473d671ca6SAl Viro *size = len; 1448dd45ab9dSAl Viro return (unsigned long)i->iov[k].iov_base + skip; 14493d671ca6SAl Viro } 14503d671ca6SAl Viro BUG(); // if it had been empty, we wouldn't get called 14513d671ca6SAl Viro } 14523d671ca6SAl Viro 14533d671ca6SAl Viro /* must be done on non-empty ITER_BVEC one */ 14543d671ca6SAl Viro static struct page *first_bvec_segment(const struct iov_iter *i, 145559dbd7d0SAl Viro size_t *size, size_t *start) 14563d671ca6SAl Viro { 14573d671ca6SAl Viro struct page *page; 14583d671ca6SAl Viro size_t skip = i->iov_offset, len; 14593d671ca6SAl Viro 14603d671ca6SAl Viro len = i->bvec->bv_len - skip; 146159dbd7d0SAl Viro if (*size > len) 146259dbd7d0SAl Viro *size = len; 14633d671ca6SAl Viro skip += i->bvec->bv_offset; 14643d671ca6SAl Viro page = i->bvec->bv_page + skip / PAGE_SIZE; 1465dda8e5d1SAl Viro *start = skip % PAGE_SIZE; 14663d671ca6SAl Viro return page; 14673d671ca6SAl Viro } 14683d671ca6SAl Viro 1469d879cb83SAl Viro ssize_t iov_iter_get_pages(struct iov_iter *i, 1470d879cb83SAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1471d879cb83SAl Viro size_t *start) 1472d879cb83SAl Viro { 14733d671ca6SAl Viro int n, res; 14743d671ca6SAl Viro 1475d879cb83SAl Viro if (maxsize > i->count) 1476d879cb83SAl Viro maxsize = i->count; 14773d671ca6SAl Viro if (!maxsize) 14783d671ca6SAl Viro return 0; 14797392ed17SAl Viro if (maxsize > MAX_RW_COUNT) 14807392ed17SAl Viro maxsize = MAX_RW_COUNT; 1481d879cb83SAl Viro 1482fcb14cb1SAl Viro if (likely(user_backed_iter(i))) { 14833337ab08SAndreas Gruenbacher unsigned int gup_flags = 0; 14843d671ca6SAl Viro unsigned long addr; 14859ea9ce04SDavid Howells 14863337ab08SAndreas Gruenbacher if (iov_iter_rw(i) != WRITE) 14873337ab08SAndreas Gruenbacher gup_flags |= FOLL_WRITE; 14883337ab08SAndreas Gruenbacher if (i->nofault) 14893337ab08SAndreas Gruenbacher gup_flags |= FOLL_NOFAULT; 14903337ab08SAndreas Gruenbacher 1491dd45ab9dSAl Viro addr = first_iovec_segment(i, &maxsize); 1492dd45ab9dSAl Viro *start = addr % PAGE_SIZE; 1493dd45ab9dSAl Viro addr &= PAGE_MASK; 149459dbd7d0SAl Viro n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1495dda8e5d1SAl Viro if (n > maxpages) 1496dda8e5d1SAl Viro n = maxpages; 14973337ab08SAndreas Gruenbacher res = get_user_pages_fast(addr, n, gup_flags, pages); 1498814a6674SAndreas Gruenbacher if (unlikely(res <= 0)) 1499d879cb83SAl Viro return res; 150059dbd7d0SAl Viro return min_t(size_t, maxsize, res * PAGE_SIZE - *start); 15013d671ca6SAl Viro } 15023d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 15033d671ca6SAl Viro struct page *page; 15043d671ca6SAl Viro 150559dbd7d0SAl Viro page = first_bvec_segment(i, &maxsize, start); 150659dbd7d0SAl Viro n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1507dda8e5d1SAl Viro if (n > maxpages) 1508dda8e5d1SAl Viro n = maxpages; 1509dda8e5d1SAl Viro for (int k = 0; k < n; k++) 15103d671ca6SAl Viro get_page(*pages++ = page++); 151159dbd7d0SAl Viro return min_t(size_t, maxsize, n * PAGE_SIZE - *start); 15123d671ca6SAl Viro } 15133d671ca6SAl Viro if (iov_iter_is_pipe(i)) 15143d671ca6SAl Viro return pipe_get_pages(i, pages, maxsize, maxpages, start); 15153d671ca6SAl Viro if (iov_iter_is_xarray(i)) 15163d671ca6SAl Viro return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); 1517d879cb83SAl Viro return -EFAULT; 1518d879cb83SAl Viro } 1519d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages); 1520d879cb83SAl Viro 1521d879cb83SAl Viro static struct page **get_pages_array(size_t n) 1522d879cb83SAl Viro { 1523752ade68SMichal Hocko return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); 1524d879cb83SAl Viro } 1525d879cb83SAl Viro 1526241699cdSAl Viro static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 1527241699cdSAl Viro struct page ***pages, size_t maxsize, 1528241699cdSAl Viro size_t *start) 1529241699cdSAl Viro { 1530241699cdSAl Viro struct page **p; 15318cefc107SDavid Howells unsigned int iter_head, npages; 1532d7760d63SIlya Dryomov ssize_t n; 1533241699cdSAl Viro 1534241699cdSAl Viro if (!sanity(i)) 1535241699cdSAl Viro return -EFAULT; 1536241699cdSAl Viro 15378cefc107SDavid Howells data_start(i, &iter_head, start); 15388cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 15398cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1540241699cdSAl Viro n = npages * PAGE_SIZE - *start; 1541241699cdSAl Viro if (maxsize > n) 1542241699cdSAl Viro maxsize = n; 1543241699cdSAl Viro else 1544241699cdSAl Viro npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1545241699cdSAl Viro p = get_pages_array(npages); 1546241699cdSAl Viro if (!p) 1547241699cdSAl Viro return -ENOMEM; 1548*e3b42964SAl Viro n = __pipe_get_pages(i, maxsize, p, iter_head, *start); 1549241699cdSAl Viro if (n > 0) 1550241699cdSAl Viro *pages = p; 1551241699cdSAl Viro else 1552241699cdSAl Viro kvfree(p); 1553241699cdSAl Viro return n; 1554241699cdSAl Viro } 1555241699cdSAl Viro 15567ff50620SDavid Howells static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, 15577ff50620SDavid Howells struct page ***pages, size_t maxsize, 15587ff50620SDavid Howells size_t *_start_offset) 15597ff50620SDavid Howells { 15607ff50620SDavid Howells struct page **p; 15617ff50620SDavid Howells unsigned nr, offset; 15627ff50620SDavid Howells pgoff_t index, count; 15636c776766SDavid Howells size_t size = maxsize; 15647ff50620SDavid Howells loff_t pos; 15657ff50620SDavid Howells 15667ff50620SDavid Howells if (!size) 15677ff50620SDavid Howells return 0; 15687ff50620SDavid Howells 15697ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 15707ff50620SDavid Howells index = pos >> PAGE_SHIFT; 15717ff50620SDavid Howells offset = pos & ~PAGE_MASK; 15727ff50620SDavid Howells *_start_offset = offset; 15737ff50620SDavid Howells 15747ff50620SDavid Howells count = 1; 15757ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 15767ff50620SDavid Howells size -= PAGE_SIZE - offset; 15777ff50620SDavid Howells count += size >> PAGE_SHIFT; 15787ff50620SDavid Howells size &= ~PAGE_MASK; 15797ff50620SDavid Howells if (size) 15807ff50620SDavid Howells count++; 15817ff50620SDavid Howells } 15827ff50620SDavid Howells 15837ff50620SDavid Howells p = get_pages_array(count); 15847ff50620SDavid Howells if (!p) 15857ff50620SDavid Howells return -ENOMEM; 15867ff50620SDavid Howells *pages = p; 15877ff50620SDavid Howells 15887ff50620SDavid Howells nr = iter_xarray_populate_pages(p, i->xarray, index, count); 15897ff50620SDavid Howells if (nr == 0) 15907ff50620SDavid Howells return 0; 15917ff50620SDavid Howells 15921c27f1fcSLinus Torvalds return min_t(size_t, nr * PAGE_SIZE - offset, maxsize); 15937ff50620SDavid Howells } 15947ff50620SDavid Howells 1595d879cb83SAl Viro ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 1596d879cb83SAl Viro struct page ***pages, size_t maxsize, 1597d879cb83SAl Viro size_t *start) 1598d879cb83SAl Viro { 1599d879cb83SAl Viro struct page **p; 16003d671ca6SAl Viro int n, res; 1601d879cb83SAl Viro 1602d879cb83SAl Viro if (maxsize > i->count) 1603d879cb83SAl Viro maxsize = i->count; 16043d671ca6SAl Viro if (!maxsize) 16053d671ca6SAl Viro return 0; 16067392ed17SAl Viro if (maxsize > MAX_RW_COUNT) 16077392ed17SAl Viro maxsize = MAX_RW_COUNT; 1608d879cb83SAl Viro 1609fcb14cb1SAl Viro if (likely(user_backed_iter(i))) { 16103337ab08SAndreas Gruenbacher unsigned int gup_flags = 0; 16113d671ca6SAl Viro unsigned long addr; 16129ea9ce04SDavid Howells 16133337ab08SAndreas Gruenbacher if (iov_iter_rw(i) != WRITE) 16143337ab08SAndreas Gruenbacher gup_flags |= FOLL_WRITE; 16153337ab08SAndreas Gruenbacher if (i->nofault) 16163337ab08SAndreas Gruenbacher gup_flags |= FOLL_NOFAULT; 16173337ab08SAndreas Gruenbacher 1618dd45ab9dSAl Viro addr = first_iovec_segment(i, &maxsize); 1619dd45ab9dSAl Viro *start = addr % PAGE_SIZE; 1620dd45ab9dSAl Viro addr &= PAGE_MASK; 162159dbd7d0SAl Viro n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1622d879cb83SAl Viro p = get_pages_array(n); 1623d879cb83SAl Viro if (!p) 1624d879cb83SAl Viro return -ENOMEM; 16253337ab08SAndreas Gruenbacher res = get_user_pages_fast(addr, n, gup_flags, p); 1626814a6674SAndreas Gruenbacher if (unlikely(res <= 0)) { 1627d879cb83SAl Viro kvfree(p); 1628814a6674SAndreas Gruenbacher *pages = NULL; 1629d879cb83SAl Viro return res; 1630d879cb83SAl Viro } 1631d879cb83SAl Viro *pages = p; 163259dbd7d0SAl Viro return min_t(size_t, maxsize, res * PAGE_SIZE - *start); 16333d671ca6SAl Viro } 16343d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 16353d671ca6SAl Viro struct page *page; 16363d671ca6SAl Viro 163759dbd7d0SAl Viro page = first_bvec_segment(i, &maxsize, start); 163859dbd7d0SAl Viro n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 16393d671ca6SAl Viro *pages = p = get_pages_array(n); 1640d879cb83SAl Viro if (!p) 1641d879cb83SAl Viro return -ENOMEM; 1642dda8e5d1SAl Viro for (int k = 0; k < n; k++) 16433d671ca6SAl Viro get_page(*p++ = page++); 164459dbd7d0SAl Viro return min_t(size_t, maxsize, n * PAGE_SIZE - *start); 16453d671ca6SAl Viro } 16463d671ca6SAl Viro if (iov_iter_is_pipe(i)) 16473d671ca6SAl Viro return pipe_get_pages_alloc(i, pages, maxsize, start); 16483d671ca6SAl Viro if (iov_iter_is_xarray(i)) 16493d671ca6SAl Viro return iter_xarray_get_pages_alloc(i, pages, maxsize, start); 1650d879cb83SAl Viro return -EFAULT; 1651d879cb83SAl Viro } 1652d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages_alloc); 1653d879cb83SAl Viro 1654d879cb83SAl Viro size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 1655d879cb83SAl Viro struct iov_iter *i) 1656d879cb83SAl Viro { 1657d879cb83SAl Viro __wsum sum, next; 1658d879cb83SAl Viro sum = *csum; 16599ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1660241699cdSAl Viro WARN_ON(1); 1661241699cdSAl Viro return 0; 1662241699cdSAl Viro } 16637baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, ({ 16647baa5099SAl Viro next = csum_and_copy_from_user(base, addr + off, len); 1665d879cb83SAl Viro sum = csum_block_add(sum, next, off); 16667baa5099SAl Viro next ? 0 : len; 1667d879cb83SAl Viro }), ({ 16687baa5099SAl Viro sum = csum_and_memcpy(addr + off, base, len, sum, off); 1669d879cb83SAl Viro }) 1670d879cb83SAl Viro ) 1671d879cb83SAl Viro *csum = sum; 1672d879cb83SAl Viro return bytes; 1673d879cb83SAl Viro } 1674d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter); 1675d879cb83SAl Viro 167652cbd23aSWillem de Bruijn size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 1677d879cb83SAl Viro struct iov_iter *i) 1678d879cb83SAl Viro { 167952cbd23aSWillem de Bruijn struct csum_state *csstate = _csstate; 1680d879cb83SAl Viro __wsum sum, next; 168178e1f386SAl Viro 168278e1f386SAl Viro if (unlikely(iov_iter_is_discard(i))) { 1683241699cdSAl Viro WARN_ON(1); /* for now */ 1684241699cdSAl Viro return 0; 1685241699cdSAl Viro } 16866852df12SAl Viro 16876852df12SAl Viro sum = csum_shift(csstate->csum, csstate->off); 16886852df12SAl Viro if (unlikely(iov_iter_is_pipe(i))) 16896852df12SAl Viro bytes = csum_and_copy_to_pipe_iter(addr, bytes, i, &sum); 16906852df12SAl Viro else iterate_and_advance(i, bytes, base, len, off, ({ 16917baa5099SAl Viro next = csum_and_copy_to_user(addr + off, base, len); 1692d879cb83SAl Viro sum = csum_block_add(sum, next, off); 16937baa5099SAl Viro next ? 0 : len; 1694d879cb83SAl Viro }), ({ 16957baa5099SAl Viro sum = csum_and_memcpy(base, addr + off, len, sum, off); 1696d879cb83SAl Viro }) 1697d879cb83SAl Viro ) 1698594e450bSAl Viro csstate->csum = csum_shift(sum, csstate->off); 1699594e450bSAl Viro csstate->off += bytes; 1700d879cb83SAl Viro return bytes; 1701d879cb83SAl Viro } 1702d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_to_iter); 1703d879cb83SAl Viro 1704d05f4435SSagi Grimberg size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, 1705d05f4435SSagi Grimberg struct iov_iter *i) 1706d05f4435SSagi Grimberg { 17077999096fSHerbert Xu #ifdef CONFIG_CRYPTO_HASH 1708d05f4435SSagi Grimberg struct ahash_request *hash = hashp; 1709d05f4435SSagi Grimberg struct scatterlist sg; 1710d05f4435SSagi Grimberg size_t copied; 1711d05f4435SSagi Grimberg 1712d05f4435SSagi Grimberg copied = copy_to_iter(addr, bytes, i); 1713d05f4435SSagi Grimberg sg_init_one(&sg, addr, copied); 1714d05f4435SSagi Grimberg ahash_request_set_crypt(hash, &sg, NULL, copied); 1715d05f4435SSagi Grimberg crypto_ahash_update(hash); 1716d05f4435SSagi Grimberg return copied; 171727fad74aSYueHaibing #else 171827fad74aSYueHaibing return 0; 171927fad74aSYueHaibing #endif 1720d05f4435SSagi Grimberg } 1721d05f4435SSagi Grimberg EXPORT_SYMBOL(hash_and_copy_to_iter); 1722d05f4435SSagi Grimberg 172366531c65SAl Viro static int iov_npages(const struct iov_iter *i, int maxpages) 1724d879cb83SAl Viro { 172566531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 172666531c65SAl Viro const struct iovec *p; 1727d879cb83SAl Viro int npages = 0; 1728d879cb83SAl Viro 172966531c65SAl Viro for (p = i->iov; size; skip = 0, p++) { 173066531c65SAl Viro unsigned offs = offset_in_page(p->iov_base + skip); 173166531c65SAl Viro size_t len = min(p->iov_len - skip, size); 1732d879cb83SAl Viro 173366531c65SAl Viro if (len) { 173466531c65SAl Viro size -= len; 173566531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 173666531c65SAl Viro if (unlikely(npages > maxpages)) 173766531c65SAl Viro return maxpages; 173866531c65SAl Viro } 173966531c65SAl Viro } 174066531c65SAl Viro return npages; 174166531c65SAl Viro } 174266531c65SAl Viro 174366531c65SAl Viro static int bvec_npages(const struct iov_iter *i, int maxpages) 174466531c65SAl Viro { 174566531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 174666531c65SAl Viro const struct bio_vec *p; 174766531c65SAl Viro int npages = 0; 174866531c65SAl Viro 174966531c65SAl Viro for (p = i->bvec; size; skip = 0, p++) { 175066531c65SAl Viro unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; 175166531c65SAl Viro size_t len = min(p->bv_len - skip, size); 175266531c65SAl Viro 175366531c65SAl Viro size -= len; 175466531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 175566531c65SAl Viro if (unlikely(npages > maxpages)) 175666531c65SAl Viro return maxpages; 175766531c65SAl Viro } 175866531c65SAl Viro return npages; 175966531c65SAl Viro } 176066531c65SAl Viro 176166531c65SAl Viro int iov_iter_npages(const struct iov_iter *i, int maxpages) 176266531c65SAl Viro { 176366531c65SAl Viro if (unlikely(!i->count)) 176466531c65SAl Viro return 0; 1765fcb14cb1SAl Viro if (likely(iter_is_ubuf(i))) { 1766fcb14cb1SAl Viro unsigned offs = offset_in_page(i->ubuf + i->iov_offset); 1767fcb14cb1SAl Viro int npages = DIV_ROUND_UP(offs + i->count, PAGE_SIZE); 1768fcb14cb1SAl Viro return min(npages, maxpages); 1769fcb14cb1SAl Viro } 177066531c65SAl Viro /* iovec and kvec have identical layouts */ 177166531c65SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 177266531c65SAl Viro return iov_npages(i, maxpages); 177366531c65SAl Viro if (iov_iter_is_bvec(i)) 177466531c65SAl Viro return bvec_npages(i, maxpages); 177566531c65SAl Viro if (iov_iter_is_pipe(i)) { 17768cefc107SDavid Howells unsigned int iter_head; 177766531c65SAl Viro int npages; 1778241699cdSAl Viro size_t off; 1779241699cdSAl Viro 1780241699cdSAl Viro if (!sanity(i)) 1781241699cdSAl Viro return 0; 1782241699cdSAl Viro 17838cefc107SDavid Howells data_start(i, &iter_head, &off); 1784241699cdSAl Viro /* some of this one + all after this one */ 178566531c65SAl Viro npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 178666531c65SAl Viro return min(npages, maxpages); 178766531c65SAl Viro } 178866531c65SAl Viro if (iov_iter_is_xarray(i)) { 1789e4f8df86SAl Viro unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; 1790e4f8df86SAl Viro int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); 179166531c65SAl Viro return min(npages, maxpages); 179266531c65SAl Viro } 179366531c65SAl Viro return 0; 1794d879cb83SAl Viro } 1795d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_npages); 1796d879cb83SAl Viro 1797d879cb83SAl Viro const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) 1798d879cb83SAl Viro { 1799d879cb83SAl Viro *new = *old; 180000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(new))) { 1801241699cdSAl Viro WARN_ON(1); 1802241699cdSAl Viro return NULL; 1803241699cdSAl Viro } 180400e23707SDavid Howells if (iov_iter_is_bvec(new)) 1805d879cb83SAl Viro return new->bvec = kmemdup(new->bvec, 1806d879cb83SAl Viro new->nr_segs * sizeof(struct bio_vec), 1807d879cb83SAl Viro flags); 1808fcb14cb1SAl Viro else if (iov_iter_is_kvec(new) || iter_is_iovec(new)) 1809d879cb83SAl Viro /* iovec and kvec have identical layout */ 1810d879cb83SAl Viro return new->iov = kmemdup(new->iov, 1811d879cb83SAl Viro new->nr_segs * sizeof(struct iovec), 1812d879cb83SAl Viro flags); 1813fcb14cb1SAl Viro return NULL; 1814d879cb83SAl Viro } 1815d879cb83SAl Viro EXPORT_SYMBOL(dup_iter); 1816bc917be8SAl Viro 1817bfdc5970SChristoph Hellwig static int copy_compat_iovec_from_user(struct iovec *iov, 1818bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1819bfdc5970SChristoph Hellwig { 1820bfdc5970SChristoph Hellwig const struct compat_iovec __user *uiov = 1821bfdc5970SChristoph Hellwig (const struct compat_iovec __user *)uvec; 1822bfdc5970SChristoph Hellwig int ret = -EFAULT, i; 1823bfdc5970SChristoph Hellwig 1824a959a978SChristoph Hellwig if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) 1825bfdc5970SChristoph Hellwig return -EFAULT; 1826bfdc5970SChristoph Hellwig 1827bfdc5970SChristoph Hellwig for (i = 0; i < nr_segs; i++) { 1828bfdc5970SChristoph Hellwig compat_uptr_t buf; 1829bfdc5970SChristoph Hellwig compat_ssize_t len; 1830bfdc5970SChristoph Hellwig 1831bfdc5970SChristoph Hellwig unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); 1832bfdc5970SChristoph Hellwig unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); 1833bfdc5970SChristoph Hellwig 1834bfdc5970SChristoph Hellwig /* check for compat_size_t not fitting in compat_ssize_t .. */ 1835bfdc5970SChristoph Hellwig if (len < 0) { 1836bfdc5970SChristoph Hellwig ret = -EINVAL; 1837bfdc5970SChristoph Hellwig goto uaccess_end; 1838bfdc5970SChristoph Hellwig } 1839bfdc5970SChristoph Hellwig iov[i].iov_base = compat_ptr(buf); 1840bfdc5970SChristoph Hellwig iov[i].iov_len = len; 1841bfdc5970SChristoph Hellwig } 1842bfdc5970SChristoph Hellwig 1843bfdc5970SChristoph Hellwig ret = 0; 1844bfdc5970SChristoph Hellwig uaccess_end: 1845bfdc5970SChristoph Hellwig user_access_end(); 1846bfdc5970SChristoph Hellwig return ret; 1847bfdc5970SChristoph Hellwig } 1848bfdc5970SChristoph Hellwig 1849bfdc5970SChristoph Hellwig static int copy_iovec_from_user(struct iovec *iov, 1850bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1851fb041b59SDavid Laight { 1852fb041b59SDavid Laight unsigned long seg; 1853bfdc5970SChristoph Hellwig 1854bfdc5970SChristoph Hellwig if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) 1855bfdc5970SChristoph Hellwig return -EFAULT; 1856bfdc5970SChristoph Hellwig for (seg = 0; seg < nr_segs; seg++) { 1857bfdc5970SChristoph Hellwig if ((ssize_t)iov[seg].iov_len < 0) 1858bfdc5970SChristoph Hellwig return -EINVAL; 1859bfdc5970SChristoph Hellwig } 1860bfdc5970SChristoph Hellwig 1861bfdc5970SChristoph Hellwig return 0; 1862bfdc5970SChristoph Hellwig } 1863bfdc5970SChristoph Hellwig 1864bfdc5970SChristoph Hellwig struct iovec *iovec_from_user(const struct iovec __user *uvec, 1865bfdc5970SChristoph Hellwig unsigned long nr_segs, unsigned long fast_segs, 1866bfdc5970SChristoph Hellwig struct iovec *fast_iov, bool compat) 1867bfdc5970SChristoph Hellwig { 1868bfdc5970SChristoph Hellwig struct iovec *iov = fast_iov; 1869bfdc5970SChristoph Hellwig int ret; 1870fb041b59SDavid Laight 1871fb041b59SDavid Laight /* 1872bfdc5970SChristoph Hellwig * SuS says "The readv() function *may* fail if the iovcnt argument was 1873bfdc5970SChristoph Hellwig * less than or equal to 0, or greater than {IOV_MAX}. Linux has 1874fb041b59SDavid Laight * traditionally returned zero for zero segments, so... 1875fb041b59SDavid Laight */ 1876bfdc5970SChristoph Hellwig if (nr_segs == 0) 1877bfdc5970SChristoph Hellwig return iov; 1878bfdc5970SChristoph Hellwig if (nr_segs > UIO_MAXIOV) 1879bfdc5970SChristoph Hellwig return ERR_PTR(-EINVAL); 1880fb041b59SDavid Laight if (nr_segs > fast_segs) { 1881fb041b59SDavid Laight iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); 1882bfdc5970SChristoph Hellwig if (!iov) 1883bfdc5970SChristoph Hellwig return ERR_PTR(-ENOMEM); 1884fb041b59SDavid Laight } 1885bfdc5970SChristoph Hellwig 1886bfdc5970SChristoph Hellwig if (compat) 1887bfdc5970SChristoph Hellwig ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); 1888bfdc5970SChristoph Hellwig else 1889bfdc5970SChristoph Hellwig ret = copy_iovec_from_user(iov, uvec, nr_segs); 1890bfdc5970SChristoph Hellwig if (ret) { 1891bfdc5970SChristoph Hellwig if (iov != fast_iov) 1892bfdc5970SChristoph Hellwig kfree(iov); 1893bfdc5970SChristoph Hellwig return ERR_PTR(ret); 1894fb041b59SDavid Laight } 1895bfdc5970SChristoph Hellwig 1896bfdc5970SChristoph Hellwig return iov; 1897bfdc5970SChristoph Hellwig } 1898bfdc5970SChristoph Hellwig 1899bfdc5970SChristoph Hellwig ssize_t __import_iovec(int type, const struct iovec __user *uvec, 1900bfdc5970SChristoph Hellwig unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, 1901bfdc5970SChristoph Hellwig struct iov_iter *i, bool compat) 1902bfdc5970SChristoph Hellwig { 1903bfdc5970SChristoph Hellwig ssize_t total_len = 0; 1904bfdc5970SChristoph Hellwig unsigned long seg; 1905bfdc5970SChristoph Hellwig struct iovec *iov; 1906bfdc5970SChristoph Hellwig 1907bfdc5970SChristoph Hellwig iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); 1908bfdc5970SChristoph Hellwig if (IS_ERR(iov)) { 1909bfdc5970SChristoph Hellwig *iovp = NULL; 1910bfdc5970SChristoph Hellwig return PTR_ERR(iov); 1911fb041b59SDavid Laight } 1912fb041b59SDavid Laight 1913fb041b59SDavid Laight /* 1914bfdc5970SChristoph Hellwig * According to the Single Unix Specification we should return EINVAL if 1915bfdc5970SChristoph Hellwig * an element length is < 0 when cast to ssize_t or if the total length 1916bfdc5970SChristoph Hellwig * would overflow the ssize_t return value of the system call. 1917fb041b59SDavid Laight * 1918fb041b59SDavid Laight * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the 1919fb041b59SDavid Laight * overflow case. 1920fb041b59SDavid Laight */ 1921fb041b59SDavid Laight for (seg = 0; seg < nr_segs; seg++) { 1922fb041b59SDavid Laight ssize_t len = (ssize_t)iov[seg].iov_len; 1923fb041b59SDavid Laight 1924bfdc5970SChristoph Hellwig if (!access_ok(iov[seg].iov_base, len)) { 1925bfdc5970SChristoph Hellwig if (iov != *iovp) 1926bfdc5970SChristoph Hellwig kfree(iov); 1927bfdc5970SChristoph Hellwig *iovp = NULL; 1928bfdc5970SChristoph Hellwig return -EFAULT; 1929fb041b59SDavid Laight } 1930bfdc5970SChristoph Hellwig 1931bfdc5970SChristoph Hellwig if (len > MAX_RW_COUNT - total_len) { 1932bfdc5970SChristoph Hellwig len = MAX_RW_COUNT - total_len; 1933fb041b59SDavid Laight iov[seg].iov_len = len; 1934fb041b59SDavid Laight } 1935bfdc5970SChristoph Hellwig total_len += len; 1936fb041b59SDavid Laight } 1937bfdc5970SChristoph Hellwig 1938bfdc5970SChristoph Hellwig iov_iter_init(i, type, iov, nr_segs, total_len); 1939bfdc5970SChristoph Hellwig if (iov == *iovp) 1940bfdc5970SChristoph Hellwig *iovp = NULL; 1941bfdc5970SChristoph Hellwig else 1942bfdc5970SChristoph Hellwig *iovp = iov; 1943bfdc5970SChristoph Hellwig return total_len; 1944fb041b59SDavid Laight } 1945fb041b59SDavid Laight 1946ffecee4fSVegard Nossum /** 1947ffecee4fSVegard Nossum * import_iovec() - Copy an array of &struct iovec from userspace 1948ffecee4fSVegard Nossum * into the kernel, check that it is valid, and initialize a new 1949ffecee4fSVegard Nossum * &struct iov_iter iterator to access it. 1950ffecee4fSVegard Nossum * 1951ffecee4fSVegard Nossum * @type: One of %READ or %WRITE. 1952bfdc5970SChristoph Hellwig * @uvec: Pointer to the userspace array. 1953ffecee4fSVegard Nossum * @nr_segs: Number of elements in userspace array. 1954ffecee4fSVegard Nossum * @fast_segs: Number of elements in @iov. 1955bfdc5970SChristoph Hellwig * @iovp: (input and output parameter) Pointer to pointer to (usually small 1956ffecee4fSVegard Nossum * on-stack) kernel array. 1957ffecee4fSVegard Nossum * @i: Pointer to iterator that will be initialized on success. 1958ffecee4fSVegard Nossum * 1959ffecee4fSVegard Nossum * If the array pointed to by *@iov is large enough to hold all @nr_segs, 1960ffecee4fSVegard Nossum * then this function places %NULL in *@iov on return. Otherwise, a new 1961ffecee4fSVegard Nossum * array will be allocated and the result placed in *@iov. This means that 1962ffecee4fSVegard Nossum * the caller may call kfree() on *@iov regardless of whether the small 1963ffecee4fSVegard Nossum * on-stack array was used or not (and regardless of whether this function 1964ffecee4fSVegard Nossum * returns an error or not). 1965ffecee4fSVegard Nossum * 196687e5e6daSJens Axboe * Return: Negative error code on error, bytes imported on success 1967ffecee4fSVegard Nossum */ 1968bfdc5970SChristoph Hellwig ssize_t import_iovec(int type, const struct iovec __user *uvec, 1969bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 1970bfdc5970SChristoph Hellwig struct iovec **iovp, struct iov_iter *i) 1971bc917be8SAl Viro { 197289cd35c5SChristoph Hellwig return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, 197389cd35c5SChristoph Hellwig in_compat_syscall()); 1974bc917be8SAl Viro } 1975bc917be8SAl Viro EXPORT_SYMBOL(import_iovec); 1976bc917be8SAl Viro 1977bc917be8SAl Viro int import_single_range(int rw, void __user *buf, size_t len, 1978bc917be8SAl Viro struct iovec *iov, struct iov_iter *i) 1979bc917be8SAl Viro { 1980bc917be8SAl Viro if (len > MAX_RW_COUNT) 1981bc917be8SAl Viro len = MAX_RW_COUNT; 198296d4f267SLinus Torvalds if (unlikely(!access_ok(buf, len))) 1983bc917be8SAl Viro return -EFAULT; 1984bc917be8SAl Viro 1985bc917be8SAl Viro iov->iov_base = buf; 1986bc917be8SAl Viro iov->iov_len = len; 1987bc917be8SAl Viro iov_iter_init(i, rw, iov, 1, len); 1988bc917be8SAl Viro return 0; 1989bc917be8SAl Viro } 1990e1267585SAl Viro EXPORT_SYMBOL(import_single_range); 19918fb0f47aSJens Axboe 19928fb0f47aSJens Axboe /** 19938fb0f47aSJens Axboe * iov_iter_restore() - Restore a &struct iov_iter to the same state as when 19948fb0f47aSJens Axboe * iov_iter_save_state() was called. 19958fb0f47aSJens Axboe * 19968fb0f47aSJens Axboe * @i: &struct iov_iter to restore 19978fb0f47aSJens Axboe * @state: state to restore from 19988fb0f47aSJens Axboe * 19998fb0f47aSJens Axboe * Used after iov_iter_save_state() to bring restore @i, if operations may 20008fb0f47aSJens Axboe * have advanced it. 20018fb0f47aSJens Axboe * 20028fb0f47aSJens Axboe * Note: only works on ITER_IOVEC, ITER_BVEC, and ITER_KVEC 20038fb0f47aSJens Axboe */ 20048fb0f47aSJens Axboe void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state) 20058fb0f47aSJens Axboe { 20068fb0f47aSJens Axboe if (WARN_ON_ONCE(!iov_iter_is_bvec(i) && !iter_is_iovec(i)) && 2007fcb14cb1SAl Viro !iov_iter_is_kvec(i) && !iter_is_ubuf(i)) 20088fb0f47aSJens Axboe return; 20098fb0f47aSJens Axboe i->iov_offset = state->iov_offset; 20108fb0f47aSJens Axboe i->count = state->count; 2011fcb14cb1SAl Viro if (iter_is_ubuf(i)) 2012fcb14cb1SAl Viro return; 20138fb0f47aSJens Axboe /* 20148fb0f47aSJens Axboe * For the *vec iters, nr_segs + iov is constant - if we increment 20158fb0f47aSJens Axboe * the vec, then we also decrement the nr_segs count. Hence we don't 20168fb0f47aSJens Axboe * need to track both of these, just one is enough and we can deduct 20178fb0f47aSJens Axboe * the other from that. ITER_KVEC and ITER_IOVEC are the same struct 20188fb0f47aSJens Axboe * size, so we can just increment the iov pointer as they are unionzed. 20198fb0f47aSJens Axboe * ITER_BVEC _may_ be the same size on some archs, but on others it is 20208fb0f47aSJens Axboe * not. Be safe and handle it separately. 20218fb0f47aSJens Axboe */ 20228fb0f47aSJens Axboe BUILD_BUG_ON(sizeof(struct iovec) != sizeof(struct kvec)); 20238fb0f47aSJens Axboe if (iov_iter_is_bvec(i)) 20248fb0f47aSJens Axboe i->bvec -= state->nr_segs - i->nr_segs; 20258fb0f47aSJens Axboe else 20268fb0f47aSJens Axboe i->iov -= state->nr_segs - i->nr_segs; 20278fb0f47aSJens Axboe i->nr_segs = state->nr_segs; 20288fb0f47aSJens Axboe } 2029