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 262*8fad7767SAl Viro static inline bool allocated(struct pipe_buffer *buf) 263*8fad7767SAl Viro { 264*8fad7767SAl Viro return buf->ops == &default_pipe_buf_ops; 265*8fad7767SAl Viro } 266*8fad7767SAl Viro 267*8fad7767SAl Viro static struct page *append_pipe(struct iov_iter *i, size_t size, 268*8fad7767SAl Viro unsigned int *off) 269*8fad7767SAl Viro { 270*8fad7767SAl Viro struct pipe_inode_info *pipe = i->pipe; 271*8fad7767SAl Viro size_t offset = i->iov_offset; 272*8fad7767SAl Viro struct pipe_buffer *buf; 273*8fad7767SAl Viro struct page *page; 274*8fad7767SAl Viro 275*8fad7767SAl Viro if (offset && offset < PAGE_SIZE) { 276*8fad7767SAl Viro // some space in the last buffer; can we add to it? 277*8fad7767SAl Viro buf = pipe_buf(pipe, pipe->head - 1); 278*8fad7767SAl Viro if (allocated(buf)) { 279*8fad7767SAl Viro size = min_t(size_t, size, PAGE_SIZE - offset); 280*8fad7767SAl Viro buf->len += size; 281*8fad7767SAl Viro i->iov_offset += size; 282*8fad7767SAl Viro i->count -= size; 283*8fad7767SAl Viro *off = offset; 284*8fad7767SAl Viro return buf->page; 285*8fad7767SAl Viro } 286*8fad7767SAl Viro } 287*8fad7767SAl Viro // OK, we need a new buffer 288*8fad7767SAl Viro *off = 0; 289*8fad7767SAl Viro size = min_t(size_t, size, PAGE_SIZE); 290*8fad7767SAl Viro if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) 291*8fad7767SAl Viro return NULL; 292*8fad7767SAl Viro page = push_anon(pipe, size); 293*8fad7767SAl Viro if (!page) 294*8fad7767SAl Viro return NULL; 295*8fad7767SAl Viro i->head = pipe->head - 1; 296*8fad7767SAl Viro i->iov_offset = size; 297*8fad7767SAl Viro i->count -= size; 298*8fad7767SAl Viro return page; 299*8fad7767SAl Viro } 300*8fad7767SAl 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 push_pipe(struct iov_iter *i, size_t size, 4548cefc107SDavid Howells int *iter_headp, size_t *offp) 455241699cdSAl Viro { 456241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 4578cefc107SDavid Howells unsigned int iter_head; 458241699cdSAl Viro size_t off; 459241699cdSAl Viro ssize_t left; 460241699cdSAl Viro 461241699cdSAl Viro if (unlikely(size > i->count)) 462241699cdSAl Viro size = i->count; 463241699cdSAl Viro if (unlikely(!size)) 464241699cdSAl Viro return 0; 465241699cdSAl Viro 466241699cdSAl Viro left = size; 4678cefc107SDavid Howells data_start(i, &iter_head, &off); 4688cefc107SDavid Howells *iter_headp = iter_head; 469241699cdSAl Viro *offp = off; 470241699cdSAl Viro if (off) { 47147b7fcaeSAl Viro struct pipe_buffer *buf = pipe_buf(pipe, iter_head); 47247b7fcaeSAl Viro 473241699cdSAl Viro left -= PAGE_SIZE - off; 474241699cdSAl Viro if (left <= 0) { 47547b7fcaeSAl Viro buf->len += size; 476241699cdSAl Viro return size; 477241699cdSAl Viro } 47847b7fcaeSAl Viro buf->len = PAGE_SIZE; 479241699cdSAl Viro } 48047b7fcaeSAl Viro while (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) { 48147b7fcaeSAl Viro struct page *page = push_anon(pipe, 48247b7fcaeSAl Viro min_t(ssize_t, left, PAGE_SIZE)); 483241699cdSAl Viro if (!page) 484241699cdSAl Viro break; 4858cefc107SDavid Howells 48647b7fcaeSAl Viro left -= PAGE_SIZE; 48747b7fcaeSAl Viro if (left <= 0) 488241699cdSAl Viro return size; 489241699cdSAl Viro } 490241699cdSAl Viro return size - left; 491241699cdSAl Viro } 492241699cdSAl Viro 493241699cdSAl Viro static size_t copy_pipe_to_iter(const void *addr, size_t bytes, 494241699cdSAl Viro struct iov_iter *i) 495241699cdSAl Viro { 496*8fad7767SAl Viro unsigned int off, chunk; 497*8fad7767SAl Viro 498*8fad7767SAl Viro if (unlikely(bytes > i->count)) 499*8fad7767SAl Viro bytes = i->count; 500*8fad7767SAl Viro if (unlikely(!bytes)) 501*8fad7767SAl Viro return 0; 502241699cdSAl Viro 503241699cdSAl Viro if (!sanity(i)) 504241699cdSAl Viro return 0; 505241699cdSAl Viro 506*8fad7767SAl Viro for (size_t n = bytes; n; n -= chunk) { 507*8fad7767SAl Viro struct page *page = append_pipe(i, n, &off); 508*8fad7767SAl Viro chunk = min_t(size_t, n, PAGE_SIZE - off); 509*8fad7767SAl Viro if (!page) 510*8fad7767SAl Viro return bytes - n; 511*8fad7767SAl Viro memcpy_to_page(page, off, addr, chunk); 512241699cdSAl Viro addr += chunk; 513*8fad7767SAl Viro } 514241699cdSAl Viro return bytes; 515241699cdSAl Viro } 516241699cdSAl Viro 517f9152895SAl Viro static __wsum csum_and_memcpy(void *to, const void *from, size_t len, 518f9152895SAl Viro __wsum sum, size_t off) 519f9152895SAl Viro { 520cc44c17bSAl Viro __wsum next = csum_partial_copy_nocheck(from, to, len); 521f9152895SAl Viro return csum_block_add(sum, next, off); 522f9152895SAl Viro } 523f9152895SAl Viro 52478e1f386SAl Viro static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, 5256852df12SAl Viro struct iov_iter *i, __wsum *sump) 52678e1f386SAl Viro { 5276852df12SAl Viro __wsum sum = *sump; 5286852df12SAl Viro size_t off = 0; 529*8fad7767SAl Viro unsigned int chunk, r; 530*8fad7767SAl Viro 531*8fad7767SAl Viro if (unlikely(bytes > i->count)) 532*8fad7767SAl Viro bytes = i->count; 533*8fad7767SAl Viro if (unlikely(!bytes)) 534*8fad7767SAl Viro return 0; 53578e1f386SAl Viro 53678e1f386SAl Viro if (!sanity(i)) 53778e1f386SAl Viro return 0; 53878e1f386SAl Viro 5396852df12SAl Viro while (bytes) { 540*8fad7767SAl Viro struct page *page = append_pipe(i, bytes, &r); 541*8fad7767SAl Viro char *p; 542*8fad7767SAl Viro 543*8fad7767SAl Viro if (!page) 544*8fad7767SAl Viro break; 545*8fad7767SAl Viro chunk = min_t(size_t, bytes, PAGE_SIZE - r); 546*8fad7767SAl Viro p = kmap_local_page(page); 5476852df12SAl Viro sum = csum_and_memcpy(p + r, addr + off, chunk, sum, off); 5482495bdccSAl Viro kunmap_local(p); 54978e1f386SAl Viro off += chunk; 550*8fad7767SAl Viro bytes -= chunk; 5516852df12SAl Viro } 5526852df12SAl Viro *sump = sum; 5536852df12SAl Viro return off; 55478e1f386SAl Viro } 55578e1f386SAl Viro 556aa28de27SAl Viro size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 557d879cb83SAl Viro { 55800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 559241699cdSAl Viro return copy_pipe_to_iter(addr, bytes, i); 560fcb14cb1SAl Viro if (user_backed_iter(i)) 56109fc68dcSAl Viro might_fault(); 5627baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 5637baa5099SAl Viro copyout(base, addr + off, len), 5647baa5099SAl Viro memcpy(base, addr + off, len) 565d879cb83SAl Viro ) 566d879cb83SAl Viro 567d879cb83SAl Viro return bytes; 568d879cb83SAl Viro } 569aa28de27SAl Viro EXPORT_SYMBOL(_copy_to_iter); 570d879cb83SAl Viro 571ec6347bbSDan Williams #ifdef CONFIG_ARCH_HAS_COPY_MC 572ec6347bbSDan Williams static int copyout_mc(void __user *to, const void *from, size_t n) 5738780356eSDan Williams { 57496d4f267SLinus Torvalds if (access_ok(to, n)) { 575d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 576ec6347bbSDan Williams n = copy_mc_to_user((__force void *) to, from, n); 5778780356eSDan Williams } 5788780356eSDan Williams return n; 5798780356eSDan Williams } 5808780356eSDan Williams 581ec6347bbSDan Williams static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, 582ca146f6fSDan Williams struct iov_iter *i) 583ca146f6fSDan Williams { 584*8fad7767SAl Viro size_t xfer = 0; 585*8fad7767SAl Viro unsigned int off, chunk; 586*8fad7767SAl Viro 587*8fad7767SAl Viro if (unlikely(bytes > i->count)) 588*8fad7767SAl Viro bytes = i->count; 589*8fad7767SAl Viro if (unlikely(!bytes)) 590*8fad7767SAl Viro return 0; 591ca146f6fSDan Williams 592ca146f6fSDan Williams if (!sanity(i)) 593ca146f6fSDan Williams return 0; 594ca146f6fSDan Williams 595*8fad7767SAl Viro while (bytes) { 596*8fad7767SAl Viro struct page *page = append_pipe(i, bytes, &off); 597ca146f6fSDan Williams unsigned long rem; 598*8fad7767SAl Viro char *p; 599*8fad7767SAl Viro 600*8fad7767SAl Viro if (!page) 601*8fad7767SAl Viro break; 602*8fad7767SAl Viro chunk = min_t(size_t, bytes, PAGE_SIZE - off); 603*8fad7767SAl Viro p = kmap_local_page(page); 6042a510a74SAl Viro rem = copy_mc_to_kernel(p + off, addr + xfer, chunk); 6052a510a74SAl Viro chunk -= rem; 6062a510a74SAl Viro kunmap_local(p); 6072a510a74SAl Viro xfer += chunk; 608*8fad7767SAl Viro bytes -= chunk; 609c3497fd0SAl Viro if (rem) { 610*8fad7767SAl Viro iov_iter_revert(i, rem); 611ca146f6fSDan Williams break; 612c3497fd0SAl Viro } 6132a510a74SAl Viro } 614ca146f6fSDan Williams return xfer; 615ca146f6fSDan Williams } 616ca146f6fSDan Williams 617bf3eeb9bSDan Williams /** 618ec6347bbSDan Williams * _copy_mc_to_iter - copy to iter with source memory error exception handling 619bf3eeb9bSDan Williams * @addr: source kernel address 620bf3eeb9bSDan Williams * @bytes: total transfer length 62144e55997SRandy Dunlap * @i: destination iterator 622bf3eeb9bSDan Williams * 623ec6347bbSDan Williams * The pmem driver deploys this for the dax operation 624ec6347bbSDan Williams * (dax_copy_to_iter()) for dax reads (bypass page-cache and the 625ec6347bbSDan Williams * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes 626ec6347bbSDan Williams * successfully copied. 627bf3eeb9bSDan Williams * 628ec6347bbSDan Williams * The main differences between this and typical _copy_to_iter(). 629bf3eeb9bSDan Williams * 630bf3eeb9bSDan Williams * * Typical tail/residue handling after a fault retries the copy 631bf3eeb9bSDan Williams * byte-by-byte until the fault happens again. Re-triggering machine 632bf3eeb9bSDan Williams * checks is potentially fatal so the implementation uses source 633bf3eeb9bSDan Williams * alignment and poison alignment assumptions to avoid re-triggering 634bf3eeb9bSDan Williams * hardware exceptions. 635bf3eeb9bSDan Williams * 636bf3eeb9bSDan Williams * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. 637bf3eeb9bSDan Williams * Compare to copy_to_iter() where only ITER_IOVEC attempts might return 638bf3eeb9bSDan Williams * a short copy. 63944e55997SRandy Dunlap * 64044e55997SRandy Dunlap * Return: number of bytes copied (may be %0) 641bf3eeb9bSDan Williams */ 642ec6347bbSDan Williams size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 6438780356eSDan Williams { 64400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 645ec6347bbSDan Williams return copy_mc_pipe_to_iter(addr, bytes, i); 646fcb14cb1SAl Viro if (user_backed_iter(i)) 6478780356eSDan Williams might_fault(); 6487baa5099SAl Viro __iterate_and_advance(i, bytes, base, len, off, 6497baa5099SAl Viro copyout_mc(base, addr + off, len), 6507baa5099SAl Viro copy_mc_to_kernel(base, addr + off, len) 6518780356eSDan Williams ) 6528780356eSDan Williams 6538780356eSDan Williams return bytes; 6548780356eSDan Williams } 655ec6347bbSDan Williams EXPORT_SYMBOL_GPL(_copy_mc_to_iter); 656ec6347bbSDan Williams #endif /* CONFIG_ARCH_HAS_COPY_MC */ 6578780356eSDan Williams 658aa28de27SAl Viro size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) 659d879cb83SAl Viro { 66000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 661241699cdSAl Viro WARN_ON(1); 662241699cdSAl Viro return 0; 663241699cdSAl Viro } 664fcb14cb1SAl Viro if (user_backed_iter(i)) 66509fc68dcSAl Viro might_fault(); 6667baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 6677baa5099SAl Viro copyin(addr + off, base, len), 6687baa5099SAl Viro memcpy(addr + off, base, len) 669d879cb83SAl Viro ) 670d879cb83SAl Viro 671d879cb83SAl Viro return bytes; 672d879cb83SAl Viro } 673aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter); 674d879cb83SAl Viro 675aa28de27SAl Viro size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) 676d879cb83SAl Viro { 67700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 678241699cdSAl Viro WARN_ON(1); 679241699cdSAl Viro return 0; 680241699cdSAl Viro } 6817baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 6827baa5099SAl Viro __copy_from_user_inatomic_nocache(addr + off, base, len), 6837baa5099SAl Viro memcpy(addr + off, base, len) 684d879cb83SAl Viro ) 685d879cb83SAl Viro 686d879cb83SAl Viro return bytes; 687d879cb83SAl Viro } 688aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_nocache); 689d879cb83SAl Viro 6900aed55afSDan Williams #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE 691abd08d7dSDan Williams /** 692abd08d7dSDan Williams * _copy_from_iter_flushcache - write destination through cpu cache 693abd08d7dSDan Williams * @addr: destination kernel address 694abd08d7dSDan Williams * @bytes: total transfer length 69544e55997SRandy Dunlap * @i: source iterator 696abd08d7dSDan Williams * 697abd08d7dSDan Williams * The pmem driver arranges for filesystem-dax to use this facility via 698abd08d7dSDan Williams * dax_copy_from_iter() for ensuring that writes to persistent memory 699abd08d7dSDan Williams * are flushed through the CPU cache. It is differentiated from 700abd08d7dSDan Williams * _copy_from_iter_nocache() in that guarantees all data is flushed for 701abd08d7dSDan Williams * all iterator types. The _copy_from_iter_nocache() only attempts to 702abd08d7dSDan Williams * bypass the cache for the ITER_IOVEC case, and on some archs may use 703abd08d7dSDan Williams * instructions that strand dirty-data in the cache. 70444e55997SRandy Dunlap * 70544e55997SRandy Dunlap * Return: number of bytes copied (may be %0) 706abd08d7dSDan Williams */ 7076a37e940SLinus Torvalds size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 7080aed55afSDan Williams { 70900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 7100aed55afSDan Williams WARN_ON(1); 7110aed55afSDan Williams return 0; 7120aed55afSDan Williams } 7137baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 7147baa5099SAl Viro __copy_from_user_flushcache(addr + off, base, len), 7157baa5099SAl Viro memcpy_flushcache(addr + off, base, len) 7160aed55afSDan Williams ) 7170aed55afSDan Williams 7180aed55afSDan Williams return bytes; 7190aed55afSDan Williams } 7206a37e940SLinus Torvalds EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); 7210aed55afSDan Williams #endif 7220aed55afSDan Williams 72372e809edSAl Viro static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) 72472e809edSAl Viro { 7256daef95bSEric Dumazet struct page *head; 7266daef95bSEric Dumazet size_t v = n + offset; 7276daef95bSEric Dumazet 7286daef95bSEric Dumazet /* 7296daef95bSEric Dumazet * The general case needs to access the page order in order 7306daef95bSEric Dumazet * to compute the page size. 7316daef95bSEric Dumazet * However, we mostly deal with order-0 pages and thus can 7326daef95bSEric Dumazet * avoid a possible cache line miss for requests that fit all 7336daef95bSEric Dumazet * page orders. 7346daef95bSEric Dumazet */ 7356daef95bSEric Dumazet if (n <= v && v <= PAGE_SIZE) 7366daef95bSEric Dumazet return true; 7376daef95bSEric Dumazet 7386daef95bSEric Dumazet head = compound_head(page); 7396daef95bSEric Dumazet v += (page - head) << PAGE_SHIFT; 740a90bcb86SPetar Penkov 741a50b854eSMatthew Wilcox (Oracle) if (likely(n <= v && v <= (page_size(head)))) 74272e809edSAl Viro return true; 74372e809edSAl Viro WARN_ON(1); 74472e809edSAl Viro return false; 74572e809edSAl Viro } 746cbbd26b8SAl Viro 74708aa6479SAl Viro static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 748d879cb83SAl Viro struct iov_iter *i) 749d879cb83SAl Viro { 75059bb69c6SAl Viro if (unlikely(iov_iter_is_pipe(i))) { 75159bb69c6SAl Viro return copy_page_to_iter_pipe(page, offset, bytes, i); 75259bb69c6SAl Viro } else { 753c1d4d6a9SAl Viro void *kaddr = kmap_local_page(page); 754c1d4d6a9SAl Viro size_t wanted = _copy_to_iter(kaddr + offset, bytes, i); 755c1d4d6a9SAl Viro kunmap_local(kaddr); 756d879cb83SAl Viro return wanted; 75728f38db7SAl Viro } 758d879cb83SAl Viro } 75908aa6479SAl Viro 76008aa6479SAl Viro size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 76108aa6479SAl Viro struct iov_iter *i) 76208aa6479SAl Viro { 76308aa6479SAl Viro size_t res = 0; 76408aa6479SAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 76508aa6479SAl Viro return 0; 76608aa6479SAl Viro page += offset / PAGE_SIZE; // first subpage 76708aa6479SAl Viro offset %= PAGE_SIZE; 76808aa6479SAl Viro while (1) { 76908aa6479SAl Viro size_t n = __copy_page_to_iter(page, offset, 77008aa6479SAl Viro min(bytes, (size_t)PAGE_SIZE - offset), i); 77108aa6479SAl Viro res += n; 77208aa6479SAl Viro bytes -= n; 77308aa6479SAl Viro if (!bytes || !n) 77408aa6479SAl Viro break; 77508aa6479SAl Viro offset += n; 77608aa6479SAl Viro if (offset == PAGE_SIZE) { 77708aa6479SAl Viro page++; 77808aa6479SAl Viro offset = 0; 77908aa6479SAl Viro } 78008aa6479SAl Viro } 78108aa6479SAl Viro return res; 78208aa6479SAl Viro } 783d879cb83SAl Viro EXPORT_SYMBOL(copy_page_to_iter); 784d879cb83SAl Viro 785d879cb83SAl Viro size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, 786d879cb83SAl Viro struct iov_iter *i) 787d879cb83SAl Viro { 78859bb69c6SAl Viro if (page_copy_sane(page, offset, bytes)) { 78955ca375cSAl Viro void *kaddr = kmap_local_page(page); 790aa28de27SAl Viro size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); 79155ca375cSAl Viro kunmap_local(kaddr); 792d879cb83SAl Viro return wanted; 79328f38db7SAl Viro } 79428f38db7SAl Viro return 0; 795d879cb83SAl Viro } 796d879cb83SAl Viro EXPORT_SYMBOL(copy_page_from_iter); 797d879cb83SAl Viro 798241699cdSAl Viro static size_t pipe_zero(size_t bytes, struct iov_iter *i) 799241699cdSAl Viro { 800*8fad7767SAl Viro unsigned int chunk, off; 801*8fad7767SAl Viro 802*8fad7767SAl Viro if (unlikely(bytes > i->count)) 803*8fad7767SAl Viro bytes = i->count; 804*8fad7767SAl Viro if (unlikely(!bytes)) 805*8fad7767SAl Viro return 0; 806241699cdSAl Viro 807241699cdSAl Viro if (!sanity(i)) 808241699cdSAl Viro return 0; 809241699cdSAl Viro 810*8fad7767SAl Viro for (size_t n = bytes; n; n -= chunk) { 811*8fad7767SAl Viro struct page *page = append_pipe(i, n, &off); 812*8fad7767SAl Viro char *p; 813241699cdSAl Viro 814*8fad7767SAl Viro if (!page) 815*8fad7767SAl Viro return bytes - n; 816*8fad7767SAl Viro chunk = min_t(size_t, n, PAGE_SIZE - off); 817*8fad7767SAl Viro p = kmap_local_page(page); 818893839fdSAl Viro memset(p + off, 0, chunk); 819893839fdSAl Viro kunmap_local(p); 820*8fad7767SAl Viro } 821241699cdSAl Viro return bytes; 822241699cdSAl Viro } 823241699cdSAl Viro 824d879cb83SAl Viro size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 825d879cb83SAl Viro { 82600e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 827241699cdSAl Viro return pipe_zero(bytes, i); 8287baa5099SAl Viro iterate_and_advance(i, bytes, base, len, count, 8297baa5099SAl Viro clear_user(base, len), 8307baa5099SAl Viro memset(base, 0, len) 831d879cb83SAl Viro ) 832d879cb83SAl Viro 833d879cb83SAl Viro return bytes; 834d879cb83SAl Viro } 835d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_zero); 836d879cb83SAl Viro 837f0b65f39SAl Viro size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, 838f0b65f39SAl Viro struct iov_iter *i) 839d879cb83SAl Viro { 840d879cb83SAl Viro char *kaddr = kmap_atomic(page), *p = kaddr + offset; 84172e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) { 84272e809edSAl Viro kunmap_atomic(kaddr); 84372e809edSAl Viro return 0; 84472e809edSAl Viro } 8459ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 846241699cdSAl Viro kunmap_atomic(kaddr); 847241699cdSAl Viro WARN_ON(1); 848241699cdSAl Viro return 0; 849241699cdSAl Viro } 8507baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 8517baa5099SAl Viro copyin(p + off, base, len), 8527baa5099SAl Viro memcpy(p + off, base, len) 853d879cb83SAl Viro ) 854d879cb83SAl Viro kunmap_atomic(kaddr); 855d879cb83SAl Viro return bytes; 856d879cb83SAl Viro } 857f0b65f39SAl Viro EXPORT_SYMBOL(copy_page_from_iter_atomic); 858d879cb83SAl Viro 859b9dc6f65SAl Viro static inline void pipe_truncate(struct iov_iter *i) 860241699cdSAl Viro { 861241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 8628cefc107SDavid Howells unsigned int p_tail = pipe->tail; 8638cefc107SDavid Howells unsigned int p_head = pipe->head; 8648cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 8658cefc107SDavid Howells 8668cefc107SDavid Howells if (!pipe_empty(p_head, p_tail)) { 8678cefc107SDavid Howells struct pipe_buffer *buf; 8688cefc107SDavid Howells unsigned int i_head = i->head; 869b9dc6f65SAl Viro size_t off = i->iov_offset; 8708cefc107SDavid Howells 871b9dc6f65SAl Viro if (off) { 8728cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 8738cefc107SDavid Howells buf->len = off - buf->offset; 8748cefc107SDavid Howells i_head++; 875b9dc6f65SAl Viro } 8768cefc107SDavid Howells while (p_head != i_head) { 8778cefc107SDavid Howells p_head--; 8788cefc107SDavid Howells pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); 879241699cdSAl Viro } 8808cefc107SDavid Howells 8818cefc107SDavid Howells pipe->head = p_head; 882241699cdSAl Viro } 883b9dc6f65SAl Viro } 884b9dc6f65SAl Viro 885b9dc6f65SAl Viro static void pipe_advance(struct iov_iter *i, size_t size) 886b9dc6f65SAl Viro { 887b9dc6f65SAl Viro struct pipe_inode_info *pipe = i->pipe; 888b9dc6f65SAl Viro if (size) { 889b9dc6f65SAl Viro struct pipe_buffer *buf; 8908cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 8918cefc107SDavid Howells unsigned int i_head = i->head; 892b9dc6f65SAl Viro size_t off = i->iov_offset, left = size; 8938cefc107SDavid Howells 894b9dc6f65SAl Viro if (off) /* make it relative to the beginning of buffer */ 8958cefc107SDavid Howells left += off - pipe->bufs[i_head & p_mask].offset; 896b9dc6f65SAl Viro while (1) { 8978cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 898b9dc6f65SAl Viro if (left <= buf->len) 899b9dc6f65SAl Viro break; 900b9dc6f65SAl Viro left -= buf->len; 9018cefc107SDavid Howells i_head++; 902b9dc6f65SAl Viro } 9038cefc107SDavid Howells i->head = i_head; 904b9dc6f65SAl Viro i->iov_offset = buf->offset + left; 905b9dc6f65SAl Viro } 906b9dc6f65SAl Viro i->count -= size; 907b9dc6f65SAl Viro /* ... and discard everything past that point */ 908b9dc6f65SAl Viro pipe_truncate(i); 909241699cdSAl Viro } 910241699cdSAl Viro 91154c8195bSPavel Begunkov static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) 91254c8195bSPavel Begunkov { 91318fa9af7SAl Viro const struct bio_vec *bvec, *end; 91454c8195bSPavel Begunkov 91518fa9af7SAl Viro if (!i->count) 91618fa9af7SAl Viro return; 91718fa9af7SAl Viro i->count -= size; 91854c8195bSPavel Begunkov 91918fa9af7SAl Viro size += i->iov_offset; 92018fa9af7SAl Viro 92118fa9af7SAl Viro for (bvec = i->bvec, end = bvec + i->nr_segs; bvec < end; bvec++) { 92218fa9af7SAl Viro if (likely(size < bvec->bv_len)) 92318fa9af7SAl Viro break; 92418fa9af7SAl Viro size -= bvec->bv_len; 92518fa9af7SAl Viro } 92618fa9af7SAl Viro i->iov_offset = size; 92718fa9af7SAl Viro i->nr_segs -= bvec - i->bvec; 92818fa9af7SAl Viro i->bvec = bvec; 92954c8195bSPavel Begunkov } 93054c8195bSPavel Begunkov 931185ac4d4SAl Viro static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) 932185ac4d4SAl Viro { 933185ac4d4SAl Viro const struct iovec *iov, *end; 934185ac4d4SAl Viro 935185ac4d4SAl Viro if (!i->count) 936185ac4d4SAl Viro return; 937185ac4d4SAl Viro i->count -= size; 938185ac4d4SAl Viro 939185ac4d4SAl Viro size += i->iov_offset; // from beginning of current segment 940185ac4d4SAl Viro for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { 941185ac4d4SAl Viro if (likely(size < iov->iov_len)) 942185ac4d4SAl Viro break; 943185ac4d4SAl Viro size -= iov->iov_len; 944185ac4d4SAl Viro } 945185ac4d4SAl Viro i->iov_offset = size; 946185ac4d4SAl Viro i->nr_segs -= iov - i->iov; 947185ac4d4SAl Viro i->iov = iov; 948185ac4d4SAl Viro } 949185ac4d4SAl Viro 950d879cb83SAl Viro void iov_iter_advance(struct iov_iter *i, size_t size) 951d879cb83SAl Viro { 9523b3fc051SAl Viro if (unlikely(i->count < size)) 9533b3fc051SAl Viro size = i->count; 954fcb14cb1SAl Viro if (likely(iter_is_ubuf(i)) || unlikely(iov_iter_is_xarray(i))) { 955fcb14cb1SAl Viro i->iov_offset += size; 956fcb14cb1SAl Viro i->count -= size; 957fcb14cb1SAl Viro } else if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { 958185ac4d4SAl Viro /* iovec and kvec have identical layouts */ 959185ac4d4SAl Viro iov_iter_iovec_advance(i, size); 960185ac4d4SAl Viro } else if (iov_iter_is_bvec(i)) { 961185ac4d4SAl Viro iov_iter_bvec_advance(i, size); 962185ac4d4SAl Viro } else if (iov_iter_is_pipe(i)) { 963241699cdSAl Viro pipe_advance(i, size); 964185ac4d4SAl Viro } else if (iov_iter_is_discard(i)) { 965185ac4d4SAl Viro i->count -= size; 9667ff50620SDavid Howells } 967d879cb83SAl Viro } 968d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_advance); 969d879cb83SAl Viro 97027c0e374SAl Viro void iov_iter_revert(struct iov_iter *i, size_t unroll) 97127c0e374SAl Viro { 97227c0e374SAl Viro if (!unroll) 97327c0e374SAl Viro return; 9745b47d59aSAl Viro if (WARN_ON(unroll > MAX_RW_COUNT)) 9755b47d59aSAl Viro return; 97627c0e374SAl Viro i->count += unroll; 97700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 97827c0e374SAl Viro struct pipe_inode_info *pipe = i->pipe; 9798cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9808cefc107SDavid Howells unsigned int i_head = i->head; 98127c0e374SAl Viro size_t off = i->iov_offset; 98227c0e374SAl Viro while (1) { 9838cefc107SDavid Howells struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; 9848cefc107SDavid Howells size_t n = off - b->offset; 98527c0e374SAl Viro if (unroll < n) { 9864fa55cefSAl Viro off -= unroll; 98727c0e374SAl Viro break; 98827c0e374SAl Viro } 98927c0e374SAl Viro unroll -= n; 9908cefc107SDavid Howells if (!unroll && i_head == i->start_head) { 99127c0e374SAl Viro off = 0; 99227c0e374SAl Viro break; 99327c0e374SAl Viro } 9948cefc107SDavid Howells i_head--; 9958cefc107SDavid Howells b = &pipe->bufs[i_head & p_mask]; 9968cefc107SDavid Howells off = b->offset + b->len; 99727c0e374SAl Viro } 99827c0e374SAl Viro i->iov_offset = off; 9998cefc107SDavid Howells i->head = i_head; 100027c0e374SAl Viro pipe_truncate(i); 100127c0e374SAl Viro return; 100227c0e374SAl Viro } 10039ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 10049ea9ce04SDavid Howells return; 100527c0e374SAl Viro if (unroll <= i->iov_offset) { 100627c0e374SAl Viro i->iov_offset -= unroll; 100727c0e374SAl Viro return; 100827c0e374SAl Viro } 100927c0e374SAl Viro unroll -= i->iov_offset; 1010fcb14cb1SAl Viro if (iov_iter_is_xarray(i) || iter_is_ubuf(i)) { 10117ff50620SDavid Howells BUG(); /* We should never go beyond the start of the specified 10127ff50620SDavid Howells * range since we might then be straying into pages that 10137ff50620SDavid Howells * aren't pinned. 10147ff50620SDavid Howells */ 10157ff50620SDavid Howells } else if (iov_iter_is_bvec(i)) { 101627c0e374SAl Viro const struct bio_vec *bvec = i->bvec; 101727c0e374SAl Viro while (1) { 101827c0e374SAl Viro size_t n = (--bvec)->bv_len; 101927c0e374SAl Viro i->nr_segs++; 102027c0e374SAl Viro if (unroll <= n) { 102127c0e374SAl Viro i->bvec = bvec; 102227c0e374SAl Viro i->iov_offset = n - unroll; 102327c0e374SAl Viro return; 102427c0e374SAl Viro } 102527c0e374SAl Viro unroll -= n; 102627c0e374SAl Viro } 102727c0e374SAl Viro } else { /* same logics for iovec and kvec */ 102827c0e374SAl Viro const struct iovec *iov = i->iov; 102927c0e374SAl Viro while (1) { 103027c0e374SAl Viro size_t n = (--iov)->iov_len; 103127c0e374SAl Viro i->nr_segs++; 103227c0e374SAl Viro if (unroll <= n) { 103327c0e374SAl Viro i->iov = iov; 103427c0e374SAl Viro i->iov_offset = n - unroll; 103527c0e374SAl Viro return; 103627c0e374SAl Viro } 103727c0e374SAl Viro unroll -= n; 103827c0e374SAl Viro } 103927c0e374SAl Viro } 104027c0e374SAl Viro } 104127c0e374SAl Viro EXPORT_SYMBOL(iov_iter_revert); 104227c0e374SAl Viro 1043d879cb83SAl Viro /* 1044d879cb83SAl Viro * Return the count of just the current iov_iter segment. 1045d879cb83SAl Viro */ 1046d879cb83SAl Viro size_t iov_iter_single_seg_count(const struct iov_iter *i) 1047d879cb83SAl Viro { 104828f38db7SAl Viro if (i->nr_segs > 1) { 104928f38db7SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 105028f38db7SAl Viro return min(i->count, i->iov->iov_len - i->iov_offset); 10517ff50620SDavid Howells if (iov_iter_is_bvec(i)) 1052d879cb83SAl Viro return min(i->count, i->bvec->bv_len - i->iov_offset); 105328f38db7SAl Viro } 105428f38db7SAl Viro return i->count; 1055d879cb83SAl Viro } 1056d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_single_seg_count); 1057d879cb83SAl Viro 1058aa563d7bSDavid Howells void iov_iter_kvec(struct iov_iter *i, unsigned int direction, 1059d879cb83SAl Viro const struct kvec *kvec, unsigned long nr_segs, 1060d879cb83SAl Viro size_t count) 1061d879cb83SAl Viro { 1062aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 10638cd54c1cSAl Viro *i = (struct iov_iter){ 10648cd54c1cSAl Viro .iter_type = ITER_KVEC, 10658cd54c1cSAl Viro .data_source = direction, 10668cd54c1cSAl Viro .kvec = kvec, 10678cd54c1cSAl Viro .nr_segs = nr_segs, 10688cd54c1cSAl Viro .iov_offset = 0, 10698cd54c1cSAl Viro .count = count 10708cd54c1cSAl Viro }; 1071d879cb83SAl Viro } 1072d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_kvec); 1073d879cb83SAl Viro 1074aa563d7bSDavid Howells void iov_iter_bvec(struct iov_iter *i, unsigned int direction, 1075d879cb83SAl Viro const struct bio_vec *bvec, unsigned long nr_segs, 1076d879cb83SAl Viro size_t count) 1077d879cb83SAl Viro { 1078aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 10798cd54c1cSAl Viro *i = (struct iov_iter){ 10808cd54c1cSAl Viro .iter_type = ITER_BVEC, 10818cd54c1cSAl Viro .data_source = direction, 10828cd54c1cSAl Viro .bvec = bvec, 10838cd54c1cSAl Viro .nr_segs = nr_segs, 10848cd54c1cSAl Viro .iov_offset = 0, 10858cd54c1cSAl Viro .count = count 10868cd54c1cSAl Viro }; 1087d879cb83SAl Viro } 1088d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_bvec); 1089d879cb83SAl Viro 1090aa563d7bSDavid Howells void iov_iter_pipe(struct iov_iter *i, unsigned int direction, 1091241699cdSAl Viro struct pipe_inode_info *pipe, 1092241699cdSAl Viro size_t count) 1093241699cdSAl Viro { 1094aa563d7bSDavid Howells BUG_ON(direction != READ); 10958cefc107SDavid Howells WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); 10968cd54c1cSAl Viro *i = (struct iov_iter){ 10978cd54c1cSAl Viro .iter_type = ITER_PIPE, 10988cd54c1cSAl Viro .data_source = false, 10998cd54c1cSAl Viro .pipe = pipe, 11008cd54c1cSAl Viro .head = pipe->head, 11018cd54c1cSAl Viro .start_head = pipe->head, 11028cd54c1cSAl Viro .iov_offset = 0, 11038cd54c1cSAl Viro .count = count 11048cd54c1cSAl Viro }; 1105241699cdSAl Viro } 1106241699cdSAl Viro EXPORT_SYMBOL(iov_iter_pipe); 1107241699cdSAl Viro 11089ea9ce04SDavid Howells /** 11097ff50620SDavid Howells * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray 11107ff50620SDavid Howells * @i: The iterator to initialise. 11117ff50620SDavid Howells * @direction: The direction of the transfer. 11127ff50620SDavid Howells * @xarray: The xarray to access. 11137ff50620SDavid Howells * @start: The start file position. 11147ff50620SDavid Howells * @count: The size of the I/O buffer in bytes. 11157ff50620SDavid Howells * 11167ff50620SDavid Howells * Set up an I/O iterator to either draw data out of the pages attached to an 11177ff50620SDavid Howells * inode or to inject data into those pages. The pages *must* be prevented 11187ff50620SDavid Howells * from evaporation, either by taking a ref on them or locking them by the 11197ff50620SDavid Howells * caller. 11207ff50620SDavid Howells */ 11217ff50620SDavid Howells void iov_iter_xarray(struct iov_iter *i, unsigned int direction, 11227ff50620SDavid Howells struct xarray *xarray, loff_t start, size_t count) 11237ff50620SDavid Howells { 11247ff50620SDavid Howells BUG_ON(direction & ~1); 11258cd54c1cSAl Viro *i = (struct iov_iter) { 11268cd54c1cSAl Viro .iter_type = ITER_XARRAY, 11278cd54c1cSAl Viro .data_source = direction, 11288cd54c1cSAl Viro .xarray = xarray, 11298cd54c1cSAl Viro .xarray_start = start, 11308cd54c1cSAl Viro .count = count, 11318cd54c1cSAl Viro .iov_offset = 0 11328cd54c1cSAl Viro }; 11337ff50620SDavid Howells } 11347ff50620SDavid Howells EXPORT_SYMBOL(iov_iter_xarray); 11357ff50620SDavid Howells 11367ff50620SDavid Howells /** 11379ea9ce04SDavid Howells * iov_iter_discard - Initialise an I/O iterator that discards data 11389ea9ce04SDavid Howells * @i: The iterator to initialise. 11399ea9ce04SDavid Howells * @direction: The direction of the transfer. 11409ea9ce04SDavid Howells * @count: The size of the I/O buffer in bytes. 11419ea9ce04SDavid Howells * 11429ea9ce04SDavid Howells * Set up an I/O iterator that just discards everything that's written to it. 11439ea9ce04SDavid Howells * It's only available as a READ iterator. 11449ea9ce04SDavid Howells */ 11459ea9ce04SDavid Howells void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) 11469ea9ce04SDavid Howells { 11479ea9ce04SDavid Howells BUG_ON(direction != READ); 11488cd54c1cSAl Viro *i = (struct iov_iter){ 11498cd54c1cSAl Viro .iter_type = ITER_DISCARD, 11508cd54c1cSAl Viro .data_source = false, 11518cd54c1cSAl Viro .count = count, 11528cd54c1cSAl Viro .iov_offset = 0 11538cd54c1cSAl Viro }; 11549ea9ce04SDavid Howells } 11559ea9ce04SDavid Howells EXPORT_SYMBOL(iov_iter_discard); 11569ea9ce04SDavid Howells 1157cfa320f7SKeith Busch static bool iov_iter_aligned_iovec(const struct iov_iter *i, unsigned addr_mask, 1158cfa320f7SKeith Busch unsigned len_mask) 1159cfa320f7SKeith Busch { 1160cfa320f7SKeith Busch size_t size = i->count; 1161cfa320f7SKeith Busch size_t skip = i->iov_offset; 1162cfa320f7SKeith Busch unsigned k; 1163cfa320f7SKeith Busch 1164cfa320f7SKeith Busch for (k = 0; k < i->nr_segs; k++, skip = 0) { 1165cfa320f7SKeith Busch size_t len = i->iov[k].iov_len - skip; 1166cfa320f7SKeith Busch 1167cfa320f7SKeith Busch if (len > size) 1168cfa320f7SKeith Busch len = size; 1169cfa320f7SKeith Busch if (len & len_mask) 1170cfa320f7SKeith Busch return false; 1171cfa320f7SKeith Busch if ((unsigned long)(i->iov[k].iov_base + skip) & addr_mask) 1172cfa320f7SKeith Busch return false; 1173cfa320f7SKeith Busch 1174cfa320f7SKeith Busch size -= len; 1175cfa320f7SKeith Busch if (!size) 1176cfa320f7SKeith Busch break; 1177cfa320f7SKeith Busch } 1178cfa320f7SKeith Busch return true; 1179cfa320f7SKeith Busch } 1180cfa320f7SKeith Busch 1181cfa320f7SKeith Busch static bool iov_iter_aligned_bvec(const struct iov_iter *i, unsigned addr_mask, 1182cfa320f7SKeith Busch unsigned len_mask) 1183cfa320f7SKeith Busch { 1184cfa320f7SKeith Busch size_t size = i->count; 1185cfa320f7SKeith Busch unsigned skip = i->iov_offset; 1186cfa320f7SKeith Busch unsigned k; 1187cfa320f7SKeith Busch 1188cfa320f7SKeith Busch for (k = 0; k < i->nr_segs; k++, skip = 0) { 1189cfa320f7SKeith Busch size_t len = i->bvec[k].bv_len - skip; 1190cfa320f7SKeith Busch 1191cfa320f7SKeith Busch if (len > size) 1192cfa320f7SKeith Busch len = size; 1193cfa320f7SKeith Busch if (len & len_mask) 1194cfa320f7SKeith Busch return false; 1195cfa320f7SKeith Busch if ((unsigned long)(i->bvec[k].bv_offset + skip) & addr_mask) 1196cfa320f7SKeith Busch return false; 1197cfa320f7SKeith Busch 1198cfa320f7SKeith Busch size -= len; 1199cfa320f7SKeith Busch if (!size) 1200cfa320f7SKeith Busch break; 1201cfa320f7SKeith Busch } 1202cfa320f7SKeith Busch return true; 1203cfa320f7SKeith Busch } 1204cfa320f7SKeith Busch 1205cfa320f7SKeith Busch /** 1206cfa320f7SKeith Busch * iov_iter_is_aligned() - Check if the addresses and lengths of each segments 1207cfa320f7SKeith Busch * are aligned to the parameters. 1208cfa320f7SKeith Busch * 1209cfa320f7SKeith Busch * @i: &struct iov_iter to restore 1210cfa320f7SKeith Busch * @addr_mask: bit mask to check against the iov element's addresses 1211cfa320f7SKeith Busch * @len_mask: bit mask to check against the iov element's lengths 1212cfa320f7SKeith Busch * 1213cfa320f7SKeith Busch * Return: false if any addresses or lengths intersect with the provided masks 1214cfa320f7SKeith Busch */ 1215cfa320f7SKeith Busch bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask, 1216cfa320f7SKeith Busch unsigned len_mask) 1217cfa320f7SKeith Busch { 1218fcb14cb1SAl Viro if (likely(iter_is_ubuf(i))) { 1219fcb14cb1SAl Viro if (i->count & len_mask) 1220fcb14cb1SAl Viro return false; 1221fcb14cb1SAl Viro if ((unsigned long)(i->ubuf + i->iov_offset) & addr_mask) 1222fcb14cb1SAl Viro return false; 1223fcb14cb1SAl Viro return true; 1224fcb14cb1SAl Viro } 1225fcb14cb1SAl Viro 1226cfa320f7SKeith Busch if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 1227cfa320f7SKeith Busch return iov_iter_aligned_iovec(i, addr_mask, len_mask); 1228cfa320f7SKeith Busch 1229cfa320f7SKeith Busch if (iov_iter_is_bvec(i)) 1230cfa320f7SKeith Busch return iov_iter_aligned_bvec(i, addr_mask, len_mask); 1231cfa320f7SKeith Busch 1232cfa320f7SKeith Busch if (iov_iter_is_pipe(i)) { 1233cfa320f7SKeith Busch unsigned int p_mask = i->pipe->ring_size - 1; 1234cfa320f7SKeith Busch size_t size = i->count; 1235cfa320f7SKeith Busch 1236cfa320f7SKeith Busch if (size & len_mask) 1237cfa320f7SKeith Busch return false; 1238cfa320f7SKeith Busch if (size && allocated(&i->pipe->bufs[i->head & p_mask])) { 1239cfa320f7SKeith Busch if (i->iov_offset & addr_mask) 1240cfa320f7SKeith Busch return false; 1241cfa320f7SKeith Busch } 1242cfa320f7SKeith Busch 1243cfa320f7SKeith Busch return true; 1244cfa320f7SKeith Busch } 1245cfa320f7SKeith Busch 1246cfa320f7SKeith Busch if (iov_iter_is_xarray(i)) { 1247cfa320f7SKeith Busch if (i->count & len_mask) 1248cfa320f7SKeith Busch return false; 1249cfa320f7SKeith Busch if ((i->xarray_start + i->iov_offset) & addr_mask) 1250cfa320f7SKeith Busch return false; 1251cfa320f7SKeith Busch } 1252cfa320f7SKeith Busch 1253cfa320f7SKeith Busch return true; 1254cfa320f7SKeith Busch } 1255cfa320f7SKeith Busch EXPORT_SYMBOL_GPL(iov_iter_is_aligned); 1256cfa320f7SKeith Busch 12579221d2e3SAl Viro static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) 1258d879cb83SAl Viro { 1259d879cb83SAl Viro unsigned long res = 0; 1260d879cb83SAl Viro size_t size = i->count; 12619221d2e3SAl Viro size_t skip = i->iov_offset; 12629221d2e3SAl Viro unsigned k; 1263d879cb83SAl Viro 12649221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 12659221d2e3SAl Viro size_t len = i->iov[k].iov_len - skip; 12669221d2e3SAl Viro if (len) { 12679221d2e3SAl Viro res |= (unsigned long)i->iov[k].iov_base + skip; 12689221d2e3SAl Viro if (len > size) 12699221d2e3SAl Viro len = size; 12709221d2e3SAl Viro res |= len; 12719221d2e3SAl Viro size -= len; 12729221d2e3SAl Viro if (!size) 12739221d2e3SAl Viro break; 12749221d2e3SAl Viro } 12759221d2e3SAl Viro } 12769221d2e3SAl Viro return res; 12779221d2e3SAl Viro } 12789221d2e3SAl Viro 12799221d2e3SAl Viro static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) 12809221d2e3SAl Viro { 12819221d2e3SAl Viro unsigned res = 0; 12829221d2e3SAl Viro size_t size = i->count; 12839221d2e3SAl Viro unsigned skip = i->iov_offset; 12849221d2e3SAl Viro unsigned k; 12859221d2e3SAl Viro 12869221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 12879221d2e3SAl Viro size_t len = i->bvec[k].bv_len - skip; 12889221d2e3SAl Viro res |= (unsigned long)i->bvec[k].bv_offset + skip; 12899221d2e3SAl Viro if (len > size) 12909221d2e3SAl Viro len = size; 12919221d2e3SAl Viro res |= len; 12929221d2e3SAl Viro size -= len; 12939221d2e3SAl Viro if (!size) 12949221d2e3SAl Viro break; 12959221d2e3SAl Viro } 12969221d2e3SAl Viro return res; 12979221d2e3SAl Viro } 12989221d2e3SAl Viro 12999221d2e3SAl Viro unsigned long iov_iter_alignment(const struct iov_iter *i) 13009221d2e3SAl Viro { 1301fcb14cb1SAl Viro if (likely(iter_is_ubuf(i))) { 1302fcb14cb1SAl Viro size_t size = i->count; 1303fcb14cb1SAl Viro if (size) 1304fcb14cb1SAl Viro return ((unsigned long)i->ubuf + i->iov_offset) | size; 1305fcb14cb1SAl Viro return 0; 1306fcb14cb1SAl Viro } 1307fcb14cb1SAl Viro 13089221d2e3SAl Viro /* iovec and kvec have identical layouts */ 13099221d2e3SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 13109221d2e3SAl Viro return iov_iter_alignment_iovec(i); 13119221d2e3SAl Viro 13129221d2e3SAl Viro if (iov_iter_is_bvec(i)) 13139221d2e3SAl Viro return iov_iter_alignment_bvec(i); 13149221d2e3SAl Viro 13159221d2e3SAl Viro if (iov_iter_is_pipe(i)) { 13169221d2e3SAl Viro size_t size = i->count; 1317e0ff126eSJan Kara 13182dcedb2aSAl Viro if (size && i->iov_offset && allocated(pipe_buf(i->pipe, i->head))) 1319241699cdSAl Viro return size | i->iov_offset; 1320241699cdSAl Viro return size; 1321241699cdSAl Viro } 13229221d2e3SAl Viro 13239221d2e3SAl Viro if (iov_iter_is_xarray(i)) 13243d14ec1fSDavid Howells return (i->xarray_start + i->iov_offset) | i->count; 13259221d2e3SAl Viro 13269221d2e3SAl Viro return 0; 1327d879cb83SAl Viro } 1328d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_alignment); 1329d879cb83SAl Viro 1330357f435dSAl Viro unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 1331357f435dSAl Viro { 1332357f435dSAl Viro unsigned long res = 0; 1333610c7a71SAl Viro unsigned long v = 0; 1334357f435dSAl Viro size_t size = i->count; 1335610c7a71SAl Viro unsigned k; 1336357f435dSAl Viro 1337fcb14cb1SAl Viro if (iter_is_ubuf(i)) 1338fcb14cb1SAl Viro return 0; 1339fcb14cb1SAl Viro 1340610c7a71SAl Viro if (WARN_ON(!iter_is_iovec(i))) 1341241699cdSAl Viro return ~0U; 1342241699cdSAl Viro 1343610c7a71SAl Viro for (k = 0; k < i->nr_segs; k++) { 1344610c7a71SAl Viro if (i->iov[k].iov_len) { 1345610c7a71SAl Viro unsigned long base = (unsigned long)i->iov[k].iov_base; 1346610c7a71SAl Viro if (v) // if not the first one 1347610c7a71SAl Viro res |= base | v; // this start | previous end 1348610c7a71SAl Viro v = base + i->iov[k].iov_len; 1349610c7a71SAl Viro if (size <= i->iov[k].iov_len) 1350610c7a71SAl Viro break; 1351610c7a71SAl Viro size -= i->iov[k].iov_len; 1352610c7a71SAl Viro } 1353610c7a71SAl Viro } 1354357f435dSAl Viro return res; 1355357f435dSAl Viro } 1356357f435dSAl Viro EXPORT_SYMBOL(iov_iter_gap_alignment); 1357357f435dSAl Viro 1358e76b6312SIlya Dryomov static inline ssize_t __pipe_get_pages(struct iov_iter *i, 1359241699cdSAl Viro size_t maxsize, 1360241699cdSAl Viro struct page **pages, 13618cefc107SDavid Howells int iter_head, 1362241699cdSAl Viro size_t *start) 1363241699cdSAl Viro { 1364241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 13658cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 13668cefc107SDavid Howells ssize_t n = push_pipe(i, maxsize, &iter_head, start); 1367241699cdSAl Viro if (!n) 1368241699cdSAl Viro return -EFAULT; 1369241699cdSAl Viro 1370241699cdSAl Viro maxsize = n; 1371241699cdSAl Viro n += *start; 13721689c73aSAl Viro while (n > 0) { 13738cefc107SDavid Howells get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); 13748cefc107SDavid Howells iter_head++; 1375241699cdSAl Viro n -= PAGE_SIZE; 1376241699cdSAl Viro } 1377241699cdSAl Viro 1378241699cdSAl Viro return maxsize; 1379241699cdSAl Viro } 1380241699cdSAl Viro 1381241699cdSAl Viro static ssize_t pipe_get_pages(struct iov_iter *i, 1382241699cdSAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1383241699cdSAl Viro size_t *start) 1384241699cdSAl Viro { 13858cefc107SDavid Howells unsigned int iter_head, npages; 1386241699cdSAl Viro size_t capacity; 1387241699cdSAl Viro 1388241699cdSAl Viro if (!sanity(i)) 1389241699cdSAl Viro return -EFAULT; 1390241699cdSAl Viro 13918cefc107SDavid Howells data_start(i, &iter_head, start); 13928cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 13938cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1394241699cdSAl Viro capacity = min(npages, maxpages) * PAGE_SIZE - *start; 1395241699cdSAl Viro 13968cefc107SDavid Howells return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); 1397241699cdSAl Viro } 1398241699cdSAl Viro 13997ff50620SDavid Howells static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, 14007ff50620SDavid Howells pgoff_t index, unsigned int nr_pages) 14017ff50620SDavid Howells { 14027ff50620SDavid Howells XA_STATE(xas, xa, index); 14037ff50620SDavid Howells struct page *page; 14047ff50620SDavid Howells unsigned int ret = 0; 14057ff50620SDavid Howells 14067ff50620SDavid Howells rcu_read_lock(); 14077ff50620SDavid Howells for (page = xas_load(&xas); page; page = xas_next(&xas)) { 14087ff50620SDavid Howells if (xas_retry(&xas, page)) 14097ff50620SDavid Howells continue; 14107ff50620SDavid Howells 14117ff50620SDavid Howells /* Has the page moved or been split? */ 14127ff50620SDavid Howells if (unlikely(page != xas_reload(&xas))) { 14137ff50620SDavid Howells xas_reset(&xas); 14147ff50620SDavid Howells continue; 14157ff50620SDavid Howells } 14167ff50620SDavid Howells 14177ff50620SDavid Howells pages[ret] = find_subpage(page, xas.xa_index); 14187ff50620SDavid Howells get_page(pages[ret]); 14197ff50620SDavid Howells if (++ret == nr_pages) 14207ff50620SDavid Howells break; 14217ff50620SDavid Howells } 14227ff50620SDavid Howells rcu_read_unlock(); 14237ff50620SDavid Howells return ret; 14247ff50620SDavid Howells } 14257ff50620SDavid Howells 14267ff50620SDavid Howells static ssize_t iter_xarray_get_pages(struct iov_iter *i, 14277ff50620SDavid Howells struct page **pages, size_t maxsize, 14287ff50620SDavid Howells unsigned maxpages, size_t *_start_offset) 14297ff50620SDavid Howells { 14307ff50620SDavid Howells unsigned nr, offset; 14317ff50620SDavid Howells pgoff_t index, count; 14326c776766SDavid Howells size_t size = maxsize; 14337ff50620SDavid Howells loff_t pos; 14347ff50620SDavid Howells 14357ff50620SDavid Howells if (!size || !maxpages) 14367ff50620SDavid Howells return 0; 14377ff50620SDavid Howells 14387ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 14397ff50620SDavid Howells index = pos >> PAGE_SHIFT; 14407ff50620SDavid Howells offset = pos & ~PAGE_MASK; 14417ff50620SDavid Howells *_start_offset = offset; 14427ff50620SDavid Howells 14437ff50620SDavid Howells count = 1; 14447ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 14457ff50620SDavid Howells size -= PAGE_SIZE - offset; 14467ff50620SDavid Howells count += size >> PAGE_SHIFT; 14477ff50620SDavid Howells size &= ~PAGE_MASK; 14487ff50620SDavid Howells if (size) 14497ff50620SDavid Howells count++; 14507ff50620SDavid Howells } 14517ff50620SDavid Howells 14527ff50620SDavid Howells if (count > maxpages) 14537ff50620SDavid Howells count = maxpages; 14547ff50620SDavid Howells 14557ff50620SDavid Howells nr = iter_xarray_populate_pages(pages, i->xarray, index, count); 14567ff50620SDavid Howells if (nr == 0) 14577ff50620SDavid Howells return 0; 14587ff50620SDavid Howells 14591c27f1fcSLinus Torvalds return min_t(size_t, nr * PAGE_SIZE - offset, maxsize); 14607ff50620SDavid Howells } 14617ff50620SDavid Howells 1462fcb14cb1SAl Viro /* must be done on non-empty ITER_UBUF or ITER_IOVEC one */ 1463dd45ab9dSAl Viro static unsigned long first_iovec_segment(const struct iov_iter *i, size_t *size) 14643d671ca6SAl Viro { 14653d671ca6SAl Viro size_t skip; 14663d671ca6SAl Viro long k; 14673d671ca6SAl Viro 1468fcb14cb1SAl Viro if (iter_is_ubuf(i)) 1469fcb14cb1SAl Viro return (unsigned long)i->ubuf + i->iov_offset; 1470fcb14cb1SAl Viro 14713d671ca6SAl Viro for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { 14723d671ca6SAl Viro size_t len = i->iov[k].iov_len - skip; 14733d671ca6SAl Viro 14743d671ca6SAl Viro if (unlikely(!len)) 14753d671ca6SAl Viro continue; 147659dbd7d0SAl Viro if (*size > len) 14773d671ca6SAl Viro *size = len; 1478dd45ab9dSAl Viro return (unsigned long)i->iov[k].iov_base + skip; 14793d671ca6SAl Viro } 14803d671ca6SAl Viro BUG(); // if it had been empty, we wouldn't get called 14813d671ca6SAl Viro } 14823d671ca6SAl Viro 14833d671ca6SAl Viro /* must be done on non-empty ITER_BVEC one */ 14843d671ca6SAl Viro static struct page *first_bvec_segment(const struct iov_iter *i, 148559dbd7d0SAl Viro size_t *size, size_t *start) 14863d671ca6SAl Viro { 14873d671ca6SAl Viro struct page *page; 14883d671ca6SAl Viro size_t skip = i->iov_offset, len; 14893d671ca6SAl Viro 14903d671ca6SAl Viro len = i->bvec->bv_len - skip; 149159dbd7d0SAl Viro if (*size > len) 149259dbd7d0SAl Viro *size = len; 14933d671ca6SAl Viro skip += i->bvec->bv_offset; 14943d671ca6SAl Viro page = i->bvec->bv_page + skip / PAGE_SIZE; 1495dda8e5d1SAl Viro *start = skip % PAGE_SIZE; 14963d671ca6SAl Viro return page; 14973d671ca6SAl Viro } 14983d671ca6SAl Viro 1499d879cb83SAl Viro ssize_t iov_iter_get_pages(struct iov_iter *i, 1500d879cb83SAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1501d879cb83SAl Viro size_t *start) 1502d879cb83SAl Viro { 15033d671ca6SAl Viro int n, res; 15043d671ca6SAl Viro 1505d879cb83SAl Viro if (maxsize > i->count) 1506d879cb83SAl Viro maxsize = i->count; 15073d671ca6SAl Viro if (!maxsize) 15083d671ca6SAl Viro return 0; 15097392ed17SAl Viro if (maxsize > MAX_RW_COUNT) 15107392ed17SAl Viro maxsize = MAX_RW_COUNT; 1511d879cb83SAl Viro 1512fcb14cb1SAl Viro if (likely(user_backed_iter(i))) { 15133337ab08SAndreas Gruenbacher unsigned int gup_flags = 0; 15143d671ca6SAl Viro unsigned long addr; 15159ea9ce04SDavid Howells 15163337ab08SAndreas Gruenbacher if (iov_iter_rw(i) != WRITE) 15173337ab08SAndreas Gruenbacher gup_flags |= FOLL_WRITE; 15183337ab08SAndreas Gruenbacher if (i->nofault) 15193337ab08SAndreas Gruenbacher gup_flags |= FOLL_NOFAULT; 15203337ab08SAndreas Gruenbacher 1521dd45ab9dSAl Viro addr = first_iovec_segment(i, &maxsize); 1522dd45ab9dSAl Viro *start = addr % PAGE_SIZE; 1523dd45ab9dSAl Viro addr &= PAGE_MASK; 152459dbd7d0SAl Viro n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1525dda8e5d1SAl Viro if (n > maxpages) 1526dda8e5d1SAl Viro n = maxpages; 15273337ab08SAndreas Gruenbacher res = get_user_pages_fast(addr, n, gup_flags, pages); 1528814a6674SAndreas Gruenbacher if (unlikely(res <= 0)) 1529d879cb83SAl Viro return res; 153059dbd7d0SAl Viro return min_t(size_t, maxsize, res * PAGE_SIZE - *start); 15313d671ca6SAl Viro } 15323d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 15333d671ca6SAl Viro struct page *page; 15343d671ca6SAl Viro 153559dbd7d0SAl Viro page = first_bvec_segment(i, &maxsize, start); 153659dbd7d0SAl Viro n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1537dda8e5d1SAl Viro if (n > maxpages) 1538dda8e5d1SAl Viro n = maxpages; 1539dda8e5d1SAl Viro for (int k = 0; k < n; k++) 15403d671ca6SAl Viro get_page(*pages++ = page++); 154159dbd7d0SAl Viro return min_t(size_t, maxsize, n * PAGE_SIZE - *start); 15423d671ca6SAl Viro } 15433d671ca6SAl Viro if (iov_iter_is_pipe(i)) 15443d671ca6SAl Viro return pipe_get_pages(i, pages, maxsize, maxpages, start); 15453d671ca6SAl Viro if (iov_iter_is_xarray(i)) 15463d671ca6SAl Viro return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); 1547d879cb83SAl Viro return -EFAULT; 1548d879cb83SAl Viro } 1549d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages); 1550d879cb83SAl Viro 1551d879cb83SAl Viro static struct page **get_pages_array(size_t n) 1552d879cb83SAl Viro { 1553752ade68SMichal Hocko return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); 1554d879cb83SAl Viro } 1555d879cb83SAl Viro 1556241699cdSAl Viro static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 1557241699cdSAl Viro struct page ***pages, size_t maxsize, 1558241699cdSAl Viro size_t *start) 1559241699cdSAl Viro { 1560241699cdSAl Viro struct page **p; 15618cefc107SDavid Howells unsigned int iter_head, npages; 1562d7760d63SIlya Dryomov ssize_t n; 1563241699cdSAl Viro 1564241699cdSAl Viro if (!sanity(i)) 1565241699cdSAl Viro return -EFAULT; 1566241699cdSAl Viro 15678cefc107SDavid Howells data_start(i, &iter_head, start); 15688cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 15698cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1570241699cdSAl Viro n = npages * PAGE_SIZE - *start; 1571241699cdSAl Viro if (maxsize > n) 1572241699cdSAl Viro maxsize = n; 1573241699cdSAl Viro else 1574241699cdSAl Viro npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1575241699cdSAl Viro p = get_pages_array(npages); 1576241699cdSAl Viro if (!p) 1577241699cdSAl Viro return -ENOMEM; 15788cefc107SDavid Howells n = __pipe_get_pages(i, maxsize, p, iter_head, start); 1579241699cdSAl Viro if (n > 0) 1580241699cdSAl Viro *pages = p; 1581241699cdSAl Viro else 1582241699cdSAl Viro kvfree(p); 1583241699cdSAl Viro return n; 1584241699cdSAl Viro } 1585241699cdSAl Viro 15867ff50620SDavid Howells static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, 15877ff50620SDavid Howells struct page ***pages, size_t maxsize, 15887ff50620SDavid Howells size_t *_start_offset) 15897ff50620SDavid Howells { 15907ff50620SDavid Howells struct page **p; 15917ff50620SDavid Howells unsigned nr, offset; 15927ff50620SDavid Howells pgoff_t index, count; 15936c776766SDavid Howells size_t size = maxsize; 15947ff50620SDavid Howells loff_t pos; 15957ff50620SDavid Howells 15967ff50620SDavid Howells if (!size) 15977ff50620SDavid Howells return 0; 15987ff50620SDavid Howells 15997ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 16007ff50620SDavid Howells index = pos >> PAGE_SHIFT; 16017ff50620SDavid Howells offset = pos & ~PAGE_MASK; 16027ff50620SDavid Howells *_start_offset = offset; 16037ff50620SDavid Howells 16047ff50620SDavid Howells count = 1; 16057ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 16067ff50620SDavid Howells size -= PAGE_SIZE - offset; 16077ff50620SDavid Howells count += size >> PAGE_SHIFT; 16087ff50620SDavid Howells size &= ~PAGE_MASK; 16097ff50620SDavid Howells if (size) 16107ff50620SDavid Howells count++; 16117ff50620SDavid Howells } 16127ff50620SDavid Howells 16137ff50620SDavid Howells p = get_pages_array(count); 16147ff50620SDavid Howells if (!p) 16157ff50620SDavid Howells return -ENOMEM; 16167ff50620SDavid Howells *pages = p; 16177ff50620SDavid Howells 16187ff50620SDavid Howells nr = iter_xarray_populate_pages(p, i->xarray, index, count); 16197ff50620SDavid Howells if (nr == 0) 16207ff50620SDavid Howells return 0; 16217ff50620SDavid Howells 16221c27f1fcSLinus Torvalds return min_t(size_t, nr * PAGE_SIZE - offset, maxsize); 16237ff50620SDavid Howells } 16247ff50620SDavid Howells 1625d879cb83SAl Viro ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 1626d879cb83SAl Viro struct page ***pages, size_t maxsize, 1627d879cb83SAl Viro size_t *start) 1628d879cb83SAl Viro { 1629d879cb83SAl Viro struct page **p; 16303d671ca6SAl Viro int n, res; 1631d879cb83SAl Viro 1632d879cb83SAl Viro if (maxsize > i->count) 1633d879cb83SAl Viro maxsize = i->count; 16343d671ca6SAl Viro if (!maxsize) 16353d671ca6SAl Viro return 0; 16367392ed17SAl Viro if (maxsize > MAX_RW_COUNT) 16377392ed17SAl Viro maxsize = MAX_RW_COUNT; 1638d879cb83SAl Viro 1639fcb14cb1SAl Viro if (likely(user_backed_iter(i))) { 16403337ab08SAndreas Gruenbacher unsigned int gup_flags = 0; 16413d671ca6SAl Viro unsigned long addr; 16429ea9ce04SDavid Howells 16433337ab08SAndreas Gruenbacher if (iov_iter_rw(i) != WRITE) 16443337ab08SAndreas Gruenbacher gup_flags |= FOLL_WRITE; 16453337ab08SAndreas Gruenbacher if (i->nofault) 16463337ab08SAndreas Gruenbacher gup_flags |= FOLL_NOFAULT; 16473337ab08SAndreas Gruenbacher 1648dd45ab9dSAl Viro addr = first_iovec_segment(i, &maxsize); 1649dd45ab9dSAl Viro *start = addr % PAGE_SIZE; 1650dd45ab9dSAl Viro addr &= PAGE_MASK; 165159dbd7d0SAl Viro n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1652d879cb83SAl Viro p = get_pages_array(n); 1653d879cb83SAl Viro if (!p) 1654d879cb83SAl Viro return -ENOMEM; 16553337ab08SAndreas Gruenbacher res = get_user_pages_fast(addr, n, gup_flags, p); 1656814a6674SAndreas Gruenbacher if (unlikely(res <= 0)) { 1657d879cb83SAl Viro kvfree(p); 1658814a6674SAndreas Gruenbacher *pages = NULL; 1659d879cb83SAl Viro return res; 1660d879cb83SAl Viro } 1661d879cb83SAl Viro *pages = p; 166259dbd7d0SAl Viro return min_t(size_t, maxsize, res * PAGE_SIZE - *start); 16633d671ca6SAl Viro } 16643d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 16653d671ca6SAl Viro struct page *page; 16663d671ca6SAl Viro 166759dbd7d0SAl Viro page = first_bvec_segment(i, &maxsize, start); 166859dbd7d0SAl Viro n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 16693d671ca6SAl Viro *pages = p = get_pages_array(n); 1670d879cb83SAl Viro if (!p) 1671d879cb83SAl Viro return -ENOMEM; 1672dda8e5d1SAl Viro for (int k = 0; k < n; k++) 16733d671ca6SAl Viro get_page(*p++ = page++); 167459dbd7d0SAl Viro return min_t(size_t, maxsize, n * PAGE_SIZE - *start); 16753d671ca6SAl Viro } 16763d671ca6SAl Viro if (iov_iter_is_pipe(i)) 16773d671ca6SAl Viro return pipe_get_pages_alloc(i, pages, maxsize, start); 16783d671ca6SAl Viro if (iov_iter_is_xarray(i)) 16793d671ca6SAl Viro return iter_xarray_get_pages_alloc(i, pages, maxsize, start); 1680d879cb83SAl Viro return -EFAULT; 1681d879cb83SAl Viro } 1682d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages_alloc); 1683d879cb83SAl Viro 1684d879cb83SAl Viro size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 1685d879cb83SAl Viro struct iov_iter *i) 1686d879cb83SAl Viro { 1687d879cb83SAl Viro __wsum sum, next; 1688d879cb83SAl Viro sum = *csum; 16899ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1690241699cdSAl Viro WARN_ON(1); 1691241699cdSAl Viro return 0; 1692241699cdSAl Viro } 16937baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, ({ 16947baa5099SAl Viro next = csum_and_copy_from_user(base, addr + off, len); 1695d879cb83SAl Viro sum = csum_block_add(sum, next, off); 16967baa5099SAl Viro next ? 0 : len; 1697d879cb83SAl Viro }), ({ 16987baa5099SAl Viro sum = csum_and_memcpy(addr + off, base, len, sum, off); 1699d879cb83SAl Viro }) 1700d879cb83SAl Viro ) 1701d879cb83SAl Viro *csum = sum; 1702d879cb83SAl Viro return bytes; 1703d879cb83SAl Viro } 1704d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter); 1705d879cb83SAl Viro 170652cbd23aSWillem de Bruijn size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 1707d879cb83SAl Viro struct iov_iter *i) 1708d879cb83SAl Viro { 170952cbd23aSWillem de Bruijn struct csum_state *csstate = _csstate; 1710d879cb83SAl Viro __wsum sum, next; 171178e1f386SAl Viro 171278e1f386SAl Viro if (unlikely(iov_iter_is_discard(i))) { 1713241699cdSAl Viro WARN_ON(1); /* for now */ 1714241699cdSAl Viro return 0; 1715241699cdSAl Viro } 17166852df12SAl Viro 17176852df12SAl Viro sum = csum_shift(csstate->csum, csstate->off); 17186852df12SAl Viro if (unlikely(iov_iter_is_pipe(i))) 17196852df12SAl Viro bytes = csum_and_copy_to_pipe_iter(addr, bytes, i, &sum); 17206852df12SAl Viro else iterate_and_advance(i, bytes, base, len, off, ({ 17217baa5099SAl Viro next = csum_and_copy_to_user(addr + off, base, len); 1722d879cb83SAl Viro sum = csum_block_add(sum, next, off); 17237baa5099SAl Viro next ? 0 : len; 1724d879cb83SAl Viro }), ({ 17257baa5099SAl Viro sum = csum_and_memcpy(base, addr + off, len, sum, off); 1726d879cb83SAl Viro }) 1727d879cb83SAl Viro ) 1728594e450bSAl Viro csstate->csum = csum_shift(sum, csstate->off); 1729594e450bSAl Viro csstate->off += bytes; 1730d879cb83SAl Viro return bytes; 1731d879cb83SAl Viro } 1732d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_to_iter); 1733d879cb83SAl Viro 1734d05f4435SSagi Grimberg size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, 1735d05f4435SSagi Grimberg struct iov_iter *i) 1736d05f4435SSagi Grimberg { 17377999096fSHerbert Xu #ifdef CONFIG_CRYPTO_HASH 1738d05f4435SSagi Grimberg struct ahash_request *hash = hashp; 1739d05f4435SSagi Grimberg struct scatterlist sg; 1740d05f4435SSagi Grimberg size_t copied; 1741d05f4435SSagi Grimberg 1742d05f4435SSagi Grimberg copied = copy_to_iter(addr, bytes, i); 1743d05f4435SSagi Grimberg sg_init_one(&sg, addr, copied); 1744d05f4435SSagi Grimberg ahash_request_set_crypt(hash, &sg, NULL, copied); 1745d05f4435SSagi Grimberg crypto_ahash_update(hash); 1746d05f4435SSagi Grimberg return copied; 174727fad74aSYueHaibing #else 174827fad74aSYueHaibing return 0; 174927fad74aSYueHaibing #endif 1750d05f4435SSagi Grimberg } 1751d05f4435SSagi Grimberg EXPORT_SYMBOL(hash_and_copy_to_iter); 1752d05f4435SSagi Grimberg 175366531c65SAl Viro static int iov_npages(const struct iov_iter *i, int maxpages) 1754d879cb83SAl Viro { 175566531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 175666531c65SAl Viro const struct iovec *p; 1757d879cb83SAl Viro int npages = 0; 1758d879cb83SAl Viro 175966531c65SAl Viro for (p = i->iov; size; skip = 0, p++) { 176066531c65SAl Viro unsigned offs = offset_in_page(p->iov_base + skip); 176166531c65SAl Viro size_t len = min(p->iov_len - skip, size); 1762d879cb83SAl Viro 176366531c65SAl Viro if (len) { 176466531c65SAl Viro size -= len; 176566531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 176666531c65SAl Viro if (unlikely(npages > maxpages)) 176766531c65SAl Viro return maxpages; 176866531c65SAl Viro } 176966531c65SAl Viro } 177066531c65SAl Viro return npages; 177166531c65SAl Viro } 177266531c65SAl Viro 177366531c65SAl Viro static int bvec_npages(const struct iov_iter *i, int maxpages) 177466531c65SAl Viro { 177566531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 177666531c65SAl Viro const struct bio_vec *p; 177766531c65SAl Viro int npages = 0; 177866531c65SAl Viro 177966531c65SAl Viro for (p = i->bvec; size; skip = 0, p++) { 178066531c65SAl Viro unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; 178166531c65SAl Viro size_t len = min(p->bv_len - skip, size); 178266531c65SAl Viro 178366531c65SAl Viro size -= len; 178466531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 178566531c65SAl Viro if (unlikely(npages > maxpages)) 178666531c65SAl Viro return maxpages; 178766531c65SAl Viro } 178866531c65SAl Viro return npages; 178966531c65SAl Viro } 179066531c65SAl Viro 179166531c65SAl Viro int iov_iter_npages(const struct iov_iter *i, int maxpages) 179266531c65SAl Viro { 179366531c65SAl Viro if (unlikely(!i->count)) 179466531c65SAl Viro return 0; 1795fcb14cb1SAl Viro if (likely(iter_is_ubuf(i))) { 1796fcb14cb1SAl Viro unsigned offs = offset_in_page(i->ubuf + i->iov_offset); 1797fcb14cb1SAl Viro int npages = DIV_ROUND_UP(offs + i->count, PAGE_SIZE); 1798fcb14cb1SAl Viro return min(npages, maxpages); 1799fcb14cb1SAl Viro } 180066531c65SAl Viro /* iovec and kvec have identical layouts */ 180166531c65SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 180266531c65SAl Viro return iov_npages(i, maxpages); 180366531c65SAl Viro if (iov_iter_is_bvec(i)) 180466531c65SAl Viro return bvec_npages(i, maxpages); 180566531c65SAl Viro if (iov_iter_is_pipe(i)) { 18068cefc107SDavid Howells unsigned int iter_head; 180766531c65SAl Viro int npages; 1808241699cdSAl Viro size_t off; 1809241699cdSAl Viro 1810241699cdSAl Viro if (!sanity(i)) 1811241699cdSAl Viro return 0; 1812241699cdSAl Viro 18138cefc107SDavid Howells data_start(i, &iter_head, &off); 1814241699cdSAl Viro /* some of this one + all after this one */ 181566531c65SAl Viro npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 181666531c65SAl Viro return min(npages, maxpages); 181766531c65SAl Viro } 181866531c65SAl Viro if (iov_iter_is_xarray(i)) { 1819e4f8df86SAl Viro unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; 1820e4f8df86SAl Viro int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); 182166531c65SAl Viro return min(npages, maxpages); 182266531c65SAl Viro } 182366531c65SAl Viro return 0; 1824d879cb83SAl Viro } 1825d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_npages); 1826d879cb83SAl Viro 1827d879cb83SAl Viro const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) 1828d879cb83SAl Viro { 1829d879cb83SAl Viro *new = *old; 183000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(new))) { 1831241699cdSAl Viro WARN_ON(1); 1832241699cdSAl Viro return NULL; 1833241699cdSAl Viro } 183400e23707SDavid Howells if (iov_iter_is_bvec(new)) 1835d879cb83SAl Viro return new->bvec = kmemdup(new->bvec, 1836d879cb83SAl Viro new->nr_segs * sizeof(struct bio_vec), 1837d879cb83SAl Viro flags); 1838fcb14cb1SAl Viro else if (iov_iter_is_kvec(new) || iter_is_iovec(new)) 1839d879cb83SAl Viro /* iovec and kvec have identical layout */ 1840d879cb83SAl Viro return new->iov = kmemdup(new->iov, 1841d879cb83SAl Viro new->nr_segs * sizeof(struct iovec), 1842d879cb83SAl Viro flags); 1843fcb14cb1SAl Viro return NULL; 1844d879cb83SAl Viro } 1845d879cb83SAl Viro EXPORT_SYMBOL(dup_iter); 1846bc917be8SAl Viro 1847bfdc5970SChristoph Hellwig static int copy_compat_iovec_from_user(struct iovec *iov, 1848bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1849bfdc5970SChristoph Hellwig { 1850bfdc5970SChristoph Hellwig const struct compat_iovec __user *uiov = 1851bfdc5970SChristoph Hellwig (const struct compat_iovec __user *)uvec; 1852bfdc5970SChristoph Hellwig int ret = -EFAULT, i; 1853bfdc5970SChristoph Hellwig 1854a959a978SChristoph Hellwig if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) 1855bfdc5970SChristoph Hellwig return -EFAULT; 1856bfdc5970SChristoph Hellwig 1857bfdc5970SChristoph Hellwig for (i = 0; i < nr_segs; i++) { 1858bfdc5970SChristoph Hellwig compat_uptr_t buf; 1859bfdc5970SChristoph Hellwig compat_ssize_t len; 1860bfdc5970SChristoph Hellwig 1861bfdc5970SChristoph Hellwig unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); 1862bfdc5970SChristoph Hellwig unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); 1863bfdc5970SChristoph Hellwig 1864bfdc5970SChristoph Hellwig /* check for compat_size_t not fitting in compat_ssize_t .. */ 1865bfdc5970SChristoph Hellwig if (len < 0) { 1866bfdc5970SChristoph Hellwig ret = -EINVAL; 1867bfdc5970SChristoph Hellwig goto uaccess_end; 1868bfdc5970SChristoph Hellwig } 1869bfdc5970SChristoph Hellwig iov[i].iov_base = compat_ptr(buf); 1870bfdc5970SChristoph Hellwig iov[i].iov_len = len; 1871bfdc5970SChristoph Hellwig } 1872bfdc5970SChristoph Hellwig 1873bfdc5970SChristoph Hellwig ret = 0; 1874bfdc5970SChristoph Hellwig uaccess_end: 1875bfdc5970SChristoph Hellwig user_access_end(); 1876bfdc5970SChristoph Hellwig return ret; 1877bfdc5970SChristoph Hellwig } 1878bfdc5970SChristoph Hellwig 1879bfdc5970SChristoph Hellwig static int copy_iovec_from_user(struct iovec *iov, 1880bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1881fb041b59SDavid Laight { 1882fb041b59SDavid Laight unsigned long seg; 1883bfdc5970SChristoph Hellwig 1884bfdc5970SChristoph Hellwig if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) 1885bfdc5970SChristoph Hellwig return -EFAULT; 1886bfdc5970SChristoph Hellwig for (seg = 0; seg < nr_segs; seg++) { 1887bfdc5970SChristoph Hellwig if ((ssize_t)iov[seg].iov_len < 0) 1888bfdc5970SChristoph Hellwig return -EINVAL; 1889bfdc5970SChristoph Hellwig } 1890bfdc5970SChristoph Hellwig 1891bfdc5970SChristoph Hellwig return 0; 1892bfdc5970SChristoph Hellwig } 1893bfdc5970SChristoph Hellwig 1894bfdc5970SChristoph Hellwig struct iovec *iovec_from_user(const struct iovec __user *uvec, 1895bfdc5970SChristoph Hellwig unsigned long nr_segs, unsigned long fast_segs, 1896bfdc5970SChristoph Hellwig struct iovec *fast_iov, bool compat) 1897bfdc5970SChristoph Hellwig { 1898bfdc5970SChristoph Hellwig struct iovec *iov = fast_iov; 1899bfdc5970SChristoph Hellwig int ret; 1900fb041b59SDavid Laight 1901fb041b59SDavid Laight /* 1902bfdc5970SChristoph Hellwig * SuS says "The readv() function *may* fail if the iovcnt argument was 1903bfdc5970SChristoph Hellwig * less than or equal to 0, or greater than {IOV_MAX}. Linux has 1904fb041b59SDavid Laight * traditionally returned zero for zero segments, so... 1905fb041b59SDavid Laight */ 1906bfdc5970SChristoph Hellwig if (nr_segs == 0) 1907bfdc5970SChristoph Hellwig return iov; 1908bfdc5970SChristoph Hellwig if (nr_segs > UIO_MAXIOV) 1909bfdc5970SChristoph Hellwig return ERR_PTR(-EINVAL); 1910fb041b59SDavid Laight if (nr_segs > fast_segs) { 1911fb041b59SDavid Laight iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); 1912bfdc5970SChristoph Hellwig if (!iov) 1913bfdc5970SChristoph Hellwig return ERR_PTR(-ENOMEM); 1914fb041b59SDavid Laight } 1915bfdc5970SChristoph Hellwig 1916bfdc5970SChristoph Hellwig if (compat) 1917bfdc5970SChristoph Hellwig ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); 1918bfdc5970SChristoph Hellwig else 1919bfdc5970SChristoph Hellwig ret = copy_iovec_from_user(iov, uvec, nr_segs); 1920bfdc5970SChristoph Hellwig if (ret) { 1921bfdc5970SChristoph Hellwig if (iov != fast_iov) 1922bfdc5970SChristoph Hellwig kfree(iov); 1923bfdc5970SChristoph Hellwig return ERR_PTR(ret); 1924fb041b59SDavid Laight } 1925bfdc5970SChristoph Hellwig 1926bfdc5970SChristoph Hellwig return iov; 1927bfdc5970SChristoph Hellwig } 1928bfdc5970SChristoph Hellwig 1929bfdc5970SChristoph Hellwig ssize_t __import_iovec(int type, const struct iovec __user *uvec, 1930bfdc5970SChristoph Hellwig unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, 1931bfdc5970SChristoph Hellwig struct iov_iter *i, bool compat) 1932bfdc5970SChristoph Hellwig { 1933bfdc5970SChristoph Hellwig ssize_t total_len = 0; 1934bfdc5970SChristoph Hellwig unsigned long seg; 1935bfdc5970SChristoph Hellwig struct iovec *iov; 1936bfdc5970SChristoph Hellwig 1937bfdc5970SChristoph Hellwig iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); 1938bfdc5970SChristoph Hellwig if (IS_ERR(iov)) { 1939bfdc5970SChristoph Hellwig *iovp = NULL; 1940bfdc5970SChristoph Hellwig return PTR_ERR(iov); 1941fb041b59SDavid Laight } 1942fb041b59SDavid Laight 1943fb041b59SDavid Laight /* 1944bfdc5970SChristoph Hellwig * According to the Single Unix Specification we should return EINVAL if 1945bfdc5970SChristoph Hellwig * an element length is < 0 when cast to ssize_t or if the total length 1946bfdc5970SChristoph Hellwig * would overflow the ssize_t return value of the system call. 1947fb041b59SDavid Laight * 1948fb041b59SDavid Laight * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the 1949fb041b59SDavid Laight * overflow case. 1950fb041b59SDavid Laight */ 1951fb041b59SDavid Laight for (seg = 0; seg < nr_segs; seg++) { 1952fb041b59SDavid Laight ssize_t len = (ssize_t)iov[seg].iov_len; 1953fb041b59SDavid Laight 1954bfdc5970SChristoph Hellwig if (!access_ok(iov[seg].iov_base, len)) { 1955bfdc5970SChristoph Hellwig if (iov != *iovp) 1956bfdc5970SChristoph Hellwig kfree(iov); 1957bfdc5970SChristoph Hellwig *iovp = NULL; 1958bfdc5970SChristoph Hellwig return -EFAULT; 1959fb041b59SDavid Laight } 1960bfdc5970SChristoph Hellwig 1961bfdc5970SChristoph Hellwig if (len > MAX_RW_COUNT - total_len) { 1962bfdc5970SChristoph Hellwig len = MAX_RW_COUNT - total_len; 1963fb041b59SDavid Laight iov[seg].iov_len = len; 1964fb041b59SDavid Laight } 1965bfdc5970SChristoph Hellwig total_len += len; 1966fb041b59SDavid Laight } 1967bfdc5970SChristoph Hellwig 1968bfdc5970SChristoph Hellwig iov_iter_init(i, type, iov, nr_segs, total_len); 1969bfdc5970SChristoph Hellwig if (iov == *iovp) 1970bfdc5970SChristoph Hellwig *iovp = NULL; 1971bfdc5970SChristoph Hellwig else 1972bfdc5970SChristoph Hellwig *iovp = iov; 1973bfdc5970SChristoph Hellwig return total_len; 1974fb041b59SDavid Laight } 1975fb041b59SDavid Laight 1976ffecee4fSVegard Nossum /** 1977ffecee4fSVegard Nossum * import_iovec() - Copy an array of &struct iovec from userspace 1978ffecee4fSVegard Nossum * into the kernel, check that it is valid, and initialize a new 1979ffecee4fSVegard Nossum * &struct iov_iter iterator to access it. 1980ffecee4fSVegard Nossum * 1981ffecee4fSVegard Nossum * @type: One of %READ or %WRITE. 1982bfdc5970SChristoph Hellwig * @uvec: Pointer to the userspace array. 1983ffecee4fSVegard Nossum * @nr_segs: Number of elements in userspace array. 1984ffecee4fSVegard Nossum * @fast_segs: Number of elements in @iov. 1985bfdc5970SChristoph Hellwig * @iovp: (input and output parameter) Pointer to pointer to (usually small 1986ffecee4fSVegard Nossum * on-stack) kernel array. 1987ffecee4fSVegard Nossum * @i: Pointer to iterator that will be initialized on success. 1988ffecee4fSVegard Nossum * 1989ffecee4fSVegard Nossum * If the array pointed to by *@iov is large enough to hold all @nr_segs, 1990ffecee4fSVegard Nossum * then this function places %NULL in *@iov on return. Otherwise, a new 1991ffecee4fSVegard Nossum * array will be allocated and the result placed in *@iov. This means that 1992ffecee4fSVegard Nossum * the caller may call kfree() on *@iov regardless of whether the small 1993ffecee4fSVegard Nossum * on-stack array was used or not (and regardless of whether this function 1994ffecee4fSVegard Nossum * returns an error or not). 1995ffecee4fSVegard Nossum * 199687e5e6daSJens Axboe * Return: Negative error code on error, bytes imported on success 1997ffecee4fSVegard Nossum */ 1998bfdc5970SChristoph Hellwig ssize_t import_iovec(int type, const struct iovec __user *uvec, 1999bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 2000bfdc5970SChristoph Hellwig struct iovec **iovp, struct iov_iter *i) 2001bc917be8SAl Viro { 200289cd35c5SChristoph Hellwig return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, 200389cd35c5SChristoph Hellwig in_compat_syscall()); 2004bc917be8SAl Viro } 2005bc917be8SAl Viro EXPORT_SYMBOL(import_iovec); 2006bc917be8SAl Viro 2007bc917be8SAl Viro int import_single_range(int rw, void __user *buf, size_t len, 2008bc917be8SAl Viro struct iovec *iov, struct iov_iter *i) 2009bc917be8SAl Viro { 2010bc917be8SAl Viro if (len > MAX_RW_COUNT) 2011bc917be8SAl Viro len = MAX_RW_COUNT; 201296d4f267SLinus Torvalds if (unlikely(!access_ok(buf, len))) 2013bc917be8SAl Viro return -EFAULT; 2014bc917be8SAl Viro 2015bc917be8SAl Viro iov->iov_base = buf; 2016bc917be8SAl Viro iov->iov_len = len; 2017bc917be8SAl Viro iov_iter_init(i, rw, iov, 1, len); 2018bc917be8SAl Viro return 0; 2019bc917be8SAl Viro } 2020e1267585SAl Viro EXPORT_SYMBOL(import_single_range); 20218fb0f47aSJens Axboe 20228fb0f47aSJens Axboe /** 20238fb0f47aSJens Axboe * iov_iter_restore() - Restore a &struct iov_iter to the same state as when 20248fb0f47aSJens Axboe * iov_iter_save_state() was called. 20258fb0f47aSJens Axboe * 20268fb0f47aSJens Axboe * @i: &struct iov_iter to restore 20278fb0f47aSJens Axboe * @state: state to restore from 20288fb0f47aSJens Axboe * 20298fb0f47aSJens Axboe * Used after iov_iter_save_state() to bring restore @i, if operations may 20308fb0f47aSJens Axboe * have advanced it. 20318fb0f47aSJens Axboe * 20328fb0f47aSJens Axboe * Note: only works on ITER_IOVEC, ITER_BVEC, and ITER_KVEC 20338fb0f47aSJens Axboe */ 20348fb0f47aSJens Axboe void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state) 20358fb0f47aSJens Axboe { 20368fb0f47aSJens Axboe if (WARN_ON_ONCE(!iov_iter_is_bvec(i) && !iter_is_iovec(i)) && 2037fcb14cb1SAl Viro !iov_iter_is_kvec(i) && !iter_is_ubuf(i)) 20388fb0f47aSJens Axboe return; 20398fb0f47aSJens Axboe i->iov_offset = state->iov_offset; 20408fb0f47aSJens Axboe i->count = state->count; 2041fcb14cb1SAl Viro if (iter_is_ubuf(i)) 2042fcb14cb1SAl Viro return; 20438fb0f47aSJens Axboe /* 20448fb0f47aSJens Axboe * For the *vec iters, nr_segs + iov is constant - if we increment 20458fb0f47aSJens Axboe * the vec, then we also decrement the nr_segs count. Hence we don't 20468fb0f47aSJens Axboe * need to track both of these, just one is enough and we can deduct 20478fb0f47aSJens Axboe * the other from that. ITER_KVEC and ITER_IOVEC are the same struct 20488fb0f47aSJens Axboe * size, so we can just increment the iov pointer as they are unionzed. 20498fb0f47aSJens Axboe * ITER_BVEC _may_ be the same size on some archs, but on others it is 20508fb0f47aSJens Axboe * not. Be safe and handle it separately. 20518fb0f47aSJens Axboe */ 20528fb0f47aSJens Axboe BUILD_BUG_ON(sizeof(struct iovec) != sizeof(struct kvec)); 20538fb0f47aSJens Axboe if (iov_iter_is_bvec(i)) 20548fb0f47aSJens Axboe i->bvec -= state->nr_segs - i->nr_segs; 20558fb0f47aSJens Axboe else 20568fb0f47aSJens Axboe i->iov -= state->nr_segs - i->nr_segs; 20578fb0f47aSJens Axboe i->nr_segs = state->nr_segs; 20588fb0f47aSJens Axboe } 2059