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 195c67aa90SAl Viro /* covers iovec and kvec alike */ 20d879cb83SAl Viro #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ 21d879cb83SAl Viro size_t left; \ 22d879cb83SAl Viro size_t wanted = n; \ 237a1bcb5dSAl Viro do { \ 24d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len - skip); \ 25d879cb83SAl Viro if (likely(__v.iov_len)) { \ 26d879cb83SAl Viro __v.iov_base = __p->iov_base + skip; \ 27d879cb83SAl Viro left = (STEP); \ 28d879cb83SAl Viro __v.iov_len -= left; \ 29d879cb83SAl Viro skip += __v.iov_len; \ 30d879cb83SAl Viro n -= __v.iov_len; \ 317a1bcb5dSAl Viro if (skip < __p->iov_len) \ 327a1bcb5dSAl Viro break; \ 33d879cb83SAl Viro } \ 34d879cb83SAl Viro __p++; \ 357a1bcb5dSAl Viro skip = 0; \ 367a1bcb5dSAl Viro } while (n); \ 37d879cb83SAl Viro n = wanted - n; \ 38d879cb83SAl Viro } 39d879cb83SAl Viro 407491a2bfSAl Viro #define iterate_bvec(i, n, __v, p, skip, STEP) { \ 417491a2bfSAl Viro size_t wanted = n; \ 427491a2bfSAl Viro while (n) { \ 437491a2bfSAl Viro unsigned offset = p->bv_offset + skip; \ 44*1b4fb5ffSAl Viro unsigned left; \ 457491a2bfSAl Viro __v.bv_offset = offset % PAGE_SIZE; \ 467491a2bfSAl Viro __v.bv_page = p->bv_page + offset / PAGE_SIZE; \ 477491a2bfSAl Viro __v.bv_len = min(min(n, p->bv_len - skip), \ 487491a2bfSAl Viro (size_t)(PAGE_SIZE - offset % PAGE_SIZE)); \ 49*1b4fb5ffSAl Viro left = (STEP); \ 50*1b4fb5ffSAl Viro __v.bv_len -= left; \ 517491a2bfSAl Viro skip += __v.bv_len; \ 527491a2bfSAl Viro if (skip == p->bv_len) { \ 537491a2bfSAl Viro skip = 0; \ 547491a2bfSAl Viro p++; \ 55d879cb83SAl Viro } \ 567491a2bfSAl Viro n -= __v.bv_len; \ 57*1b4fb5ffSAl Viro if (left) \ 58*1b4fb5ffSAl Viro break; \ 597491a2bfSAl Viro } \ 607491a2bfSAl Viro n = wanted - n; \ 61d879cb83SAl Viro } 62d879cb83SAl Viro 637ff50620SDavid Howells #define iterate_xarray(i, n, __v, skip, STEP) { \ 64*1b4fb5ffSAl Viro __label__ __out; \ 657ff50620SDavid Howells struct page *head = NULL; \ 667ff50620SDavid Howells size_t wanted = n, seg, offset; \ 677ff50620SDavid Howells loff_t start = i->xarray_start + skip; \ 687ff50620SDavid Howells pgoff_t index = start >> PAGE_SHIFT; \ 697ff50620SDavid Howells int j; \ 707ff50620SDavid Howells \ 717ff50620SDavid Howells XA_STATE(xas, i->xarray, index); \ 727ff50620SDavid Howells \ 737ff50620SDavid Howells rcu_read_lock(); \ 747ff50620SDavid Howells xas_for_each(&xas, head, ULONG_MAX) { \ 75*1b4fb5ffSAl Viro unsigned left; \ 767ff50620SDavid Howells if (xas_retry(&xas, head)) \ 777ff50620SDavid Howells continue; \ 787ff50620SDavid Howells if (WARN_ON(xa_is_value(head))) \ 797ff50620SDavid Howells break; \ 807ff50620SDavid Howells if (WARN_ON(PageHuge(head))) \ 817ff50620SDavid Howells break; \ 827ff50620SDavid Howells for (j = (head->index < index) ? index - head->index : 0; \ 837ff50620SDavid Howells j < thp_nr_pages(head); j++) { \ 847ff50620SDavid Howells __v.bv_page = head + j; \ 857ff50620SDavid Howells offset = (i->xarray_start + skip) & ~PAGE_MASK; \ 867ff50620SDavid Howells seg = PAGE_SIZE - offset; \ 877ff50620SDavid Howells __v.bv_offset = offset; \ 887ff50620SDavid Howells __v.bv_len = min(n, seg); \ 89*1b4fb5ffSAl Viro left = (STEP); \ 90*1b4fb5ffSAl Viro __v.bv_len -= left; \ 917ff50620SDavid Howells n -= __v.bv_len; \ 927ff50620SDavid Howells skip += __v.bv_len; \ 93*1b4fb5ffSAl Viro if (left || n == 0) \ 94*1b4fb5ffSAl Viro goto __out; \ 957ff50620SDavid Howells } \ 967ff50620SDavid Howells } \ 97*1b4fb5ffSAl Viro __out: \ 987ff50620SDavid Howells rcu_read_unlock(); \ 997ff50620SDavid Howells n = wanted - n; \ 1007ff50620SDavid Howells } 1017ff50620SDavid Howells 102*1b4fb5ffSAl Viro #define __iterate_and_advance(i, n, v, I, B, K, X) { \ 103dd254f5aSAl Viro if (unlikely(i->count < n)) \ 104dd254f5aSAl Viro n = i->count; \ 105f5da8354SAl Viro if (likely(n)) { \ 106d879cb83SAl Viro size_t skip = i->iov_offset; \ 10728f38db7SAl Viro if (likely(iter_is_iovec(i))) { \ 1085c67aa90SAl Viro const struct iovec *iov = i->iov; \ 109d879cb83SAl Viro struct iovec v; \ 110d879cb83SAl Viro iterate_iovec(i, n, v, iov, skip, (I)) \ 111d879cb83SAl Viro i->nr_segs -= iov - i->iov; \ 112d879cb83SAl Viro i->iov = iov; \ 11328f38db7SAl Viro } else if (iov_iter_is_bvec(i)) { \ 11428f38db7SAl Viro const struct bio_vec *bvec = i->bvec; \ 11528f38db7SAl Viro struct bio_vec v; \ 1167491a2bfSAl Viro iterate_bvec(i, n, v, bvec, skip, (B)) \ 1177491a2bfSAl Viro i->nr_segs -= bvec - i->bvec; \ 1187491a2bfSAl Viro i->bvec = bvec; \ 11928f38db7SAl Viro } else if (iov_iter_is_kvec(i)) { \ 1205c67aa90SAl Viro const struct kvec *kvec = i->kvec; \ 12128f38db7SAl Viro struct kvec v; \ 122*1b4fb5ffSAl Viro iterate_iovec(i, n, v, kvec, skip, (K)) \ 12328f38db7SAl Viro i->nr_segs -= kvec - i->kvec; \ 12428f38db7SAl Viro i->kvec = kvec; \ 12528f38db7SAl Viro } else if (iov_iter_is_xarray(i)) { \ 12628f38db7SAl Viro struct bio_vec v; \ 12728f38db7SAl Viro iterate_xarray(i, n, v, skip, (X)) \ 128d879cb83SAl Viro } \ 129d879cb83SAl Viro i->count -= n; \ 130d879cb83SAl Viro i->iov_offset = skip; \ 131dd254f5aSAl Viro } \ 132d879cb83SAl Viro } 133*1b4fb5ffSAl Viro #define iterate_and_advance(i, n, v, I, B, K, X) \ 134*1b4fb5ffSAl Viro __iterate_and_advance(i, n, v, I, ((void)(B),0), \ 135*1b4fb5ffSAl Viro ((void)(K),0), ((void)(X),0)) 136d879cb83SAl Viro 13709fc68dcSAl Viro static int copyout(void __user *to, const void *from, size_t n) 13809fc68dcSAl Viro { 1394d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1404d0e9df5SAlbert van der Linde return n; 14196d4f267SLinus Torvalds if (access_ok(to, n)) { 142d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 14309fc68dcSAl Viro n = raw_copy_to_user(to, from, n); 14409fc68dcSAl Viro } 14509fc68dcSAl Viro return n; 14609fc68dcSAl Viro } 14709fc68dcSAl Viro 14809fc68dcSAl Viro static int copyin(void *to, const void __user *from, size_t n) 14909fc68dcSAl Viro { 1504d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1514d0e9df5SAlbert van der Linde return n; 15296d4f267SLinus Torvalds if (access_ok(from, n)) { 153d0ef4c36SMarco Elver instrument_copy_from_user(to, from, n); 15409fc68dcSAl Viro n = raw_copy_from_user(to, from, n); 15509fc68dcSAl Viro } 15609fc68dcSAl Viro return n; 15709fc68dcSAl Viro } 15809fc68dcSAl Viro 159d879cb83SAl Viro static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, 160d879cb83SAl Viro struct iov_iter *i) 161d879cb83SAl Viro { 162d879cb83SAl Viro size_t skip, copy, left, wanted; 163d879cb83SAl Viro const struct iovec *iov; 164d879cb83SAl Viro char __user *buf; 165d879cb83SAl Viro void *kaddr, *from; 166d879cb83SAl Viro 167d879cb83SAl Viro if (unlikely(bytes > i->count)) 168d879cb83SAl Viro bytes = i->count; 169d879cb83SAl Viro 170d879cb83SAl Viro if (unlikely(!bytes)) 171d879cb83SAl Viro return 0; 172d879cb83SAl Viro 17309fc68dcSAl Viro might_fault(); 174d879cb83SAl Viro wanted = bytes; 175d879cb83SAl Viro iov = i->iov; 176d879cb83SAl Viro skip = i->iov_offset; 177d879cb83SAl Viro buf = iov->iov_base + skip; 178d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 179d879cb83SAl Viro 1803fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { 181d879cb83SAl Viro kaddr = kmap_atomic(page); 182d879cb83SAl Viro from = kaddr + offset; 183d879cb83SAl Viro 184d879cb83SAl Viro /* first chunk, usually the only one */ 18509fc68dcSAl Viro left = copyout(buf, from, copy); 186d879cb83SAl Viro copy -= left; 187d879cb83SAl Viro skip += copy; 188d879cb83SAl Viro from += copy; 189d879cb83SAl Viro bytes -= copy; 190d879cb83SAl Viro 191d879cb83SAl Viro while (unlikely(!left && bytes)) { 192d879cb83SAl Viro iov++; 193d879cb83SAl Viro buf = iov->iov_base; 194d879cb83SAl Viro copy = min(bytes, iov->iov_len); 19509fc68dcSAl Viro left = copyout(buf, from, copy); 196d879cb83SAl Viro copy -= left; 197d879cb83SAl Viro skip = copy; 198d879cb83SAl Viro from += copy; 199d879cb83SAl Viro bytes -= copy; 200d879cb83SAl Viro } 201d879cb83SAl Viro if (likely(!bytes)) { 202d879cb83SAl Viro kunmap_atomic(kaddr); 203d879cb83SAl Viro goto done; 204d879cb83SAl Viro } 205d879cb83SAl Viro offset = from - kaddr; 206d879cb83SAl Viro buf += copy; 207d879cb83SAl Viro kunmap_atomic(kaddr); 208d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 209d879cb83SAl Viro } 210d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 2113fa6c507SMikulas Patocka 212d879cb83SAl Viro kaddr = kmap(page); 213d879cb83SAl Viro from = kaddr + offset; 21409fc68dcSAl Viro left = copyout(buf, from, copy); 215d879cb83SAl Viro copy -= left; 216d879cb83SAl Viro skip += copy; 217d879cb83SAl Viro from += copy; 218d879cb83SAl Viro bytes -= copy; 219d879cb83SAl Viro while (unlikely(!left && bytes)) { 220d879cb83SAl Viro iov++; 221d879cb83SAl Viro buf = iov->iov_base; 222d879cb83SAl Viro copy = min(bytes, iov->iov_len); 22309fc68dcSAl Viro left = copyout(buf, from, copy); 224d879cb83SAl Viro copy -= left; 225d879cb83SAl Viro skip = copy; 226d879cb83SAl Viro from += copy; 227d879cb83SAl Viro bytes -= copy; 228d879cb83SAl Viro } 229d879cb83SAl Viro kunmap(page); 2303fa6c507SMikulas Patocka 231d879cb83SAl Viro done: 232d879cb83SAl Viro if (skip == iov->iov_len) { 233d879cb83SAl Viro iov++; 234d879cb83SAl Viro skip = 0; 235d879cb83SAl Viro } 236d879cb83SAl Viro i->count -= wanted - bytes; 237d879cb83SAl Viro i->nr_segs -= iov - i->iov; 238d879cb83SAl Viro i->iov = iov; 239d879cb83SAl Viro i->iov_offset = skip; 240d879cb83SAl Viro return wanted - bytes; 241d879cb83SAl Viro } 242d879cb83SAl Viro 243d879cb83SAl Viro static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, 244d879cb83SAl Viro struct iov_iter *i) 245d879cb83SAl Viro { 246d879cb83SAl Viro size_t skip, copy, left, wanted; 247d879cb83SAl Viro const struct iovec *iov; 248d879cb83SAl Viro char __user *buf; 249d879cb83SAl Viro void *kaddr, *to; 250d879cb83SAl Viro 251d879cb83SAl Viro if (unlikely(bytes > i->count)) 252d879cb83SAl Viro bytes = i->count; 253d879cb83SAl Viro 254d879cb83SAl Viro if (unlikely(!bytes)) 255d879cb83SAl Viro return 0; 256d879cb83SAl Viro 25709fc68dcSAl Viro might_fault(); 258d879cb83SAl Viro wanted = bytes; 259d879cb83SAl Viro iov = i->iov; 260d879cb83SAl Viro skip = i->iov_offset; 261d879cb83SAl Viro buf = iov->iov_base + skip; 262d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 263d879cb83SAl Viro 2643fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { 265d879cb83SAl Viro kaddr = kmap_atomic(page); 266d879cb83SAl Viro to = kaddr + offset; 267d879cb83SAl Viro 268d879cb83SAl Viro /* first chunk, usually the only one */ 26909fc68dcSAl Viro left = copyin(to, buf, copy); 270d879cb83SAl Viro copy -= left; 271d879cb83SAl Viro skip += copy; 272d879cb83SAl Viro to += copy; 273d879cb83SAl Viro bytes -= copy; 274d879cb83SAl Viro 275d879cb83SAl Viro while (unlikely(!left && bytes)) { 276d879cb83SAl Viro iov++; 277d879cb83SAl Viro buf = iov->iov_base; 278d879cb83SAl Viro copy = min(bytes, iov->iov_len); 27909fc68dcSAl Viro left = copyin(to, buf, copy); 280d879cb83SAl Viro copy -= left; 281d879cb83SAl Viro skip = copy; 282d879cb83SAl Viro to += copy; 283d879cb83SAl Viro bytes -= copy; 284d879cb83SAl Viro } 285d879cb83SAl Viro if (likely(!bytes)) { 286d879cb83SAl Viro kunmap_atomic(kaddr); 287d879cb83SAl Viro goto done; 288d879cb83SAl Viro } 289d879cb83SAl Viro offset = to - kaddr; 290d879cb83SAl Viro buf += copy; 291d879cb83SAl Viro kunmap_atomic(kaddr); 292d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 293d879cb83SAl Viro } 294d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 2953fa6c507SMikulas Patocka 296d879cb83SAl Viro kaddr = kmap(page); 297d879cb83SAl Viro to = kaddr + offset; 29809fc68dcSAl Viro left = copyin(to, buf, copy); 299d879cb83SAl Viro copy -= left; 300d879cb83SAl Viro skip += copy; 301d879cb83SAl Viro to += copy; 302d879cb83SAl Viro bytes -= copy; 303d879cb83SAl Viro while (unlikely(!left && bytes)) { 304d879cb83SAl Viro iov++; 305d879cb83SAl Viro buf = iov->iov_base; 306d879cb83SAl Viro copy = min(bytes, iov->iov_len); 30709fc68dcSAl Viro left = copyin(to, buf, copy); 308d879cb83SAl Viro copy -= left; 309d879cb83SAl Viro skip = copy; 310d879cb83SAl Viro to += copy; 311d879cb83SAl Viro bytes -= copy; 312d879cb83SAl Viro } 313d879cb83SAl Viro kunmap(page); 3143fa6c507SMikulas Patocka 315d879cb83SAl Viro done: 316d879cb83SAl Viro if (skip == iov->iov_len) { 317d879cb83SAl Viro iov++; 318d879cb83SAl Viro skip = 0; 319d879cb83SAl Viro } 320d879cb83SAl Viro i->count -= wanted - bytes; 321d879cb83SAl Viro i->nr_segs -= iov - i->iov; 322d879cb83SAl Viro i->iov = iov; 323d879cb83SAl Viro i->iov_offset = skip; 324d879cb83SAl Viro return wanted - bytes; 325d879cb83SAl Viro } 326d879cb83SAl Viro 327241699cdSAl Viro #ifdef PIPE_PARANOIA 328241699cdSAl Viro static bool sanity(const struct iov_iter *i) 329241699cdSAl Viro { 330241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 3318cefc107SDavid Howells unsigned int p_head = pipe->head; 3328cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3338cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3348cefc107SDavid Howells unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); 3358cefc107SDavid Howells unsigned int i_head = i->head; 3368cefc107SDavid Howells unsigned int idx; 3378cefc107SDavid Howells 338241699cdSAl Viro if (i->iov_offset) { 339241699cdSAl Viro struct pipe_buffer *p; 3408cefc107SDavid Howells if (unlikely(p_occupancy == 0)) 341241699cdSAl Viro goto Bad; // pipe must be non-empty 3428cefc107SDavid Howells if (unlikely(i_head != p_head - 1)) 343241699cdSAl Viro goto Bad; // must be at the last buffer... 344241699cdSAl Viro 3458cefc107SDavid Howells p = &pipe->bufs[i_head & p_mask]; 346241699cdSAl Viro if (unlikely(p->offset + p->len != i->iov_offset)) 347241699cdSAl Viro goto Bad; // ... at the end of segment 348241699cdSAl Viro } else { 3498cefc107SDavid Howells if (i_head != p_head) 350241699cdSAl Viro goto Bad; // must be right after the last buffer 351241699cdSAl Viro } 352241699cdSAl Viro return true; 353241699cdSAl Viro Bad: 3548cefc107SDavid Howells printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); 3558cefc107SDavid Howells printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", 3568cefc107SDavid Howells p_head, p_tail, pipe->ring_size); 3578cefc107SDavid Howells for (idx = 0; idx < pipe->ring_size; idx++) 358241699cdSAl Viro printk(KERN_ERR "[%p %p %d %d]\n", 359241699cdSAl Viro pipe->bufs[idx].ops, 360241699cdSAl Viro pipe->bufs[idx].page, 361241699cdSAl Viro pipe->bufs[idx].offset, 362241699cdSAl Viro pipe->bufs[idx].len); 363241699cdSAl Viro WARN_ON(1); 364241699cdSAl Viro return false; 365241699cdSAl Viro } 366241699cdSAl Viro #else 367241699cdSAl Viro #define sanity(i) true 368241699cdSAl Viro #endif 369241699cdSAl Viro 370241699cdSAl Viro static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, 371241699cdSAl Viro struct iov_iter *i) 372241699cdSAl Viro { 373241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 374241699cdSAl Viro struct pipe_buffer *buf; 3758cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3768cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3778cefc107SDavid Howells unsigned int i_head = i->head; 378241699cdSAl Viro size_t off; 379241699cdSAl Viro 380241699cdSAl Viro if (unlikely(bytes > i->count)) 381241699cdSAl Viro bytes = i->count; 382241699cdSAl Viro 383241699cdSAl Viro if (unlikely(!bytes)) 384241699cdSAl Viro return 0; 385241699cdSAl Viro 386241699cdSAl Viro if (!sanity(i)) 387241699cdSAl Viro return 0; 388241699cdSAl Viro 389241699cdSAl Viro off = i->iov_offset; 3908cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 391241699cdSAl Viro if (off) { 392241699cdSAl Viro if (offset == off && buf->page == page) { 393241699cdSAl Viro /* merge with the last one */ 394241699cdSAl Viro buf->len += bytes; 395241699cdSAl Viro i->iov_offset += bytes; 396241699cdSAl Viro goto out; 397241699cdSAl Viro } 3988cefc107SDavid Howells i_head++; 3998cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 400241699cdSAl Viro } 4016718b6f8SDavid Howells if (pipe_full(i_head, p_tail, pipe->max_usage)) 402241699cdSAl Viro return 0; 4038cefc107SDavid Howells 404241699cdSAl Viro buf->ops = &page_cache_pipe_buf_ops; 4058cefc107SDavid Howells get_page(page); 4068cefc107SDavid Howells buf->page = page; 407241699cdSAl Viro buf->offset = offset; 408241699cdSAl Viro buf->len = bytes; 4098cefc107SDavid Howells 4108cefc107SDavid Howells pipe->head = i_head + 1; 411241699cdSAl Viro i->iov_offset = offset + bytes; 4128cefc107SDavid Howells i->head = i_head; 413241699cdSAl Viro out: 414241699cdSAl Viro i->count -= bytes; 415241699cdSAl Viro return bytes; 416241699cdSAl Viro } 417241699cdSAl Viro 418d879cb83SAl Viro /* 419171a0203SAnton Altaparmakov * Fault in one or more iovecs of the given iov_iter, to a maximum length of 420171a0203SAnton Altaparmakov * bytes. For each iovec, fault in each page that constitutes the iovec. 421171a0203SAnton Altaparmakov * 422171a0203SAnton Altaparmakov * Return 0 on success, or non-zero if the memory could not be accessed (i.e. 423171a0203SAnton Altaparmakov * because it is an invalid address). 424171a0203SAnton Altaparmakov */ 4258409a0d2SAl Viro int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes) 426171a0203SAnton Altaparmakov { 4270e8f0d67SAl Viro if (iter_is_iovec(i)) { 4288409a0d2SAl Viro const struct iovec *p; 4298409a0d2SAl Viro size_t skip; 4308409a0d2SAl Viro 4318409a0d2SAl Viro if (bytes > i->count) 4328409a0d2SAl Viro bytes = i->count; 4338409a0d2SAl Viro for (p = i->iov, skip = i->iov_offset; bytes; p++, skip = 0) { 4348409a0d2SAl Viro size_t len = min(bytes, p->iov_len - skip); 4358409a0d2SAl Viro int err; 4368409a0d2SAl Viro 4378409a0d2SAl Viro if (unlikely(!len)) 4388409a0d2SAl Viro continue; 4398409a0d2SAl Viro err = fault_in_pages_readable(p->iov_base + skip, len); 440171a0203SAnton Altaparmakov if (unlikely(err)) 441171a0203SAnton Altaparmakov return err; 4428409a0d2SAl Viro bytes -= len; 4438409a0d2SAl Viro } 444171a0203SAnton Altaparmakov } 445171a0203SAnton Altaparmakov return 0; 446171a0203SAnton Altaparmakov } 447d4690f1eSAl Viro EXPORT_SYMBOL(iov_iter_fault_in_readable); 448171a0203SAnton Altaparmakov 449aa563d7bSDavid Howells void iov_iter_init(struct iov_iter *i, unsigned int direction, 450d879cb83SAl Viro const struct iovec *iov, unsigned long nr_segs, 451d879cb83SAl Viro size_t count) 452d879cb83SAl Viro { 453aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 4548cd54c1cSAl Viro WARN_ON_ONCE(uaccess_kernel()); 4558cd54c1cSAl Viro *i = (struct iov_iter) { 4568cd54c1cSAl Viro .iter_type = ITER_IOVEC, 4578cd54c1cSAl Viro .data_source = direction, 4588cd54c1cSAl Viro .iov = iov, 4598cd54c1cSAl Viro .nr_segs = nr_segs, 4608cd54c1cSAl Viro .iov_offset = 0, 4618cd54c1cSAl Viro .count = count 4628cd54c1cSAl Viro }; 463d879cb83SAl Viro } 464d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_init); 465d879cb83SAl Viro 466241699cdSAl Viro static inline bool allocated(struct pipe_buffer *buf) 467241699cdSAl Viro { 468241699cdSAl Viro return buf->ops == &default_pipe_buf_ops; 469241699cdSAl Viro } 470241699cdSAl Viro 4718cefc107SDavid Howells static inline void data_start(const struct iov_iter *i, 4728cefc107SDavid Howells unsigned int *iter_headp, size_t *offp) 473241699cdSAl Viro { 4748cefc107SDavid Howells unsigned int p_mask = i->pipe->ring_size - 1; 4758cefc107SDavid Howells unsigned int iter_head = i->head; 476241699cdSAl Viro size_t off = i->iov_offset; 4778cefc107SDavid Howells 4788cefc107SDavid Howells if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || 4798cefc107SDavid Howells off == PAGE_SIZE)) { 4808cefc107SDavid Howells iter_head++; 481241699cdSAl Viro off = 0; 482241699cdSAl Viro } 4838cefc107SDavid Howells *iter_headp = iter_head; 484241699cdSAl Viro *offp = off; 485241699cdSAl Viro } 486241699cdSAl Viro 487241699cdSAl Viro static size_t push_pipe(struct iov_iter *i, size_t size, 4888cefc107SDavid Howells int *iter_headp, size_t *offp) 489241699cdSAl Viro { 490241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 4918cefc107SDavid Howells unsigned int p_tail = pipe->tail; 4928cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 4938cefc107SDavid Howells unsigned int iter_head; 494241699cdSAl Viro size_t off; 495241699cdSAl Viro ssize_t left; 496241699cdSAl Viro 497241699cdSAl Viro if (unlikely(size > i->count)) 498241699cdSAl Viro size = i->count; 499241699cdSAl Viro if (unlikely(!size)) 500241699cdSAl Viro return 0; 501241699cdSAl Viro 502241699cdSAl Viro left = size; 5038cefc107SDavid Howells data_start(i, &iter_head, &off); 5048cefc107SDavid Howells *iter_headp = iter_head; 505241699cdSAl Viro *offp = off; 506241699cdSAl Viro if (off) { 507241699cdSAl Viro left -= PAGE_SIZE - off; 508241699cdSAl Viro if (left <= 0) { 5098cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len += size; 510241699cdSAl Viro return size; 511241699cdSAl Viro } 5128cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; 5138cefc107SDavid Howells iter_head++; 514241699cdSAl Viro } 5156718b6f8SDavid Howells while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { 5168cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; 517241699cdSAl Viro struct page *page = alloc_page(GFP_USER); 518241699cdSAl Viro if (!page) 519241699cdSAl Viro break; 5208cefc107SDavid Howells 5218cefc107SDavid Howells buf->ops = &default_pipe_buf_ops; 5228cefc107SDavid Howells buf->page = page; 5238cefc107SDavid Howells buf->offset = 0; 5248cefc107SDavid Howells buf->len = min_t(ssize_t, left, PAGE_SIZE); 5258cefc107SDavid Howells left -= buf->len; 5268cefc107SDavid Howells iter_head++; 5278cefc107SDavid Howells pipe->head = iter_head; 5288cefc107SDavid Howells 5298cefc107SDavid Howells if (left == 0) 530241699cdSAl Viro return size; 531241699cdSAl Viro } 532241699cdSAl Viro return size - left; 533241699cdSAl Viro } 534241699cdSAl Viro 535241699cdSAl Viro static size_t copy_pipe_to_iter(const void *addr, size_t bytes, 536241699cdSAl Viro struct iov_iter *i) 537241699cdSAl Viro { 538241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5398cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5408cefc107SDavid Howells unsigned int i_head; 541241699cdSAl Viro size_t n, off; 542241699cdSAl Viro 543241699cdSAl Viro if (!sanity(i)) 544241699cdSAl Viro return 0; 545241699cdSAl Viro 5468cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 547241699cdSAl Viro if (unlikely(!n)) 548241699cdSAl Viro return 0; 5498cefc107SDavid Howells do { 550241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 5518cefc107SDavid Howells memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); 5528cefc107SDavid Howells i->head = i_head; 553241699cdSAl Viro i->iov_offset = off + chunk; 554241699cdSAl Viro n -= chunk; 555241699cdSAl Viro addr += chunk; 5568cefc107SDavid Howells off = 0; 5578cefc107SDavid Howells i_head++; 5588cefc107SDavid Howells } while (n); 559241699cdSAl Viro i->count -= bytes; 560241699cdSAl Viro return bytes; 561241699cdSAl Viro } 562241699cdSAl Viro 563f9152895SAl Viro static __wsum csum_and_memcpy(void *to, const void *from, size_t len, 564f9152895SAl Viro __wsum sum, size_t off) 565f9152895SAl Viro { 566cc44c17bSAl Viro __wsum next = csum_partial_copy_nocheck(from, to, len); 567f9152895SAl Viro return csum_block_add(sum, next, off); 568f9152895SAl Viro } 569f9152895SAl Viro 57078e1f386SAl Viro static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, 57152cbd23aSWillem de Bruijn struct csum_state *csstate, 57252cbd23aSWillem de Bruijn struct iov_iter *i) 57378e1f386SAl Viro { 57478e1f386SAl Viro struct pipe_inode_info *pipe = i->pipe; 5758cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 57652cbd23aSWillem de Bruijn __wsum sum = csstate->csum; 57752cbd23aSWillem de Bruijn size_t off = csstate->off; 5788cefc107SDavid Howells unsigned int i_head; 57978e1f386SAl Viro size_t n, r; 58078e1f386SAl Viro 58178e1f386SAl Viro if (!sanity(i)) 58278e1f386SAl Viro return 0; 58378e1f386SAl Viro 5848cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &r); 58578e1f386SAl Viro if (unlikely(!n)) 58678e1f386SAl Viro return 0; 5878cefc107SDavid Howells do { 58878e1f386SAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - r); 5898cefc107SDavid Howells char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); 590f9152895SAl Viro sum = csum_and_memcpy(p + r, addr, chunk, sum, off); 59178e1f386SAl Viro kunmap_atomic(p); 5928cefc107SDavid Howells i->head = i_head; 59378e1f386SAl Viro i->iov_offset = r + chunk; 59478e1f386SAl Viro n -= chunk; 59578e1f386SAl Viro off += chunk; 59678e1f386SAl Viro addr += chunk; 5978cefc107SDavid Howells r = 0; 5988cefc107SDavid Howells i_head++; 5998cefc107SDavid Howells } while (n); 60078e1f386SAl Viro i->count -= bytes; 60152cbd23aSWillem de Bruijn csstate->csum = sum; 60252cbd23aSWillem de Bruijn csstate->off = off; 60378e1f386SAl Viro return bytes; 60478e1f386SAl Viro } 60578e1f386SAl Viro 606aa28de27SAl Viro size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 607d879cb83SAl Viro { 60836f7a8a4SAl Viro const char *from = addr; 60900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 610241699cdSAl Viro return copy_pipe_to_iter(addr, bytes, i); 61109fc68dcSAl Viro if (iter_is_iovec(i)) 61209fc68dcSAl Viro might_fault(); 613d879cb83SAl Viro iterate_and_advance(i, bytes, v, 61409fc68dcSAl Viro copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 615d879cb83SAl Viro memcpy_to_page(v.bv_page, v.bv_offset, 616d879cb83SAl Viro (from += v.bv_len) - v.bv_len, v.bv_len), 6177ff50620SDavid Howells memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 6187ff50620SDavid Howells memcpy_to_page(v.bv_page, v.bv_offset, 6197ff50620SDavid Howells (from += v.bv_len) - v.bv_len, v.bv_len) 620d879cb83SAl Viro ) 621d879cb83SAl Viro 622d879cb83SAl Viro return bytes; 623d879cb83SAl Viro } 624aa28de27SAl Viro EXPORT_SYMBOL(_copy_to_iter); 625d879cb83SAl Viro 626ec6347bbSDan Williams #ifdef CONFIG_ARCH_HAS_COPY_MC 627ec6347bbSDan Williams static int copyout_mc(void __user *to, const void *from, size_t n) 6288780356eSDan Williams { 62996d4f267SLinus Torvalds if (access_ok(to, n)) { 630d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 631ec6347bbSDan Williams n = copy_mc_to_user((__force void *) to, from, n); 6328780356eSDan Williams } 6338780356eSDan Williams return n; 6348780356eSDan Williams } 6358780356eSDan Williams 636ec6347bbSDan Williams static unsigned long copy_mc_to_page(struct page *page, size_t offset, 6378780356eSDan Williams const char *from, size_t len) 6388780356eSDan Williams { 6398780356eSDan Williams unsigned long ret; 6408780356eSDan Williams char *to; 6418780356eSDan Williams 6428780356eSDan Williams to = kmap_atomic(page); 643ec6347bbSDan Williams ret = copy_mc_to_kernel(to + offset, from, len); 6448780356eSDan Williams kunmap_atomic(to); 6458780356eSDan Williams 6468780356eSDan Williams return ret; 6478780356eSDan Williams } 6488780356eSDan Williams 649ec6347bbSDan Williams static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, 650ca146f6fSDan Williams struct iov_iter *i) 651ca146f6fSDan Williams { 652ca146f6fSDan Williams struct pipe_inode_info *pipe = i->pipe; 6538cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 6548cefc107SDavid Howells unsigned int i_head; 655ca146f6fSDan Williams size_t n, off, xfer = 0; 656ca146f6fSDan Williams 657ca146f6fSDan Williams if (!sanity(i)) 658ca146f6fSDan Williams return 0; 659ca146f6fSDan Williams 6608cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 661ca146f6fSDan Williams if (unlikely(!n)) 662ca146f6fSDan Williams return 0; 6638cefc107SDavid Howells do { 664ca146f6fSDan Williams size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 665ca146f6fSDan Williams unsigned long rem; 666ca146f6fSDan Williams 667ec6347bbSDan Williams rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, 6688cefc107SDavid Howells off, addr, chunk); 6698cefc107SDavid Howells i->head = i_head; 670ca146f6fSDan Williams i->iov_offset = off + chunk - rem; 671ca146f6fSDan Williams xfer += chunk - rem; 672ca146f6fSDan Williams if (rem) 673ca146f6fSDan Williams break; 674ca146f6fSDan Williams n -= chunk; 675ca146f6fSDan Williams addr += chunk; 6768cefc107SDavid Howells off = 0; 6778cefc107SDavid Howells i_head++; 6788cefc107SDavid Howells } while (n); 679ca146f6fSDan Williams i->count -= xfer; 680ca146f6fSDan Williams return xfer; 681ca146f6fSDan Williams } 682ca146f6fSDan Williams 683bf3eeb9bSDan Williams /** 684ec6347bbSDan Williams * _copy_mc_to_iter - copy to iter with source memory error exception handling 685bf3eeb9bSDan Williams * @addr: source kernel address 686bf3eeb9bSDan Williams * @bytes: total transfer length 687bf3eeb9bSDan Williams * @iter: destination iterator 688bf3eeb9bSDan Williams * 689ec6347bbSDan Williams * The pmem driver deploys this for the dax operation 690ec6347bbSDan Williams * (dax_copy_to_iter()) for dax reads (bypass page-cache and the 691ec6347bbSDan Williams * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes 692ec6347bbSDan Williams * successfully copied. 693bf3eeb9bSDan Williams * 694ec6347bbSDan Williams * The main differences between this and typical _copy_to_iter(). 695bf3eeb9bSDan Williams * 696bf3eeb9bSDan Williams * * Typical tail/residue handling after a fault retries the copy 697bf3eeb9bSDan Williams * byte-by-byte until the fault happens again. Re-triggering machine 698bf3eeb9bSDan Williams * checks is potentially fatal so the implementation uses source 699bf3eeb9bSDan Williams * alignment and poison alignment assumptions to avoid re-triggering 700bf3eeb9bSDan Williams * hardware exceptions. 701bf3eeb9bSDan Williams * 702bf3eeb9bSDan Williams * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. 703bf3eeb9bSDan Williams * Compare to copy_to_iter() where only ITER_IOVEC attempts might return 704bf3eeb9bSDan Williams * a short copy. 705bf3eeb9bSDan Williams */ 706ec6347bbSDan Williams size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 7078780356eSDan Williams { 7088780356eSDan Williams const char *from = addr; 7098780356eSDan Williams 71000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 711ec6347bbSDan Williams return copy_mc_pipe_to_iter(addr, bytes, i); 7128780356eSDan Williams if (iter_is_iovec(i)) 7138780356eSDan Williams might_fault(); 714*1b4fb5ffSAl Viro __iterate_and_advance(i, bytes, v, 715ec6347bbSDan Williams copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len, 716ec6347bbSDan Williams v.iov_len), 717*1b4fb5ffSAl Viro copy_mc_to_page(v.bv_page, v.bv_offset, 718*1b4fb5ffSAl Viro (from += v.bv_len) - v.bv_len, v.bv_len), 719*1b4fb5ffSAl Viro copy_mc_to_kernel(v.iov_base, (from += v.iov_len) 720*1b4fb5ffSAl Viro - v.iov_len, v.iov_len), 721*1b4fb5ffSAl Viro copy_mc_to_page(v.bv_page, v.bv_offset, 722*1b4fb5ffSAl Viro (from += v.bv_len) - v.bv_len, v.bv_len) 7238780356eSDan Williams ) 7248780356eSDan Williams 7258780356eSDan Williams return bytes; 7268780356eSDan Williams } 727ec6347bbSDan Williams EXPORT_SYMBOL_GPL(_copy_mc_to_iter); 728ec6347bbSDan Williams #endif /* CONFIG_ARCH_HAS_COPY_MC */ 7298780356eSDan Williams 730aa28de27SAl Viro size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) 731d879cb83SAl Viro { 732d879cb83SAl Viro char *to = addr; 73300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 734241699cdSAl Viro WARN_ON(1); 735241699cdSAl Viro return 0; 736241699cdSAl Viro } 73709fc68dcSAl Viro if (iter_is_iovec(i)) 73809fc68dcSAl Viro might_fault(); 739d879cb83SAl Viro iterate_and_advance(i, bytes, v, 74009fc68dcSAl Viro copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 741d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 742d879cb83SAl Viro v.bv_offset, v.bv_len), 7437ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 7447ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 7457ff50620SDavid Howells v.bv_offset, v.bv_len) 746d879cb83SAl Viro ) 747d879cb83SAl Viro 748d879cb83SAl Viro return bytes; 749d879cb83SAl Viro } 750aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter); 751d879cb83SAl Viro 752aa28de27SAl Viro size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) 753d879cb83SAl Viro { 754d879cb83SAl Viro char *to = addr; 75500e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 756241699cdSAl Viro WARN_ON(1); 757241699cdSAl Viro return 0; 758241699cdSAl Viro } 759d879cb83SAl Viro iterate_and_advance(i, bytes, v, 7603f763453SAl Viro __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, 761d879cb83SAl Viro v.iov_base, v.iov_len), 762d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 763d879cb83SAl Viro v.bv_offset, v.bv_len), 7647ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 7657ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 7667ff50620SDavid Howells v.bv_offset, v.bv_len) 767d879cb83SAl Viro ) 768d879cb83SAl Viro 769d879cb83SAl Viro return bytes; 770d879cb83SAl Viro } 771aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_nocache); 772d879cb83SAl Viro 7730aed55afSDan Williams #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE 774abd08d7dSDan Williams /** 775abd08d7dSDan Williams * _copy_from_iter_flushcache - write destination through cpu cache 776abd08d7dSDan Williams * @addr: destination kernel address 777abd08d7dSDan Williams * @bytes: total transfer length 778abd08d7dSDan Williams * @iter: source iterator 779abd08d7dSDan Williams * 780abd08d7dSDan Williams * The pmem driver arranges for filesystem-dax to use this facility via 781abd08d7dSDan Williams * dax_copy_from_iter() for ensuring that writes to persistent memory 782abd08d7dSDan Williams * are flushed through the CPU cache. It is differentiated from 783abd08d7dSDan Williams * _copy_from_iter_nocache() in that guarantees all data is flushed for 784abd08d7dSDan Williams * all iterator types. The _copy_from_iter_nocache() only attempts to 785abd08d7dSDan Williams * bypass the cache for the ITER_IOVEC case, and on some archs may use 786abd08d7dSDan Williams * instructions that strand dirty-data in the cache. 787abd08d7dSDan Williams */ 7886a37e940SLinus Torvalds size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 7890aed55afSDan Williams { 7900aed55afSDan Williams char *to = addr; 79100e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 7920aed55afSDan Williams WARN_ON(1); 7930aed55afSDan Williams return 0; 7940aed55afSDan Williams } 7950aed55afSDan Williams iterate_and_advance(i, bytes, v, 7960aed55afSDan Williams __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, 7970aed55afSDan Williams v.iov_base, v.iov_len), 7980aed55afSDan Williams memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 7990aed55afSDan Williams v.bv_offset, v.bv_len), 8000aed55afSDan Williams memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, 8017ff50620SDavid Howells v.iov_len), 8027ff50620SDavid Howells memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 8037ff50620SDavid Howells v.bv_offset, v.bv_len) 8040aed55afSDan Williams ) 8050aed55afSDan Williams 8060aed55afSDan Williams return bytes; 8070aed55afSDan Williams } 8086a37e940SLinus Torvalds EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); 8090aed55afSDan Williams #endif 8100aed55afSDan Williams 81172e809edSAl Viro static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) 81272e809edSAl Viro { 8136daef95bSEric Dumazet struct page *head; 8146daef95bSEric Dumazet size_t v = n + offset; 8156daef95bSEric Dumazet 8166daef95bSEric Dumazet /* 8176daef95bSEric Dumazet * The general case needs to access the page order in order 8186daef95bSEric Dumazet * to compute the page size. 8196daef95bSEric Dumazet * However, we mostly deal with order-0 pages and thus can 8206daef95bSEric Dumazet * avoid a possible cache line miss for requests that fit all 8216daef95bSEric Dumazet * page orders. 8226daef95bSEric Dumazet */ 8236daef95bSEric Dumazet if (n <= v && v <= PAGE_SIZE) 8246daef95bSEric Dumazet return true; 8256daef95bSEric Dumazet 8266daef95bSEric Dumazet head = compound_head(page); 8276daef95bSEric Dumazet v += (page - head) << PAGE_SHIFT; 828a90bcb86SPetar Penkov 829a50b854eSMatthew Wilcox (Oracle) if (likely(n <= v && v <= (page_size(head)))) 83072e809edSAl Viro return true; 83172e809edSAl Viro WARN_ON(1); 83272e809edSAl Viro return false; 83372e809edSAl Viro } 834cbbd26b8SAl Viro 83508aa6479SAl Viro static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 836d879cb83SAl Viro struct iov_iter *i) 837d879cb83SAl Viro { 83828f38db7SAl Viro if (likely(iter_is_iovec(i))) 83928f38db7SAl Viro return copy_page_to_iter_iovec(page, offset, bytes, i); 84028f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 841d879cb83SAl Viro void *kaddr = kmap_atomic(page); 842d879cb83SAl Viro size_t wanted = copy_to_iter(kaddr + offset, bytes, i); 843d879cb83SAl Viro kunmap_atomic(kaddr); 844d879cb83SAl Viro return wanted; 84528f38db7SAl Viro } 84628f38db7SAl Viro if (iov_iter_is_pipe(i)) 84728f38db7SAl Viro return copy_page_to_iter_pipe(page, offset, bytes, i); 84828f38db7SAl Viro if (unlikely(iov_iter_is_discard(i))) { 849a506abc7SAl Viro if (unlikely(i->count < bytes)) 850a506abc7SAl Viro bytes = i->count; 851a506abc7SAl Viro i->count -= bytes; 8529ea9ce04SDavid Howells return bytes; 85328f38db7SAl Viro } 85428f38db7SAl Viro WARN_ON(1); 85528f38db7SAl Viro return 0; 856d879cb83SAl Viro } 85708aa6479SAl Viro 85808aa6479SAl Viro size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 85908aa6479SAl Viro struct iov_iter *i) 86008aa6479SAl Viro { 86108aa6479SAl Viro size_t res = 0; 86208aa6479SAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 86308aa6479SAl Viro return 0; 86408aa6479SAl Viro page += offset / PAGE_SIZE; // first subpage 86508aa6479SAl Viro offset %= PAGE_SIZE; 86608aa6479SAl Viro while (1) { 86708aa6479SAl Viro size_t n = __copy_page_to_iter(page, offset, 86808aa6479SAl Viro min(bytes, (size_t)PAGE_SIZE - offset), i); 86908aa6479SAl Viro res += n; 87008aa6479SAl Viro bytes -= n; 87108aa6479SAl Viro if (!bytes || !n) 87208aa6479SAl Viro break; 87308aa6479SAl Viro offset += n; 87408aa6479SAl Viro if (offset == PAGE_SIZE) { 87508aa6479SAl Viro page++; 87608aa6479SAl Viro offset = 0; 87708aa6479SAl Viro } 87808aa6479SAl Viro } 87908aa6479SAl Viro return res; 88008aa6479SAl Viro } 881d879cb83SAl Viro EXPORT_SYMBOL(copy_page_to_iter); 882d879cb83SAl Viro 883d879cb83SAl Viro size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, 884d879cb83SAl Viro struct iov_iter *i) 885d879cb83SAl Viro { 88672e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 88772e809edSAl Viro return 0; 88828f38db7SAl Viro if (likely(iter_is_iovec(i))) 88928f38db7SAl Viro return copy_page_from_iter_iovec(page, offset, bytes, i); 89028f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 891d879cb83SAl Viro void *kaddr = kmap_atomic(page); 892aa28de27SAl Viro size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); 893d879cb83SAl Viro kunmap_atomic(kaddr); 894d879cb83SAl Viro return wanted; 89528f38db7SAl Viro } 89628f38db7SAl Viro WARN_ON(1); 89728f38db7SAl Viro return 0; 898d879cb83SAl Viro } 899d879cb83SAl Viro EXPORT_SYMBOL(copy_page_from_iter); 900d879cb83SAl Viro 901241699cdSAl Viro static size_t pipe_zero(size_t bytes, struct iov_iter *i) 902241699cdSAl Viro { 903241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 9048cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9058cefc107SDavid Howells unsigned int i_head; 906241699cdSAl Viro size_t n, off; 907241699cdSAl Viro 908241699cdSAl Viro if (!sanity(i)) 909241699cdSAl Viro return 0; 910241699cdSAl Viro 9118cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 912241699cdSAl Viro if (unlikely(!n)) 913241699cdSAl Viro return 0; 914241699cdSAl Viro 9158cefc107SDavid Howells do { 916241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 9178cefc107SDavid Howells memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); 9188cefc107SDavid Howells i->head = i_head; 919241699cdSAl Viro i->iov_offset = off + chunk; 920241699cdSAl Viro n -= chunk; 9218cefc107SDavid Howells off = 0; 9228cefc107SDavid Howells i_head++; 9238cefc107SDavid Howells } while (n); 924241699cdSAl Viro i->count -= bytes; 925241699cdSAl Viro return bytes; 926241699cdSAl Viro } 927241699cdSAl Viro 928d879cb83SAl Viro size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 929d879cb83SAl Viro { 93000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 931241699cdSAl Viro return pipe_zero(bytes, i); 932d879cb83SAl Viro iterate_and_advance(i, bytes, v, 93309fc68dcSAl Viro clear_user(v.iov_base, v.iov_len), 934d879cb83SAl Viro memzero_page(v.bv_page, v.bv_offset, v.bv_len), 9357ff50620SDavid Howells memset(v.iov_base, 0, v.iov_len), 9367ff50620SDavid Howells memzero_page(v.bv_page, v.bv_offset, v.bv_len) 937d879cb83SAl Viro ) 938d879cb83SAl Viro 939d879cb83SAl Viro return bytes; 940d879cb83SAl Viro } 941d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_zero); 942d879cb83SAl Viro 943f0b65f39SAl Viro size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, 944f0b65f39SAl Viro struct iov_iter *i) 945d879cb83SAl Viro { 946d879cb83SAl Viro char *kaddr = kmap_atomic(page), *p = kaddr + offset; 94772e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) { 94872e809edSAl Viro kunmap_atomic(kaddr); 94972e809edSAl Viro return 0; 95072e809edSAl Viro } 9519ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 952241699cdSAl Viro kunmap_atomic(kaddr); 953241699cdSAl Viro WARN_ON(1); 954241699cdSAl Viro return 0; 955241699cdSAl Viro } 956f0b65f39SAl Viro iterate_and_advance(i, bytes, v, 95709fc68dcSAl Viro copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 958d879cb83SAl Viro memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 959d879cb83SAl Viro v.bv_offset, v.bv_len), 9607ff50620SDavid Howells memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 9617ff50620SDavid Howells memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 9627ff50620SDavid Howells v.bv_offset, v.bv_len) 963d879cb83SAl Viro ) 964d879cb83SAl Viro kunmap_atomic(kaddr); 965d879cb83SAl Viro return bytes; 966d879cb83SAl Viro } 967f0b65f39SAl Viro EXPORT_SYMBOL(copy_page_from_iter_atomic); 968d879cb83SAl Viro 969b9dc6f65SAl Viro static inline void pipe_truncate(struct iov_iter *i) 970241699cdSAl Viro { 971241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 9728cefc107SDavid Howells unsigned int p_tail = pipe->tail; 9738cefc107SDavid Howells unsigned int p_head = pipe->head; 9748cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9758cefc107SDavid Howells 9768cefc107SDavid Howells if (!pipe_empty(p_head, p_tail)) { 9778cefc107SDavid Howells struct pipe_buffer *buf; 9788cefc107SDavid Howells unsigned int i_head = i->head; 979b9dc6f65SAl Viro size_t off = i->iov_offset; 9808cefc107SDavid Howells 981b9dc6f65SAl Viro if (off) { 9828cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 9838cefc107SDavid Howells buf->len = off - buf->offset; 9848cefc107SDavid Howells i_head++; 985b9dc6f65SAl Viro } 9868cefc107SDavid Howells while (p_head != i_head) { 9878cefc107SDavid Howells p_head--; 9888cefc107SDavid Howells pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); 989241699cdSAl Viro } 9908cefc107SDavid Howells 9918cefc107SDavid Howells pipe->head = p_head; 992241699cdSAl Viro } 993b9dc6f65SAl Viro } 994b9dc6f65SAl Viro 995b9dc6f65SAl Viro static void pipe_advance(struct iov_iter *i, size_t size) 996b9dc6f65SAl Viro { 997b9dc6f65SAl Viro struct pipe_inode_info *pipe = i->pipe; 998b9dc6f65SAl Viro if (size) { 999b9dc6f65SAl Viro struct pipe_buffer *buf; 10008cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10018cefc107SDavid Howells unsigned int i_head = i->head; 1002b9dc6f65SAl Viro size_t off = i->iov_offset, left = size; 10038cefc107SDavid Howells 1004b9dc6f65SAl Viro if (off) /* make it relative to the beginning of buffer */ 10058cefc107SDavid Howells left += off - pipe->bufs[i_head & p_mask].offset; 1006b9dc6f65SAl Viro while (1) { 10078cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 1008b9dc6f65SAl Viro if (left <= buf->len) 1009b9dc6f65SAl Viro break; 1010b9dc6f65SAl Viro left -= buf->len; 10118cefc107SDavid Howells i_head++; 1012b9dc6f65SAl Viro } 10138cefc107SDavid Howells i->head = i_head; 1014b9dc6f65SAl Viro i->iov_offset = buf->offset + left; 1015b9dc6f65SAl Viro } 1016b9dc6f65SAl Viro i->count -= size; 1017b9dc6f65SAl Viro /* ... and discard everything past that point */ 1018b9dc6f65SAl Viro pipe_truncate(i); 1019241699cdSAl Viro } 1020241699cdSAl Viro 102154c8195bSPavel Begunkov static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) 102254c8195bSPavel Begunkov { 102354c8195bSPavel Begunkov struct bvec_iter bi; 102454c8195bSPavel Begunkov 102554c8195bSPavel Begunkov bi.bi_size = i->count; 102654c8195bSPavel Begunkov bi.bi_bvec_done = i->iov_offset; 102754c8195bSPavel Begunkov bi.bi_idx = 0; 102854c8195bSPavel Begunkov bvec_iter_advance(i->bvec, &bi, size); 102954c8195bSPavel Begunkov 103054c8195bSPavel Begunkov i->bvec += bi.bi_idx; 103154c8195bSPavel Begunkov i->nr_segs -= bi.bi_idx; 103254c8195bSPavel Begunkov i->count = bi.bi_size; 103354c8195bSPavel Begunkov i->iov_offset = bi.bi_bvec_done; 103454c8195bSPavel Begunkov } 103554c8195bSPavel Begunkov 1036185ac4d4SAl Viro static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) 1037185ac4d4SAl Viro { 1038185ac4d4SAl Viro const struct iovec *iov, *end; 1039185ac4d4SAl Viro 1040185ac4d4SAl Viro if (!i->count) 1041185ac4d4SAl Viro return; 1042185ac4d4SAl Viro i->count -= size; 1043185ac4d4SAl Viro 1044185ac4d4SAl Viro size += i->iov_offset; // from beginning of current segment 1045185ac4d4SAl Viro for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { 1046185ac4d4SAl Viro if (likely(size < iov->iov_len)) 1047185ac4d4SAl Viro break; 1048185ac4d4SAl Viro size -= iov->iov_len; 1049185ac4d4SAl Viro } 1050185ac4d4SAl Viro i->iov_offset = size; 1051185ac4d4SAl Viro i->nr_segs -= iov - i->iov; 1052185ac4d4SAl Viro i->iov = iov; 1053185ac4d4SAl Viro } 1054185ac4d4SAl Viro 1055d879cb83SAl Viro void iov_iter_advance(struct iov_iter *i, size_t size) 1056d879cb83SAl Viro { 10573b3fc051SAl Viro if (unlikely(i->count < size)) 10583b3fc051SAl Viro size = i->count; 1059185ac4d4SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { 1060185ac4d4SAl Viro /* iovec and kvec have identical layouts */ 1061185ac4d4SAl Viro iov_iter_iovec_advance(i, size); 1062185ac4d4SAl Viro } else if (iov_iter_is_bvec(i)) { 1063185ac4d4SAl Viro iov_iter_bvec_advance(i, size); 1064185ac4d4SAl Viro } else if (iov_iter_is_pipe(i)) { 1065241699cdSAl Viro pipe_advance(i, size); 1066185ac4d4SAl Viro } else if (unlikely(iov_iter_is_xarray(i))) { 10677ff50620SDavid Howells i->iov_offset += size; 10687ff50620SDavid Howells i->count -= size; 1069185ac4d4SAl Viro } else if (iov_iter_is_discard(i)) { 1070185ac4d4SAl Viro i->count -= size; 10717ff50620SDavid Howells } 1072d879cb83SAl Viro } 1073d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_advance); 1074d879cb83SAl Viro 107527c0e374SAl Viro void iov_iter_revert(struct iov_iter *i, size_t unroll) 107627c0e374SAl Viro { 107727c0e374SAl Viro if (!unroll) 107827c0e374SAl Viro return; 10795b47d59aSAl Viro if (WARN_ON(unroll > MAX_RW_COUNT)) 10805b47d59aSAl Viro return; 108127c0e374SAl Viro i->count += unroll; 108200e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 108327c0e374SAl Viro struct pipe_inode_info *pipe = i->pipe; 10848cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10858cefc107SDavid Howells unsigned int i_head = i->head; 108627c0e374SAl Viro size_t off = i->iov_offset; 108727c0e374SAl Viro while (1) { 10888cefc107SDavid Howells struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; 10898cefc107SDavid Howells size_t n = off - b->offset; 109027c0e374SAl Viro if (unroll < n) { 10914fa55cefSAl Viro off -= unroll; 109227c0e374SAl Viro break; 109327c0e374SAl Viro } 109427c0e374SAl Viro unroll -= n; 10958cefc107SDavid Howells if (!unroll && i_head == i->start_head) { 109627c0e374SAl Viro off = 0; 109727c0e374SAl Viro break; 109827c0e374SAl Viro } 10998cefc107SDavid Howells i_head--; 11008cefc107SDavid Howells b = &pipe->bufs[i_head & p_mask]; 11018cefc107SDavid Howells off = b->offset + b->len; 110227c0e374SAl Viro } 110327c0e374SAl Viro i->iov_offset = off; 11048cefc107SDavid Howells i->head = i_head; 110527c0e374SAl Viro pipe_truncate(i); 110627c0e374SAl Viro return; 110727c0e374SAl Viro } 11089ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 11099ea9ce04SDavid Howells return; 111027c0e374SAl Viro if (unroll <= i->iov_offset) { 111127c0e374SAl Viro i->iov_offset -= unroll; 111227c0e374SAl Viro return; 111327c0e374SAl Viro } 111427c0e374SAl Viro unroll -= i->iov_offset; 11157ff50620SDavid Howells if (iov_iter_is_xarray(i)) { 11167ff50620SDavid Howells BUG(); /* We should never go beyond the start of the specified 11177ff50620SDavid Howells * range since we might then be straying into pages that 11187ff50620SDavid Howells * aren't pinned. 11197ff50620SDavid Howells */ 11207ff50620SDavid Howells } else if (iov_iter_is_bvec(i)) { 112127c0e374SAl Viro const struct bio_vec *bvec = i->bvec; 112227c0e374SAl Viro while (1) { 112327c0e374SAl Viro size_t n = (--bvec)->bv_len; 112427c0e374SAl Viro i->nr_segs++; 112527c0e374SAl Viro if (unroll <= n) { 112627c0e374SAl Viro i->bvec = bvec; 112727c0e374SAl Viro i->iov_offset = n - unroll; 112827c0e374SAl Viro return; 112927c0e374SAl Viro } 113027c0e374SAl Viro unroll -= n; 113127c0e374SAl Viro } 113227c0e374SAl Viro } else { /* same logics for iovec and kvec */ 113327c0e374SAl Viro const struct iovec *iov = i->iov; 113427c0e374SAl Viro while (1) { 113527c0e374SAl Viro size_t n = (--iov)->iov_len; 113627c0e374SAl Viro i->nr_segs++; 113727c0e374SAl Viro if (unroll <= n) { 113827c0e374SAl Viro i->iov = iov; 113927c0e374SAl Viro i->iov_offset = n - unroll; 114027c0e374SAl Viro return; 114127c0e374SAl Viro } 114227c0e374SAl Viro unroll -= n; 114327c0e374SAl Viro } 114427c0e374SAl Viro } 114527c0e374SAl Viro } 114627c0e374SAl Viro EXPORT_SYMBOL(iov_iter_revert); 114727c0e374SAl Viro 1148d879cb83SAl Viro /* 1149d879cb83SAl Viro * Return the count of just the current iov_iter segment. 1150d879cb83SAl Viro */ 1151d879cb83SAl Viro size_t iov_iter_single_seg_count(const struct iov_iter *i) 1152d879cb83SAl Viro { 115328f38db7SAl Viro if (i->nr_segs > 1) { 115428f38db7SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 115528f38db7SAl Viro return min(i->count, i->iov->iov_len - i->iov_offset); 11567ff50620SDavid Howells if (iov_iter_is_bvec(i)) 1157d879cb83SAl Viro return min(i->count, i->bvec->bv_len - i->iov_offset); 115828f38db7SAl Viro } 115928f38db7SAl Viro return i->count; 1160d879cb83SAl Viro } 1161d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_single_seg_count); 1162d879cb83SAl Viro 1163aa563d7bSDavid Howells void iov_iter_kvec(struct iov_iter *i, unsigned int direction, 1164d879cb83SAl Viro const struct kvec *kvec, unsigned long nr_segs, 1165d879cb83SAl Viro size_t count) 1166d879cb83SAl Viro { 1167aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 11688cd54c1cSAl Viro *i = (struct iov_iter){ 11698cd54c1cSAl Viro .iter_type = ITER_KVEC, 11708cd54c1cSAl Viro .data_source = direction, 11718cd54c1cSAl Viro .kvec = kvec, 11728cd54c1cSAl Viro .nr_segs = nr_segs, 11738cd54c1cSAl Viro .iov_offset = 0, 11748cd54c1cSAl Viro .count = count 11758cd54c1cSAl Viro }; 1176d879cb83SAl Viro } 1177d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_kvec); 1178d879cb83SAl Viro 1179aa563d7bSDavid Howells void iov_iter_bvec(struct iov_iter *i, unsigned int direction, 1180d879cb83SAl Viro const struct bio_vec *bvec, unsigned long nr_segs, 1181d879cb83SAl Viro size_t count) 1182d879cb83SAl Viro { 1183aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 11848cd54c1cSAl Viro *i = (struct iov_iter){ 11858cd54c1cSAl Viro .iter_type = ITER_BVEC, 11868cd54c1cSAl Viro .data_source = direction, 11878cd54c1cSAl Viro .bvec = bvec, 11888cd54c1cSAl Viro .nr_segs = nr_segs, 11898cd54c1cSAl Viro .iov_offset = 0, 11908cd54c1cSAl Viro .count = count 11918cd54c1cSAl Viro }; 1192d879cb83SAl Viro } 1193d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_bvec); 1194d879cb83SAl Viro 1195aa563d7bSDavid Howells void iov_iter_pipe(struct iov_iter *i, unsigned int direction, 1196241699cdSAl Viro struct pipe_inode_info *pipe, 1197241699cdSAl Viro size_t count) 1198241699cdSAl Viro { 1199aa563d7bSDavid Howells BUG_ON(direction != READ); 12008cefc107SDavid Howells WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); 12018cd54c1cSAl Viro *i = (struct iov_iter){ 12028cd54c1cSAl Viro .iter_type = ITER_PIPE, 12038cd54c1cSAl Viro .data_source = false, 12048cd54c1cSAl Viro .pipe = pipe, 12058cd54c1cSAl Viro .head = pipe->head, 12068cd54c1cSAl Viro .start_head = pipe->head, 12078cd54c1cSAl Viro .iov_offset = 0, 12088cd54c1cSAl Viro .count = count 12098cd54c1cSAl Viro }; 1210241699cdSAl Viro } 1211241699cdSAl Viro EXPORT_SYMBOL(iov_iter_pipe); 1212241699cdSAl Viro 12139ea9ce04SDavid Howells /** 12147ff50620SDavid Howells * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray 12157ff50620SDavid Howells * @i: The iterator to initialise. 12167ff50620SDavid Howells * @direction: The direction of the transfer. 12177ff50620SDavid Howells * @xarray: The xarray to access. 12187ff50620SDavid Howells * @start: The start file position. 12197ff50620SDavid Howells * @count: The size of the I/O buffer in bytes. 12207ff50620SDavid Howells * 12217ff50620SDavid Howells * Set up an I/O iterator to either draw data out of the pages attached to an 12227ff50620SDavid Howells * inode or to inject data into those pages. The pages *must* be prevented 12237ff50620SDavid Howells * from evaporation, either by taking a ref on them or locking them by the 12247ff50620SDavid Howells * caller. 12257ff50620SDavid Howells */ 12267ff50620SDavid Howells void iov_iter_xarray(struct iov_iter *i, unsigned int direction, 12277ff50620SDavid Howells struct xarray *xarray, loff_t start, size_t count) 12287ff50620SDavid Howells { 12297ff50620SDavid Howells BUG_ON(direction & ~1); 12308cd54c1cSAl Viro *i = (struct iov_iter) { 12318cd54c1cSAl Viro .iter_type = ITER_XARRAY, 12328cd54c1cSAl Viro .data_source = direction, 12338cd54c1cSAl Viro .xarray = xarray, 12348cd54c1cSAl Viro .xarray_start = start, 12358cd54c1cSAl Viro .count = count, 12368cd54c1cSAl Viro .iov_offset = 0 12378cd54c1cSAl Viro }; 12387ff50620SDavid Howells } 12397ff50620SDavid Howells EXPORT_SYMBOL(iov_iter_xarray); 12407ff50620SDavid Howells 12417ff50620SDavid Howells /** 12429ea9ce04SDavid Howells * iov_iter_discard - Initialise an I/O iterator that discards data 12439ea9ce04SDavid Howells * @i: The iterator to initialise. 12449ea9ce04SDavid Howells * @direction: The direction of the transfer. 12459ea9ce04SDavid Howells * @count: The size of the I/O buffer in bytes. 12469ea9ce04SDavid Howells * 12479ea9ce04SDavid Howells * Set up an I/O iterator that just discards everything that's written to it. 12489ea9ce04SDavid Howells * It's only available as a READ iterator. 12499ea9ce04SDavid Howells */ 12509ea9ce04SDavid Howells void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) 12519ea9ce04SDavid Howells { 12529ea9ce04SDavid Howells BUG_ON(direction != READ); 12538cd54c1cSAl Viro *i = (struct iov_iter){ 12548cd54c1cSAl Viro .iter_type = ITER_DISCARD, 12558cd54c1cSAl Viro .data_source = false, 12568cd54c1cSAl Viro .count = count, 12578cd54c1cSAl Viro .iov_offset = 0 12588cd54c1cSAl Viro }; 12599ea9ce04SDavid Howells } 12609ea9ce04SDavid Howells EXPORT_SYMBOL(iov_iter_discard); 12619ea9ce04SDavid Howells 12629221d2e3SAl Viro static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) 1263d879cb83SAl Viro { 1264d879cb83SAl Viro unsigned long res = 0; 1265d879cb83SAl Viro size_t size = i->count; 12669221d2e3SAl Viro size_t skip = i->iov_offset; 12679221d2e3SAl Viro unsigned k; 1268d879cb83SAl Viro 12699221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 12709221d2e3SAl Viro size_t len = i->iov[k].iov_len - skip; 12719221d2e3SAl Viro if (len) { 12729221d2e3SAl Viro res |= (unsigned long)i->iov[k].iov_base + skip; 12739221d2e3SAl Viro if (len > size) 12749221d2e3SAl Viro len = size; 12759221d2e3SAl Viro res |= len; 12769221d2e3SAl Viro size -= len; 12779221d2e3SAl Viro if (!size) 12789221d2e3SAl Viro break; 12799221d2e3SAl Viro } 12809221d2e3SAl Viro } 12819221d2e3SAl Viro return res; 12829221d2e3SAl Viro } 12839221d2e3SAl Viro 12849221d2e3SAl Viro static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) 12859221d2e3SAl Viro { 12869221d2e3SAl Viro unsigned res = 0; 12879221d2e3SAl Viro size_t size = i->count; 12889221d2e3SAl Viro unsigned skip = i->iov_offset; 12899221d2e3SAl Viro unsigned k; 12909221d2e3SAl Viro 12919221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 12929221d2e3SAl Viro size_t len = i->bvec[k].bv_len - skip; 12939221d2e3SAl Viro res |= (unsigned long)i->bvec[k].bv_offset + skip; 12949221d2e3SAl Viro if (len > size) 12959221d2e3SAl Viro len = size; 12969221d2e3SAl Viro res |= len; 12979221d2e3SAl Viro size -= len; 12989221d2e3SAl Viro if (!size) 12999221d2e3SAl Viro break; 13009221d2e3SAl Viro } 13019221d2e3SAl Viro return res; 13029221d2e3SAl Viro } 13039221d2e3SAl Viro 13049221d2e3SAl Viro unsigned long iov_iter_alignment(const struct iov_iter *i) 13059221d2e3SAl Viro { 13069221d2e3SAl Viro /* iovec and kvec have identical layouts */ 13079221d2e3SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 13089221d2e3SAl Viro return iov_iter_alignment_iovec(i); 13099221d2e3SAl Viro 13109221d2e3SAl Viro if (iov_iter_is_bvec(i)) 13119221d2e3SAl Viro return iov_iter_alignment_bvec(i); 13129221d2e3SAl Viro 13139221d2e3SAl Viro if (iov_iter_is_pipe(i)) { 1314e0ff126eSJan Kara unsigned int p_mask = i->pipe->ring_size - 1; 13159221d2e3SAl Viro size_t size = i->count; 1316e0ff126eSJan Kara 13178cefc107SDavid Howells if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) 1318241699cdSAl Viro return size | i->iov_offset; 1319241699cdSAl Viro return size; 1320241699cdSAl Viro } 13219221d2e3SAl Viro 13229221d2e3SAl Viro if (iov_iter_is_xarray(i)) 13233d14ec1fSDavid Howells return (i->xarray_start + i->iov_offset) | i->count; 13249221d2e3SAl Viro 13259221d2e3SAl Viro return 0; 1326d879cb83SAl Viro } 1327d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_alignment); 1328d879cb83SAl Viro 1329357f435dSAl Viro unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 1330357f435dSAl Viro { 1331357f435dSAl Viro unsigned long res = 0; 1332610c7a71SAl Viro unsigned long v = 0; 1333357f435dSAl Viro size_t size = i->count; 1334610c7a71SAl Viro unsigned k; 1335357f435dSAl Viro 1336610c7a71SAl Viro if (WARN_ON(!iter_is_iovec(i))) 1337241699cdSAl Viro return ~0U; 1338241699cdSAl Viro 1339610c7a71SAl Viro for (k = 0; k < i->nr_segs; k++) { 1340610c7a71SAl Viro if (i->iov[k].iov_len) { 1341610c7a71SAl Viro unsigned long base = (unsigned long)i->iov[k].iov_base; 1342610c7a71SAl Viro if (v) // if not the first one 1343610c7a71SAl Viro res |= base | v; // this start | previous end 1344610c7a71SAl Viro v = base + i->iov[k].iov_len; 1345610c7a71SAl Viro if (size <= i->iov[k].iov_len) 1346610c7a71SAl Viro break; 1347610c7a71SAl Viro size -= i->iov[k].iov_len; 1348610c7a71SAl Viro } 1349610c7a71SAl Viro } 1350357f435dSAl Viro return res; 1351357f435dSAl Viro } 1352357f435dSAl Viro EXPORT_SYMBOL(iov_iter_gap_alignment); 1353357f435dSAl Viro 1354e76b6312SIlya Dryomov static inline ssize_t __pipe_get_pages(struct iov_iter *i, 1355241699cdSAl Viro size_t maxsize, 1356241699cdSAl Viro struct page **pages, 13578cefc107SDavid Howells int iter_head, 1358241699cdSAl Viro size_t *start) 1359241699cdSAl Viro { 1360241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 13618cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 13628cefc107SDavid Howells ssize_t n = push_pipe(i, maxsize, &iter_head, start); 1363241699cdSAl Viro if (!n) 1364241699cdSAl Viro return -EFAULT; 1365241699cdSAl Viro 1366241699cdSAl Viro maxsize = n; 1367241699cdSAl Viro n += *start; 13681689c73aSAl Viro while (n > 0) { 13698cefc107SDavid Howells get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); 13708cefc107SDavid Howells iter_head++; 1371241699cdSAl Viro n -= PAGE_SIZE; 1372241699cdSAl Viro } 1373241699cdSAl Viro 1374241699cdSAl Viro return maxsize; 1375241699cdSAl Viro } 1376241699cdSAl Viro 1377241699cdSAl Viro static ssize_t pipe_get_pages(struct iov_iter *i, 1378241699cdSAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1379241699cdSAl Viro size_t *start) 1380241699cdSAl Viro { 13818cefc107SDavid Howells unsigned int iter_head, npages; 1382241699cdSAl Viro size_t capacity; 1383241699cdSAl Viro 1384241699cdSAl Viro if (!sanity(i)) 1385241699cdSAl Viro return -EFAULT; 1386241699cdSAl Viro 13878cefc107SDavid Howells data_start(i, &iter_head, start); 13888cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 13898cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1390241699cdSAl Viro capacity = min(npages, maxpages) * PAGE_SIZE - *start; 1391241699cdSAl Viro 13928cefc107SDavid Howells return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); 1393241699cdSAl Viro } 1394241699cdSAl Viro 13957ff50620SDavid Howells static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, 13967ff50620SDavid Howells pgoff_t index, unsigned int nr_pages) 13977ff50620SDavid Howells { 13987ff50620SDavid Howells XA_STATE(xas, xa, index); 13997ff50620SDavid Howells struct page *page; 14007ff50620SDavid Howells unsigned int ret = 0; 14017ff50620SDavid Howells 14027ff50620SDavid Howells rcu_read_lock(); 14037ff50620SDavid Howells for (page = xas_load(&xas); page; page = xas_next(&xas)) { 14047ff50620SDavid Howells if (xas_retry(&xas, page)) 14057ff50620SDavid Howells continue; 14067ff50620SDavid Howells 14077ff50620SDavid Howells /* Has the page moved or been split? */ 14087ff50620SDavid Howells if (unlikely(page != xas_reload(&xas))) { 14097ff50620SDavid Howells xas_reset(&xas); 14107ff50620SDavid Howells continue; 14117ff50620SDavid Howells } 14127ff50620SDavid Howells 14137ff50620SDavid Howells pages[ret] = find_subpage(page, xas.xa_index); 14147ff50620SDavid Howells get_page(pages[ret]); 14157ff50620SDavid Howells if (++ret == nr_pages) 14167ff50620SDavid Howells break; 14177ff50620SDavid Howells } 14187ff50620SDavid Howells rcu_read_unlock(); 14197ff50620SDavid Howells return ret; 14207ff50620SDavid Howells } 14217ff50620SDavid Howells 14227ff50620SDavid Howells static ssize_t iter_xarray_get_pages(struct iov_iter *i, 14237ff50620SDavid Howells struct page **pages, size_t maxsize, 14247ff50620SDavid Howells unsigned maxpages, size_t *_start_offset) 14257ff50620SDavid Howells { 14267ff50620SDavid Howells unsigned nr, offset; 14277ff50620SDavid Howells pgoff_t index, count; 14287ff50620SDavid Howells size_t size = maxsize, actual; 14297ff50620SDavid Howells loff_t pos; 14307ff50620SDavid Howells 14317ff50620SDavid Howells if (!size || !maxpages) 14327ff50620SDavid Howells return 0; 14337ff50620SDavid Howells 14347ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 14357ff50620SDavid Howells index = pos >> PAGE_SHIFT; 14367ff50620SDavid Howells offset = pos & ~PAGE_MASK; 14377ff50620SDavid Howells *_start_offset = offset; 14387ff50620SDavid Howells 14397ff50620SDavid Howells count = 1; 14407ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 14417ff50620SDavid Howells size -= PAGE_SIZE - offset; 14427ff50620SDavid Howells count += size >> PAGE_SHIFT; 14437ff50620SDavid Howells size &= ~PAGE_MASK; 14447ff50620SDavid Howells if (size) 14457ff50620SDavid Howells count++; 14467ff50620SDavid Howells } 14477ff50620SDavid Howells 14487ff50620SDavid Howells if (count > maxpages) 14497ff50620SDavid Howells count = maxpages; 14507ff50620SDavid Howells 14517ff50620SDavid Howells nr = iter_xarray_populate_pages(pages, i->xarray, index, count); 14527ff50620SDavid Howells if (nr == 0) 14537ff50620SDavid Howells return 0; 14547ff50620SDavid Howells 14557ff50620SDavid Howells actual = PAGE_SIZE * nr; 14567ff50620SDavid Howells actual -= offset; 14577ff50620SDavid Howells if (nr == count && size > 0) { 14587ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 14597ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 14607ff50620SDavid Howells } 14617ff50620SDavid Howells return actual; 14627ff50620SDavid Howells } 14637ff50620SDavid Howells 14643d671ca6SAl Viro /* must be done on non-empty ITER_IOVEC one */ 14653d671ca6SAl Viro static unsigned long first_iovec_segment(const struct iov_iter *i, 14663d671ca6SAl Viro size_t *size, size_t *start, 14673d671ca6SAl Viro size_t maxsize, unsigned maxpages) 14683d671ca6SAl Viro { 14693d671ca6SAl Viro size_t skip; 14703d671ca6SAl Viro long k; 14713d671ca6SAl Viro 14723d671ca6SAl Viro for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { 14733d671ca6SAl Viro unsigned long addr = (unsigned long)i->iov[k].iov_base + skip; 14743d671ca6SAl Viro size_t len = i->iov[k].iov_len - skip; 14753d671ca6SAl Viro 14763d671ca6SAl Viro if (unlikely(!len)) 14773d671ca6SAl Viro continue; 14783d671ca6SAl Viro if (len > maxsize) 14793d671ca6SAl Viro len = maxsize; 14803d671ca6SAl Viro len += (*start = addr % PAGE_SIZE); 14813d671ca6SAl Viro if (len > maxpages * PAGE_SIZE) 14823d671ca6SAl Viro len = maxpages * PAGE_SIZE; 14833d671ca6SAl Viro *size = len; 14843d671ca6SAl Viro return addr & PAGE_MASK; 14853d671ca6SAl Viro } 14863d671ca6SAl Viro BUG(); // if it had been empty, we wouldn't get called 14873d671ca6SAl Viro } 14883d671ca6SAl Viro 14893d671ca6SAl Viro /* must be done on non-empty ITER_BVEC one */ 14903d671ca6SAl Viro static struct page *first_bvec_segment(const struct iov_iter *i, 14913d671ca6SAl Viro size_t *size, size_t *start, 14923d671ca6SAl Viro size_t maxsize, unsigned maxpages) 14933d671ca6SAl Viro { 14943d671ca6SAl Viro struct page *page; 14953d671ca6SAl Viro size_t skip = i->iov_offset, len; 14963d671ca6SAl Viro 14973d671ca6SAl Viro len = i->bvec->bv_len - skip; 14983d671ca6SAl Viro if (len > maxsize) 14993d671ca6SAl Viro len = maxsize; 15003d671ca6SAl Viro skip += i->bvec->bv_offset; 15013d671ca6SAl Viro page = i->bvec->bv_page + skip / PAGE_SIZE; 15023d671ca6SAl Viro len += (*start = skip % PAGE_SIZE); 15033d671ca6SAl Viro if (len > maxpages * PAGE_SIZE) 15043d671ca6SAl Viro len = maxpages * PAGE_SIZE; 15053d671ca6SAl Viro *size = len; 15063d671ca6SAl Viro return page; 15073d671ca6SAl Viro } 15083d671ca6SAl Viro 1509d879cb83SAl Viro ssize_t iov_iter_get_pages(struct iov_iter *i, 1510d879cb83SAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1511d879cb83SAl Viro size_t *start) 1512d879cb83SAl Viro { 15133d671ca6SAl Viro size_t len; 15143d671ca6SAl Viro int n, res; 15153d671ca6SAl Viro 1516d879cb83SAl Viro if (maxsize > i->count) 1517d879cb83SAl Viro maxsize = i->count; 15183d671ca6SAl Viro if (!maxsize) 15193d671ca6SAl Viro return 0; 1520d879cb83SAl Viro 15213d671ca6SAl Viro if (likely(iter_is_iovec(i))) { 15223d671ca6SAl Viro unsigned long addr; 15239ea9ce04SDavid Howells 15243d671ca6SAl Viro addr = first_iovec_segment(i, &len, start, maxsize, maxpages); 1525d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 152673b0140bSIra Weiny res = get_user_pages_fast(addr, n, 152773b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, 152873b0140bSIra Weiny pages); 1529d879cb83SAl Viro if (unlikely(res < 0)) 1530d879cb83SAl Viro return res; 1531d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 15323d671ca6SAl Viro } 15333d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 15343d671ca6SAl Viro struct page *page; 15353d671ca6SAl Viro 15363d671ca6SAl Viro page = first_bvec_segment(i, &len, start, maxsize, maxpages); 15373d671ca6SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 15383d671ca6SAl Viro while (n--) 15393d671ca6SAl Viro get_page(*pages++ = page++); 15403d671ca6SAl Viro return len - *start; 15413d671ca6SAl Viro } 15423d671ca6SAl Viro if (iov_iter_is_pipe(i)) 15433d671ca6SAl Viro return pipe_get_pages(i, pages, maxsize, maxpages, start); 15443d671ca6SAl Viro if (iov_iter_is_xarray(i)) 15453d671ca6SAl Viro return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); 1546d879cb83SAl Viro return -EFAULT; 1547d879cb83SAl Viro } 1548d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages); 1549d879cb83SAl Viro 1550d879cb83SAl Viro static struct page **get_pages_array(size_t n) 1551d879cb83SAl Viro { 1552752ade68SMichal Hocko return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); 1553d879cb83SAl Viro } 1554d879cb83SAl Viro 1555241699cdSAl Viro static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 1556241699cdSAl Viro struct page ***pages, size_t maxsize, 1557241699cdSAl Viro size_t *start) 1558241699cdSAl Viro { 1559241699cdSAl Viro struct page **p; 15608cefc107SDavid Howells unsigned int iter_head, npages; 1561d7760d63SIlya Dryomov ssize_t n; 1562241699cdSAl Viro 1563241699cdSAl Viro if (!sanity(i)) 1564241699cdSAl Viro return -EFAULT; 1565241699cdSAl Viro 15668cefc107SDavid Howells data_start(i, &iter_head, start); 15678cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 15688cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1569241699cdSAl Viro n = npages * PAGE_SIZE - *start; 1570241699cdSAl Viro if (maxsize > n) 1571241699cdSAl Viro maxsize = n; 1572241699cdSAl Viro else 1573241699cdSAl Viro npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1574241699cdSAl Viro p = get_pages_array(npages); 1575241699cdSAl Viro if (!p) 1576241699cdSAl Viro return -ENOMEM; 15778cefc107SDavid Howells n = __pipe_get_pages(i, maxsize, p, iter_head, start); 1578241699cdSAl Viro if (n > 0) 1579241699cdSAl Viro *pages = p; 1580241699cdSAl Viro else 1581241699cdSAl Viro kvfree(p); 1582241699cdSAl Viro return n; 1583241699cdSAl Viro } 1584241699cdSAl Viro 15857ff50620SDavid Howells static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, 15867ff50620SDavid Howells struct page ***pages, size_t maxsize, 15877ff50620SDavid Howells size_t *_start_offset) 15887ff50620SDavid Howells { 15897ff50620SDavid Howells struct page **p; 15907ff50620SDavid Howells unsigned nr, offset; 15917ff50620SDavid Howells pgoff_t index, count; 15927ff50620SDavid Howells size_t size = maxsize, actual; 15937ff50620SDavid Howells loff_t pos; 15947ff50620SDavid Howells 15957ff50620SDavid Howells if (!size) 15967ff50620SDavid Howells return 0; 15977ff50620SDavid Howells 15987ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 15997ff50620SDavid Howells index = pos >> PAGE_SHIFT; 16007ff50620SDavid Howells offset = pos & ~PAGE_MASK; 16017ff50620SDavid Howells *_start_offset = offset; 16027ff50620SDavid Howells 16037ff50620SDavid Howells count = 1; 16047ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 16057ff50620SDavid Howells size -= PAGE_SIZE - offset; 16067ff50620SDavid Howells count += size >> PAGE_SHIFT; 16077ff50620SDavid Howells size &= ~PAGE_MASK; 16087ff50620SDavid Howells if (size) 16097ff50620SDavid Howells count++; 16107ff50620SDavid Howells } 16117ff50620SDavid Howells 16127ff50620SDavid Howells p = get_pages_array(count); 16137ff50620SDavid Howells if (!p) 16147ff50620SDavid Howells return -ENOMEM; 16157ff50620SDavid Howells *pages = p; 16167ff50620SDavid Howells 16177ff50620SDavid Howells nr = iter_xarray_populate_pages(p, i->xarray, index, count); 16187ff50620SDavid Howells if (nr == 0) 16197ff50620SDavid Howells return 0; 16207ff50620SDavid Howells 16217ff50620SDavid Howells actual = PAGE_SIZE * nr; 16227ff50620SDavid Howells actual -= offset; 16237ff50620SDavid Howells if (nr == count && size > 0) { 16247ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 16257ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 16267ff50620SDavid Howells } 16277ff50620SDavid Howells return actual; 16287ff50620SDavid Howells } 16297ff50620SDavid Howells 1630d879cb83SAl Viro ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 1631d879cb83SAl Viro struct page ***pages, size_t maxsize, 1632d879cb83SAl Viro size_t *start) 1633d879cb83SAl Viro { 1634d879cb83SAl Viro struct page **p; 16353d671ca6SAl Viro size_t len; 16363d671ca6SAl Viro int n, res; 1637d879cb83SAl Viro 1638d879cb83SAl Viro if (maxsize > i->count) 1639d879cb83SAl Viro maxsize = i->count; 16403d671ca6SAl Viro if (!maxsize) 16413d671ca6SAl Viro return 0; 1642d879cb83SAl Viro 16433d671ca6SAl Viro if (likely(iter_is_iovec(i))) { 16443d671ca6SAl Viro unsigned long addr; 16459ea9ce04SDavid Howells 16463d671ca6SAl Viro addr = first_iovec_segment(i, &len, start, maxsize, ~0U); 1647d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 1648d879cb83SAl Viro p = get_pages_array(n); 1649d879cb83SAl Viro if (!p) 1650d879cb83SAl Viro return -ENOMEM; 165173b0140bSIra Weiny res = get_user_pages_fast(addr, n, 165273b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); 1653d879cb83SAl Viro if (unlikely(res < 0)) { 1654d879cb83SAl Viro kvfree(p); 1655d879cb83SAl Viro return res; 1656d879cb83SAl Viro } 1657d879cb83SAl Viro *pages = p; 1658d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 16593d671ca6SAl Viro } 16603d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 16613d671ca6SAl Viro struct page *page; 16623d671ca6SAl Viro 16633d671ca6SAl Viro page = first_bvec_segment(i, &len, start, maxsize, ~0U); 16643d671ca6SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 16653d671ca6SAl Viro *pages = p = get_pages_array(n); 1666d879cb83SAl Viro if (!p) 1667d879cb83SAl Viro return -ENOMEM; 16683d671ca6SAl Viro while (n--) 16693d671ca6SAl Viro get_page(*p++ = page++); 16703d671ca6SAl Viro return len - *start; 16713d671ca6SAl Viro } 16723d671ca6SAl Viro if (iov_iter_is_pipe(i)) 16733d671ca6SAl Viro return pipe_get_pages_alloc(i, pages, maxsize, start); 16743d671ca6SAl Viro if (iov_iter_is_xarray(i)) 16753d671ca6SAl Viro return iter_xarray_get_pages_alloc(i, pages, maxsize, start); 1676d879cb83SAl Viro return -EFAULT; 1677d879cb83SAl Viro } 1678d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages_alloc); 1679d879cb83SAl Viro 1680d879cb83SAl Viro size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 1681d879cb83SAl Viro struct iov_iter *i) 1682d879cb83SAl Viro { 1683d879cb83SAl Viro char *to = addr; 1684d879cb83SAl Viro __wsum sum, next; 1685d879cb83SAl Viro size_t off = 0; 1686d879cb83SAl Viro sum = *csum; 16879ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1688241699cdSAl Viro WARN_ON(1); 1689241699cdSAl Viro return 0; 1690241699cdSAl Viro } 1691d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1692d879cb83SAl Viro next = csum_and_copy_from_user(v.iov_base, 1693d879cb83SAl Viro (to += v.iov_len) - v.iov_len, 1694c693cc46SAl Viro v.iov_len); 1695c693cc46SAl Viro if (next) { 1696d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1697d879cb83SAl Viro off += v.iov_len; 1698d879cb83SAl Viro } 1699c693cc46SAl Viro next ? 0 : v.iov_len; 1700d879cb83SAl Viro }), ({ 1701d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1702f9152895SAl Viro sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 1703f9152895SAl Viro p + v.bv_offset, v.bv_len, 1704f9152895SAl Viro sum, off); 1705d879cb83SAl Viro kunmap_atomic(p); 1706d879cb83SAl Viro off += v.bv_len; 1707d879cb83SAl Viro }),({ 1708f9152895SAl Viro sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, 1709f9152895SAl Viro v.iov_base, v.iov_len, 1710f9152895SAl Viro sum, off); 1711d879cb83SAl Viro off += v.iov_len; 17127ff50620SDavid Howells }), ({ 17137ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 17147ff50620SDavid Howells sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 17157ff50620SDavid Howells p + v.bv_offset, v.bv_len, 17167ff50620SDavid Howells sum, off); 17177ff50620SDavid Howells kunmap_atomic(p); 17187ff50620SDavid Howells off += v.bv_len; 1719d879cb83SAl Viro }) 1720d879cb83SAl Viro ) 1721d879cb83SAl Viro *csum = sum; 1722d879cb83SAl Viro return bytes; 1723d879cb83SAl Viro } 1724d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter); 1725d879cb83SAl Viro 172652cbd23aSWillem de Bruijn size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 1727d879cb83SAl Viro struct iov_iter *i) 1728d879cb83SAl Viro { 172952cbd23aSWillem de Bruijn struct csum_state *csstate = _csstate; 173036f7a8a4SAl Viro const char *from = addr; 1731d879cb83SAl Viro __wsum sum, next; 173252cbd23aSWillem de Bruijn size_t off; 173378e1f386SAl Viro 173478e1f386SAl Viro if (unlikely(iov_iter_is_pipe(i))) 173552cbd23aSWillem de Bruijn return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); 173678e1f386SAl Viro 1737594e450bSAl Viro sum = csum_shift(csstate->csum, csstate->off); 1738594e450bSAl Viro off = 0; 173978e1f386SAl Viro if (unlikely(iov_iter_is_discard(i))) { 1740241699cdSAl Viro WARN_ON(1); /* for now */ 1741241699cdSAl Viro return 0; 1742241699cdSAl Viro } 1743d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1744d879cb83SAl Viro next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, 1745d879cb83SAl Viro v.iov_base, 1746c693cc46SAl Viro v.iov_len); 1747c693cc46SAl Viro if (next) { 1748d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1749d879cb83SAl Viro off += v.iov_len; 1750d879cb83SAl Viro } 1751c693cc46SAl Viro next ? 0 : v.iov_len; 1752d879cb83SAl Viro }), ({ 1753d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1754f9152895SAl Viro sum = csum_and_memcpy(p + v.bv_offset, 1755f9152895SAl Viro (from += v.bv_len) - v.bv_len, 1756f9152895SAl Viro v.bv_len, sum, off); 1757d879cb83SAl Viro kunmap_atomic(p); 1758d879cb83SAl Viro off += v.bv_len; 1759d879cb83SAl Viro }),({ 1760f9152895SAl Viro sum = csum_and_memcpy(v.iov_base, 1761f9152895SAl Viro (from += v.iov_len) - v.iov_len, 1762f9152895SAl Viro v.iov_len, sum, off); 1763d879cb83SAl Viro off += v.iov_len; 17647ff50620SDavid Howells }), ({ 17657ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 17667ff50620SDavid Howells sum = csum_and_memcpy(p + v.bv_offset, 17677ff50620SDavid Howells (from += v.bv_len) - v.bv_len, 17687ff50620SDavid Howells v.bv_len, sum, off); 17697ff50620SDavid Howells kunmap_atomic(p); 17707ff50620SDavid Howells off += v.bv_len; 1771d879cb83SAl Viro }) 1772d879cb83SAl Viro ) 1773594e450bSAl Viro csstate->csum = csum_shift(sum, csstate->off); 1774594e450bSAl Viro csstate->off += bytes; 1775d879cb83SAl Viro return bytes; 1776d879cb83SAl Viro } 1777d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_to_iter); 1778d879cb83SAl Viro 1779d05f4435SSagi Grimberg size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, 1780d05f4435SSagi Grimberg struct iov_iter *i) 1781d05f4435SSagi Grimberg { 17827999096fSHerbert Xu #ifdef CONFIG_CRYPTO_HASH 1783d05f4435SSagi Grimberg struct ahash_request *hash = hashp; 1784d05f4435SSagi Grimberg struct scatterlist sg; 1785d05f4435SSagi Grimberg size_t copied; 1786d05f4435SSagi Grimberg 1787d05f4435SSagi Grimberg copied = copy_to_iter(addr, bytes, i); 1788d05f4435SSagi Grimberg sg_init_one(&sg, addr, copied); 1789d05f4435SSagi Grimberg ahash_request_set_crypt(hash, &sg, NULL, copied); 1790d05f4435SSagi Grimberg crypto_ahash_update(hash); 1791d05f4435SSagi Grimberg return copied; 179227fad74aSYueHaibing #else 179327fad74aSYueHaibing return 0; 179427fad74aSYueHaibing #endif 1795d05f4435SSagi Grimberg } 1796d05f4435SSagi Grimberg EXPORT_SYMBOL(hash_and_copy_to_iter); 1797d05f4435SSagi Grimberg 179866531c65SAl Viro static int iov_npages(const struct iov_iter *i, int maxpages) 1799d879cb83SAl Viro { 180066531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 180166531c65SAl Viro const struct iovec *p; 1802d879cb83SAl Viro int npages = 0; 1803d879cb83SAl Viro 180466531c65SAl Viro for (p = i->iov; size; skip = 0, p++) { 180566531c65SAl Viro unsigned offs = offset_in_page(p->iov_base + skip); 180666531c65SAl Viro size_t len = min(p->iov_len - skip, size); 1807d879cb83SAl Viro 180866531c65SAl Viro if (len) { 180966531c65SAl Viro size -= len; 181066531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 181166531c65SAl Viro if (unlikely(npages > maxpages)) 181266531c65SAl Viro return maxpages; 181366531c65SAl Viro } 181466531c65SAl Viro } 181566531c65SAl Viro return npages; 181666531c65SAl Viro } 181766531c65SAl Viro 181866531c65SAl Viro static int bvec_npages(const struct iov_iter *i, int maxpages) 181966531c65SAl Viro { 182066531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 182166531c65SAl Viro const struct bio_vec *p; 182266531c65SAl Viro int npages = 0; 182366531c65SAl Viro 182466531c65SAl Viro for (p = i->bvec; size; skip = 0, p++) { 182566531c65SAl Viro unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; 182666531c65SAl Viro size_t len = min(p->bv_len - skip, size); 182766531c65SAl Viro 182866531c65SAl Viro size -= len; 182966531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 183066531c65SAl Viro if (unlikely(npages > maxpages)) 183166531c65SAl Viro return maxpages; 183266531c65SAl Viro } 183366531c65SAl Viro return npages; 183466531c65SAl Viro } 183566531c65SAl Viro 183666531c65SAl Viro int iov_iter_npages(const struct iov_iter *i, int maxpages) 183766531c65SAl Viro { 183866531c65SAl Viro if (unlikely(!i->count)) 183966531c65SAl Viro return 0; 184066531c65SAl Viro /* iovec and kvec have identical layouts */ 184166531c65SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 184266531c65SAl Viro return iov_npages(i, maxpages); 184366531c65SAl Viro if (iov_iter_is_bvec(i)) 184466531c65SAl Viro return bvec_npages(i, maxpages); 184566531c65SAl Viro if (iov_iter_is_pipe(i)) { 18468cefc107SDavid Howells unsigned int iter_head; 184766531c65SAl Viro int npages; 1848241699cdSAl Viro size_t off; 1849241699cdSAl Viro 1850241699cdSAl Viro if (!sanity(i)) 1851241699cdSAl Viro return 0; 1852241699cdSAl Viro 18538cefc107SDavid Howells data_start(i, &iter_head, &off); 1854241699cdSAl Viro /* some of this one + all after this one */ 185566531c65SAl Viro npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 185666531c65SAl Viro return min(npages, maxpages); 185766531c65SAl Viro } 185866531c65SAl Viro if (iov_iter_is_xarray(i)) { 1859e4f8df86SAl Viro unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; 1860e4f8df86SAl Viro int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); 186166531c65SAl Viro return min(npages, maxpages); 186266531c65SAl Viro } 186366531c65SAl Viro return 0; 1864d879cb83SAl Viro } 1865d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_npages); 1866d879cb83SAl Viro 1867d879cb83SAl Viro const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) 1868d879cb83SAl Viro { 1869d879cb83SAl Viro *new = *old; 187000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(new))) { 1871241699cdSAl Viro WARN_ON(1); 1872241699cdSAl Viro return NULL; 1873241699cdSAl Viro } 18747ff50620SDavid Howells if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) 18759ea9ce04SDavid Howells return NULL; 187600e23707SDavid Howells if (iov_iter_is_bvec(new)) 1877d879cb83SAl Viro return new->bvec = kmemdup(new->bvec, 1878d879cb83SAl Viro new->nr_segs * sizeof(struct bio_vec), 1879d879cb83SAl Viro flags); 1880d879cb83SAl Viro else 1881d879cb83SAl Viro /* iovec and kvec have identical layout */ 1882d879cb83SAl Viro return new->iov = kmemdup(new->iov, 1883d879cb83SAl Viro new->nr_segs * sizeof(struct iovec), 1884d879cb83SAl Viro flags); 1885d879cb83SAl Viro } 1886d879cb83SAl Viro EXPORT_SYMBOL(dup_iter); 1887bc917be8SAl Viro 1888bfdc5970SChristoph Hellwig static int copy_compat_iovec_from_user(struct iovec *iov, 1889bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1890bfdc5970SChristoph Hellwig { 1891bfdc5970SChristoph Hellwig const struct compat_iovec __user *uiov = 1892bfdc5970SChristoph Hellwig (const struct compat_iovec __user *)uvec; 1893bfdc5970SChristoph Hellwig int ret = -EFAULT, i; 1894bfdc5970SChristoph Hellwig 1895a959a978SChristoph Hellwig if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) 1896bfdc5970SChristoph Hellwig return -EFAULT; 1897bfdc5970SChristoph Hellwig 1898bfdc5970SChristoph Hellwig for (i = 0; i < nr_segs; i++) { 1899bfdc5970SChristoph Hellwig compat_uptr_t buf; 1900bfdc5970SChristoph Hellwig compat_ssize_t len; 1901bfdc5970SChristoph Hellwig 1902bfdc5970SChristoph Hellwig unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); 1903bfdc5970SChristoph Hellwig unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); 1904bfdc5970SChristoph Hellwig 1905bfdc5970SChristoph Hellwig /* check for compat_size_t not fitting in compat_ssize_t .. */ 1906bfdc5970SChristoph Hellwig if (len < 0) { 1907bfdc5970SChristoph Hellwig ret = -EINVAL; 1908bfdc5970SChristoph Hellwig goto uaccess_end; 1909bfdc5970SChristoph Hellwig } 1910bfdc5970SChristoph Hellwig iov[i].iov_base = compat_ptr(buf); 1911bfdc5970SChristoph Hellwig iov[i].iov_len = len; 1912bfdc5970SChristoph Hellwig } 1913bfdc5970SChristoph Hellwig 1914bfdc5970SChristoph Hellwig ret = 0; 1915bfdc5970SChristoph Hellwig uaccess_end: 1916bfdc5970SChristoph Hellwig user_access_end(); 1917bfdc5970SChristoph Hellwig return ret; 1918bfdc5970SChristoph Hellwig } 1919bfdc5970SChristoph Hellwig 1920bfdc5970SChristoph Hellwig static int copy_iovec_from_user(struct iovec *iov, 1921bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1922fb041b59SDavid Laight { 1923fb041b59SDavid Laight unsigned long seg; 1924bfdc5970SChristoph Hellwig 1925bfdc5970SChristoph Hellwig if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) 1926bfdc5970SChristoph Hellwig return -EFAULT; 1927bfdc5970SChristoph Hellwig for (seg = 0; seg < nr_segs; seg++) { 1928bfdc5970SChristoph Hellwig if ((ssize_t)iov[seg].iov_len < 0) 1929bfdc5970SChristoph Hellwig return -EINVAL; 1930bfdc5970SChristoph Hellwig } 1931bfdc5970SChristoph Hellwig 1932bfdc5970SChristoph Hellwig return 0; 1933bfdc5970SChristoph Hellwig } 1934bfdc5970SChristoph Hellwig 1935bfdc5970SChristoph Hellwig struct iovec *iovec_from_user(const struct iovec __user *uvec, 1936bfdc5970SChristoph Hellwig unsigned long nr_segs, unsigned long fast_segs, 1937bfdc5970SChristoph Hellwig struct iovec *fast_iov, bool compat) 1938bfdc5970SChristoph Hellwig { 1939bfdc5970SChristoph Hellwig struct iovec *iov = fast_iov; 1940bfdc5970SChristoph Hellwig int ret; 1941fb041b59SDavid Laight 1942fb041b59SDavid Laight /* 1943bfdc5970SChristoph Hellwig * SuS says "The readv() function *may* fail if the iovcnt argument was 1944bfdc5970SChristoph Hellwig * less than or equal to 0, or greater than {IOV_MAX}. Linux has 1945fb041b59SDavid Laight * traditionally returned zero for zero segments, so... 1946fb041b59SDavid Laight */ 1947bfdc5970SChristoph Hellwig if (nr_segs == 0) 1948bfdc5970SChristoph Hellwig return iov; 1949bfdc5970SChristoph Hellwig if (nr_segs > UIO_MAXIOV) 1950bfdc5970SChristoph Hellwig return ERR_PTR(-EINVAL); 1951fb041b59SDavid Laight if (nr_segs > fast_segs) { 1952fb041b59SDavid Laight iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); 1953bfdc5970SChristoph Hellwig if (!iov) 1954bfdc5970SChristoph Hellwig return ERR_PTR(-ENOMEM); 1955fb041b59SDavid Laight } 1956bfdc5970SChristoph Hellwig 1957bfdc5970SChristoph Hellwig if (compat) 1958bfdc5970SChristoph Hellwig ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); 1959bfdc5970SChristoph Hellwig else 1960bfdc5970SChristoph Hellwig ret = copy_iovec_from_user(iov, uvec, nr_segs); 1961bfdc5970SChristoph Hellwig if (ret) { 1962bfdc5970SChristoph Hellwig if (iov != fast_iov) 1963bfdc5970SChristoph Hellwig kfree(iov); 1964bfdc5970SChristoph Hellwig return ERR_PTR(ret); 1965fb041b59SDavid Laight } 1966bfdc5970SChristoph Hellwig 1967bfdc5970SChristoph Hellwig return iov; 1968bfdc5970SChristoph Hellwig } 1969bfdc5970SChristoph Hellwig 1970bfdc5970SChristoph Hellwig ssize_t __import_iovec(int type, const struct iovec __user *uvec, 1971bfdc5970SChristoph Hellwig unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, 1972bfdc5970SChristoph Hellwig struct iov_iter *i, bool compat) 1973bfdc5970SChristoph Hellwig { 1974bfdc5970SChristoph Hellwig ssize_t total_len = 0; 1975bfdc5970SChristoph Hellwig unsigned long seg; 1976bfdc5970SChristoph Hellwig struct iovec *iov; 1977bfdc5970SChristoph Hellwig 1978bfdc5970SChristoph Hellwig iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); 1979bfdc5970SChristoph Hellwig if (IS_ERR(iov)) { 1980bfdc5970SChristoph Hellwig *iovp = NULL; 1981bfdc5970SChristoph Hellwig return PTR_ERR(iov); 1982fb041b59SDavid Laight } 1983fb041b59SDavid Laight 1984fb041b59SDavid Laight /* 1985bfdc5970SChristoph Hellwig * According to the Single Unix Specification we should return EINVAL if 1986bfdc5970SChristoph Hellwig * an element length is < 0 when cast to ssize_t or if the total length 1987bfdc5970SChristoph Hellwig * would overflow the ssize_t return value of the system call. 1988fb041b59SDavid Laight * 1989fb041b59SDavid Laight * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the 1990fb041b59SDavid Laight * overflow case. 1991fb041b59SDavid Laight */ 1992fb041b59SDavid Laight for (seg = 0; seg < nr_segs; seg++) { 1993fb041b59SDavid Laight ssize_t len = (ssize_t)iov[seg].iov_len; 1994fb041b59SDavid Laight 1995bfdc5970SChristoph Hellwig if (!access_ok(iov[seg].iov_base, len)) { 1996bfdc5970SChristoph Hellwig if (iov != *iovp) 1997bfdc5970SChristoph Hellwig kfree(iov); 1998bfdc5970SChristoph Hellwig *iovp = NULL; 1999bfdc5970SChristoph Hellwig return -EFAULT; 2000fb041b59SDavid Laight } 2001bfdc5970SChristoph Hellwig 2002bfdc5970SChristoph Hellwig if (len > MAX_RW_COUNT - total_len) { 2003bfdc5970SChristoph Hellwig len = MAX_RW_COUNT - total_len; 2004fb041b59SDavid Laight iov[seg].iov_len = len; 2005fb041b59SDavid Laight } 2006bfdc5970SChristoph Hellwig total_len += len; 2007fb041b59SDavid Laight } 2008bfdc5970SChristoph Hellwig 2009bfdc5970SChristoph Hellwig iov_iter_init(i, type, iov, nr_segs, total_len); 2010bfdc5970SChristoph Hellwig if (iov == *iovp) 2011bfdc5970SChristoph Hellwig *iovp = NULL; 2012bfdc5970SChristoph Hellwig else 2013bfdc5970SChristoph Hellwig *iovp = iov; 2014bfdc5970SChristoph Hellwig return total_len; 2015fb041b59SDavid Laight } 2016fb041b59SDavid Laight 2017ffecee4fSVegard Nossum /** 2018ffecee4fSVegard Nossum * import_iovec() - Copy an array of &struct iovec from userspace 2019ffecee4fSVegard Nossum * into the kernel, check that it is valid, and initialize a new 2020ffecee4fSVegard Nossum * &struct iov_iter iterator to access it. 2021ffecee4fSVegard Nossum * 2022ffecee4fSVegard Nossum * @type: One of %READ or %WRITE. 2023bfdc5970SChristoph Hellwig * @uvec: Pointer to the userspace array. 2024ffecee4fSVegard Nossum * @nr_segs: Number of elements in userspace array. 2025ffecee4fSVegard Nossum * @fast_segs: Number of elements in @iov. 2026bfdc5970SChristoph Hellwig * @iovp: (input and output parameter) Pointer to pointer to (usually small 2027ffecee4fSVegard Nossum * on-stack) kernel array. 2028ffecee4fSVegard Nossum * @i: Pointer to iterator that will be initialized on success. 2029ffecee4fSVegard Nossum * 2030ffecee4fSVegard Nossum * If the array pointed to by *@iov is large enough to hold all @nr_segs, 2031ffecee4fSVegard Nossum * then this function places %NULL in *@iov on return. Otherwise, a new 2032ffecee4fSVegard Nossum * array will be allocated and the result placed in *@iov. This means that 2033ffecee4fSVegard Nossum * the caller may call kfree() on *@iov regardless of whether the small 2034ffecee4fSVegard Nossum * on-stack array was used or not (and regardless of whether this function 2035ffecee4fSVegard Nossum * returns an error or not). 2036ffecee4fSVegard Nossum * 203787e5e6daSJens Axboe * Return: Negative error code on error, bytes imported on success 2038ffecee4fSVegard Nossum */ 2039bfdc5970SChristoph Hellwig ssize_t import_iovec(int type, const struct iovec __user *uvec, 2040bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 2041bfdc5970SChristoph Hellwig struct iovec **iovp, struct iov_iter *i) 2042bc917be8SAl Viro { 204389cd35c5SChristoph Hellwig return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, 204489cd35c5SChristoph Hellwig in_compat_syscall()); 2045bc917be8SAl Viro } 2046bc917be8SAl Viro EXPORT_SYMBOL(import_iovec); 2047bc917be8SAl Viro 2048bc917be8SAl Viro int import_single_range(int rw, void __user *buf, size_t len, 2049bc917be8SAl Viro struct iovec *iov, struct iov_iter *i) 2050bc917be8SAl Viro { 2051bc917be8SAl Viro if (len > MAX_RW_COUNT) 2052bc917be8SAl Viro len = MAX_RW_COUNT; 205396d4f267SLinus Torvalds if (unlikely(!access_ok(buf, len))) 2054bc917be8SAl Viro return -EFAULT; 2055bc917be8SAl Viro 2056bc917be8SAl Viro iov->iov_base = buf; 2057bc917be8SAl Viro iov->iov_len = len; 2058bc917be8SAl Viro iov_iter_init(i, rw, iov, 1, len); 2059bc917be8SAl Viro return 0; 2060bc917be8SAl Viro } 2061e1267585SAl Viro EXPORT_SYMBOL(import_single_range); 2062