1457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 27999096fSHerbert Xu #include <crypto/hash.h> 3d879cb83SAl Viro #include <linux/export.h> 42f8b5444SChristoph Hellwig #include <linux/bvec.h> 54d0e9df5SAlbert van der Linde #include <linux/fault-inject-usercopy.h> 6d879cb83SAl Viro #include <linux/uio.h> 7d879cb83SAl Viro #include <linux/pagemap.h> 828961998SIra Weiny #include <linux/highmem.h> 9d879cb83SAl Viro #include <linux/slab.h> 10d879cb83SAl Viro #include <linux/vmalloc.h> 11241699cdSAl Viro #include <linux/splice.h> 12bfdc5970SChristoph Hellwig #include <linux/compat.h> 13d879cb83SAl Viro #include <net/checksum.h> 14d05f4435SSagi Grimberg #include <linux/scatterlist.h> 15d0ef4c36SMarco Elver #include <linux/instrumented.h> 16d879cb83SAl Viro 17241699cdSAl Viro #define PIPE_PARANOIA /* for now */ 18241699cdSAl Viro 19d879cb83SAl Viro #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ 20d879cb83SAl Viro size_t left; \ 21d879cb83SAl Viro size_t wanted = n; \ 22d879cb83SAl Viro __p = i->iov; \ 23*7a1bcb5dSAl 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; \ 31*7a1bcb5dSAl Viro if (skip < __p->iov_len) \ 32*7a1bcb5dSAl Viro break; \ 33d879cb83SAl Viro } \ 34d879cb83SAl Viro __p++; \ 35*7a1bcb5dSAl Viro skip = 0; \ 36*7a1bcb5dSAl Viro } while (n); \ 37d879cb83SAl Viro n = wanted - n; \ 38d879cb83SAl Viro } 39d879cb83SAl Viro 40d879cb83SAl Viro #define iterate_kvec(i, n, __v, __p, skip, STEP) { \ 41d879cb83SAl Viro size_t wanted = n; \ 42d879cb83SAl Viro __p = i->kvec; \ 43*7a1bcb5dSAl Viro do { \ 44d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len - skip); \ 45d879cb83SAl Viro if (likely(__v.iov_len)) { \ 46d879cb83SAl Viro __v.iov_base = __p->iov_base + skip; \ 47d879cb83SAl Viro (void)(STEP); \ 48d879cb83SAl Viro skip += __v.iov_len; \ 49d879cb83SAl Viro n -= __v.iov_len; \ 50*7a1bcb5dSAl Viro if (skip < __p->iov_len) \ 51*7a1bcb5dSAl Viro break; \ 52d879cb83SAl Viro } \ 53d879cb83SAl Viro __p++; \ 54*7a1bcb5dSAl Viro skip = 0; \ 55*7a1bcb5dSAl Viro } while (n); \ 56*7a1bcb5dSAl Viro n = wanted - n; \ 57d879cb83SAl Viro } 58d879cb83SAl Viro 591bdc76aeSMing Lei #define iterate_bvec(i, n, __v, __bi, skip, STEP) { \ 601bdc76aeSMing Lei struct bvec_iter __start; \ 611bdc76aeSMing Lei __start.bi_size = n; \ 621bdc76aeSMing Lei __start.bi_bvec_done = skip; \ 631bdc76aeSMing Lei __start.bi_idx = 0; \ 641bdc76aeSMing Lei for_each_bvec(__v, i->bvec, __bi, __start) { \ 65d879cb83SAl Viro (void)(STEP); \ 66d879cb83SAl Viro } \ 67d879cb83SAl Viro } 68d879cb83SAl Viro 697ff50620SDavid Howells #define iterate_xarray(i, n, __v, skip, STEP) { \ 707ff50620SDavid Howells struct page *head = NULL; \ 717ff50620SDavid Howells size_t wanted = n, seg, offset; \ 727ff50620SDavid Howells loff_t start = i->xarray_start + skip; \ 737ff50620SDavid Howells pgoff_t index = start >> PAGE_SHIFT; \ 747ff50620SDavid Howells int j; \ 757ff50620SDavid Howells \ 767ff50620SDavid Howells XA_STATE(xas, i->xarray, index); \ 777ff50620SDavid Howells \ 787ff50620SDavid Howells rcu_read_lock(); \ 797ff50620SDavid Howells xas_for_each(&xas, head, ULONG_MAX) { \ 807ff50620SDavid Howells if (xas_retry(&xas, head)) \ 817ff50620SDavid Howells continue; \ 827ff50620SDavid Howells if (WARN_ON(xa_is_value(head))) \ 837ff50620SDavid Howells break; \ 847ff50620SDavid Howells if (WARN_ON(PageHuge(head))) \ 857ff50620SDavid Howells break; \ 867ff50620SDavid Howells for (j = (head->index < index) ? index - head->index : 0; \ 877ff50620SDavid Howells j < thp_nr_pages(head); j++) { \ 887ff50620SDavid Howells __v.bv_page = head + j; \ 897ff50620SDavid Howells offset = (i->xarray_start + skip) & ~PAGE_MASK; \ 907ff50620SDavid Howells seg = PAGE_SIZE - offset; \ 917ff50620SDavid Howells __v.bv_offset = offset; \ 927ff50620SDavid Howells __v.bv_len = min(n, seg); \ 937ff50620SDavid Howells (void)(STEP); \ 947ff50620SDavid Howells n -= __v.bv_len; \ 957ff50620SDavid Howells skip += __v.bv_len; \ 967ff50620SDavid Howells if (n == 0) \ 977ff50620SDavid Howells break; \ 987ff50620SDavid Howells } \ 997ff50620SDavid Howells if (n == 0) \ 1007ff50620SDavid Howells break; \ 1017ff50620SDavid Howells } \ 1027ff50620SDavid Howells rcu_read_unlock(); \ 1037ff50620SDavid Howells n = wanted - n; \ 1047ff50620SDavid Howells } 1057ff50620SDavid Howells 1067ff50620SDavid Howells #define iterate_and_advance(i, n, v, I, B, K, X) { \ 107dd254f5aSAl Viro if (unlikely(i->count < n)) \ 108dd254f5aSAl Viro n = i->count; \ 109f5da8354SAl Viro if (likely(n)) { \ 110d879cb83SAl Viro size_t skip = i->iov_offset; \ 11128f38db7SAl Viro if (likely(iter_is_iovec(i))) { \ 112d879cb83SAl Viro const struct iovec *iov; \ 113d879cb83SAl Viro struct iovec v; \ 114d879cb83SAl Viro iterate_iovec(i, n, v, iov, skip, (I)) \ 115d879cb83SAl Viro i->nr_segs -= iov - i->iov; \ 116d879cb83SAl Viro i->iov = iov; \ 11728f38db7SAl Viro } else if (iov_iter_is_bvec(i)) { \ 11828f38db7SAl Viro const struct bio_vec *bvec = i->bvec; \ 11928f38db7SAl Viro struct bio_vec v; \ 12028f38db7SAl Viro struct bvec_iter __bi; \ 12128f38db7SAl Viro iterate_bvec(i, n, v, __bi, skip, (B)) \ 12228f38db7SAl Viro i->bvec = __bvec_iter_bvec(i->bvec, __bi); \ 12328f38db7SAl Viro i->nr_segs -= i->bvec - bvec; \ 12428f38db7SAl Viro skip = __bi.bi_bvec_done; \ 12528f38db7SAl Viro } else if (iov_iter_is_kvec(i)) { \ 12628f38db7SAl Viro const struct kvec *kvec; \ 12728f38db7SAl Viro struct kvec v; \ 12828f38db7SAl Viro iterate_kvec(i, n, v, kvec, skip, (K)) \ 12928f38db7SAl Viro i->nr_segs -= kvec - i->kvec; \ 13028f38db7SAl Viro i->kvec = kvec; \ 13128f38db7SAl Viro } else if (iov_iter_is_xarray(i)) { \ 13228f38db7SAl Viro struct bio_vec v; \ 13328f38db7SAl Viro iterate_xarray(i, n, v, skip, (X)) \ 134d879cb83SAl Viro } \ 135d879cb83SAl Viro i->count -= n; \ 136d879cb83SAl Viro i->iov_offset = skip; \ 137dd254f5aSAl Viro } \ 138d879cb83SAl Viro } 139d879cb83SAl Viro 14009fc68dcSAl Viro static int copyout(void __user *to, const void *from, size_t n) 14109fc68dcSAl Viro { 1424d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1434d0e9df5SAlbert van der Linde return n; 14496d4f267SLinus Torvalds if (access_ok(to, n)) { 145d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 14609fc68dcSAl Viro n = raw_copy_to_user(to, from, n); 14709fc68dcSAl Viro } 14809fc68dcSAl Viro return n; 14909fc68dcSAl Viro } 15009fc68dcSAl Viro 15109fc68dcSAl Viro static int copyin(void *to, const void __user *from, size_t n) 15209fc68dcSAl Viro { 1534d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1544d0e9df5SAlbert van der Linde return n; 15596d4f267SLinus Torvalds if (access_ok(from, n)) { 156d0ef4c36SMarco Elver instrument_copy_from_user(to, from, n); 15709fc68dcSAl Viro n = raw_copy_from_user(to, from, n); 15809fc68dcSAl Viro } 15909fc68dcSAl Viro return n; 16009fc68dcSAl Viro } 16109fc68dcSAl Viro 162d879cb83SAl Viro static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, 163d879cb83SAl Viro struct iov_iter *i) 164d879cb83SAl Viro { 165d879cb83SAl Viro size_t skip, copy, left, wanted; 166d879cb83SAl Viro const struct iovec *iov; 167d879cb83SAl Viro char __user *buf; 168d879cb83SAl Viro void *kaddr, *from; 169d879cb83SAl Viro 170d879cb83SAl Viro if (unlikely(bytes > i->count)) 171d879cb83SAl Viro bytes = i->count; 172d879cb83SAl Viro 173d879cb83SAl Viro if (unlikely(!bytes)) 174d879cb83SAl Viro return 0; 175d879cb83SAl Viro 17609fc68dcSAl Viro might_fault(); 177d879cb83SAl Viro wanted = bytes; 178d879cb83SAl Viro iov = i->iov; 179d879cb83SAl Viro skip = i->iov_offset; 180d879cb83SAl Viro buf = iov->iov_base + skip; 181d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 182d879cb83SAl Viro 1833fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { 184d879cb83SAl Viro kaddr = kmap_atomic(page); 185d879cb83SAl Viro from = kaddr + offset; 186d879cb83SAl Viro 187d879cb83SAl Viro /* first chunk, usually the only one */ 18809fc68dcSAl Viro left = copyout(buf, from, copy); 189d879cb83SAl Viro copy -= left; 190d879cb83SAl Viro skip += copy; 191d879cb83SAl Viro from += copy; 192d879cb83SAl Viro bytes -= copy; 193d879cb83SAl Viro 194d879cb83SAl Viro while (unlikely(!left && bytes)) { 195d879cb83SAl Viro iov++; 196d879cb83SAl Viro buf = iov->iov_base; 197d879cb83SAl Viro copy = min(bytes, iov->iov_len); 19809fc68dcSAl Viro left = copyout(buf, from, copy); 199d879cb83SAl Viro copy -= left; 200d879cb83SAl Viro skip = copy; 201d879cb83SAl Viro from += copy; 202d879cb83SAl Viro bytes -= copy; 203d879cb83SAl Viro } 204d879cb83SAl Viro if (likely(!bytes)) { 205d879cb83SAl Viro kunmap_atomic(kaddr); 206d879cb83SAl Viro goto done; 207d879cb83SAl Viro } 208d879cb83SAl Viro offset = from - kaddr; 209d879cb83SAl Viro buf += copy; 210d879cb83SAl Viro kunmap_atomic(kaddr); 211d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 212d879cb83SAl Viro } 213d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 2143fa6c507SMikulas Patocka 215d879cb83SAl Viro kaddr = kmap(page); 216d879cb83SAl Viro from = kaddr + offset; 21709fc68dcSAl Viro left = copyout(buf, from, copy); 218d879cb83SAl Viro copy -= left; 219d879cb83SAl Viro skip += copy; 220d879cb83SAl Viro from += copy; 221d879cb83SAl Viro bytes -= copy; 222d879cb83SAl Viro while (unlikely(!left && bytes)) { 223d879cb83SAl Viro iov++; 224d879cb83SAl Viro buf = iov->iov_base; 225d879cb83SAl Viro copy = min(bytes, iov->iov_len); 22609fc68dcSAl Viro left = copyout(buf, from, copy); 227d879cb83SAl Viro copy -= left; 228d879cb83SAl Viro skip = copy; 229d879cb83SAl Viro from += copy; 230d879cb83SAl Viro bytes -= copy; 231d879cb83SAl Viro } 232d879cb83SAl Viro kunmap(page); 2333fa6c507SMikulas Patocka 234d879cb83SAl Viro done: 235d879cb83SAl Viro if (skip == iov->iov_len) { 236d879cb83SAl Viro iov++; 237d879cb83SAl Viro skip = 0; 238d879cb83SAl Viro } 239d879cb83SAl Viro i->count -= wanted - bytes; 240d879cb83SAl Viro i->nr_segs -= iov - i->iov; 241d879cb83SAl Viro i->iov = iov; 242d879cb83SAl Viro i->iov_offset = skip; 243d879cb83SAl Viro return wanted - bytes; 244d879cb83SAl Viro } 245d879cb83SAl Viro 246d879cb83SAl Viro static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, 247d879cb83SAl Viro struct iov_iter *i) 248d879cb83SAl Viro { 249d879cb83SAl Viro size_t skip, copy, left, wanted; 250d879cb83SAl Viro const struct iovec *iov; 251d879cb83SAl Viro char __user *buf; 252d879cb83SAl Viro void *kaddr, *to; 253d879cb83SAl Viro 254d879cb83SAl Viro if (unlikely(bytes > i->count)) 255d879cb83SAl Viro bytes = i->count; 256d879cb83SAl Viro 257d879cb83SAl Viro if (unlikely(!bytes)) 258d879cb83SAl Viro return 0; 259d879cb83SAl Viro 26009fc68dcSAl Viro might_fault(); 261d879cb83SAl Viro wanted = bytes; 262d879cb83SAl Viro iov = i->iov; 263d879cb83SAl Viro skip = i->iov_offset; 264d879cb83SAl Viro buf = iov->iov_base + skip; 265d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 266d879cb83SAl Viro 2673fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { 268d879cb83SAl Viro kaddr = kmap_atomic(page); 269d879cb83SAl Viro to = kaddr + offset; 270d879cb83SAl Viro 271d879cb83SAl Viro /* first chunk, usually the only one */ 27209fc68dcSAl Viro left = copyin(to, buf, copy); 273d879cb83SAl Viro copy -= left; 274d879cb83SAl Viro skip += copy; 275d879cb83SAl Viro to += copy; 276d879cb83SAl Viro bytes -= copy; 277d879cb83SAl Viro 278d879cb83SAl Viro while (unlikely(!left && bytes)) { 279d879cb83SAl Viro iov++; 280d879cb83SAl Viro buf = iov->iov_base; 281d879cb83SAl Viro copy = min(bytes, iov->iov_len); 28209fc68dcSAl Viro left = copyin(to, buf, copy); 283d879cb83SAl Viro copy -= left; 284d879cb83SAl Viro skip = copy; 285d879cb83SAl Viro to += copy; 286d879cb83SAl Viro bytes -= copy; 287d879cb83SAl Viro } 288d879cb83SAl Viro if (likely(!bytes)) { 289d879cb83SAl Viro kunmap_atomic(kaddr); 290d879cb83SAl Viro goto done; 291d879cb83SAl Viro } 292d879cb83SAl Viro offset = to - kaddr; 293d879cb83SAl Viro buf += copy; 294d879cb83SAl Viro kunmap_atomic(kaddr); 295d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 296d879cb83SAl Viro } 297d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 2983fa6c507SMikulas Patocka 299d879cb83SAl Viro kaddr = kmap(page); 300d879cb83SAl Viro to = kaddr + offset; 30109fc68dcSAl Viro left = copyin(to, buf, copy); 302d879cb83SAl Viro copy -= left; 303d879cb83SAl Viro skip += copy; 304d879cb83SAl Viro to += copy; 305d879cb83SAl Viro bytes -= copy; 306d879cb83SAl Viro while (unlikely(!left && bytes)) { 307d879cb83SAl Viro iov++; 308d879cb83SAl Viro buf = iov->iov_base; 309d879cb83SAl Viro copy = min(bytes, iov->iov_len); 31009fc68dcSAl Viro left = copyin(to, buf, copy); 311d879cb83SAl Viro copy -= left; 312d879cb83SAl Viro skip = copy; 313d879cb83SAl Viro to += copy; 314d879cb83SAl Viro bytes -= copy; 315d879cb83SAl Viro } 316d879cb83SAl Viro kunmap(page); 3173fa6c507SMikulas Patocka 318d879cb83SAl Viro done: 319d879cb83SAl Viro if (skip == iov->iov_len) { 320d879cb83SAl Viro iov++; 321d879cb83SAl Viro skip = 0; 322d879cb83SAl Viro } 323d879cb83SAl Viro i->count -= wanted - bytes; 324d879cb83SAl Viro i->nr_segs -= iov - i->iov; 325d879cb83SAl Viro i->iov = iov; 326d879cb83SAl Viro i->iov_offset = skip; 327d879cb83SAl Viro return wanted - bytes; 328d879cb83SAl Viro } 329d879cb83SAl Viro 330241699cdSAl Viro #ifdef PIPE_PARANOIA 331241699cdSAl Viro static bool sanity(const struct iov_iter *i) 332241699cdSAl Viro { 333241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 3348cefc107SDavid Howells unsigned int p_head = pipe->head; 3358cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3368cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3378cefc107SDavid Howells unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); 3388cefc107SDavid Howells unsigned int i_head = i->head; 3398cefc107SDavid Howells unsigned int idx; 3408cefc107SDavid Howells 341241699cdSAl Viro if (i->iov_offset) { 342241699cdSAl Viro struct pipe_buffer *p; 3438cefc107SDavid Howells if (unlikely(p_occupancy == 0)) 344241699cdSAl Viro goto Bad; // pipe must be non-empty 3458cefc107SDavid Howells if (unlikely(i_head != p_head - 1)) 346241699cdSAl Viro goto Bad; // must be at the last buffer... 347241699cdSAl Viro 3488cefc107SDavid Howells p = &pipe->bufs[i_head & p_mask]; 349241699cdSAl Viro if (unlikely(p->offset + p->len != i->iov_offset)) 350241699cdSAl Viro goto Bad; // ... at the end of segment 351241699cdSAl Viro } else { 3528cefc107SDavid Howells if (i_head != p_head) 353241699cdSAl Viro goto Bad; // must be right after the last buffer 354241699cdSAl Viro } 355241699cdSAl Viro return true; 356241699cdSAl Viro Bad: 3578cefc107SDavid Howells printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); 3588cefc107SDavid Howells printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", 3598cefc107SDavid Howells p_head, p_tail, pipe->ring_size); 3608cefc107SDavid Howells for (idx = 0; idx < pipe->ring_size; idx++) 361241699cdSAl Viro printk(KERN_ERR "[%p %p %d %d]\n", 362241699cdSAl Viro pipe->bufs[idx].ops, 363241699cdSAl Viro pipe->bufs[idx].page, 364241699cdSAl Viro pipe->bufs[idx].offset, 365241699cdSAl Viro pipe->bufs[idx].len); 366241699cdSAl Viro WARN_ON(1); 367241699cdSAl Viro return false; 368241699cdSAl Viro } 369241699cdSAl Viro #else 370241699cdSAl Viro #define sanity(i) true 371241699cdSAl Viro #endif 372241699cdSAl Viro 373241699cdSAl Viro static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, 374241699cdSAl Viro struct iov_iter *i) 375241699cdSAl Viro { 376241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 377241699cdSAl Viro struct pipe_buffer *buf; 3788cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3798cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3808cefc107SDavid Howells unsigned int i_head = i->head; 381241699cdSAl Viro size_t off; 382241699cdSAl Viro 383241699cdSAl Viro if (unlikely(bytes > i->count)) 384241699cdSAl Viro bytes = i->count; 385241699cdSAl Viro 386241699cdSAl Viro if (unlikely(!bytes)) 387241699cdSAl Viro return 0; 388241699cdSAl Viro 389241699cdSAl Viro if (!sanity(i)) 390241699cdSAl Viro return 0; 391241699cdSAl Viro 392241699cdSAl Viro off = i->iov_offset; 3938cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 394241699cdSAl Viro if (off) { 395241699cdSAl Viro if (offset == off && buf->page == page) { 396241699cdSAl Viro /* merge with the last one */ 397241699cdSAl Viro buf->len += bytes; 398241699cdSAl Viro i->iov_offset += bytes; 399241699cdSAl Viro goto out; 400241699cdSAl Viro } 4018cefc107SDavid Howells i_head++; 4028cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 403241699cdSAl Viro } 4046718b6f8SDavid Howells if (pipe_full(i_head, p_tail, pipe->max_usage)) 405241699cdSAl Viro return 0; 4068cefc107SDavid Howells 407241699cdSAl Viro buf->ops = &page_cache_pipe_buf_ops; 4088cefc107SDavid Howells get_page(page); 4098cefc107SDavid Howells buf->page = page; 410241699cdSAl Viro buf->offset = offset; 411241699cdSAl Viro buf->len = bytes; 4128cefc107SDavid Howells 4138cefc107SDavid Howells pipe->head = i_head + 1; 414241699cdSAl Viro i->iov_offset = offset + bytes; 4158cefc107SDavid Howells i->head = i_head; 416241699cdSAl Viro out: 417241699cdSAl Viro i->count -= bytes; 418241699cdSAl Viro return bytes; 419241699cdSAl Viro } 420241699cdSAl Viro 421d879cb83SAl Viro /* 422171a0203SAnton Altaparmakov * Fault in one or more iovecs of the given iov_iter, to a maximum length of 423171a0203SAnton Altaparmakov * bytes. For each iovec, fault in each page that constitutes the iovec. 424171a0203SAnton Altaparmakov * 425171a0203SAnton Altaparmakov * Return 0 on success, or non-zero if the memory could not be accessed (i.e. 426171a0203SAnton Altaparmakov * because it is an invalid address). 427171a0203SAnton Altaparmakov */ 4288409a0d2SAl Viro int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes) 429171a0203SAnton Altaparmakov { 4300e8f0d67SAl Viro if (iter_is_iovec(i)) { 4318409a0d2SAl Viro const struct iovec *p; 4328409a0d2SAl Viro size_t skip; 4338409a0d2SAl Viro 4348409a0d2SAl Viro if (bytes > i->count) 4358409a0d2SAl Viro bytes = i->count; 4368409a0d2SAl Viro for (p = i->iov, skip = i->iov_offset; bytes; p++, skip = 0) { 4378409a0d2SAl Viro size_t len = min(bytes, p->iov_len - skip); 4388409a0d2SAl Viro int err; 4398409a0d2SAl Viro 4408409a0d2SAl Viro if (unlikely(!len)) 4418409a0d2SAl Viro continue; 4428409a0d2SAl Viro err = fault_in_pages_readable(p->iov_base + skip, len); 443171a0203SAnton Altaparmakov if (unlikely(err)) 444171a0203SAnton Altaparmakov return err; 4458409a0d2SAl Viro bytes -= len; 4468409a0d2SAl Viro } 447171a0203SAnton Altaparmakov } 448171a0203SAnton Altaparmakov return 0; 449171a0203SAnton Altaparmakov } 450d4690f1eSAl Viro EXPORT_SYMBOL(iov_iter_fault_in_readable); 451171a0203SAnton Altaparmakov 452aa563d7bSDavid Howells void iov_iter_init(struct iov_iter *i, unsigned int direction, 453d879cb83SAl Viro const struct iovec *iov, unsigned long nr_segs, 454d879cb83SAl Viro size_t count) 455d879cb83SAl Viro { 456aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 4578cd54c1cSAl Viro WARN_ON_ONCE(uaccess_kernel()); 4588cd54c1cSAl Viro *i = (struct iov_iter) { 4598cd54c1cSAl Viro .iter_type = ITER_IOVEC, 4608cd54c1cSAl Viro .data_source = direction, 4618cd54c1cSAl Viro .iov = iov, 4628cd54c1cSAl Viro .nr_segs = nr_segs, 4638cd54c1cSAl Viro .iov_offset = 0, 4648cd54c1cSAl Viro .count = count 4658cd54c1cSAl Viro }; 466d879cb83SAl Viro } 467d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_init); 468d879cb83SAl Viro 469241699cdSAl Viro static inline bool allocated(struct pipe_buffer *buf) 470241699cdSAl Viro { 471241699cdSAl Viro return buf->ops == &default_pipe_buf_ops; 472241699cdSAl Viro } 473241699cdSAl Viro 4748cefc107SDavid Howells static inline void data_start(const struct iov_iter *i, 4758cefc107SDavid Howells unsigned int *iter_headp, size_t *offp) 476241699cdSAl Viro { 4778cefc107SDavid Howells unsigned int p_mask = i->pipe->ring_size - 1; 4788cefc107SDavid Howells unsigned int iter_head = i->head; 479241699cdSAl Viro size_t off = i->iov_offset; 4808cefc107SDavid Howells 4818cefc107SDavid Howells if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || 4828cefc107SDavid Howells off == PAGE_SIZE)) { 4838cefc107SDavid Howells iter_head++; 484241699cdSAl Viro off = 0; 485241699cdSAl Viro } 4868cefc107SDavid Howells *iter_headp = iter_head; 487241699cdSAl Viro *offp = off; 488241699cdSAl Viro } 489241699cdSAl Viro 490241699cdSAl Viro static size_t push_pipe(struct iov_iter *i, size_t size, 4918cefc107SDavid Howells int *iter_headp, size_t *offp) 492241699cdSAl Viro { 493241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 4948cefc107SDavid Howells unsigned int p_tail = pipe->tail; 4958cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 4968cefc107SDavid Howells unsigned int iter_head; 497241699cdSAl Viro size_t off; 498241699cdSAl Viro ssize_t left; 499241699cdSAl Viro 500241699cdSAl Viro if (unlikely(size > i->count)) 501241699cdSAl Viro size = i->count; 502241699cdSAl Viro if (unlikely(!size)) 503241699cdSAl Viro return 0; 504241699cdSAl Viro 505241699cdSAl Viro left = size; 5068cefc107SDavid Howells data_start(i, &iter_head, &off); 5078cefc107SDavid Howells *iter_headp = iter_head; 508241699cdSAl Viro *offp = off; 509241699cdSAl Viro if (off) { 510241699cdSAl Viro left -= PAGE_SIZE - off; 511241699cdSAl Viro if (left <= 0) { 5128cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len += size; 513241699cdSAl Viro return size; 514241699cdSAl Viro } 5158cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; 5168cefc107SDavid Howells iter_head++; 517241699cdSAl Viro } 5186718b6f8SDavid Howells while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { 5198cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; 520241699cdSAl Viro struct page *page = alloc_page(GFP_USER); 521241699cdSAl Viro if (!page) 522241699cdSAl Viro break; 5238cefc107SDavid Howells 5248cefc107SDavid Howells buf->ops = &default_pipe_buf_ops; 5258cefc107SDavid Howells buf->page = page; 5268cefc107SDavid Howells buf->offset = 0; 5278cefc107SDavid Howells buf->len = min_t(ssize_t, left, PAGE_SIZE); 5288cefc107SDavid Howells left -= buf->len; 5298cefc107SDavid Howells iter_head++; 5308cefc107SDavid Howells pipe->head = iter_head; 5318cefc107SDavid Howells 5328cefc107SDavid Howells if (left == 0) 533241699cdSAl Viro return size; 534241699cdSAl Viro } 535241699cdSAl Viro return size - left; 536241699cdSAl Viro } 537241699cdSAl Viro 538241699cdSAl Viro static size_t copy_pipe_to_iter(const void *addr, size_t bytes, 539241699cdSAl Viro struct iov_iter *i) 540241699cdSAl Viro { 541241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5428cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5438cefc107SDavid Howells unsigned int i_head; 544241699cdSAl Viro size_t n, off; 545241699cdSAl Viro 546241699cdSAl Viro if (!sanity(i)) 547241699cdSAl Viro return 0; 548241699cdSAl Viro 5498cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 550241699cdSAl Viro if (unlikely(!n)) 551241699cdSAl Viro return 0; 5528cefc107SDavid Howells do { 553241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 5548cefc107SDavid Howells memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); 5558cefc107SDavid Howells i->head = i_head; 556241699cdSAl Viro i->iov_offset = off + chunk; 557241699cdSAl Viro n -= chunk; 558241699cdSAl Viro addr += chunk; 5598cefc107SDavid Howells off = 0; 5608cefc107SDavid Howells i_head++; 5618cefc107SDavid Howells } while (n); 562241699cdSAl Viro i->count -= bytes; 563241699cdSAl Viro return bytes; 564241699cdSAl Viro } 565241699cdSAl Viro 566f9152895SAl Viro static __wsum csum_and_memcpy(void *to, const void *from, size_t len, 567f9152895SAl Viro __wsum sum, size_t off) 568f9152895SAl Viro { 569cc44c17bSAl Viro __wsum next = csum_partial_copy_nocheck(from, to, len); 570f9152895SAl Viro return csum_block_add(sum, next, off); 571f9152895SAl Viro } 572f9152895SAl Viro 57378e1f386SAl Viro static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, 57452cbd23aSWillem de Bruijn struct csum_state *csstate, 57552cbd23aSWillem de Bruijn struct iov_iter *i) 57678e1f386SAl Viro { 57778e1f386SAl Viro struct pipe_inode_info *pipe = i->pipe; 5788cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 57952cbd23aSWillem de Bruijn __wsum sum = csstate->csum; 58052cbd23aSWillem de Bruijn size_t off = csstate->off; 5818cefc107SDavid Howells unsigned int i_head; 58278e1f386SAl Viro size_t n, r; 58378e1f386SAl Viro 58478e1f386SAl Viro if (!sanity(i)) 58578e1f386SAl Viro return 0; 58678e1f386SAl Viro 5878cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &r); 58878e1f386SAl Viro if (unlikely(!n)) 58978e1f386SAl Viro return 0; 5908cefc107SDavid Howells do { 59178e1f386SAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - r); 5928cefc107SDavid Howells char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); 593f9152895SAl Viro sum = csum_and_memcpy(p + r, addr, chunk, sum, off); 59478e1f386SAl Viro kunmap_atomic(p); 5958cefc107SDavid Howells i->head = i_head; 59678e1f386SAl Viro i->iov_offset = r + chunk; 59778e1f386SAl Viro n -= chunk; 59878e1f386SAl Viro off += chunk; 59978e1f386SAl Viro addr += chunk; 6008cefc107SDavid Howells r = 0; 6018cefc107SDavid Howells i_head++; 6028cefc107SDavid Howells } while (n); 60378e1f386SAl Viro i->count -= bytes; 60452cbd23aSWillem de Bruijn csstate->csum = sum; 60552cbd23aSWillem de Bruijn csstate->off = off; 60678e1f386SAl Viro return bytes; 60778e1f386SAl Viro } 60878e1f386SAl Viro 609aa28de27SAl Viro size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 610d879cb83SAl Viro { 61136f7a8a4SAl Viro const char *from = addr; 61200e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 613241699cdSAl Viro return copy_pipe_to_iter(addr, bytes, i); 61409fc68dcSAl Viro if (iter_is_iovec(i)) 61509fc68dcSAl Viro might_fault(); 616d879cb83SAl Viro iterate_and_advance(i, bytes, v, 61709fc68dcSAl Viro copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 618d879cb83SAl Viro memcpy_to_page(v.bv_page, v.bv_offset, 619d879cb83SAl Viro (from += v.bv_len) - v.bv_len, v.bv_len), 6207ff50620SDavid Howells memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 6217ff50620SDavid Howells memcpy_to_page(v.bv_page, v.bv_offset, 6227ff50620SDavid Howells (from += v.bv_len) - v.bv_len, v.bv_len) 623d879cb83SAl Viro ) 624d879cb83SAl Viro 625d879cb83SAl Viro return bytes; 626d879cb83SAl Viro } 627aa28de27SAl Viro EXPORT_SYMBOL(_copy_to_iter); 628d879cb83SAl Viro 629ec6347bbSDan Williams #ifdef CONFIG_ARCH_HAS_COPY_MC 630ec6347bbSDan Williams static int copyout_mc(void __user *to, const void *from, size_t n) 6318780356eSDan Williams { 63296d4f267SLinus Torvalds if (access_ok(to, n)) { 633d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 634ec6347bbSDan Williams n = copy_mc_to_user((__force void *) to, from, n); 6358780356eSDan Williams } 6368780356eSDan Williams return n; 6378780356eSDan Williams } 6388780356eSDan Williams 639ec6347bbSDan Williams static unsigned long copy_mc_to_page(struct page *page, size_t offset, 6408780356eSDan Williams const char *from, size_t len) 6418780356eSDan Williams { 6428780356eSDan Williams unsigned long ret; 6438780356eSDan Williams char *to; 6448780356eSDan Williams 6458780356eSDan Williams to = kmap_atomic(page); 646ec6347bbSDan Williams ret = copy_mc_to_kernel(to + offset, from, len); 6478780356eSDan Williams kunmap_atomic(to); 6488780356eSDan Williams 6498780356eSDan Williams return ret; 6508780356eSDan Williams } 6518780356eSDan Williams 652ec6347bbSDan Williams static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, 653ca146f6fSDan Williams struct iov_iter *i) 654ca146f6fSDan Williams { 655ca146f6fSDan Williams struct pipe_inode_info *pipe = i->pipe; 6568cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 6578cefc107SDavid Howells unsigned int i_head; 658ca146f6fSDan Williams size_t n, off, xfer = 0; 659ca146f6fSDan Williams 660ca146f6fSDan Williams if (!sanity(i)) 661ca146f6fSDan Williams return 0; 662ca146f6fSDan Williams 6638cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 664ca146f6fSDan Williams if (unlikely(!n)) 665ca146f6fSDan Williams return 0; 6668cefc107SDavid Howells do { 667ca146f6fSDan Williams size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 668ca146f6fSDan Williams unsigned long rem; 669ca146f6fSDan Williams 670ec6347bbSDan Williams rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, 6718cefc107SDavid Howells off, addr, chunk); 6728cefc107SDavid Howells i->head = i_head; 673ca146f6fSDan Williams i->iov_offset = off + chunk - rem; 674ca146f6fSDan Williams xfer += chunk - rem; 675ca146f6fSDan Williams if (rem) 676ca146f6fSDan Williams break; 677ca146f6fSDan Williams n -= chunk; 678ca146f6fSDan Williams addr += chunk; 6798cefc107SDavid Howells off = 0; 6808cefc107SDavid Howells i_head++; 6818cefc107SDavid Howells } while (n); 682ca146f6fSDan Williams i->count -= xfer; 683ca146f6fSDan Williams return xfer; 684ca146f6fSDan Williams } 685ca146f6fSDan Williams 686bf3eeb9bSDan Williams /** 687ec6347bbSDan Williams * _copy_mc_to_iter - copy to iter with source memory error exception handling 688bf3eeb9bSDan Williams * @addr: source kernel address 689bf3eeb9bSDan Williams * @bytes: total transfer length 690bf3eeb9bSDan Williams * @iter: destination iterator 691bf3eeb9bSDan Williams * 692ec6347bbSDan Williams * The pmem driver deploys this for the dax operation 693ec6347bbSDan Williams * (dax_copy_to_iter()) for dax reads (bypass page-cache and the 694ec6347bbSDan Williams * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes 695ec6347bbSDan Williams * successfully copied. 696bf3eeb9bSDan Williams * 697ec6347bbSDan Williams * The main differences between this and typical _copy_to_iter(). 698bf3eeb9bSDan Williams * 699bf3eeb9bSDan Williams * * Typical tail/residue handling after a fault retries the copy 700bf3eeb9bSDan Williams * byte-by-byte until the fault happens again. Re-triggering machine 701bf3eeb9bSDan Williams * checks is potentially fatal so the implementation uses source 702bf3eeb9bSDan Williams * alignment and poison alignment assumptions to avoid re-triggering 703bf3eeb9bSDan Williams * hardware exceptions. 704bf3eeb9bSDan Williams * 705bf3eeb9bSDan Williams * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. 706bf3eeb9bSDan Williams * Compare to copy_to_iter() where only ITER_IOVEC attempts might return 707bf3eeb9bSDan Williams * a short copy. 708bf3eeb9bSDan Williams */ 709ec6347bbSDan Williams size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 7108780356eSDan Williams { 7118780356eSDan Williams const char *from = addr; 7128780356eSDan Williams unsigned long rem, curr_addr, s_addr = (unsigned long) addr; 7138780356eSDan Williams 71400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 715ec6347bbSDan Williams return copy_mc_pipe_to_iter(addr, bytes, i); 7168780356eSDan Williams if (iter_is_iovec(i)) 7178780356eSDan Williams might_fault(); 7188780356eSDan Williams iterate_and_advance(i, bytes, v, 719ec6347bbSDan Williams copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len, 720ec6347bbSDan Williams v.iov_len), 7218780356eSDan Williams ({ 722ec6347bbSDan Williams rem = copy_mc_to_page(v.bv_page, v.bv_offset, 7238780356eSDan Williams (from += v.bv_len) - v.bv_len, v.bv_len); 7248780356eSDan Williams if (rem) { 7258780356eSDan Williams curr_addr = (unsigned long) from; 7268780356eSDan Williams bytes = curr_addr - s_addr - rem; 7278780356eSDan Williams return bytes; 7288780356eSDan Williams } 7298780356eSDan Williams }), 7308780356eSDan Williams ({ 731ec6347bbSDan Williams rem = copy_mc_to_kernel(v.iov_base, (from += v.iov_len) 732ec6347bbSDan Williams - v.iov_len, v.iov_len); 7338780356eSDan Williams if (rem) { 7348780356eSDan Williams curr_addr = (unsigned long) from; 7358780356eSDan Williams bytes = curr_addr - s_addr - rem; 7368780356eSDan Williams return bytes; 7378780356eSDan Williams } 7387ff50620SDavid Howells }), 7397ff50620SDavid Howells ({ 7407ff50620SDavid Howells rem = copy_mc_to_page(v.bv_page, v.bv_offset, 7417ff50620SDavid Howells (from += v.bv_len) - v.bv_len, v.bv_len); 7427ff50620SDavid Howells if (rem) { 7437ff50620SDavid Howells curr_addr = (unsigned long) from; 7447ff50620SDavid Howells bytes = curr_addr - s_addr - rem; 7457ff50620SDavid Howells rcu_read_unlock(); 7463d14ec1fSDavid Howells i->iov_offset += bytes; 7473d14ec1fSDavid Howells i->count -= bytes; 7487ff50620SDavid Howells return bytes; 7497ff50620SDavid Howells } 7508780356eSDan Williams }) 7518780356eSDan Williams ) 7528780356eSDan Williams 7538780356eSDan Williams return bytes; 7548780356eSDan Williams } 755ec6347bbSDan Williams EXPORT_SYMBOL_GPL(_copy_mc_to_iter); 756ec6347bbSDan Williams #endif /* CONFIG_ARCH_HAS_COPY_MC */ 7578780356eSDan Williams 758aa28de27SAl Viro size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) 759d879cb83SAl Viro { 760d879cb83SAl Viro char *to = addr; 76100e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 762241699cdSAl Viro WARN_ON(1); 763241699cdSAl Viro return 0; 764241699cdSAl Viro } 76509fc68dcSAl Viro if (iter_is_iovec(i)) 76609fc68dcSAl Viro might_fault(); 767d879cb83SAl Viro iterate_and_advance(i, bytes, v, 76809fc68dcSAl Viro copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 769d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 770d879cb83SAl Viro v.bv_offset, v.bv_len), 7717ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 7727ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 7737ff50620SDavid Howells v.bv_offset, v.bv_len) 774d879cb83SAl Viro ) 775d879cb83SAl Viro 776d879cb83SAl Viro return bytes; 777d879cb83SAl Viro } 778aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter); 779d879cb83SAl Viro 780aa28de27SAl Viro size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) 781d879cb83SAl Viro { 782d879cb83SAl Viro char *to = addr; 78300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 784241699cdSAl Viro WARN_ON(1); 785241699cdSAl Viro return 0; 786241699cdSAl Viro } 787d879cb83SAl Viro iterate_and_advance(i, bytes, v, 7883f763453SAl Viro __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, 789d879cb83SAl Viro v.iov_base, v.iov_len), 790d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 791d879cb83SAl Viro v.bv_offset, v.bv_len), 7927ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 7937ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 7947ff50620SDavid Howells v.bv_offset, v.bv_len) 795d879cb83SAl Viro ) 796d879cb83SAl Viro 797d879cb83SAl Viro return bytes; 798d879cb83SAl Viro } 799aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_nocache); 800d879cb83SAl Viro 8010aed55afSDan Williams #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE 802abd08d7dSDan Williams /** 803abd08d7dSDan Williams * _copy_from_iter_flushcache - write destination through cpu cache 804abd08d7dSDan Williams * @addr: destination kernel address 805abd08d7dSDan Williams * @bytes: total transfer length 806abd08d7dSDan Williams * @iter: source iterator 807abd08d7dSDan Williams * 808abd08d7dSDan Williams * The pmem driver arranges for filesystem-dax to use this facility via 809abd08d7dSDan Williams * dax_copy_from_iter() for ensuring that writes to persistent memory 810abd08d7dSDan Williams * are flushed through the CPU cache. It is differentiated from 811abd08d7dSDan Williams * _copy_from_iter_nocache() in that guarantees all data is flushed for 812abd08d7dSDan Williams * all iterator types. The _copy_from_iter_nocache() only attempts to 813abd08d7dSDan Williams * bypass the cache for the ITER_IOVEC case, and on some archs may use 814abd08d7dSDan Williams * instructions that strand dirty-data in the cache. 815abd08d7dSDan Williams */ 8166a37e940SLinus Torvalds size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 8170aed55afSDan Williams { 8180aed55afSDan Williams char *to = addr; 81900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 8200aed55afSDan Williams WARN_ON(1); 8210aed55afSDan Williams return 0; 8220aed55afSDan Williams } 8230aed55afSDan Williams iterate_and_advance(i, bytes, v, 8240aed55afSDan Williams __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, 8250aed55afSDan Williams v.iov_base, v.iov_len), 8260aed55afSDan Williams memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 8270aed55afSDan Williams v.bv_offset, v.bv_len), 8280aed55afSDan Williams memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, 8297ff50620SDavid Howells v.iov_len), 8307ff50620SDavid Howells memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 8317ff50620SDavid Howells v.bv_offset, v.bv_len) 8320aed55afSDan Williams ) 8330aed55afSDan Williams 8340aed55afSDan Williams return bytes; 8350aed55afSDan Williams } 8366a37e940SLinus Torvalds EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); 8370aed55afSDan Williams #endif 8380aed55afSDan Williams 83972e809edSAl Viro static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) 84072e809edSAl Viro { 8416daef95bSEric Dumazet struct page *head; 8426daef95bSEric Dumazet size_t v = n + offset; 8436daef95bSEric Dumazet 8446daef95bSEric Dumazet /* 8456daef95bSEric Dumazet * The general case needs to access the page order in order 8466daef95bSEric Dumazet * to compute the page size. 8476daef95bSEric Dumazet * However, we mostly deal with order-0 pages and thus can 8486daef95bSEric Dumazet * avoid a possible cache line miss for requests that fit all 8496daef95bSEric Dumazet * page orders. 8506daef95bSEric Dumazet */ 8516daef95bSEric Dumazet if (n <= v && v <= PAGE_SIZE) 8526daef95bSEric Dumazet return true; 8536daef95bSEric Dumazet 8546daef95bSEric Dumazet head = compound_head(page); 8556daef95bSEric Dumazet v += (page - head) << PAGE_SHIFT; 856a90bcb86SPetar Penkov 857a50b854eSMatthew Wilcox (Oracle) if (likely(n <= v && v <= (page_size(head)))) 85872e809edSAl Viro return true; 85972e809edSAl Viro WARN_ON(1); 86072e809edSAl Viro return false; 86172e809edSAl Viro } 862cbbd26b8SAl Viro 86308aa6479SAl Viro static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 864d879cb83SAl Viro struct iov_iter *i) 865d879cb83SAl Viro { 86628f38db7SAl Viro if (likely(iter_is_iovec(i))) 86728f38db7SAl Viro return copy_page_to_iter_iovec(page, offset, bytes, i); 86828f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 869d879cb83SAl Viro void *kaddr = kmap_atomic(page); 870d879cb83SAl Viro size_t wanted = copy_to_iter(kaddr + offset, bytes, i); 871d879cb83SAl Viro kunmap_atomic(kaddr); 872d879cb83SAl Viro return wanted; 87328f38db7SAl Viro } 87428f38db7SAl Viro if (iov_iter_is_pipe(i)) 87528f38db7SAl Viro return copy_page_to_iter_pipe(page, offset, bytes, i); 87628f38db7SAl Viro if (unlikely(iov_iter_is_discard(i))) { 877a506abc7SAl Viro if (unlikely(i->count < bytes)) 878a506abc7SAl Viro bytes = i->count; 879a506abc7SAl Viro i->count -= bytes; 8809ea9ce04SDavid Howells return bytes; 88128f38db7SAl Viro } 88228f38db7SAl Viro WARN_ON(1); 88328f38db7SAl Viro return 0; 884d879cb83SAl Viro } 88508aa6479SAl Viro 88608aa6479SAl Viro size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 88708aa6479SAl Viro struct iov_iter *i) 88808aa6479SAl Viro { 88908aa6479SAl Viro size_t res = 0; 89008aa6479SAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 89108aa6479SAl Viro return 0; 89208aa6479SAl Viro page += offset / PAGE_SIZE; // first subpage 89308aa6479SAl Viro offset %= PAGE_SIZE; 89408aa6479SAl Viro while (1) { 89508aa6479SAl Viro size_t n = __copy_page_to_iter(page, offset, 89608aa6479SAl Viro min(bytes, (size_t)PAGE_SIZE - offset), i); 89708aa6479SAl Viro res += n; 89808aa6479SAl Viro bytes -= n; 89908aa6479SAl Viro if (!bytes || !n) 90008aa6479SAl Viro break; 90108aa6479SAl Viro offset += n; 90208aa6479SAl Viro if (offset == PAGE_SIZE) { 90308aa6479SAl Viro page++; 90408aa6479SAl Viro offset = 0; 90508aa6479SAl Viro } 90608aa6479SAl Viro } 90708aa6479SAl Viro return res; 90808aa6479SAl Viro } 909d879cb83SAl Viro EXPORT_SYMBOL(copy_page_to_iter); 910d879cb83SAl Viro 911d879cb83SAl Viro size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, 912d879cb83SAl Viro struct iov_iter *i) 913d879cb83SAl Viro { 91472e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 91572e809edSAl Viro return 0; 91628f38db7SAl Viro if (likely(iter_is_iovec(i))) 91728f38db7SAl Viro return copy_page_from_iter_iovec(page, offset, bytes, i); 91828f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 919d879cb83SAl Viro void *kaddr = kmap_atomic(page); 920aa28de27SAl Viro size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); 921d879cb83SAl Viro kunmap_atomic(kaddr); 922d879cb83SAl Viro return wanted; 92328f38db7SAl Viro } 92428f38db7SAl Viro WARN_ON(1); 92528f38db7SAl Viro return 0; 926d879cb83SAl Viro } 927d879cb83SAl Viro EXPORT_SYMBOL(copy_page_from_iter); 928d879cb83SAl Viro 929241699cdSAl Viro static size_t pipe_zero(size_t bytes, struct iov_iter *i) 930241699cdSAl Viro { 931241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 9328cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9338cefc107SDavid Howells unsigned int i_head; 934241699cdSAl Viro size_t n, off; 935241699cdSAl Viro 936241699cdSAl Viro if (!sanity(i)) 937241699cdSAl Viro return 0; 938241699cdSAl Viro 9398cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 940241699cdSAl Viro if (unlikely(!n)) 941241699cdSAl Viro return 0; 942241699cdSAl Viro 9438cefc107SDavid Howells do { 944241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 9458cefc107SDavid Howells memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); 9468cefc107SDavid Howells i->head = i_head; 947241699cdSAl Viro i->iov_offset = off + chunk; 948241699cdSAl Viro n -= chunk; 9498cefc107SDavid Howells off = 0; 9508cefc107SDavid Howells i_head++; 9518cefc107SDavid Howells } while (n); 952241699cdSAl Viro i->count -= bytes; 953241699cdSAl Viro return bytes; 954241699cdSAl Viro } 955241699cdSAl Viro 956d879cb83SAl Viro size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 957d879cb83SAl Viro { 95800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 959241699cdSAl Viro return pipe_zero(bytes, i); 960d879cb83SAl Viro iterate_and_advance(i, bytes, v, 96109fc68dcSAl Viro clear_user(v.iov_base, v.iov_len), 962d879cb83SAl Viro memzero_page(v.bv_page, v.bv_offset, v.bv_len), 9637ff50620SDavid Howells memset(v.iov_base, 0, v.iov_len), 9647ff50620SDavid Howells memzero_page(v.bv_page, v.bv_offset, v.bv_len) 965d879cb83SAl Viro ) 966d879cb83SAl Viro 967d879cb83SAl Viro return bytes; 968d879cb83SAl Viro } 969d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_zero); 970d879cb83SAl Viro 971f0b65f39SAl Viro size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, 972f0b65f39SAl Viro struct iov_iter *i) 973d879cb83SAl Viro { 974d879cb83SAl Viro char *kaddr = kmap_atomic(page), *p = kaddr + offset; 97572e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) { 97672e809edSAl Viro kunmap_atomic(kaddr); 97772e809edSAl Viro return 0; 97872e809edSAl Viro } 9799ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 980241699cdSAl Viro kunmap_atomic(kaddr); 981241699cdSAl Viro WARN_ON(1); 982241699cdSAl Viro return 0; 983241699cdSAl Viro } 984f0b65f39SAl Viro iterate_and_advance(i, bytes, v, 98509fc68dcSAl Viro copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 986d879cb83SAl Viro memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 987d879cb83SAl Viro v.bv_offset, v.bv_len), 9887ff50620SDavid Howells memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 9897ff50620SDavid Howells memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 9907ff50620SDavid Howells v.bv_offset, v.bv_len) 991d879cb83SAl Viro ) 992d879cb83SAl Viro kunmap_atomic(kaddr); 993d879cb83SAl Viro return bytes; 994d879cb83SAl Viro } 995f0b65f39SAl Viro EXPORT_SYMBOL(copy_page_from_iter_atomic); 996d879cb83SAl Viro 997b9dc6f65SAl Viro static inline void pipe_truncate(struct iov_iter *i) 998241699cdSAl Viro { 999241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 10008cefc107SDavid Howells unsigned int p_tail = pipe->tail; 10018cefc107SDavid Howells unsigned int p_head = pipe->head; 10028cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10038cefc107SDavid Howells 10048cefc107SDavid Howells if (!pipe_empty(p_head, p_tail)) { 10058cefc107SDavid Howells struct pipe_buffer *buf; 10068cefc107SDavid Howells unsigned int i_head = i->head; 1007b9dc6f65SAl Viro size_t off = i->iov_offset; 10088cefc107SDavid Howells 1009b9dc6f65SAl Viro if (off) { 10108cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 10118cefc107SDavid Howells buf->len = off - buf->offset; 10128cefc107SDavid Howells i_head++; 1013b9dc6f65SAl Viro } 10148cefc107SDavid Howells while (p_head != i_head) { 10158cefc107SDavid Howells p_head--; 10168cefc107SDavid Howells pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); 1017241699cdSAl Viro } 10188cefc107SDavid Howells 10198cefc107SDavid Howells pipe->head = p_head; 1020241699cdSAl Viro } 1021b9dc6f65SAl Viro } 1022b9dc6f65SAl Viro 1023b9dc6f65SAl Viro static void pipe_advance(struct iov_iter *i, size_t size) 1024b9dc6f65SAl Viro { 1025b9dc6f65SAl Viro struct pipe_inode_info *pipe = i->pipe; 1026b9dc6f65SAl Viro if (size) { 1027b9dc6f65SAl Viro struct pipe_buffer *buf; 10288cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10298cefc107SDavid Howells unsigned int i_head = i->head; 1030b9dc6f65SAl Viro size_t off = i->iov_offset, left = size; 10318cefc107SDavid Howells 1032b9dc6f65SAl Viro if (off) /* make it relative to the beginning of buffer */ 10338cefc107SDavid Howells left += off - pipe->bufs[i_head & p_mask].offset; 1034b9dc6f65SAl Viro while (1) { 10358cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 1036b9dc6f65SAl Viro if (left <= buf->len) 1037b9dc6f65SAl Viro break; 1038b9dc6f65SAl Viro left -= buf->len; 10398cefc107SDavid Howells i_head++; 1040b9dc6f65SAl Viro } 10418cefc107SDavid Howells i->head = i_head; 1042b9dc6f65SAl Viro i->iov_offset = buf->offset + left; 1043b9dc6f65SAl Viro } 1044b9dc6f65SAl Viro i->count -= size; 1045b9dc6f65SAl Viro /* ... and discard everything past that point */ 1046b9dc6f65SAl Viro pipe_truncate(i); 1047241699cdSAl Viro } 1048241699cdSAl Viro 104954c8195bSPavel Begunkov static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) 105054c8195bSPavel Begunkov { 105154c8195bSPavel Begunkov struct bvec_iter bi; 105254c8195bSPavel Begunkov 105354c8195bSPavel Begunkov bi.bi_size = i->count; 105454c8195bSPavel Begunkov bi.bi_bvec_done = i->iov_offset; 105554c8195bSPavel Begunkov bi.bi_idx = 0; 105654c8195bSPavel Begunkov bvec_iter_advance(i->bvec, &bi, size); 105754c8195bSPavel Begunkov 105854c8195bSPavel Begunkov i->bvec += bi.bi_idx; 105954c8195bSPavel Begunkov i->nr_segs -= bi.bi_idx; 106054c8195bSPavel Begunkov i->count = bi.bi_size; 106154c8195bSPavel Begunkov i->iov_offset = bi.bi_bvec_done; 106254c8195bSPavel Begunkov } 106354c8195bSPavel Begunkov 1064185ac4d4SAl Viro static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) 1065185ac4d4SAl Viro { 1066185ac4d4SAl Viro const struct iovec *iov, *end; 1067185ac4d4SAl Viro 1068185ac4d4SAl Viro if (!i->count) 1069185ac4d4SAl Viro return; 1070185ac4d4SAl Viro i->count -= size; 1071185ac4d4SAl Viro 1072185ac4d4SAl Viro size += i->iov_offset; // from beginning of current segment 1073185ac4d4SAl Viro for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { 1074185ac4d4SAl Viro if (likely(size < iov->iov_len)) 1075185ac4d4SAl Viro break; 1076185ac4d4SAl Viro size -= iov->iov_len; 1077185ac4d4SAl Viro } 1078185ac4d4SAl Viro i->iov_offset = size; 1079185ac4d4SAl Viro i->nr_segs -= iov - i->iov; 1080185ac4d4SAl Viro i->iov = iov; 1081185ac4d4SAl Viro } 1082185ac4d4SAl Viro 1083d879cb83SAl Viro void iov_iter_advance(struct iov_iter *i, size_t size) 1084d879cb83SAl Viro { 10853b3fc051SAl Viro if (unlikely(i->count < size)) 10863b3fc051SAl Viro size = i->count; 1087185ac4d4SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { 1088185ac4d4SAl Viro /* iovec and kvec have identical layouts */ 1089185ac4d4SAl Viro iov_iter_iovec_advance(i, size); 1090185ac4d4SAl Viro } else if (iov_iter_is_bvec(i)) { 1091185ac4d4SAl Viro iov_iter_bvec_advance(i, size); 1092185ac4d4SAl Viro } else if (iov_iter_is_pipe(i)) { 1093241699cdSAl Viro pipe_advance(i, size); 1094185ac4d4SAl Viro } else if (unlikely(iov_iter_is_xarray(i))) { 10957ff50620SDavid Howells i->iov_offset += size; 10967ff50620SDavid Howells i->count -= size; 1097185ac4d4SAl Viro } else if (iov_iter_is_discard(i)) { 1098185ac4d4SAl Viro i->count -= size; 10997ff50620SDavid Howells } 1100d879cb83SAl Viro } 1101d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_advance); 1102d879cb83SAl Viro 110327c0e374SAl Viro void iov_iter_revert(struct iov_iter *i, size_t unroll) 110427c0e374SAl Viro { 110527c0e374SAl Viro if (!unroll) 110627c0e374SAl Viro return; 11075b47d59aSAl Viro if (WARN_ON(unroll > MAX_RW_COUNT)) 11085b47d59aSAl Viro return; 110927c0e374SAl Viro i->count += unroll; 111000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 111127c0e374SAl Viro struct pipe_inode_info *pipe = i->pipe; 11128cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 11138cefc107SDavid Howells unsigned int i_head = i->head; 111427c0e374SAl Viro size_t off = i->iov_offset; 111527c0e374SAl Viro while (1) { 11168cefc107SDavid Howells struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; 11178cefc107SDavid Howells size_t n = off - b->offset; 111827c0e374SAl Viro if (unroll < n) { 11194fa55cefSAl Viro off -= unroll; 112027c0e374SAl Viro break; 112127c0e374SAl Viro } 112227c0e374SAl Viro unroll -= n; 11238cefc107SDavid Howells if (!unroll && i_head == i->start_head) { 112427c0e374SAl Viro off = 0; 112527c0e374SAl Viro break; 112627c0e374SAl Viro } 11278cefc107SDavid Howells i_head--; 11288cefc107SDavid Howells b = &pipe->bufs[i_head & p_mask]; 11298cefc107SDavid Howells off = b->offset + b->len; 113027c0e374SAl Viro } 113127c0e374SAl Viro i->iov_offset = off; 11328cefc107SDavid Howells i->head = i_head; 113327c0e374SAl Viro pipe_truncate(i); 113427c0e374SAl Viro return; 113527c0e374SAl Viro } 11369ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 11379ea9ce04SDavid Howells return; 113827c0e374SAl Viro if (unroll <= i->iov_offset) { 113927c0e374SAl Viro i->iov_offset -= unroll; 114027c0e374SAl Viro return; 114127c0e374SAl Viro } 114227c0e374SAl Viro unroll -= i->iov_offset; 11437ff50620SDavid Howells if (iov_iter_is_xarray(i)) { 11447ff50620SDavid Howells BUG(); /* We should never go beyond the start of the specified 11457ff50620SDavid Howells * range since we might then be straying into pages that 11467ff50620SDavid Howells * aren't pinned. 11477ff50620SDavid Howells */ 11487ff50620SDavid Howells } else if (iov_iter_is_bvec(i)) { 114927c0e374SAl Viro const struct bio_vec *bvec = i->bvec; 115027c0e374SAl Viro while (1) { 115127c0e374SAl Viro size_t n = (--bvec)->bv_len; 115227c0e374SAl Viro i->nr_segs++; 115327c0e374SAl Viro if (unroll <= n) { 115427c0e374SAl Viro i->bvec = bvec; 115527c0e374SAl Viro i->iov_offset = n - unroll; 115627c0e374SAl Viro return; 115727c0e374SAl Viro } 115827c0e374SAl Viro unroll -= n; 115927c0e374SAl Viro } 116027c0e374SAl Viro } else { /* same logics for iovec and kvec */ 116127c0e374SAl Viro const struct iovec *iov = i->iov; 116227c0e374SAl Viro while (1) { 116327c0e374SAl Viro size_t n = (--iov)->iov_len; 116427c0e374SAl Viro i->nr_segs++; 116527c0e374SAl Viro if (unroll <= n) { 116627c0e374SAl Viro i->iov = iov; 116727c0e374SAl Viro i->iov_offset = n - unroll; 116827c0e374SAl Viro return; 116927c0e374SAl Viro } 117027c0e374SAl Viro unroll -= n; 117127c0e374SAl Viro } 117227c0e374SAl Viro } 117327c0e374SAl Viro } 117427c0e374SAl Viro EXPORT_SYMBOL(iov_iter_revert); 117527c0e374SAl Viro 1176d879cb83SAl Viro /* 1177d879cb83SAl Viro * Return the count of just the current iov_iter segment. 1178d879cb83SAl Viro */ 1179d879cb83SAl Viro size_t iov_iter_single_seg_count(const struct iov_iter *i) 1180d879cb83SAl Viro { 118128f38db7SAl Viro if (i->nr_segs > 1) { 118228f38db7SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 118328f38db7SAl Viro return min(i->count, i->iov->iov_len - i->iov_offset); 11847ff50620SDavid Howells if (iov_iter_is_bvec(i)) 1185d879cb83SAl Viro return min(i->count, i->bvec->bv_len - i->iov_offset); 118628f38db7SAl Viro } 118728f38db7SAl Viro return i->count; 1188d879cb83SAl Viro } 1189d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_single_seg_count); 1190d879cb83SAl Viro 1191aa563d7bSDavid Howells void iov_iter_kvec(struct iov_iter *i, unsigned int direction, 1192d879cb83SAl Viro const struct kvec *kvec, unsigned long nr_segs, 1193d879cb83SAl Viro size_t count) 1194d879cb83SAl Viro { 1195aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 11968cd54c1cSAl Viro *i = (struct iov_iter){ 11978cd54c1cSAl Viro .iter_type = ITER_KVEC, 11988cd54c1cSAl Viro .data_source = direction, 11998cd54c1cSAl Viro .kvec = kvec, 12008cd54c1cSAl Viro .nr_segs = nr_segs, 12018cd54c1cSAl Viro .iov_offset = 0, 12028cd54c1cSAl Viro .count = count 12038cd54c1cSAl Viro }; 1204d879cb83SAl Viro } 1205d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_kvec); 1206d879cb83SAl Viro 1207aa563d7bSDavid Howells void iov_iter_bvec(struct iov_iter *i, unsigned int direction, 1208d879cb83SAl Viro const struct bio_vec *bvec, unsigned long nr_segs, 1209d879cb83SAl Viro size_t count) 1210d879cb83SAl Viro { 1211aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 12128cd54c1cSAl Viro *i = (struct iov_iter){ 12138cd54c1cSAl Viro .iter_type = ITER_BVEC, 12148cd54c1cSAl Viro .data_source = direction, 12158cd54c1cSAl Viro .bvec = bvec, 12168cd54c1cSAl Viro .nr_segs = nr_segs, 12178cd54c1cSAl Viro .iov_offset = 0, 12188cd54c1cSAl Viro .count = count 12198cd54c1cSAl Viro }; 1220d879cb83SAl Viro } 1221d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_bvec); 1222d879cb83SAl Viro 1223aa563d7bSDavid Howells void iov_iter_pipe(struct iov_iter *i, unsigned int direction, 1224241699cdSAl Viro struct pipe_inode_info *pipe, 1225241699cdSAl Viro size_t count) 1226241699cdSAl Viro { 1227aa563d7bSDavid Howells BUG_ON(direction != READ); 12288cefc107SDavid Howells WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); 12298cd54c1cSAl Viro *i = (struct iov_iter){ 12308cd54c1cSAl Viro .iter_type = ITER_PIPE, 12318cd54c1cSAl Viro .data_source = false, 12328cd54c1cSAl Viro .pipe = pipe, 12338cd54c1cSAl Viro .head = pipe->head, 12348cd54c1cSAl Viro .start_head = pipe->head, 12358cd54c1cSAl Viro .iov_offset = 0, 12368cd54c1cSAl Viro .count = count 12378cd54c1cSAl Viro }; 1238241699cdSAl Viro } 1239241699cdSAl Viro EXPORT_SYMBOL(iov_iter_pipe); 1240241699cdSAl Viro 12419ea9ce04SDavid Howells /** 12427ff50620SDavid Howells * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray 12437ff50620SDavid Howells * @i: The iterator to initialise. 12447ff50620SDavid Howells * @direction: The direction of the transfer. 12457ff50620SDavid Howells * @xarray: The xarray to access. 12467ff50620SDavid Howells * @start: The start file position. 12477ff50620SDavid Howells * @count: The size of the I/O buffer in bytes. 12487ff50620SDavid Howells * 12497ff50620SDavid Howells * Set up an I/O iterator to either draw data out of the pages attached to an 12507ff50620SDavid Howells * inode or to inject data into those pages. The pages *must* be prevented 12517ff50620SDavid Howells * from evaporation, either by taking a ref on them or locking them by the 12527ff50620SDavid Howells * caller. 12537ff50620SDavid Howells */ 12547ff50620SDavid Howells void iov_iter_xarray(struct iov_iter *i, unsigned int direction, 12557ff50620SDavid Howells struct xarray *xarray, loff_t start, size_t count) 12567ff50620SDavid Howells { 12577ff50620SDavid Howells BUG_ON(direction & ~1); 12588cd54c1cSAl Viro *i = (struct iov_iter) { 12598cd54c1cSAl Viro .iter_type = ITER_XARRAY, 12608cd54c1cSAl Viro .data_source = direction, 12618cd54c1cSAl Viro .xarray = xarray, 12628cd54c1cSAl Viro .xarray_start = start, 12638cd54c1cSAl Viro .count = count, 12648cd54c1cSAl Viro .iov_offset = 0 12658cd54c1cSAl Viro }; 12667ff50620SDavid Howells } 12677ff50620SDavid Howells EXPORT_SYMBOL(iov_iter_xarray); 12687ff50620SDavid Howells 12697ff50620SDavid Howells /** 12709ea9ce04SDavid Howells * iov_iter_discard - Initialise an I/O iterator that discards data 12719ea9ce04SDavid Howells * @i: The iterator to initialise. 12729ea9ce04SDavid Howells * @direction: The direction of the transfer. 12739ea9ce04SDavid Howells * @count: The size of the I/O buffer in bytes. 12749ea9ce04SDavid Howells * 12759ea9ce04SDavid Howells * Set up an I/O iterator that just discards everything that's written to it. 12769ea9ce04SDavid Howells * It's only available as a READ iterator. 12779ea9ce04SDavid Howells */ 12789ea9ce04SDavid Howells void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) 12799ea9ce04SDavid Howells { 12809ea9ce04SDavid Howells BUG_ON(direction != READ); 12818cd54c1cSAl Viro *i = (struct iov_iter){ 12828cd54c1cSAl Viro .iter_type = ITER_DISCARD, 12838cd54c1cSAl Viro .data_source = false, 12848cd54c1cSAl Viro .count = count, 12858cd54c1cSAl Viro .iov_offset = 0 12868cd54c1cSAl Viro }; 12879ea9ce04SDavid Howells } 12889ea9ce04SDavid Howells EXPORT_SYMBOL(iov_iter_discard); 12899ea9ce04SDavid Howells 12909221d2e3SAl Viro static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) 1291d879cb83SAl Viro { 1292d879cb83SAl Viro unsigned long res = 0; 1293d879cb83SAl Viro size_t size = i->count; 12949221d2e3SAl Viro size_t skip = i->iov_offset; 12959221d2e3SAl Viro unsigned k; 1296d879cb83SAl Viro 12979221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 12989221d2e3SAl Viro size_t len = i->iov[k].iov_len - skip; 12999221d2e3SAl Viro if (len) { 13009221d2e3SAl Viro res |= (unsigned long)i->iov[k].iov_base + skip; 13019221d2e3SAl Viro if (len > size) 13029221d2e3SAl Viro len = size; 13039221d2e3SAl Viro res |= len; 13049221d2e3SAl Viro size -= len; 13059221d2e3SAl Viro if (!size) 13069221d2e3SAl Viro break; 13079221d2e3SAl Viro } 13089221d2e3SAl Viro } 13099221d2e3SAl Viro return res; 13109221d2e3SAl Viro } 13119221d2e3SAl Viro 13129221d2e3SAl Viro static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) 13139221d2e3SAl Viro { 13149221d2e3SAl Viro unsigned res = 0; 13159221d2e3SAl Viro size_t size = i->count; 13169221d2e3SAl Viro unsigned skip = i->iov_offset; 13179221d2e3SAl Viro unsigned k; 13189221d2e3SAl Viro 13199221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 13209221d2e3SAl Viro size_t len = i->bvec[k].bv_len - skip; 13219221d2e3SAl Viro res |= (unsigned long)i->bvec[k].bv_offset + skip; 13229221d2e3SAl Viro if (len > size) 13239221d2e3SAl Viro len = size; 13249221d2e3SAl Viro res |= len; 13259221d2e3SAl Viro size -= len; 13269221d2e3SAl Viro if (!size) 13279221d2e3SAl Viro break; 13289221d2e3SAl Viro } 13299221d2e3SAl Viro return res; 13309221d2e3SAl Viro } 13319221d2e3SAl Viro 13329221d2e3SAl Viro unsigned long iov_iter_alignment(const struct iov_iter *i) 13339221d2e3SAl Viro { 13349221d2e3SAl Viro /* iovec and kvec have identical layouts */ 13359221d2e3SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 13369221d2e3SAl Viro return iov_iter_alignment_iovec(i); 13379221d2e3SAl Viro 13389221d2e3SAl Viro if (iov_iter_is_bvec(i)) 13399221d2e3SAl Viro return iov_iter_alignment_bvec(i); 13409221d2e3SAl Viro 13419221d2e3SAl Viro if (iov_iter_is_pipe(i)) { 1342e0ff126eSJan Kara unsigned int p_mask = i->pipe->ring_size - 1; 13439221d2e3SAl Viro size_t size = i->count; 1344e0ff126eSJan Kara 13458cefc107SDavid Howells if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) 1346241699cdSAl Viro return size | i->iov_offset; 1347241699cdSAl Viro return size; 1348241699cdSAl Viro } 13499221d2e3SAl Viro 13509221d2e3SAl Viro if (iov_iter_is_xarray(i)) 13513d14ec1fSDavid Howells return (i->xarray_start + i->iov_offset) | i->count; 13529221d2e3SAl Viro 13539221d2e3SAl Viro return 0; 1354d879cb83SAl Viro } 1355d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_alignment); 1356d879cb83SAl Viro 1357357f435dSAl Viro unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 1358357f435dSAl Viro { 1359357f435dSAl Viro unsigned long res = 0; 1360610c7a71SAl Viro unsigned long v = 0; 1361357f435dSAl Viro size_t size = i->count; 1362610c7a71SAl Viro unsigned k; 1363357f435dSAl Viro 1364610c7a71SAl Viro if (WARN_ON(!iter_is_iovec(i))) 1365241699cdSAl Viro return ~0U; 1366241699cdSAl Viro 1367610c7a71SAl Viro for (k = 0; k < i->nr_segs; k++) { 1368610c7a71SAl Viro if (i->iov[k].iov_len) { 1369610c7a71SAl Viro unsigned long base = (unsigned long)i->iov[k].iov_base; 1370610c7a71SAl Viro if (v) // if not the first one 1371610c7a71SAl Viro res |= base | v; // this start | previous end 1372610c7a71SAl Viro v = base + i->iov[k].iov_len; 1373610c7a71SAl Viro if (size <= i->iov[k].iov_len) 1374610c7a71SAl Viro break; 1375610c7a71SAl Viro size -= i->iov[k].iov_len; 1376610c7a71SAl Viro } 1377610c7a71SAl Viro } 1378357f435dSAl Viro return res; 1379357f435dSAl Viro } 1380357f435dSAl Viro EXPORT_SYMBOL(iov_iter_gap_alignment); 1381357f435dSAl Viro 1382e76b6312SIlya Dryomov static inline ssize_t __pipe_get_pages(struct iov_iter *i, 1383241699cdSAl Viro size_t maxsize, 1384241699cdSAl Viro struct page **pages, 13858cefc107SDavid Howells int iter_head, 1386241699cdSAl Viro size_t *start) 1387241699cdSAl Viro { 1388241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 13898cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 13908cefc107SDavid Howells ssize_t n = push_pipe(i, maxsize, &iter_head, start); 1391241699cdSAl Viro if (!n) 1392241699cdSAl Viro return -EFAULT; 1393241699cdSAl Viro 1394241699cdSAl Viro maxsize = n; 1395241699cdSAl Viro n += *start; 13961689c73aSAl Viro while (n > 0) { 13978cefc107SDavid Howells get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); 13988cefc107SDavid Howells iter_head++; 1399241699cdSAl Viro n -= PAGE_SIZE; 1400241699cdSAl Viro } 1401241699cdSAl Viro 1402241699cdSAl Viro return maxsize; 1403241699cdSAl Viro } 1404241699cdSAl Viro 1405241699cdSAl Viro static ssize_t pipe_get_pages(struct iov_iter *i, 1406241699cdSAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1407241699cdSAl Viro size_t *start) 1408241699cdSAl Viro { 14098cefc107SDavid Howells unsigned int iter_head, npages; 1410241699cdSAl Viro size_t capacity; 1411241699cdSAl Viro 1412241699cdSAl Viro if (!sanity(i)) 1413241699cdSAl Viro return -EFAULT; 1414241699cdSAl Viro 14158cefc107SDavid Howells data_start(i, &iter_head, start); 14168cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 14178cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1418241699cdSAl Viro capacity = min(npages, maxpages) * PAGE_SIZE - *start; 1419241699cdSAl Viro 14208cefc107SDavid Howells return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); 1421241699cdSAl Viro } 1422241699cdSAl Viro 14237ff50620SDavid Howells static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, 14247ff50620SDavid Howells pgoff_t index, unsigned int nr_pages) 14257ff50620SDavid Howells { 14267ff50620SDavid Howells XA_STATE(xas, xa, index); 14277ff50620SDavid Howells struct page *page; 14287ff50620SDavid Howells unsigned int ret = 0; 14297ff50620SDavid Howells 14307ff50620SDavid Howells rcu_read_lock(); 14317ff50620SDavid Howells for (page = xas_load(&xas); page; page = xas_next(&xas)) { 14327ff50620SDavid Howells if (xas_retry(&xas, page)) 14337ff50620SDavid Howells continue; 14347ff50620SDavid Howells 14357ff50620SDavid Howells /* Has the page moved or been split? */ 14367ff50620SDavid Howells if (unlikely(page != xas_reload(&xas))) { 14377ff50620SDavid Howells xas_reset(&xas); 14387ff50620SDavid Howells continue; 14397ff50620SDavid Howells } 14407ff50620SDavid Howells 14417ff50620SDavid Howells pages[ret] = find_subpage(page, xas.xa_index); 14427ff50620SDavid Howells get_page(pages[ret]); 14437ff50620SDavid Howells if (++ret == nr_pages) 14447ff50620SDavid Howells break; 14457ff50620SDavid Howells } 14467ff50620SDavid Howells rcu_read_unlock(); 14477ff50620SDavid Howells return ret; 14487ff50620SDavid Howells } 14497ff50620SDavid Howells 14507ff50620SDavid Howells static ssize_t iter_xarray_get_pages(struct iov_iter *i, 14517ff50620SDavid Howells struct page **pages, size_t maxsize, 14527ff50620SDavid Howells unsigned maxpages, size_t *_start_offset) 14537ff50620SDavid Howells { 14547ff50620SDavid Howells unsigned nr, offset; 14557ff50620SDavid Howells pgoff_t index, count; 14567ff50620SDavid Howells size_t size = maxsize, actual; 14577ff50620SDavid Howells loff_t pos; 14587ff50620SDavid Howells 14597ff50620SDavid Howells if (!size || !maxpages) 14607ff50620SDavid Howells return 0; 14617ff50620SDavid Howells 14627ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 14637ff50620SDavid Howells index = pos >> PAGE_SHIFT; 14647ff50620SDavid Howells offset = pos & ~PAGE_MASK; 14657ff50620SDavid Howells *_start_offset = offset; 14667ff50620SDavid Howells 14677ff50620SDavid Howells count = 1; 14687ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 14697ff50620SDavid Howells size -= PAGE_SIZE - offset; 14707ff50620SDavid Howells count += size >> PAGE_SHIFT; 14717ff50620SDavid Howells size &= ~PAGE_MASK; 14727ff50620SDavid Howells if (size) 14737ff50620SDavid Howells count++; 14747ff50620SDavid Howells } 14757ff50620SDavid Howells 14767ff50620SDavid Howells if (count > maxpages) 14777ff50620SDavid Howells count = maxpages; 14787ff50620SDavid Howells 14797ff50620SDavid Howells nr = iter_xarray_populate_pages(pages, i->xarray, index, count); 14807ff50620SDavid Howells if (nr == 0) 14817ff50620SDavid Howells return 0; 14827ff50620SDavid Howells 14837ff50620SDavid Howells actual = PAGE_SIZE * nr; 14847ff50620SDavid Howells actual -= offset; 14857ff50620SDavid Howells if (nr == count && size > 0) { 14867ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 14877ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 14887ff50620SDavid Howells } 14897ff50620SDavid Howells return actual; 14907ff50620SDavid Howells } 14917ff50620SDavid Howells 14923d671ca6SAl Viro /* must be done on non-empty ITER_IOVEC one */ 14933d671ca6SAl Viro static unsigned long first_iovec_segment(const struct iov_iter *i, 14943d671ca6SAl Viro size_t *size, size_t *start, 14953d671ca6SAl Viro size_t maxsize, unsigned maxpages) 14963d671ca6SAl Viro { 14973d671ca6SAl Viro size_t skip; 14983d671ca6SAl Viro long k; 14993d671ca6SAl Viro 15003d671ca6SAl Viro for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { 15013d671ca6SAl Viro unsigned long addr = (unsigned long)i->iov[k].iov_base + skip; 15023d671ca6SAl Viro size_t len = i->iov[k].iov_len - skip; 15033d671ca6SAl Viro 15043d671ca6SAl Viro if (unlikely(!len)) 15053d671ca6SAl Viro continue; 15063d671ca6SAl Viro if (len > maxsize) 15073d671ca6SAl Viro len = maxsize; 15083d671ca6SAl Viro len += (*start = addr % PAGE_SIZE); 15093d671ca6SAl Viro if (len > maxpages * PAGE_SIZE) 15103d671ca6SAl Viro len = maxpages * PAGE_SIZE; 15113d671ca6SAl Viro *size = len; 15123d671ca6SAl Viro return addr & PAGE_MASK; 15133d671ca6SAl Viro } 15143d671ca6SAl Viro BUG(); // if it had been empty, we wouldn't get called 15153d671ca6SAl Viro } 15163d671ca6SAl Viro 15173d671ca6SAl Viro /* must be done on non-empty ITER_BVEC one */ 15183d671ca6SAl Viro static struct page *first_bvec_segment(const struct iov_iter *i, 15193d671ca6SAl Viro size_t *size, size_t *start, 15203d671ca6SAl Viro size_t maxsize, unsigned maxpages) 15213d671ca6SAl Viro { 15223d671ca6SAl Viro struct page *page; 15233d671ca6SAl Viro size_t skip = i->iov_offset, len; 15243d671ca6SAl Viro 15253d671ca6SAl Viro len = i->bvec->bv_len - skip; 15263d671ca6SAl Viro if (len > maxsize) 15273d671ca6SAl Viro len = maxsize; 15283d671ca6SAl Viro skip += i->bvec->bv_offset; 15293d671ca6SAl Viro page = i->bvec->bv_page + skip / PAGE_SIZE; 15303d671ca6SAl Viro len += (*start = skip % PAGE_SIZE); 15313d671ca6SAl Viro if (len > maxpages * PAGE_SIZE) 15323d671ca6SAl Viro len = maxpages * PAGE_SIZE; 15333d671ca6SAl Viro *size = len; 15343d671ca6SAl Viro return page; 15353d671ca6SAl Viro } 15363d671ca6SAl Viro 1537d879cb83SAl Viro ssize_t iov_iter_get_pages(struct iov_iter *i, 1538d879cb83SAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1539d879cb83SAl Viro size_t *start) 1540d879cb83SAl Viro { 15413d671ca6SAl Viro size_t len; 15423d671ca6SAl Viro int n, res; 15433d671ca6SAl Viro 1544d879cb83SAl Viro if (maxsize > i->count) 1545d879cb83SAl Viro maxsize = i->count; 15463d671ca6SAl Viro if (!maxsize) 15473d671ca6SAl Viro return 0; 1548d879cb83SAl Viro 15493d671ca6SAl Viro if (likely(iter_is_iovec(i))) { 15503d671ca6SAl Viro unsigned long addr; 15519ea9ce04SDavid Howells 15523d671ca6SAl Viro addr = first_iovec_segment(i, &len, start, maxsize, maxpages); 1553d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 155473b0140bSIra Weiny res = get_user_pages_fast(addr, n, 155573b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, 155673b0140bSIra Weiny pages); 1557d879cb83SAl Viro if (unlikely(res < 0)) 1558d879cb83SAl Viro return res; 1559d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 15603d671ca6SAl Viro } 15613d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 15623d671ca6SAl Viro struct page *page; 15633d671ca6SAl Viro 15643d671ca6SAl Viro page = first_bvec_segment(i, &len, start, maxsize, maxpages); 15653d671ca6SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 15663d671ca6SAl Viro while (n--) 15673d671ca6SAl Viro get_page(*pages++ = page++); 15683d671ca6SAl Viro return len - *start; 15693d671ca6SAl Viro } 15703d671ca6SAl Viro if (iov_iter_is_pipe(i)) 15713d671ca6SAl Viro return pipe_get_pages(i, pages, maxsize, maxpages, start); 15723d671ca6SAl Viro if (iov_iter_is_xarray(i)) 15733d671ca6SAl Viro return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); 1574d879cb83SAl Viro return -EFAULT; 1575d879cb83SAl Viro } 1576d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages); 1577d879cb83SAl Viro 1578d879cb83SAl Viro static struct page **get_pages_array(size_t n) 1579d879cb83SAl Viro { 1580752ade68SMichal Hocko return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); 1581d879cb83SAl Viro } 1582d879cb83SAl Viro 1583241699cdSAl Viro static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 1584241699cdSAl Viro struct page ***pages, size_t maxsize, 1585241699cdSAl Viro size_t *start) 1586241699cdSAl Viro { 1587241699cdSAl Viro struct page **p; 15888cefc107SDavid Howells unsigned int iter_head, npages; 1589d7760d63SIlya Dryomov ssize_t n; 1590241699cdSAl Viro 1591241699cdSAl Viro if (!sanity(i)) 1592241699cdSAl Viro return -EFAULT; 1593241699cdSAl Viro 15948cefc107SDavid Howells data_start(i, &iter_head, start); 15958cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 15968cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1597241699cdSAl Viro n = npages * PAGE_SIZE - *start; 1598241699cdSAl Viro if (maxsize > n) 1599241699cdSAl Viro maxsize = n; 1600241699cdSAl Viro else 1601241699cdSAl Viro npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1602241699cdSAl Viro p = get_pages_array(npages); 1603241699cdSAl Viro if (!p) 1604241699cdSAl Viro return -ENOMEM; 16058cefc107SDavid Howells n = __pipe_get_pages(i, maxsize, p, iter_head, start); 1606241699cdSAl Viro if (n > 0) 1607241699cdSAl Viro *pages = p; 1608241699cdSAl Viro else 1609241699cdSAl Viro kvfree(p); 1610241699cdSAl Viro return n; 1611241699cdSAl Viro } 1612241699cdSAl Viro 16137ff50620SDavid Howells static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, 16147ff50620SDavid Howells struct page ***pages, size_t maxsize, 16157ff50620SDavid Howells size_t *_start_offset) 16167ff50620SDavid Howells { 16177ff50620SDavid Howells struct page **p; 16187ff50620SDavid Howells unsigned nr, offset; 16197ff50620SDavid Howells pgoff_t index, count; 16207ff50620SDavid Howells size_t size = maxsize, actual; 16217ff50620SDavid Howells loff_t pos; 16227ff50620SDavid Howells 16237ff50620SDavid Howells if (!size) 16247ff50620SDavid Howells return 0; 16257ff50620SDavid Howells 16267ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 16277ff50620SDavid Howells index = pos >> PAGE_SHIFT; 16287ff50620SDavid Howells offset = pos & ~PAGE_MASK; 16297ff50620SDavid Howells *_start_offset = offset; 16307ff50620SDavid Howells 16317ff50620SDavid Howells count = 1; 16327ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 16337ff50620SDavid Howells size -= PAGE_SIZE - offset; 16347ff50620SDavid Howells count += size >> PAGE_SHIFT; 16357ff50620SDavid Howells size &= ~PAGE_MASK; 16367ff50620SDavid Howells if (size) 16377ff50620SDavid Howells count++; 16387ff50620SDavid Howells } 16397ff50620SDavid Howells 16407ff50620SDavid Howells p = get_pages_array(count); 16417ff50620SDavid Howells if (!p) 16427ff50620SDavid Howells return -ENOMEM; 16437ff50620SDavid Howells *pages = p; 16447ff50620SDavid Howells 16457ff50620SDavid Howells nr = iter_xarray_populate_pages(p, i->xarray, index, count); 16467ff50620SDavid Howells if (nr == 0) 16477ff50620SDavid Howells return 0; 16487ff50620SDavid Howells 16497ff50620SDavid Howells actual = PAGE_SIZE * nr; 16507ff50620SDavid Howells actual -= offset; 16517ff50620SDavid Howells if (nr == count && size > 0) { 16527ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 16537ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 16547ff50620SDavid Howells } 16557ff50620SDavid Howells return actual; 16567ff50620SDavid Howells } 16577ff50620SDavid Howells 1658d879cb83SAl Viro ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 1659d879cb83SAl Viro struct page ***pages, size_t maxsize, 1660d879cb83SAl Viro size_t *start) 1661d879cb83SAl Viro { 1662d879cb83SAl Viro struct page **p; 16633d671ca6SAl Viro size_t len; 16643d671ca6SAl Viro int n, res; 1665d879cb83SAl Viro 1666d879cb83SAl Viro if (maxsize > i->count) 1667d879cb83SAl Viro maxsize = i->count; 16683d671ca6SAl Viro if (!maxsize) 16693d671ca6SAl Viro return 0; 1670d879cb83SAl Viro 16713d671ca6SAl Viro if (likely(iter_is_iovec(i))) { 16723d671ca6SAl Viro unsigned long addr; 16739ea9ce04SDavid Howells 16743d671ca6SAl Viro addr = first_iovec_segment(i, &len, start, maxsize, ~0U); 1675d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 1676d879cb83SAl Viro p = get_pages_array(n); 1677d879cb83SAl Viro if (!p) 1678d879cb83SAl Viro return -ENOMEM; 167973b0140bSIra Weiny res = get_user_pages_fast(addr, n, 168073b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); 1681d879cb83SAl Viro if (unlikely(res < 0)) { 1682d879cb83SAl Viro kvfree(p); 1683d879cb83SAl Viro return res; 1684d879cb83SAl Viro } 1685d879cb83SAl Viro *pages = p; 1686d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 16873d671ca6SAl Viro } 16883d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 16893d671ca6SAl Viro struct page *page; 16903d671ca6SAl Viro 16913d671ca6SAl Viro page = first_bvec_segment(i, &len, start, maxsize, ~0U); 16923d671ca6SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 16933d671ca6SAl Viro *pages = p = get_pages_array(n); 1694d879cb83SAl Viro if (!p) 1695d879cb83SAl Viro return -ENOMEM; 16963d671ca6SAl Viro while (n--) 16973d671ca6SAl Viro get_page(*p++ = page++); 16983d671ca6SAl Viro return len - *start; 16993d671ca6SAl Viro } 17003d671ca6SAl Viro if (iov_iter_is_pipe(i)) 17013d671ca6SAl Viro return pipe_get_pages_alloc(i, pages, maxsize, start); 17023d671ca6SAl Viro if (iov_iter_is_xarray(i)) 17033d671ca6SAl Viro return iter_xarray_get_pages_alloc(i, pages, maxsize, start); 1704d879cb83SAl Viro return -EFAULT; 1705d879cb83SAl Viro } 1706d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages_alloc); 1707d879cb83SAl Viro 1708d879cb83SAl Viro size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 1709d879cb83SAl Viro struct iov_iter *i) 1710d879cb83SAl Viro { 1711d879cb83SAl Viro char *to = addr; 1712d879cb83SAl Viro __wsum sum, next; 1713d879cb83SAl Viro size_t off = 0; 1714d879cb83SAl Viro sum = *csum; 17159ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1716241699cdSAl Viro WARN_ON(1); 1717241699cdSAl Viro return 0; 1718241699cdSAl Viro } 1719d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1720d879cb83SAl Viro next = csum_and_copy_from_user(v.iov_base, 1721d879cb83SAl Viro (to += v.iov_len) - v.iov_len, 1722c693cc46SAl Viro v.iov_len); 1723c693cc46SAl Viro if (next) { 1724d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1725d879cb83SAl Viro off += v.iov_len; 1726d879cb83SAl Viro } 1727c693cc46SAl Viro next ? 0 : v.iov_len; 1728d879cb83SAl Viro }), ({ 1729d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1730f9152895SAl Viro sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 1731f9152895SAl Viro p + v.bv_offset, v.bv_len, 1732f9152895SAl Viro sum, off); 1733d879cb83SAl Viro kunmap_atomic(p); 1734d879cb83SAl Viro off += v.bv_len; 1735d879cb83SAl Viro }),({ 1736f9152895SAl Viro sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, 1737f9152895SAl Viro v.iov_base, v.iov_len, 1738f9152895SAl Viro sum, off); 1739d879cb83SAl Viro off += v.iov_len; 17407ff50620SDavid Howells }), ({ 17417ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 17427ff50620SDavid Howells sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 17437ff50620SDavid Howells p + v.bv_offset, v.bv_len, 17447ff50620SDavid Howells sum, off); 17457ff50620SDavid Howells kunmap_atomic(p); 17467ff50620SDavid Howells off += v.bv_len; 1747d879cb83SAl Viro }) 1748d879cb83SAl Viro ) 1749d879cb83SAl Viro *csum = sum; 1750d879cb83SAl Viro return bytes; 1751d879cb83SAl Viro } 1752d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter); 1753d879cb83SAl Viro 175452cbd23aSWillem de Bruijn size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 1755d879cb83SAl Viro struct iov_iter *i) 1756d879cb83SAl Viro { 175752cbd23aSWillem de Bruijn struct csum_state *csstate = _csstate; 175836f7a8a4SAl Viro const char *from = addr; 1759d879cb83SAl Viro __wsum sum, next; 176052cbd23aSWillem de Bruijn size_t off; 176178e1f386SAl Viro 176278e1f386SAl Viro if (unlikely(iov_iter_is_pipe(i))) 176352cbd23aSWillem de Bruijn return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); 176478e1f386SAl Viro 1765594e450bSAl Viro sum = csum_shift(csstate->csum, csstate->off); 1766594e450bSAl Viro off = 0; 176778e1f386SAl Viro if (unlikely(iov_iter_is_discard(i))) { 1768241699cdSAl Viro WARN_ON(1); /* for now */ 1769241699cdSAl Viro return 0; 1770241699cdSAl Viro } 1771d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1772d879cb83SAl Viro next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, 1773d879cb83SAl Viro v.iov_base, 1774c693cc46SAl Viro v.iov_len); 1775c693cc46SAl Viro if (next) { 1776d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1777d879cb83SAl Viro off += v.iov_len; 1778d879cb83SAl Viro } 1779c693cc46SAl Viro next ? 0 : v.iov_len; 1780d879cb83SAl Viro }), ({ 1781d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1782f9152895SAl Viro sum = csum_and_memcpy(p + v.bv_offset, 1783f9152895SAl Viro (from += v.bv_len) - v.bv_len, 1784f9152895SAl Viro v.bv_len, sum, off); 1785d879cb83SAl Viro kunmap_atomic(p); 1786d879cb83SAl Viro off += v.bv_len; 1787d879cb83SAl Viro }),({ 1788f9152895SAl Viro sum = csum_and_memcpy(v.iov_base, 1789f9152895SAl Viro (from += v.iov_len) - v.iov_len, 1790f9152895SAl Viro v.iov_len, sum, off); 1791d879cb83SAl Viro off += v.iov_len; 17927ff50620SDavid Howells }), ({ 17937ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 17947ff50620SDavid Howells sum = csum_and_memcpy(p + v.bv_offset, 17957ff50620SDavid Howells (from += v.bv_len) - v.bv_len, 17967ff50620SDavid Howells v.bv_len, sum, off); 17977ff50620SDavid Howells kunmap_atomic(p); 17987ff50620SDavid Howells off += v.bv_len; 1799d879cb83SAl Viro }) 1800d879cb83SAl Viro ) 1801594e450bSAl Viro csstate->csum = csum_shift(sum, csstate->off); 1802594e450bSAl Viro csstate->off += bytes; 1803d879cb83SAl Viro return bytes; 1804d879cb83SAl Viro } 1805d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_to_iter); 1806d879cb83SAl Viro 1807d05f4435SSagi Grimberg size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, 1808d05f4435SSagi Grimberg struct iov_iter *i) 1809d05f4435SSagi Grimberg { 18107999096fSHerbert Xu #ifdef CONFIG_CRYPTO_HASH 1811d05f4435SSagi Grimberg struct ahash_request *hash = hashp; 1812d05f4435SSagi Grimberg struct scatterlist sg; 1813d05f4435SSagi Grimberg size_t copied; 1814d05f4435SSagi Grimberg 1815d05f4435SSagi Grimberg copied = copy_to_iter(addr, bytes, i); 1816d05f4435SSagi Grimberg sg_init_one(&sg, addr, copied); 1817d05f4435SSagi Grimberg ahash_request_set_crypt(hash, &sg, NULL, copied); 1818d05f4435SSagi Grimberg crypto_ahash_update(hash); 1819d05f4435SSagi Grimberg return copied; 182027fad74aSYueHaibing #else 182127fad74aSYueHaibing return 0; 182227fad74aSYueHaibing #endif 1823d05f4435SSagi Grimberg } 1824d05f4435SSagi Grimberg EXPORT_SYMBOL(hash_and_copy_to_iter); 1825d05f4435SSagi Grimberg 182666531c65SAl Viro static int iov_npages(const struct iov_iter *i, int maxpages) 1827d879cb83SAl Viro { 182866531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 182966531c65SAl Viro const struct iovec *p; 1830d879cb83SAl Viro int npages = 0; 1831d879cb83SAl Viro 183266531c65SAl Viro for (p = i->iov; size; skip = 0, p++) { 183366531c65SAl Viro unsigned offs = offset_in_page(p->iov_base + skip); 183466531c65SAl Viro size_t len = min(p->iov_len - skip, size); 1835d879cb83SAl Viro 183666531c65SAl Viro if (len) { 183766531c65SAl Viro size -= len; 183866531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 183966531c65SAl Viro if (unlikely(npages > maxpages)) 184066531c65SAl Viro return maxpages; 184166531c65SAl Viro } 184266531c65SAl Viro } 184366531c65SAl Viro return npages; 184466531c65SAl Viro } 184566531c65SAl Viro 184666531c65SAl Viro static int bvec_npages(const struct iov_iter *i, int maxpages) 184766531c65SAl Viro { 184866531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 184966531c65SAl Viro const struct bio_vec *p; 185066531c65SAl Viro int npages = 0; 185166531c65SAl Viro 185266531c65SAl Viro for (p = i->bvec; size; skip = 0, p++) { 185366531c65SAl Viro unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; 185466531c65SAl Viro size_t len = min(p->bv_len - skip, size); 185566531c65SAl Viro 185666531c65SAl Viro size -= len; 185766531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 185866531c65SAl Viro if (unlikely(npages > maxpages)) 185966531c65SAl Viro return maxpages; 186066531c65SAl Viro } 186166531c65SAl Viro return npages; 186266531c65SAl Viro } 186366531c65SAl Viro 186466531c65SAl Viro int iov_iter_npages(const struct iov_iter *i, int maxpages) 186566531c65SAl Viro { 186666531c65SAl Viro if (unlikely(!i->count)) 186766531c65SAl Viro return 0; 186866531c65SAl Viro /* iovec and kvec have identical layouts */ 186966531c65SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 187066531c65SAl Viro return iov_npages(i, maxpages); 187166531c65SAl Viro if (iov_iter_is_bvec(i)) 187266531c65SAl Viro return bvec_npages(i, maxpages); 187366531c65SAl Viro if (iov_iter_is_pipe(i)) { 18748cefc107SDavid Howells unsigned int iter_head; 187566531c65SAl Viro int npages; 1876241699cdSAl Viro size_t off; 1877241699cdSAl Viro 1878241699cdSAl Viro if (!sanity(i)) 1879241699cdSAl Viro return 0; 1880241699cdSAl Viro 18818cefc107SDavid Howells data_start(i, &iter_head, &off); 1882241699cdSAl Viro /* some of this one + all after this one */ 188366531c65SAl Viro npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 188466531c65SAl Viro return min(npages, maxpages); 188566531c65SAl Viro } 188666531c65SAl Viro if (iov_iter_is_xarray(i)) { 1887e4f8df86SAl Viro unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; 1888e4f8df86SAl Viro int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); 188966531c65SAl Viro return min(npages, maxpages); 189066531c65SAl Viro } 189166531c65SAl Viro return 0; 1892d879cb83SAl Viro } 1893d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_npages); 1894d879cb83SAl Viro 1895d879cb83SAl Viro const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) 1896d879cb83SAl Viro { 1897d879cb83SAl Viro *new = *old; 189800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(new))) { 1899241699cdSAl Viro WARN_ON(1); 1900241699cdSAl Viro return NULL; 1901241699cdSAl Viro } 19027ff50620SDavid Howells if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) 19039ea9ce04SDavid Howells return NULL; 190400e23707SDavid Howells if (iov_iter_is_bvec(new)) 1905d879cb83SAl Viro return new->bvec = kmemdup(new->bvec, 1906d879cb83SAl Viro new->nr_segs * sizeof(struct bio_vec), 1907d879cb83SAl Viro flags); 1908d879cb83SAl Viro else 1909d879cb83SAl Viro /* iovec and kvec have identical layout */ 1910d879cb83SAl Viro return new->iov = kmemdup(new->iov, 1911d879cb83SAl Viro new->nr_segs * sizeof(struct iovec), 1912d879cb83SAl Viro flags); 1913d879cb83SAl Viro } 1914d879cb83SAl Viro EXPORT_SYMBOL(dup_iter); 1915bc917be8SAl Viro 1916bfdc5970SChristoph Hellwig static int copy_compat_iovec_from_user(struct iovec *iov, 1917bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1918bfdc5970SChristoph Hellwig { 1919bfdc5970SChristoph Hellwig const struct compat_iovec __user *uiov = 1920bfdc5970SChristoph Hellwig (const struct compat_iovec __user *)uvec; 1921bfdc5970SChristoph Hellwig int ret = -EFAULT, i; 1922bfdc5970SChristoph Hellwig 1923a959a978SChristoph Hellwig if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) 1924bfdc5970SChristoph Hellwig return -EFAULT; 1925bfdc5970SChristoph Hellwig 1926bfdc5970SChristoph Hellwig for (i = 0; i < nr_segs; i++) { 1927bfdc5970SChristoph Hellwig compat_uptr_t buf; 1928bfdc5970SChristoph Hellwig compat_ssize_t len; 1929bfdc5970SChristoph Hellwig 1930bfdc5970SChristoph Hellwig unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); 1931bfdc5970SChristoph Hellwig unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); 1932bfdc5970SChristoph Hellwig 1933bfdc5970SChristoph Hellwig /* check for compat_size_t not fitting in compat_ssize_t .. */ 1934bfdc5970SChristoph Hellwig if (len < 0) { 1935bfdc5970SChristoph Hellwig ret = -EINVAL; 1936bfdc5970SChristoph Hellwig goto uaccess_end; 1937bfdc5970SChristoph Hellwig } 1938bfdc5970SChristoph Hellwig iov[i].iov_base = compat_ptr(buf); 1939bfdc5970SChristoph Hellwig iov[i].iov_len = len; 1940bfdc5970SChristoph Hellwig } 1941bfdc5970SChristoph Hellwig 1942bfdc5970SChristoph Hellwig ret = 0; 1943bfdc5970SChristoph Hellwig uaccess_end: 1944bfdc5970SChristoph Hellwig user_access_end(); 1945bfdc5970SChristoph Hellwig return ret; 1946bfdc5970SChristoph Hellwig } 1947bfdc5970SChristoph Hellwig 1948bfdc5970SChristoph Hellwig static int copy_iovec_from_user(struct iovec *iov, 1949bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1950fb041b59SDavid Laight { 1951fb041b59SDavid Laight unsigned long seg; 1952bfdc5970SChristoph Hellwig 1953bfdc5970SChristoph Hellwig if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) 1954bfdc5970SChristoph Hellwig return -EFAULT; 1955bfdc5970SChristoph Hellwig for (seg = 0; seg < nr_segs; seg++) { 1956bfdc5970SChristoph Hellwig if ((ssize_t)iov[seg].iov_len < 0) 1957bfdc5970SChristoph Hellwig return -EINVAL; 1958bfdc5970SChristoph Hellwig } 1959bfdc5970SChristoph Hellwig 1960bfdc5970SChristoph Hellwig return 0; 1961bfdc5970SChristoph Hellwig } 1962bfdc5970SChristoph Hellwig 1963bfdc5970SChristoph Hellwig struct iovec *iovec_from_user(const struct iovec __user *uvec, 1964bfdc5970SChristoph Hellwig unsigned long nr_segs, unsigned long fast_segs, 1965bfdc5970SChristoph Hellwig struct iovec *fast_iov, bool compat) 1966bfdc5970SChristoph Hellwig { 1967bfdc5970SChristoph Hellwig struct iovec *iov = fast_iov; 1968bfdc5970SChristoph Hellwig int ret; 1969fb041b59SDavid Laight 1970fb041b59SDavid Laight /* 1971bfdc5970SChristoph Hellwig * SuS says "The readv() function *may* fail if the iovcnt argument was 1972bfdc5970SChristoph Hellwig * less than or equal to 0, or greater than {IOV_MAX}. Linux has 1973fb041b59SDavid Laight * traditionally returned zero for zero segments, so... 1974fb041b59SDavid Laight */ 1975bfdc5970SChristoph Hellwig if (nr_segs == 0) 1976bfdc5970SChristoph Hellwig return iov; 1977bfdc5970SChristoph Hellwig if (nr_segs > UIO_MAXIOV) 1978bfdc5970SChristoph Hellwig return ERR_PTR(-EINVAL); 1979fb041b59SDavid Laight if (nr_segs > fast_segs) { 1980fb041b59SDavid Laight iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); 1981bfdc5970SChristoph Hellwig if (!iov) 1982bfdc5970SChristoph Hellwig return ERR_PTR(-ENOMEM); 1983fb041b59SDavid Laight } 1984bfdc5970SChristoph Hellwig 1985bfdc5970SChristoph Hellwig if (compat) 1986bfdc5970SChristoph Hellwig ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); 1987bfdc5970SChristoph Hellwig else 1988bfdc5970SChristoph Hellwig ret = copy_iovec_from_user(iov, uvec, nr_segs); 1989bfdc5970SChristoph Hellwig if (ret) { 1990bfdc5970SChristoph Hellwig if (iov != fast_iov) 1991bfdc5970SChristoph Hellwig kfree(iov); 1992bfdc5970SChristoph Hellwig return ERR_PTR(ret); 1993fb041b59SDavid Laight } 1994bfdc5970SChristoph Hellwig 1995bfdc5970SChristoph Hellwig return iov; 1996bfdc5970SChristoph Hellwig } 1997bfdc5970SChristoph Hellwig 1998bfdc5970SChristoph Hellwig ssize_t __import_iovec(int type, const struct iovec __user *uvec, 1999bfdc5970SChristoph Hellwig unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, 2000bfdc5970SChristoph Hellwig struct iov_iter *i, bool compat) 2001bfdc5970SChristoph Hellwig { 2002bfdc5970SChristoph Hellwig ssize_t total_len = 0; 2003bfdc5970SChristoph Hellwig unsigned long seg; 2004bfdc5970SChristoph Hellwig struct iovec *iov; 2005bfdc5970SChristoph Hellwig 2006bfdc5970SChristoph Hellwig iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); 2007bfdc5970SChristoph Hellwig if (IS_ERR(iov)) { 2008bfdc5970SChristoph Hellwig *iovp = NULL; 2009bfdc5970SChristoph Hellwig return PTR_ERR(iov); 2010fb041b59SDavid Laight } 2011fb041b59SDavid Laight 2012fb041b59SDavid Laight /* 2013bfdc5970SChristoph Hellwig * According to the Single Unix Specification we should return EINVAL if 2014bfdc5970SChristoph Hellwig * an element length is < 0 when cast to ssize_t or if the total length 2015bfdc5970SChristoph Hellwig * would overflow the ssize_t return value of the system call. 2016fb041b59SDavid Laight * 2017fb041b59SDavid Laight * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the 2018fb041b59SDavid Laight * overflow case. 2019fb041b59SDavid Laight */ 2020fb041b59SDavid Laight for (seg = 0; seg < nr_segs; seg++) { 2021fb041b59SDavid Laight ssize_t len = (ssize_t)iov[seg].iov_len; 2022fb041b59SDavid Laight 2023bfdc5970SChristoph Hellwig if (!access_ok(iov[seg].iov_base, len)) { 2024bfdc5970SChristoph Hellwig if (iov != *iovp) 2025bfdc5970SChristoph Hellwig kfree(iov); 2026bfdc5970SChristoph Hellwig *iovp = NULL; 2027bfdc5970SChristoph Hellwig return -EFAULT; 2028fb041b59SDavid Laight } 2029bfdc5970SChristoph Hellwig 2030bfdc5970SChristoph Hellwig if (len > MAX_RW_COUNT - total_len) { 2031bfdc5970SChristoph Hellwig len = MAX_RW_COUNT - total_len; 2032fb041b59SDavid Laight iov[seg].iov_len = len; 2033fb041b59SDavid Laight } 2034bfdc5970SChristoph Hellwig total_len += len; 2035fb041b59SDavid Laight } 2036bfdc5970SChristoph Hellwig 2037bfdc5970SChristoph Hellwig iov_iter_init(i, type, iov, nr_segs, total_len); 2038bfdc5970SChristoph Hellwig if (iov == *iovp) 2039bfdc5970SChristoph Hellwig *iovp = NULL; 2040bfdc5970SChristoph Hellwig else 2041bfdc5970SChristoph Hellwig *iovp = iov; 2042bfdc5970SChristoph Hellwig return total_len; 2043fb041b59SDavid Laight } 2044fb041b59SDavid Laight 2045ffecee4fSVegard Nossum /** 2046ffecee4fSVegard Nossum * import_iovec() - Copy an array of &struct iovec from userspace 2047ffecee4fSVegard Nossum * into the kernel, check that it is valid, and initialize a new 2048ffecee4fSVegard Nossum * &struct iov_iter iterator to access it. 2049ffecee4fSVegard Nossum * 2050ffecee4fSVegard Nossum * @type: One of %READ or %WRITE. 2051bfdc5970SChristoph Hellwig * @uvec: Pointer to the userspace array. 2052ffecee4fSVegard Nossum * @nr_segs: Number of elements in userspace array. 2053ffecee4fSVegard Nossum * @fast_segs: Number of elements in @iov. 2054bfdc5970SChristoph Hellwig * @iovp: (input and output parameter) Pointer to pointer to (usually small 2055ffecee4fSVegard Nossum * on-stack) kernel array. 2056ffecee4fSVegard Nossum * @i: Pointer to iterator that will be initialized on success. 2057ffecee4fSVegard Nossum * 2058ffecee4fSVegard Nossum * If the array pointed to by *@iov is large enough to hold all @nr_segs, 2059ffecee4fSVegard Nossum * then this function places %NULL in *@iov on return. Otherwise, a new 2060ffecee4fSVegard Nossum * array will be allocated and the result placed in *@iov. This means that 2061ffecee4fSVegard Nossum * the caller may call kfree() on *@iov regardless of whether the small 2062ffecee4fSVegard Nossum * on-stack array was used or not (and regardless of whether this function 2063ffecee4fSVegard Nossum * returns an error or not). 2064ffecee4fSVegard Nossum * 206587e5e6daSJens Axboe * Return: Negative error code on error, bytes imported on success 2066ffecee4fSVegard Nossum */ 2067bfdc5970SChristoph Hellwig ssize_t import_iovec(int type, const struct iovec __user *uvec, 2068bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 2069bfdc5970SChristoph Hellwig struct iovec **iovp, struct iov_iter *i) 2070bc917be8SAl Viro { 207189cd35c5SChristoph Hellwig return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, 207289cd35c5SChristoph Hellwig in_compat_syscall()); 2073bc917be8SAl Viro } 2074bc917be8SAl Viro EXPORT_SYMBOL(import_iovec); 2075bc917be8SAl Viro 2076bc917be8SAl Viro int import_single_range(int rw, void __user *buf, size_t len, 2077bc917be8SAl Viro struct iovec *iov, struct iov_iter *i) 2078bc917be8SAl Viro { 2079bc917be8SAl Viro if (len > MAX_RW_COUNT) 2080bc917be8SAl Viro len = MAX_RW_COUNT; 208196d4f267SLinus Torvalds if (unlikely(!access_ok(buf, len))) 2082bc917be8SAl Viro return -EFAULT; 2083bc917be8SAl Viro 2084bc917be8SAl Viro iov->iov_base = buf; 2085bc917be8SAl Viro iov->iov_len = len; 2086bc917be8SAl Viro iov_iter_init(i, rw, iov, 1, len); 2087bc917be8SAl Viro return 0; 2088bc917be8SAl Viro } 2089e1267585SAl Viro EXPORT_SYMBOL(import_single_range); 2090