1457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 27999096fSHerbert Xu #include <crypto/hash.h> 3d879cb83SAl Viro #include <linux/export.h> 42f8b5444SChristoph Hellwig #include <linux/bvec.h> 54d0e9df5SAlbert van der Linde #include <linux/fault-inject-usercopy.h> 6d879cb83SAl Viro #include <linux/uio.h> 7d879cb83SAl Viro #include <linux/pagemap.h> 828961998SIra Weiny #include <linux/highmem.h> 9d879cb83SAl Viro #include <linux/slab.h> 10d879cb83SAl Viro #include <linux/vmalloc.h> 11241699cdSAl Viro #include <linux/splice.h> 12bfdc5970SChristoph Hellwig #include <linux/compat.h> 13d879cb83SAl Viro #include <net/checksum.h> 14d05f4435SSagi Grimberg #include <linux/scatterlist.h> 15d0ef4c36SMarco Elver #include <linux/instrumented.h> 16d879cb83SAl Viro 17241699cdSAl Viro #define PIPE_PARANOIA /* for now */ 18241699cdSAl Viro 195c67aa90SAl Viro /* covers iovec and kvec alike */ 20a6e4ec7bSAl Viro #define iterate_iovec(i, n, base, len, off, __p, STEP) { \ 217baa5099SAl Viro size_t off = 0; \ 22a6e4ec7bSAl Viro size_t skip = i->iov_offset; \ 237a1bcb5dSAl Viro do { \ 247baa5099SAl Viro len = min(n, __p->iov_len - skip); \ 257baa5099SAl Viro if (likely(len)) { \ 267baa5099SAl Viro base = __p->iov_base + skip; \ 277baa5099SAl Viro len -= (STEP); \ 287baa5099SAl Viro off += len; \ 297baa5099SAl Viro skip += len; \ 307baa5099SAl Viro n -= len; \ 317a1bcb5dSAl Viro if (skip < __p->iov_len) \ 327a1bcb5dSAl Viro break; \ 33d879cb83SAl Viro } \ 34d879cb83SAl Viro __p++; \ 357a1bcb5dSAl Viro skip = 0; \ 367a1bcb5dSAl Viro } while (n); \ 37a6e4ec7bSAl Viro i->iov_offset = skip; \ 387baa5099SAl Viro n = off; \ 39d879cb83SAl Viro } 40d879cb83SAl Viro 41a6e4ec7bSAl Viro #define iterate_bvec(i, n, base, len, off, p, STEP) { \ 427baa5099SAl Viro size_t off = 0; \ 43a6e4ec7bSAl Viro unsigned skip = i->iov_offset; \ 447491a2bfSAl Viro while (n) { \ 457491a2bfSAl Viro unsigned offset = p->bv_offset + skip; \ 461b4fb5ffSAl Viro unsigned left; \ 4721b56c84SAl Viro void *kaddr = kmap_local_page(p->bv_page + \ 4821b56c84SAl Viro offset / PAGE_SIZE); \ 497baa5099SAl Viro base = kaddr + offset % PAGE_SIZE; \ 50a6e4ec7bSAl Viro len = min(min(n, (size_t)(p->bv_len - skip)), \ 517491a2bfSAl Viro (size_t)(PAGE_SIZE - offset % PAGE_SIZE)); \ 521b4fb5ffSAl Viro left = (STEP); \ 5321b56c84SAl Viro kunmap_local(kaddr); \ 547baa5099SAl Viro len -= left; \ 557baa5099SAl Viro off += len; \ 567baa5099SAl Viro skip += len; \ 577491a2bfSAl Viro if (skip == p->bv_len) { \ 587491a2bfSAl Viro skip = 0; \ 597491a2bfSAl Viro p++; \ 60d879cb83SAl Viro } \ 617baa5099SAl Viro n -= len; \ 621b4fb5ffSAl Viro if (left) \ 631b4fb5ffSAl Viro break; \ 647491a2bfSAl Viro } \ 65a6e4ec7bSAl Viro i->iov_offset = skip; \ 667baa5099SAl Viro n = off; \ 67d879cb83SAl Viro } 68d879cb83SAl Viro 69a6e4ec7bSAl Viro #define iterate_xarray(i, n, base, len, __off, STEP) { \ 701b4fb5ffSAl Viro __label__ __out; \ 71622838f3SAl Viro size_t __off = 0; \ 727ff50620SDavid Howells struct page *head = NULL; \ 73a6e4ec7bSAl Viro loff_t start = i->xarray_start + i->iov_offset; \ 744b179e9aSAl Viro unsigned offset = start % PAGE_SIZE; \ 754b179e9aSAl Viro pgoff_t index = start / PAGE_SIZE; \ 767ff50620SDavid Howells int j; \ 777ff50620SDavid Howells \ 787ff50620SDavid Howells XA_STATE(xas, i->xarray, index); \ 797ff50620SDavid Howells \ 807ff50620SDavid Howells rcu_read_lock(); \ 817ff50620SDavid Howells xas_for_each(&xas, head, ULONG_MAX) { \ 821b4fb5ffSAl Viro unsigned left; \ 837ff50620SDavid Howells if (xas_retry(&xas, head)) \ 847ff50620SDavid Howells continue; \ 857ff50620SDavid Howells if (WARN_ON(xa_is_value(head))) \ 867ff50620SDavid Howells break; \ 877ff50620SDavid Howells if (WARN_ON(PageHuge(head))) \ 887ff50620SDavid Howells break; \ 897ff50620SDavid Howells for (j = (head->index < index) ? index - head->index : 0; \ 907ff50620SDavid Howells j < thp_nr_pages(head); j++) { \ 9121b56c84SAl Viro void *kaddr = kmap_local_page(head + j); \ 927baa5099SAl Viro base = kaddr + offset; \ 937baa5099SAl Viro len = PAGE_SIZE - offset; \ 947baa5099SAl Viro len = min(n, len); \ 951b4fb5ffSAl Viro left = (STEP); \ 9621b56c84SAl Viro kunmap_local(kaddr); \ 977baa5099SAl Viro len -= left; \ 987baa5099SAl Viro __off += len; \ 997baa5099SAl Viro n -= len; \ 1001b4fb5ffSAl Viro if (left || n == 0) \ 1011b4fb5ffSAl Viro goto __out; \ 1024b179e9aSAl Viro offset = 0; \ 1037ff50620SDavid Howells } \ 1047ff50620SDavid Howells } \ 1051b4fb5ffSAl Viro __out: \ 1067ff50620SDavid Howells rcu_read_unlock(); \ 107a6e4ec7bSAl Viro i->iov_offset += __off; \ 108622838f3SAl Viro n = __off; \ 1097ff50620SDavid Howells } 1107ff50620SDavid Howells 1117baa5099SAl Viro #define __iterate_and_advance(i, n, base, len, off, I, K) { \ 112dd254f5aSAl Viro if (unlikely(i->count < n)) \ 113dd254f5aSAl Viro n = i->count; \ 114f5da8354SAl Viro if (likely(n)) { \ 11528f38db7SAl Viro if (likely(iter_is_iovec(i))) { \ 1165c67aa90SAl Viro const struct iovec *iov = i->iov; \ 1177baa5099SAl Viro void __user *base; \ 1187baa5099SAl Viro size_t len; \ 1197baa5099SAl Viro iterate_iovec(i, n, base, len, off, \ 120a6e4ec7bSAl Viro iov, (I)) \ 121d879cb83SAl Viro i->nr_segs -= iov - i->iov; \ 122d879cb83SAl Viro i->iov = iov; \ 12328f38db7SAl Viro } else if (iov_iter_is_bvec(i)) { \ 12428f38db7SAl Viro const struct bio_vec *bvec = i->bvec; \ 1257baa5099SAl Viro void *base; \ 1267baa5099SAl Viro size_t len; \ 1277baa5099SAl Viro iterate_bvec(i, n, base, len, off, \ 128a6e4ec7bSAl Viro bvec, (K)) \ 1297491a2bfSAl Viro i->nr_segs -= bvec - i->bvec; \ 1307491a2bfSAl Viro i->bvec = bvec; \ 13128f38db7SAl Viro } else if (iov_iter_is_kvec(i)) { \ 1325c67aa90SAl Viro const struct kvec *kvec = i->kvec; \ 1337baa5099SAl Viro void *base; \ 1347baa5099SAl Viro size_t len; \ 1357baa5099SAl Viro iterate_iovec(i, n, base, len, off, \ 136a6e4ec7bSAl Viro kvec, (K)) \ 13728f38db7SAl Viro i->nr_segs -= kvec - i->kvec; \ 13828f38db7SAl Viro i->kvec = kvec; \ 13928f38db7SAl Viro } else if (iov_iter_is_xarray(i)) { \ 1407baa5099SAl Viro void *base; \ 1417baa5099SAl Viro size_t len; \ 1427baa5099SAl Viro iterate_xarray(i, n, base, len, off, \ 143a6e4ec7bSAl Viro (K)) \ 144d879cb83SAl Viro } \ 145d879cb83SAl Viro i->count -= n; \ 146dd254f5aSAl Viro } \ 147d879cb83SAl Viro } 1487baa5099SAl Viro #define iterate_and_advance(i, n, base, len, off, I, K) \ 1497baa5099SAl Viro __iterate_and_advance(i, n, base, len, off, I, ((void)(K),0)) 150d879cb83SAl Viro 15109fc68dcSAl Viro static int copyout(void __user *to, const void *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(to, n)) { 156d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 15709fc68dcSAl Viro n = raw_copy_to_user(to, from, n); 15809fc68dcSAl Viro } 15909fc68dcSAl Viro return n; 16009fc68dcSAl Viro } 16109fc68dcSAl Viro 16209fc68dcSAl Viro static int copyin(void *to, const void __user *from, size_t n) 16309fc68dcSAl Viro { 1644d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1654d0e9df5SAlbert van der Linde return n; 16696d4f267SLinus Torvalds if (access_ok(from, n)) { 167d0ef4c36SMarco Elver instrument_copy_from_user(to, from, n); 16809fc68dcSAl Viro n = raw_copy_from_user(to, from, n); 16909fc68dcSAl Viro } 17009fc68dcSAl Viro return n; 17109fc68dcSAl Viro } 17209fc68dcSAl Viro 173d879cb83SAl Viro static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, 174d879cb83SAl Viro struct iov_iter *i) 175d879cb83SAl Viro { 176d879cb83SAl Viro size_t skip, copy, left, wanted; 177d879cb83SAl Viro const struct iovec *iov; 178d879cb83SAl Viro char __user *buf; 179d879cb83SAl Viro void *kaddr, *from; 180d879cb83SAl Viro 181d879cb83SAl Viro if (unlikely(bytes > i->count)) 182d879cb83SAl Viro bytes = i->count; 183d879cb83SAl Viro 184d879cb83SAl Viro if (unlikely(!bytes)) 185d879cb83SAl Viro return 0; 186d879cb83SAl Viro 18709fc68dcSAl Viro might_fault(); 188d879cb83SAl Viro wanted = bytes; 189d879cb83SAl Viro iov = i->iov; 190d879cb83SAl Viro skip = i->iov_offset; 191d879cb83SAl Viro buf = iov->iov_base + skip; 192d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 193d879cb83SAl Viro 1943fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { 195d879cb83SAl Viro kaddr = kmap_atomic(page); 196d879cb83SAl Viro from = kaddr + offset; 197d879cb83SAl Viro 198d879cb83SAl Viro /* first chunk, usually the only one */ 19909fc68dcSAl Viro left = copyout(buf, from, copy); 200d879cb83SAl Viro copy -= left; 201d879cb83SAl Viro skip += copy; 202d879cb83SAl Viro from += copy; 203d879cb83SAl Viro bytes -= copy; 204d879cb83SAl Viro 205d879cb83SAl Viro while (unlikely(!left && bytes)) { 206d879cb83SAl Viro iov++; 207d879cb83SAl Viro buf = iov->iov_base; 208d879cb83SAl Viro copy = min(bytes, iov->iov_len); 20909fc68dcSAl Viro left = copyout(buf, from, copy); 210d879cb83SAl Viro copy -= left; 211d879cb83SAl Viro skip = copy; 212d879cb83SAl Viro from += copy; 213d879cb83SAl Viro bytes -= copy; 214d879cb83SAl Viro } 215d879cb83SAl Viro if (likely(!bytes)) { 216d879cb83SAl Viro kunmap_atomic(kaddr); 217d879cb83SAl Viro goto done; 218d879cb83SAl Viro } 219d879cb83SAl Viro offset = from - kaddr; 220d879cb83SAl Viro buf += copy; 221d879cb83SAl Viro kunmap_atomic(kaddr); 222d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 223d879cb83SAl Viro } 224d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 2253fa6c507SMikulas Patocka 226d879cb83SAl Viro kaddr = kmap(page); 227d879cb83SAl Viro from = kaddr + offset; 22809fc68dcSAl Viro left = copyout(buf, from, copy); 229d879cb83SAl Viro copy -= left; 230d879cb83SAl Viro skip += copy; 231d879cb83SAl Viro from += copy; 232d879cb83SAl Viro bytes -= copy; 233d879cb83SAl Viro while (unlikely(!left && bytes)) { 234d879cb83SAl Viro iov++; 235d879cb83SAl Viro buf = iov->iov_base; 236d879cb83SAl Viro copy = min(bytes, iov->iov_len); 23709fc68dcSAl Viro left = copyout(buf, from, copy); 238d879cb83SAl Viro copy -= left; 239d879cb83SAl Viro skip = copy; 240d879cb83SAl Viro from += copy; 241d879cb83SAl Viro bytes -= copy; 242d879cb83SAl Viro } 243d879cb83SAl Viro kunmap(page); 2443fa6c507SMikulas Patocka 245d879cb83SAl Viro done: 246d879cb83SAl Viro if (skip == iov->iov_len) { 247d879cb83SAl Viro iov++; 248d879cb83SAl Viro skip = 0; 249d879cb83SAl Viro } 250d879cb83SAl Viro i->count -= wanted - bytes; 251d879cb83SAl Viro i->nr_segs -= iov - i->iov; 252d879cb83SAl Viro i->iov = iov; 253d879cb83SAl Viro i->iov_offset = skip; 254d879cb83SAl Viro return wanted - bytes; 255d879cb83SAl Viro } 256d879cb83SAl Viro 257d879cb83SAl Viro static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, 258d879cb83SAl Viro struct iov_iter *i) 259d879cb83SAl Viro { 260d879cb83SAl Viro size_t skip, copy, left, wanted; 261d879cb83SAl Viro const struct iovec *iov; 262d879cb83SAl Viro char __user *buf; 263d879cb83SAl Viro void *kaddr, *to; 264d879cb83SAl Viro 265d879cb83SAl Viro if (unlikely(bytes > i->count)) 266d879cb83SAl Viro bytes = i->count; 267d879cb83SAl Viro 268d879cb83SAl Viro if (unlikely(!bytes)) 269d879cb83SAl Viro return 0; 270d879cb83SAl Viro 27109fc68dcSAl Viro might_fault(); 272d879cb83SAl Viro wanted = bytes; 273d879cb83SAl Viro iov = i->iov; 274d879cb83SAl Viro skip = i->iov_offset; 275d879cb83SAl Viro buf = iov->iov_base + skip; 276d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 277d879cb83SAl Viro 2783fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { 279d879cb83SAl Viro kaddr = kmap_atomic(page); 280d879cb83SAl Viro to = kaddr + offset; 281d879cb83SAl Viro 282d879cb83SAl Viro /* first chunk, usually the only one */ 28309fc68dcSAl Viro left = copyin(to, buf, copy); 284d879cb83SAl Viro copy -= left; 285d879cb83SAl Viro skip += copy; 286d879cb83SAl Viro to += copy; 287d879cb83SAl Viro bytes -= copy; 288d879cb83SAl Viro 289d879cb83SAl Viro while (unlikely(!left && bytes)) { 290d879cb83SAl Viro iov++; 291d879cb83SAl Viro buf = iov->iov_base; 292d879cb83SAl Viro copy = min(bytes, iov->iov_len); 29309fc68dcSAl Viro left = copyin(to, buf, copy); 294d879cb83SAl Viro copy -= left; 295d879cb83SAl Viro skip = copy; 296d879cb83SAl Viro to += copy; 297d879cb83SAl Viro bytes -= copy; 298d879cb83SAl Viro } 299d879cb83SAl Viro if (likely(!bytes)) { 300d879cb83SAl Viro kunmap_atomic(kaddr); 301d879cb83SAl Viro goto done; 302d879cb83SAl Viro } 303d879cb83SAl Viro offset = to - kaddr; 304d879cb83SAl Viro buf += copy; 305d879cb83SAl Viro kunmap_atomic(kaddr); 306d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 307d879cb83SAl Viro } 308d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 3093fa6c507SMikulas Patocka 310d879cb83SAl Viro kaddr = kmap(page); 311d879cb83SAl Viro to = kaddr + offset; 31209fc68dcSAl Viro left = copyin(to, buf, copy); 313d879cb83SAl Viro copy -= left; 314d879cb83SAl Viro skip += copy; 315d879cb83SAl Viro to += copy; 316d879cb83SAl Viro bytes -= copy; 317d879cb83SAl Viro while (unlikely(!left && bytes)) { 318d879cb83SAl Viro iov++; 319d879cb83SAl Viro buf = iov->iov_base; 320d879cb83SAl Viro copy = min(bytes, iov->iov_len); 32109fc68dcSAl Viro left = copyin(to, buf, copy); 322d879cb83SAl Viro copy -= left; 323d879cb83SAl Viro skip = copy; 324d879cb83SAl Viro to += copy; 325d879cb83SAl Viro bytes -= copy; 326d879cb83SAl Viro } 327d879cb83SAl Viro kunmap(page); 3283fa6c507SMikulas Patocka 329d879cb83SAl Viro done: 330d879cb83SAl Viro if (skip == iov->iov_len) { 331d879cb83SAl Viro iov++; 332d879cb83SAl Viro skip = 0; 333d879cb83SAl Viro } 334d879cb83SAl Viro i->count -= wanted - bytes; 335d879cb83SAl Viro i->nr_segs -= iov - i->iov; 336d879cb83SAl Viro i->iov = iov; 337d879cb83SAl Viro i->iov_offset = skip; 338d879cb83SAl Viro return wanted - bytes; 339d879cb83SAl Viro } 340d879cb83SAl Viro 341241699cdSAl Viro #ifdef PIPE_PARANOIA 342241699cdSAl Viro static bool sanity(const struct iov_iter *i) 343241699cdSAl Viro { 344241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 3458cefc107SDavid Howells unsigned int p_head = pipe->head; 3468cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3478cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3488cefc107SDavid Howells unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); 3498cefc107SDavid Howells unsigned int i_head = i->head; 3508cefc107SDavid Howells unsigned int idx; 3518cefc107SDavid Howells 352241699cdSAl Viro if (i->iov_offset) { 353241699cdSAl Viro struct pipe_buffer *p; 3548cefc107SDavid Howells if (unlikely(p_occupancy == 0)) 355241699cdSAl Viro goto Bad; // pipe must be non-empty 3568cefc107SDavid Howells if (unlikely(i_head != p_head - 1)) 357241699cdSAl Viro goto Bad; // must be at the last buffer... 358241699cdSAl Viro 3598cefc107SDavid Howells p = &pipe->bufs[i_head & p_mask]; 360241699cdSAl Viro if (unlikely(p->offset + p->len != i->iov_offset)) 361241699cdSAl Viro goto Bad; // ... at the end of segment 362241699cdSAl Viro } else { 3638cefc107SDavid Howells if (i_head != p_head) 364241699cdSAl Viro goto Bad; // must be right after the last buffer 365241699cdSAl Viro } 366241699cdSAl Viro return true; 367241699cdSAl Viro Bad: 3688cefc107SDavid Howells printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); 3698cefc107SDavid Howells printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", 3708cefc107SDavid Howells p_head, p_tail, pipe->ring_size); 3718cefc107SDavid Howells for (idx = 0; idx < pipe->ring_size; idx++) 372241699cdSAl Viro printk(KERN_ERR "[%p %p %d %d]\n", 373241699cdSAl Viro pipe->bufs[idx].ops, 374241699cdSAl Viro pipe->bufs[idx].page, 375241699cdSAl Viro pipe->bufs[idx].offset, 376241699cdSAl Viro pipe->bufs[idx].len); 377241699cdSAl Viro WARN_ON(1); 378241699cdSAl Viro return false; 379241699cdSAl Viro } 380241699cdSAl Viro #else 381241699cdSAl Viro #define sanity(i) true 382241699cdSAl Viro #endif 383241699cdSAl Viro 384241699cdSAl Viro static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, 385241699cdSAl Viro struct iov_iter *i) 386241699cdSAl Viro { 387241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 388241699cdSAl Viro struct pipe_buffer *buf; 3898cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3908cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3918cefc107SDavid Howells unsigned int i_head = i->head; 392241699cdSAl Viro size_t off; 393241699cdSAl Viro 394241699cdSAl Viro if (unlikely(bytes > i->count)) 395241699cdSAl Viro bytes = i->count; 396241699cdSAl Viro 397241699cdSAl Viro if (unlikely(!bytes)) 398241699cdSAl Viro return 0; 399241699cdSAl Viro 400241699cdSAl Viro if (!sanity(i)) 401241699cdSAl Viro return 0; 402241699cdSAl Viro 403241699cdSAl Viro off = i->iov_offset; 4048cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 405241699cdSAl Viro if (off) { 406241699cdSAl Viro if (offset == off && buf->page == page) { 407241699cdSAl Viro /* merge with the last one */ 408241699cdSAl Viro buf->len += bytes; 409241699cdSAl Viro i->iov_offset += bytes; 410241699cdSAl Viro goto out; 411241699cdSAl Viro } 4128cefc107SDavid Howells i_head++; 4138cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 414241699cdSAl Viro } 4156718b6f8SDavid Howells if (pipe_full(i_head, p_tail, pipe->max_usage)) 416241699cdSAl Viro return 0; 4178cefc107SDavid Howells 418241699cdSAl Viro buf->ops = &page_cache_pipe_buf_ops; 4198cefc107SDavid Howells get_page(page); 4208cefc107SDavid Howells buf->page = page; 421241699cdSAl Viro buf->offset = offset; 422241699cdSAl Viro buf->len = bytes; 4238cefc107SDavid Howells 4248cefc107SDavid Howells pipe->head = i_head + 1; 425241699cdSAl Viro i->iov_offset = offset + bytes; 4268cefc107SDavid Howells i->head = i_head; 427241699cdSAl Viro out: 428241699cdSAl Viro i->count -= bytes; 429241699cdSAl Viro return bytes; 430241699cdSAl Viro } 431241699cdSAl Viro 432d879cb83SAl Viro /* 433171a0203SAnton Altaparmakov * Fault in one or more iovecs of the given iov_iter, to a maximum length of 434171a0203SAnton Altaparmakov * bytes. For each iovec, fault in each page that constitutes the iovec. 435171a0203SAnton Altaparmakov * 436171a0203SAnton Altaparmakov * Return 0 on success, or non-zero if the memory could not be accessed (i.e. 437171a0203SAnton Altaparmakov * because it is an invalid address). 438171a0203SAnton Altaparmakov */ 4398409a0d2SAl Viro int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes) 440171a0203SAnton Altaparmakov { 4410e8f0d67SAl Viro if (iter_is_iovec(i)) { 4428409a0d2SAl Viro const struct iovec *p; 4438409a0d2SAl Viro size_t skip; 4448409a0d2SAl Viro 4458409a0d2SAl Viro if (bytes > i->count) 4468409a0d2SAl Viro bytes = i->count; 4478409a0d2SAl Viro for (p = i->iov, skip = i->iov_offset; bytes; p++, skip = 0) { 4488409a0d2SAl Viro size_t len = min(bytes, p->iov_len - skip); 4498409a0d2SAl Viro int err; 4508409a0d2SAl Viro 4518409a0d2SAl Viro if (unlikely(!len)) 4528409a0d2SAl Viro continue; 4538409a0d2SAl Viro err = fault_in_pages_readable(p->iov_base + skip, len); 454171a0203SAnton Altaparmakov if (unlikely(err)) 455171a0203SAnton Altaparmakov return err; 4568409a0d2SAl Viro bytes -= len; 4578409a0d2SAl Viro } 458171a0203SAnton Altaparmakov } 459171a0203SAnton Altaparmakov return 0; 460171a0203SAnton Altaparmakov } 461d4690f1eSAl Viro EXPORT_SYMBOL(iov_iter_fault_in_readable); 462171a0203SAnton Altaparmakov 463aa563d7bSDavid Howells void iov_iter_init(struct iov_iter *i, unsigned int direction, 464d879cb83SAl Viro const struct iovec *iov, unsigned long nr_segs, 465d879cb83SAl Viro size_t count) 466d879cb83SAl Viro { 467aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 4688cd54c1cSAl Viro WARN_ON_ONCE(uaccess_kernel()); 4698cd54c1cSAl Viro *i = (struct iov_iter) { 4708cd54c1cSAl Viro .iter_type = ITER_IOVEC, 4718cd54c1cSAl Viro .data_source = direction, 4728cd54c1cSAl Viro .iov = iov, 4738cd54c1cSAl Viro .nr_segs = nr_segs, 4748cd54c1cSAl Viro .iov_offset = 0, 4758cd54c1cSAl Viro .count = count 4768cd54c1cSAl Viro }; 477d879cb83SAl Viro } 478d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_init); 479d879cb83SAl Viro 480241699cdSAl Viro static inline bool allocated(struct pipe_buffer *buf) 481241699cdSAl Viro { 482241699cdSAl Viro return buf->ops == &default_pipe_buf_ops; 483241699cdSAl Viro } 484241699cdSAl Viro 4858cefc107SDavid Howells static inline void data_start(const struct iov_iter *i, 4868cefc107SDavid Howells unsigned int *iter_headp, size_t *offp) 487241699cdSAl Viro { 4888cefc107SDavid Howells unsigned int p_mask = i->pipe->ring_size - 1; 4898cefc107SDavid Howells unsigned int iter_head = i->head; 490241699cdSAl Viro size_t off = i->iov_offset; 4918cefc107SDavid Howells 4928cefc107SDavid Howells if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || 4938cefc107SDavid Howells off == PAGE_SIZE)) { 4948cefc107SDavid Howells iter_head++; 495241699cdSAl Viro off = 0; 496241699cdSAl Viro } 4978cefc107SDavid Howells *iter_headp = iter_head; 498241699cdSAl Viro *offp = off; 499241699cdSAl Viro } 500241699cdSAl Viro 501241699cdSAl Viro static size_t push_pipe(struct iov_iter *i, size_t size, 5028cefc107SDavid Howells int *iter_headp, size_t *offp) 503241699cdSAl Viro { 504241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5058cefc107SDavid Howells unsigned int p_tail = pipe->tail; 5068cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5078cefc107SDavid Howells unsigned int iter_head; 508241699cdSAl Viro size_t off; 509241699cdSAl Viro ssize_t left; 510241699cdSAl Viro 511241699cdSAl Viro if (unlikely(size > i->count)) 512241699cdSAl Viro size = i->count; 513241699cdSAl Viro if (unlikely(!size)) 514241699cdSAl Viro return 0; 515241699cdSAl Viro 516241699cdSAl Viro left = size; 5178cefc107SDavid Howells data_start(i, &iter_head, &off); 5188cefc107SDavid Howells *iter_headp = iter_head; 519241699cdSAl Viro *offp = off; 520241699cdSAl Viro if (off) { 521241699cdSAl Viro left -= PAGE_SIZE - off; 522241699cdSAl Viro if (left <= 0) { 5238cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len += size; 524241699cdSAl Viro return size; 525241699cdSAl Viro } 5268cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; 5278cefc107SDavid Howells iter_head++; 528241699cdSAl Viro } 5296718b6f8SDavid Howells while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { 5308cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; 531241699cdSAl Viro struct page *page = alloc_page(GFP_USER); 532241699cdSAl Viro if (!page) 533241699cdSAl Viro break; 5348cefc107SDavid Howells 5358cefc107SDavid Howells buf->ops = &default_pipe_buf_ops; 5368cefc107SDavid Howells buf->page = page; 5378cefc107SDavid Howells buf->offset = 0; 5388cefc107SDavid Howells buf->len = min_t(ssize_t, left, PAGE_SIZE); 5398cefc107SDavid Howells left -= buf->len; 5408cefc107SDavid Howells iter_head++; 5418cefc107SDavid Howells pipe->head = iter_head; 5428cefc107SDavid Howells 5438cefc107SDavid Howells if (left == 0) 544241699cdSAl Viro return size; 545241699cdSAl Viro } 546241699cdSAl Viro return size - left; 547241699cdSAl Viro } 548241699cdSAl Viro 549241699cdSAl Viro static size_t copy_pipe_to_iter(const void *addr, size_t bytes, 550241699cdSAl Viro struct iov_iter *i) 551241699cdSAl Viro { 552241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5538cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5548cefc107SDavid Howells unsigned int i_head; 555241699cdSAl Viro size_t n, off; 556241699cdSAl Viro 557241699cdSAl Viro if (!sanity(i)) 558241699cdSAl Viro return 0; 559241699cdSAl Viro 5608cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 561241699cdSAl Viro if (unlikely(!n)) 562241699cdSAl Viro return 0; 5638cefc107SDavid Howells do { 564241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 5658cefc107SDavid Howells memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); 5668cefc107SDavid Howells i->head = i_head; 567241699cdSAl Viro i->iov_offset = off + chunk; 568241699cdSAl Viro n -= chunk; 569241699cdSAl Viro addr += chunk; 5708cefc107SDavid Howells off = 0; 5718cefc107SDavid Howells i_head++; 5728cefc107SDavid Howells } while (n); 573241699cdSAl Viro i->count -= bytes; 574241699cdSAl Viro return bytes; 575241699cdSAl Viro } 576241699cdSAl Viro 577f9152895SAl Viro static __wsum csum_and_memcpy(void *to, const void *from, size_t len, 578f9152895SAl Viro __wsum sum, size_t off) 579f9152895SAl Viro { 580cc44c17bSAl Viro __wsum next = csum_partial_copy_nocheck(from, to, len); 581f9152895SAl Viro return csum_block_add(sum, next, off); 582f9152895SAl Viro } 583f9152895SAl Viro 58478e1f386SAl Viro static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, 58552cbd23aSWillem de Bruijn struct csum_state *csstate, 58652cbd23aSWillem de Bruijn struct iov_iter *i) 58778e1f386SAl Viro { 58878e1f386SAl Viro struct pipe_inode_info *pipe = i->pipe; 5898cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 59052cbd23aSWillem de Bruijn __wsum sum = csstate->csum; 59152cbd23aSWillem de Bruijn size_t off = csstate->off; 5928cefc107SDavid Howells unsigned int i_head; 59378e1f386SAl Viro size_t n, r; 59478e1f386SAl Viro 59578e1f386SAl Viro if (!sanity(i)) 59678e1f386SAl Viro return 0; 59778e1f386SAl Viro 5988cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &r); 59978e1f386SAl Viro if (unlikely(!n)) 60078e1f386SAl Viro return 0; 6018cefc107SDavid Howells do { 60278e1f386SAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - r); 6038cefc107SDavid Howells char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); 604f9152895SAl Viro sum = csum_and_memcpy(p + r, addr, chunk, sum, off); 60578e1f386SAl Viro kunmap_atomic(p); 6068cefc107SDavid Howells i->head = i_head; 60778e1f386SAl Viro i->iov_offset = r + chunk; 60878e1f386SAl Viro n -= chunk; 60978e1f386SAl Viro off += chunk; 61078e1f386SAl Viro addr += chunk; 6118cefc107SDavid Howells r = 0; 6128cefc107SDavid Howells i_head++; 6138cefc107SDavid Howells } while (n); 61478e1f386SAl Viro i->count -= bytes; 61552cbd23aSWillem de Bruijn csstate->csum = sum; 61652cbd23aSWillem de Bruijn csstate->off = off; 61778e1f386SAl Viro return bytes; 61878e1f386SAl Viro } 61978e1f386SAl Viro 620aa28de27SAl Viro size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 621d879cb83SAl Viro { 62200e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 623241699cdSAl Viro return copy_pipe_to_iter(addr, bytes, i); 62409fc68dcSAl Viro if (iter_is_iovec(i)) 62509fc68dcSAl Viro might_fault(); 6267baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 6277baa5099SAl Viro copyout(base, addr + off, len), 6287baa5099SAl Viro memcpy(base, addr + off, len) 629d879cb83SAl Viro ) 630d879cb83SAl Viro 631d879cb83SAl Viro return bytes; 632d879cb83SAl Viro } 633aa28de27SAl Viro EXPORT_SYMBOL(_copy_to_iter); 634d879cb83SAl Viro 635ec6347bbSDan Williams #ifdef CONFIG_ARCH_HAS_COPY_MC 636ec6347bbSDan Williams static int copyout_mc(void __user *to, const void *from, size_t n) 6378780356eSDan Williams { 63896d4f267SLinus Torvalds if (access_ok(to, n)) { 639d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 640ec6347bbSDan Williams n = copy_mc_to_user((__force void *) to, from, n); 6418780356eSDan Williams } 6428780356eSDan Williams return n; 6438780356eSDan Williams } 6448780356eSDan Williams 645ec6347bbSDan Williams static unsigned long copy_mc_to_page(struct page *page, size_t offset, 6468780356eSDan Williams const char *from, size_t len) 6478780356eSDan Williams { 6488780356eSDan Williams unsigned long ret; 6498780356eSDan Williams char *to; 6508780356eSDan Williams 6518780356eSDan Williams to = kmap_atomic(page); 652ec6347bbSDan Williams ret = copy_mc_to_kernel(to + offset, from, len); 6538780356eSDan Williams kunmap_atomic(to); 6548780356eSDan Williams 6558780356eSDan Williams return ret; 6568780356eSDan Williams } 6578780356eSDan Williams 658ec6347bbSDan Williams static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, 659ca146f6fSDan Williams struct iov_iter *i) 660ca146f6fSDan Williams { 661ca146f6fSDan Williams struct pipe_inode_info *pipe = i->pipe; 6628cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 6638cefc107SDavid Howells unsigned int i_head; 664ca146f6fSDan Williams size_t n, off, xfer = 0; 665ca146f6fSDan Williams 666ca146f6fSDan Williams if (!sanity(i)) 667ca146f6fSDan Williams return 0; 668ca146f6fSDan Williams 6698cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 670ca146f6fSDan Williams if (unlikely(!n)) 671ca146f6fSDan Williams return 0; 6728cefc107SDavid Howells do { 673ca146f6fSDan Williams size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 674ca146f6fSDan Williams unsigned long rem; 675ca146f6fSDan Williams 676ec6347bbSDan Williams rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, 6778cefc107SDavid Howells off, addr, chunk); 6788cefc107SDavid Howells i->head = i_head; 679ca146f6fSDan Williams i->iov_offset = off + chunk - rem; 680ca146f6fSDan Williams xfer += chunk - rem; 681ca146f6fSDan Williams if (rem) 682ca146f6fSDan Williams break; 683ca146f6fSDan Williams n -= chunk; 684ca146f6fSDan Williams addr += chunk; 6858cefc107SDavid Howells off = 0; 6868cefc107SDavid Howells i_head++; 6878cefc107SDavid Howells } while (n); 688ca146f6fSDan Williams i->count -= xfer; 689ca146f6fSDan Williams return xfer; 690ca146f6fSDan Williams } 691ca146f6fSDan Williams 692bf3eeb9bSDan Williams /** 693ec6347bbSDan Williams * _copy_mc_to_iter - copy to iter with source memory error exception handling 694bf3eeb9bSDan Williams * @addr: source kernel address 695bf3eeb9bSDan Williams * @bytes: total transfer length 696bf3eeb9bSDan Williams * @iter: destination iterator 697bf3eeb9bSDan Williams * 698ec6347bbSDan Williams * The pmem driver deploys this for the dax operation 699ec6347bbSDan Williams * (dax_copy_to_iter()) for dax reads (bypass page-cache and the 700ec6347bbSDan Williams * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes 701ec6347bbSDan Williams * successfully copied. 702bf3eeb9bSDan Williams * 703ec6347bbSDan Williams * The main differences between this and typical _copy_to_iter(). 704bf3eeb9bSDan Williams * 705bf3eeb9bSDan Williams * * Typical tail/residue handling after a fault retries the copy 706bf3eeb9bSDan Williams * byte-by-byte until the fault happens again. Re-triggering machine 707bf3eeb9bSDan Williams * checks is potentially fatal so the implementation uses source 708bf3eeb9bSDan Williams * alignment and poison alignment assumptions to avoid re-triggering 709bf3eeb9bSDan Williams * hardware exceptions. 710bf3eeb9bSDan Williams * 711bf3eeb9bSDan Williams * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. 712bf3eeb9bSDan Williams * Compare to copy_to_iter() where only ITER_IOVEC attempts might return 713bf3eeb9bSDan Williams * a short copy. 714bf3eeb9bSDan Williams */ 715ec6347bbSDan Williams size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 7168780356eSDan Williams { 71700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 718ec6347bbSDan Williams return copy_mc_pipe_to_iter(addr, bytes, i); 7198780356eSDan Williams if (iter_is_iovec(i)) 7208780356eSDan Williams might_fault(); 7217baa5099SAl Viro __iterate_and_advance(i, bytes, base, len, off, 7227baa5099SAl Viro copyout_mc(base, addr + off, len), 7237baa5099SAl Viro copy_mc_to_kernel(base, addr + off, len) 7248780356eSDan Williams ) 7258780356eSDan Williams 7268780356eSDan Williams return bytes; 7278780356eSDan Williams } 728ec6347bbSDan Williams EXPORT_SYMBOL_GPL(_copy_mc_to_iter); 729ec6347bbSDan Williams #endif /* CONFIG_ARCH_HAS_COPY_MC */ 7308780356eSDan Williams 731aa28de27SAl Viro size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) 732d879cb83SAl Viro { 73300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 734241699cdSAl Viro WARN_ON(1); 735241699cdSAl Viro return 0; 736241699cdSAl Viro } 73709fc68dcSAl Viro if (iter_is_iovec(i)) 73809fc68dcSAl Viro might_fault(); 7397baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 7407baa5099SAl Viro copyin(addr + off, base, len), 7417baa5099SAl Viro memcpy(addr + off, base, len) 742d879cb83SAl Viro ) 743d879cb83SAl Viro 744d879cb83SAl Viro return bytes; 745d879cb83SAl Viro } 746aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter); 747d879cb83SAl Viro 748aa28de27SAl Viro size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) 749d879cb83SAl Viro { 75000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 751241699cdSAl Viro WARN_ON(1); 752241699cdSAl Viro return 0; 753241699cdSAl Viro } 7547baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 7557baa5099SAl Viro __copy_from_user_inatomic_nocache(addr + off, base, len), 7567baa5099SAl Viro memcpy(addr + off, base, len) 757d879cb83SAl Viro ) 758d879cb83SAl Viro 759d879cb83SAl Viro return bytes; 760d879cb83SAl Viro } 761aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_nocache); 762d879cb83SAl Viro 7630aed55afSDan Williams #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE 764abd08d7dSDan Williams /** 765abd08d7dSDan Williams * _copy_from_iter_flushcache - write destination through cpu cache 766abd08d7dSDan Williams * @addr: destination kernel address 767abd08d7dSDan Williams * @bytes: total transfer length 768abd08d7dSDan Williams * @iter: source iterator 769abd08d7dSDan Williams * 770abd08d7dSDan Williams * The pmem driver arranges for filesystem-dax to use this facility via 771abd08d7dSDan Williams * dax_copy_from_iter() for ensuring that writes to persistent memory 772abd08d7dSDan Williams * are flushed through the CPU cache. It is differentiated from 773abd08d7dSDan Williams * _copy_from_iter_nocache() in that guarantees all data is flushed for 774abd08d7dSDan Williams * all iterator types. The _copy_from_iter_nocache() only attempts to 775abd08d7dSDan Williams * bypass the cache for the ITER_IOVEC case, and on some archs may use 776abd08d7dSDan Williams * instructions that strand dirty-data in the cache. 777abd08d7dSDan Williams */ 7786a37e940SLinus Torvalds size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 7790aed55afSDan Williams { 78000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 7810aed55afSDan Williams WARN_ON(1); 7820aed55afSDan Williams return 0; 7830aed55afSDan Williams } 7847baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 7857baa5099SAl Viro __copy_from_user_flushcache(addr + off, base, len), 7867baa5099SAl Viro memcpy_flushcache(addr + off, base, len) 7870aed55afSDan Williams ) 7880aed55afSDan Williams 7890aed55afSDan Williams return bytes; 7900aed55afSDan Williams } 7916a37e940SLinus Torvalds EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); 7920aed55afSDan Williams #endif 7930aed55afSDan Williams 79472e809edSAl Viro static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) 79572e809edSAl Viro { 7966daef95bSEric Dumazet struct page *head; 7976daef95bSEric Dumazet size_t v = n + offset; 7986daef95bSEric Dumazet 7996daef95bSEric Dumazet /* 8006daef95bSEric Dumazet * The general case needs to access the page order in order 8016daef95bSEric Dumazet * to compute the page size. 8026daef95bSEric Dumazet * However, we mostly deal with order-0 pages and thus can 8036daef95bSEric Dumazet * avoid a possible cache line miss for requests that fit all 8046daef95bSEric Dumazet * page orders. 8056daef95bSEric Dumazet */ 8066daef95bSEric Dumazet if (n <= v && v <= PAGE_SIZE) 8076daef95bSEric Dumazet return true; 8086daef95bSEric Dumazet 8096daef95bSEric Dumazet head = compound_head(page); 8106daef95bSEric Dumazet v += (page - head) << PAGE_SHIFT; 811a90bcb86SPetar Penkov 812a50b854eSMatthew Wilcox (Oracle) if (likely(n <= v && v <= (page_size(head)))) 81372e809edSAl Viro return true; 81472e809edSAl Viro WARN_ON(1); 81572e809edSAl Viro return false; 81672e809edSAl Viro } 817cbbd26b8SAl Viro 81808aa6479SAl Viro static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 819d879cb83SAl Viro struct iov_iter *i) 820d879cb83SAl Viro { 82128f38db7SAl Viro if (likely(iter_is_iovec(i))) 82228f38db7SAl Viro return copy_page_to_iter_iovec(page, offset, bytes, i); 82328f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 824*c1d4d6a9SAl Viro void *kaddr = kmap_local_page(page); 825*c1d4d6a9SAl Viro size_t wanted = _copy_to_iter(kaddr + offset, bytes, i); 826*c1d4d6a9SAl Viro kunmap_local(kaddr); 827d879cb83SAl Viro return wanted; 82828f38db7SAl Viro } 82928f38db7SAl Viro if (iov_iter_is_pipe(i)) 83028f38db7SAl Viro return copy_page_to_iter_pipe(page, offset, bytes, i); 83128f38db7SAl Viro if (unlikely(iov_iter_is_discard(i))) { 832a506abc7SAl Viro if (unlikely(i->count < bytes)) 833a506abc7SAl Viro bytes = i->count; 834a506abc7SAl Viro i->count -= bytes; 8359ea9ce04SDavid Howells return bytes; 83628f38db7SAl Viro } 83728f38db7SAl Viro WARN_ON(1); 83828f38db7SAl Viro return 0; 839d879cb83SAl Viro } 84008aa6479SAl Viro 84108aa6479SAl Viro size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 84208aa6479SAl Viro struct iov_iter *i) 84308aa6479SAl Viro { 84408aa6479SAl Viro size_t res = 0; 84508aa6479SAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 84608aa6479SAl Viro return 0; 84708aa6479SAl Viro page += offset / PAGE_SIZE; // first subpage 84808aa6479SAl Viro offset %= PAGE_SIZE; 84908aa6479SAl Viro while (1) { 85008aa6479SAl Viro size_t n = __copy_page_to_iter(page, offset, 85108aa6479SAl Viro min(bytes, (size_t)PAGE_SIZE - offset), i); 85208aa6479SAl Viro res += n; 85308aa6479SAl Viro bytes -= n; 85408aa6479SAl Viro if (!bytes || !n) 85508aa6479SAl Viro break; 85608aa6479SAl Viro offset += n; 85708aa6479SAl Viro if (offset == PAGE_SIZE) { 85808aa6479SAl Viro page++; 85908aa6479SAl Viro offset = 0; 86008aa6479SAl Viro } 86108aa6479SAl Viro } 86208aa6479SAl Viro return res; 86308aa6479SAl Viro } 864d879cb83SAl Viro EXPORT_SYMBOL(copy_page_to_iter); 865d879cb83SAl Viro 866d879cb83SAl Viro size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, 867d879cb83SAl Viro struct iov_iter *i) 868d879cb83SAl Viro { 86972e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 87072e809edSAl Viro return 0; 87128f38db7SAl Viro if (likely(iter_is_iovec(i))) 87228f38db7SAl Viro return copy_page_from_iter_iovec(page, offset, bytes, i); 87328f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 874d879cb83SAl Viro void *kaddr = kmap_atomic(page); 875aa28de27SAl Viro size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); 876d879cb83SAl Viro kunmap_atomic(kaddr); 877d879cb83SAl Viro return wanted; 87828f38db7SAl Viro } 87928f38db7SAl Viro WARN_ON(1); 88028f38db7SAl Viro return 0; 881d879cb83SAl Viro } 882d879cb83SAl Viro EXPORT_SYMBOL(copy_page_from_iter); 883d879cb83SAl Viro 884241699cdSAl Viro static size_t pipe_zero(size_t bytes, struct iov_iter *i) 885241699cdSAl Viro { 886241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 8878cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 8888cefc107SDavid Howells unsigned int i_head; 889241699cdSAl Viro size_t n, off; 890241699cdSAl Viro 891241699cdSAl Viro if (!sanity(i)) 892241699cdSAl Viro return 0; 893241699cdSAl Viro 8948cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 895241699cdSAl Viro if (unlikely(!n)) 896241699cdSAl Viro return 0; 897241699cdSAl Viro 8988cefc107SDavid Howells do { 899241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 9008cefc107SDavid Howells memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); 9018cefc107SDavid Howells i->head = i_head; 902241699cdSAl Viro i->iov_offset = off + chunk; 903241699cdSAl Viro n -= chunk; 9048cefc107SDavid Howells off = 0; 9058cefc107SDavid Howells i_head++; 9068cefc107SDavid Howells } while (n); 907241699cdSAl Viro i->count -= bytes; 908241699cdSAl Viro return bytes; 909241699cdSAl Viro } 910241699cdSAl Viro 911d879cb83SAl Viro size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 912d879cb83SAl Viro { 91300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 914241699cdSAl Viro return pipe_zero(bytes, i); 9157baa5099SAl Viro iterate_and_advance(i, bytes, base, len, count, 9167baa5099SAl Viro clear_user(base, len), 9177baa5099SAl Viro memset(base, 0, len) 918d879cb83SAl Viro ) 919d879cb83SAl Viro 920d879cb83SAl Viro return bytes; 921d879cb83SAl Viro } 922d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_zero); 923d879cb83SAl Viro 924f0b65f39SAl Viro size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, 925f0b65f39SAl Viro struct iov_iter *i) 926d879cb83SAl Viro { 927d879cb83SAl Viro char *kaddr = kmap_atomic(page), *p = kaddr + offset; 92872e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) { 92972e809edSAl Viro kunmap_atomic(kaddr); 93072e809edSAl Viro return 0; 93172e809edSAl Viro } 9329ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 933241699cdSAl Viro kunmap_atomic(kaddr); 934241699cdSAl Viro WARN_ON(1); 935241699cdSAl Viro return 0; 936241699cdSAl Viro } 9377baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 9387baa5099SAl Viro copyin(p + off, base, len), 9397baa5099SAl Viro memcpy(p + off, base, len) 940d879cb83SAl Viro ) 941d879cb83SAl Viro kunmap_atomic(kaddr); 942d879cb83SAl Viro return bytes; 943d879cb83SAl Viro } 944f0b65f39SAl Viro EXPORT_SYMBOL(copy_page_from_iter_atomic); 945d879cb83SAl Viro 946b9dc6f65SAl Viro static inline void pipe_truncate(struct iov_iter *i) 947241699cdSAl Viro { 948241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 9498cefc107SDavid Howells unsigned int p_tail = pipe->tail; 9508cefc107SDavid Howells unsigned int p_head = pipe->head; 9518cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9528cefc107SDavid Howells 9538cefc107SDavid Howells if (!pipe_empty(p_head, p_tail)) { 9548cefc107SDavid Howells struct pipe_buffer *buf; 9558cefc107SDavid Howells unsigned int i_head = i->head; 956b9dc6f65SAl Viro size_t off = i->iov_offset; 9578cefc107SDavid Howells 958b9dc6f65SAl Viro if (off) { 9598cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 9608cefc107SDavid Howells buf->len = off - buf->offset; 9618cefc107SDavid Howells i_head++; 962b9dc6f65SAl Viro } 9638cefc107SDavid Howells while (p_head != i_head) { 9648cefc107SDavid Howells p_head--; 9658cefc107SDavid Howells pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); 966241699cdSAl Viro } 9678cefc107SDavid Howells 9688cefc107SDavid Howells pipe->head = p_head; 969241699cdSAl Viro } 970b9dc6f65SAl Viro } 971b9dc6f65SAl Viro 972b9dc6f65SAl Viro static void pipe_advance(struct iov_iter *i, size_t size) 973b9dc6f65SAl Viro { 974b9dc6f65SAl Viro struct pipe_inode_info *pipe = i->pipe; 975b9dc6f65SAl Viro if (size) { 976b9dc6f65SAl Viro struct pipe_buffer *buf; 9778cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9788cefc107SDavid Howells unsigned int i_head = i->head; 979b9dc6f65SAl Viro size_t off = i->iov_offset, left = size; 9808cefc107SDavid Howells 981b9dc6f65SAl Viro if (off) /* make it relative to the beginning of buffer */ 9828cefc107SDavid Howells left += off - pipe->bufs[i_head & p_mask].offset; 983b9dc6f65SAl Viro while (1) { 9848cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 985b9dc6f65SAl Viro if (left <= buf->len) 986b9dc6f65SAl Viro break; 987b9dc6f65SAl Viro left -= buf->len; 9888cefc107SDavid Howells i_head++; 989b9dc6f65SAl Viro } 9908cefc107SDavid Howells i->head = i_head; 991b9dc6f65SAl Viro i->iov_offset = buf->offset + left; 992b9dc6f65SAl Viro } 993b9dc6f65SAl Viro i->count -= size; 994b9dc6f65SAl Viro /* ... and discard everything past that point */ 995b9dc6f65SAl Viro pipe_truncate(i); 996241699cdSAl Viro } 997241699cdSAl Viro 99854c8195bSPavel Begunkov static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) 99954c8195bSPavel Begunkov { 100054c8195bSPavel Begunkov struct bvec_iter bi; 100154c8195bSPavel Begunkov 100254c8195bSPavel Begunkov bi.bi_size = i->count; 100354c8195bSPavel Begunkov bi.bi_bvec_done = i->iov_offset; 100454c8195bSPavel Begunkov bi.bi_idx = 0; 100554c8195bSPavel Begunkov bvec_iter_advance(i->bvec, &bi, size); 100654c8195bSPavel Begunkov 100754c8195bSPavel Begunkov i->bvec += bi.bi_idx; 100854c8195bSPavel Begunkov i->nr_segs -= bi.bi_idx; 100954c8195bSPavel Begunkov i->count = bi.bi_size; 101054c8195bSPavel Begunkov i->iov_offset = bi.bi_bvec_done; 101154c8195bSPavel Begunkov } 101254c8195bSPavel Begunkov 1013185ac4d4SAl Viro static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) 1014185ac4d4SAl Viro { 1015185ac4d4SAl Viro const struct iovec *iov, *end; 1016185ac4d4SAl Viro 1017185ac4d4SAl Viro if (!i->count) 1018185ac4d4SAl Viro return; 1019185ac4d4SAl Viro i->count -= size; 1020185ac4d4SAl Viro 1021185ac4d4SAl Viro size += i->iov_offset; // from beginning of current segment 1022185ac4d4SAl Viro for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { 1023185ac4d4SAl Viro if (likely(size < iov->iov_len)) 1024185ac4d4SAl Viro break; 1025185ac4d4SAl Viro size -= iov->iov_len; 1026185ac4d4SAl Viro } 1027185ac4d4SAl Viro i->iov_offset = size; 1028185ac4d4SAl Viro i->nr_segs -= iov - i->iov; 1029185ac4d4SAl Viro i->iov = iov; 1030185ac4d4SAl Viro } 1031185ac4d4SAl Viro 1032d879cb83SAl Viro void iov_iter_advance(struct iov_iter *i, size_t size) 1033d879cb83SAl Viro { 10343b3fc051SAl Viro if (unlikely(i->count < size)) 10353b3fc051SAl Viro size = i->count; 1036185ac4d4SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { 1037185ac4d4SAl Viro /* iovec and kvec have identical layouts */ 1038185ac4d4SAl Viro iov_iter_iovec_advance(i, size); 1039185ac4d4SAl Viro } else if (iov_iter_is_bvec(i)) { 1040185ac4d4SAl Viro iov_iter_bvec_advance(i, size); 1041185ac4d4SAl Viro } else if (iov_iter_is_pipe(i)) { 1042241699cdSAl Viro pipe_advance(i, size); 1043185ac4d4SAl Viro } else if (unlikely(iov_iter_is_xarray(i))) { 10447ff50620SDavid Howells i->iov_offset += size; 10457ff50620SDavid Howells i->count -= size; 1046185ac4d4SAl Viro } else if (iov_iter_is_discard(i)) { 1047185ac4d4SAl Viro i->count -= size; 10487ff50620SDavid Howells } 1049d879cb83SAl Viro } 1050d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_advance); 1051d879cb83SAl Viro 105227c0e374SAl Viro void iov_iter_revert(struct iov_iter *i, size_t unroll) 105327c0e374SAl Viro { 105427c0e374SAl Viro if (!unroll) 105527c0e374SAl Viro return; 10565b47d59aSAl Viro if (WARN_ON(unroll > MAX_RW_COUNT)) 10575b47d59aSAl Viro return; 105827c0e374SAl Viro i->count += unroll; 105900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 106027c0e374SAl Viro struct pipe_inode_info *pipe = i->pipe; 10618cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10628cefc107SDavid Howells unsigned int i_head = i->head; 106327c0e374SAl Viro size_t off = i->iov_offset; 106427c0e374SAl Viro while (1) { 10658cefc107SDavid Howells struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; 10668cefc107SDavid Howells size_t n = off - b->offset; 106727c0e374SAl Viro if (unroll < n) { 10684fa55cefSAl Viro off -= unroll; 106927c0e374SAl Viro break; 107027c0e374SAl Viro } 107127c0e374SAl Viro unroll -= n; 10728cefc107SDavid Howells if (!unroll && i_head == i->start_head) { 107327c0e374SAl Viro off = 0; 107427c0e374SAl Viro break; 107527c0e374SAl Viro } 10768cefc107SDavid Howells i_head--; 10778cefc107SDavid Howells b = &pipe->bufs[i_head & p_mask]; 10788cefc107SDavid Howells off = b->offset + b->len; 107927c0e374SAl Viro } 108027c0e374SAl Viro i->iov_offset = off; 10818cefc107SDavid Howells i->head = i_head; 108227c0e374SAl Viro pipe_truncate(i); 108327c0e374SAl Viro return; 108427c0e374SAl Viro } 10859ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 10869ea9ce04SDavid Howells return; 108727c0e374SAl Viro if (unroll <= i->iov_offset) { 108827c0e374SAl Viro i->iov_offset -= unroll; 108927c0e374SAl Viro return; 109027c0e374SAl Viro } 109127c0e374SAl Viro unroll -= i->iov_offset; 10927ff50620SDavid Howells if (iov_iter_is_xarray(i)) { 10937ff50620SDavid Howells BUG(); /* We should never go beyond the start of the specified 10947ff50620SDavid Howells * range since we might then be straying into pages that 10957ff50620SDavid Howells * aren't pinned. 10967ff50620SDavid Howells */ 10977ff50620SDavid Howells } else if (iov_iter_is_bvec(i)) { 109827c0e374SAl Viro const struct bio_vec *bvec = i->bvec; 109927c0e374SAl Viro while (1) { 110027c0e374SAl Viro size_t n = (--bvec)->bv_len; 110127c0e374SAl Viro i->nr_segs++; 110227c0e374SAl Viro if (unroll <= n) { 110327c0e374SAl Viro i->bvec = bvec; 110427c0e374SAl Viro i->iov_offset = n - unroll; 110527c0e374SAl Viro return; 110627c0e374SAl Viro } 110727c0e374SAl Viro unroll -= n; 110827c0e374SAl Viro } 110927c0e374SAl Viro } else { /* same logics for iovec and kvec */ 111027c0e374SAl Viro const struct iovec *iov = i->iov; 111127c0e374SAl Viro while (1) { 111227c0e374SAl Viro size_t n = (--iov)->iov_len; 111327c0e374SAl Viro i->nr_segs++; 111427c0e374SAl Viro if (unroll <= n) { 111527c0e374SAl Viro i->iov = iov; 111627c0e374SAl Viro i->iov_offset = n - unroll; 111727c0e374SAl Viro return; 111827c0e374SAl Viro } 111927c0e374SAl Viro unroll -= n; 112027c0e374SAl Viro } 112127c0e374SAl Viro } 112227c0e374SAl Viro } 112327c0e374SAl Viro EXPORT_SYMBOL(iov_iter_revert); 112427c0e374SAl Viro 1125d879cb83SAl Viro /* 1126d879cb83SAl Viro * Return the count of just the current iov_iter segment. 1127d879cb83SAl Viro */ 1128d879cb83SAl Viro size_t iov_iter_single_seg_count(const struct iov_iter *i) 1129d879cb83SAl Viro { 113028f38db7SAl Viro if (i->nr_segs > 1) { 113128f38db7SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 113228f38db7SAl Viro return min(i->count, i->iov->iov_len - i->iov_offset); 11337ff50620SDavid Howells if (iov_iter_is_bvec(i)) 1134d879cb83SAl Viro return min(i->count, i->bvec->bv_len - i->iov_offset); 113528f38db7SAl Viro } 113628f38db7SAl Viro return i->count; 1137d879cb83SAl Viro } 1138d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_single_seg_count); 1139d879cb83SAl Viro 1140aa563d7bSDavid Howells void iov_iter_kvec(struct iov_iter *i, unsigned int direction, 1141d879cb83SAl Viro const struct kvec *kvec, unsigned long nr_segs, 1142d879cb83SAl Viro size_t count) 1143d879cb83SAl Viro { 1144aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 11458cd54c1cSAl Viro *i = (struct iov_iter){ 11468cd54c1cSAl Viro .iter_type = ITER_KVEC, 11478cd54c1cSAl Viro .data_source = direction, 11488cd54c1cSAl Viro .kvec = kvec, 11498cd54c1cSAl Viro .nr_segs = nr_segs, 11508cd54c1cSAl Viro .iov_offset = 0, 11518cd54c1cSAl Viro .count = count 11528cd54c1cSAl Viro }; 1153d879cb83SAl Viro } 1154d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_kvec); 1155d879cb83SAl Viro 1156aa563d7bSDavid Howells void iov_iter_bvec(struct iov_iter *i, unsigned int direction, 1157d879cb83SAl Viro const struct bio_vec *bvec, unsigned long nr_segs, 1158d879cb83SAl Viro size_t count) 1159d879cb83SAl Viro { 1160aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 11618cd54c1cSAl Viro *i = (struct iov_iter){ 11628cd54c1cSAl Viro .iter_type = ITER_BVEC, 11638cd54c1cSAl Viro .data_source = direction, 11648cd54c1cSAl Viro .bvec = bvec, 11658cd54c1cSAl Viro .nr_segs = nr_segs, 11668cd54c1cSAl Viro .iov_offset = 0, 11678cd54c1cSAl Viro .count = count 11688cd54c1cSAl Viro }; 1169d879cb83SAl Viro } 1170d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_bvec); 1171d879cb83SAl Viro 1172aa563d7bSDavid Howells void iov_iter_pipe(struct iov_iter *i, unsigned int direction, 1173241699cdSAl Viro struct pipe_inode_info *pipe, 1174241699cdSAl Viro size_t count) 1175241699cdSAl Viro { 1176aa563d7bSDavid Howells BUG_ON(direction != READ); 11778cefc107SDavid Howells WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); 11788cd54c1cSAl Viro *i = (struct iov_iter){ 11798cd54c1cSAl Viro .iter_type = ITER_PIPE, 11808cd54c1cSAl Viro .data_source = false, 11818cd54c1cSAl Viro .pipe = pipe, 11828cd54c1cSAl Viro .head = pipe->head, 11838cd54c1cSAl Viro .start_head = pipe->head, 11848cd54c1cSAl Viro .iov_offset = 0, 11858cd54c1cSAl Viro .count = count 11868cd54c1cSAl Viro }; 1187241699cdSAl Viro } 1188241699cdSAl Viro EXPORT_SYMBOL(iov_iter_pipe); 1189241699cdSAl Viro 11909ea9ce04SDavid Howells /** 11917ff50620SDavid Howells * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray 11927ff50620SDavid Howells * @i: The iterator to initialise. 11937ff50620SDavid Howells * @direction: The direction of the transfer. 11947ff50620SDavid Howells * @xarray: The xarray to access. 11957ff50620SDavid Howells * @start: The start file position. 11967ff50620SDavid Howells * @count: The size of the I/O buffer in bytes. 11977ff50620SDavid Howells * 11987ff50620SDavid Howells * Set up an I/O iterator to either draw data out of the pages attached to an 11997ff50620SDavid Howells * inode or to inject data into those pages. The pages *must* be prevented 12007ff50620SDavid Howells * from evaporation, either by taking a ref on them or locking them by the 12017ff50620SDavid Howells * caller. 12027ff50620SDavid Howells */ 12037ff50620SDavid Howells void iov_iter_xarray(struct iov_iter *i, unsigned int direction, 12047ff50620SDavid Howells struct xarray *xarray, loff_t start, size_t count) 12057ff50620SDavid Howells { 12067ff50620SDavid Howells BUG_ON(direction & ~1); 12078cd54c1cSAl Viro *i = (struct iov_iter) { 12088cd54c1cSAl Viro .iter_type = ITER_XARRAY, 12098cd54c1cSAl Viro .data_source = direction, 12108cd54c1cSAl Viro .xarray = xarray, 12118cd54c1cSAl Viro .xarray_start = start, 12128cd54c1cSAl Viro .count = count, 12138cd54c1cSAl Viro .iov_offset = 0 12148cd54c1cSAl Viro }; 12157ff50620SDavid Howells } 12167ff50620SDavid Howells EXPORT_SYMBOL(iov_iter_xarray); 12177ff50620SDavid Howells 12187ff50620SDavid Howells /** 12199ea9ce04SDavid Howells * iov_iter_discard - Initialise an I/O iterator that discards data 12209ea9ce04SDavid Howells * @i: The iterator to initialise. 12219ea9ce04SDavid Howells * @direction: The direction of the transfer. 12229ea9ce04SDavid Howells * @count: The size of the I/O buffer in bytes. 12239ea9ce04SDavid Howells * 12249ea9ce04SDavid Howells * Set up an I/O iterator that just discards everything that's written to it. 12259ea9ce04SDavid Howells * It's only available as a READ iterator. 12269ea9ce04SDavid Howells */ 12279ea9ce04SDavid Howells void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) 12289ea9ce04SDavid Howells { 12299ea9ce04SDavid Howells BUG_ON(direction != READ); 12308cd54c1cSAl Viro *i = (struct iov_iter){ 12318cd54c1cSAl Viro .iter_type = ITER_DISCARD, 12328cd54c1cSAl Viro .data_source = false, 12338cd54c1cSAl Viro .count = count, 12348cd54c1cSAl Viro .iov_offset = 0 12358cd54c1cSAl Viro }; 12369ea9ce04SDavid Howells } 12379ea9ce04SDavid Howells EXPORT_SYMBOL(iov_iter_discard); 12389ea9ce04SDavid Howells 12399221d2e3SAl Viro static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) 1240d879cb83SAl Viro { 1241d879cb83SAl Viro unsigned long res = 0; 1242d879cb83SAl Viro size_t size = i->count; 12439221d2e3SAl Viro size_t skip = i->iov_offset; 12449221d2e3SAl Viro unsigned k; 1245d879cb83SAl Viro 12469221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 12479221d2e3SAl Viro size_t len = i->iov[k].iov_len - skip; 12489221d2e3SAl Viro if (len) { 12499221d2e3SAl Viro res |= (unsigned long)i->iov[k].iov_base + skip; 12509221d2e3SAl Viro if (len > size) 12519221d2e3SAl Viro len = size; 12529221d2e3SAl Viro res |= len; 12539221d2e3SAl Viro size -= len; 12549221d2e3SAl Viro if (!size) 12559221d2e3SAl Viro break; 12569221d2e3SAl Viro } 12579221d2e3SAl Viro } 12589221d2e3SAl Viro return res; 12599221d2e3SAl Viro } 12609221d2e3SAl Viro 12619221d2e3SAl Viro static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) 12629221d2e3SAl Viro { 12639221d2e3SAl Viro unsigned res = 0; 12649221d2e3SAl Viro size_t size = i->count; 12659221d2e3SAl Viro unsigned skip = i->iov_offset; 12669221d2e3SAl Viro unsigned k; 12679221d2e3SAl Viro 12689221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 12699221d2e3SAl Viro size_t len = i->bvec[k].bv_len - skip; 12709221d2e3SAl Viro res |= (unsigned long)i->bvec[k].bv_offset + skip; 12719221d2e3SAl Viro if (len > size) 12729221d2e3SAl Viro len = size; 12739221d2e3SAl Viro res |= len; 12749221d2e3SAl Viro size -= len; 12759221d2e3SAl Viro if (!size) 12769221d2e3SAl Viro break; 12779221d2e3SAl Viro } 12789221d2e3SAl Viro return res; 12799221d2e3SAl Viro } 12809221d2e3SAl Viro 12819221d2e3SAl Viro unsigned long iov_iter_alignment(const struct iov_iter *i) 12829221d2e3SAl Viro { 12839221d2e3SAl Viro /* iovec and kvec have identical layouts */ 12849221d2e3SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 12859221d2e3SAl Viro return iov_iter_alignment_iovec(i); 12869221d2e3SAl Viro 12879221d2e3SAl Viro if (iov_iter_is_bvec(i)) 12889221d2e3SAl Viro return iov_iter_alignment_bvec(i); 12899221d2e3SAl Viro 12909221d2e3SAl Viro if (iov_iter_is_pipe(i)) { 1291e0ff126eSJan Kara unsigned int p_mask = i->pipe->ring_size - 1; 12929221d2e3SAl Viro size_t size = i->count; 1293e0ff126eSJan Kara 12948cefc107SDavid Howells if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) 1295241699cdSAl Viro return size | i->iov_offset; 1296241699cdSAl Viro return size; 1297241699cdSAl Viro } 12989221d2e3SAl Viro 12999221d2e3SAl Viro if (iov_iter_is_xarray(i)) 13003d14ec1fSDavid Howells return (i->xarray_start + i->iov_offset) | i->count; 13019221d2e3SAl Viro 13029221d2e3SAl Viro return 0; 1303d879cb83SAl Viro } 1304d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_alignment); 1305d879cb83SAl Viro 1306357f435dSAl Viro unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 1307357f435dSAl Viro { 1308357f435dSAl Viro unsigned long res = 0; 1309610c7a71SAl Viro unsigned long v = 0; 1310357f435dSAl Viro size_t size = i->count; 1311610c7a71SAl Viro unsigned k; 1312357f435dSAl Viro 1313610c7a71SAl Viro if (WARN_ON(!iter_is_iovec(i))) 1314241699cdSAl Viro return ~0U; 1315241699cdSAl Viro 1316610c7a71SAl Viro for (k = 0; k < i->nr_segs; k++) { 1317610c7a71SAl Viro if (i->iov[k].iov_len) { 1318610c7a71SAl Viro unsigned long base = (unsigned long)i->iov[k].iov_base; 1319610c7a71SAl Viro if (v) // if not the first one 1320610c7a71SAl Viro res |= base | v; // this start | previous end 1321610c7a71SAl Viro v = base + i->iov[k].iov_len; 1322610c7a71SAl Viro if (size <= i->iov[k].iov_len) 1323610c7a71SAl Viro break; 1324610c7a71SAl Viro size -= i->iov[k].iov_len; 1325610c7a71SAl Viro } 1326610c7a71SAl Viro } 1327357f435dSAl Viro return res; 1328357f435dSAl Viro } 1329357f435dSAl Viro EXPORT_SYMBOL(iov_iter_gap_alignment); 1330357f435dSAl Viro 1331e76b6312SIlya Dryomov static inline ssize_t __pipe_get_pages(struct iov_iter *i, 1332241699cdSAl Viro size_t maxsize, 1333241699cdSAl Viro struct page **pages, 13348cefc107SDavid Howells int iter_head, 1335241699cdSAl Viro size_t *start) 1336241699cdSAl Viro { 1337241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 13388cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 13398cefc107SDavid Howells ssize_t n = push_pipe(i, maxsize, &iter_head, start); 1340241699cdSAl Viro if (!n) 1341241699cdSAl Viro return -EFAULT; 1342241699cdSAl Viro 1343241699cdSAl Viro maxsize = n; 1344241699cdSAl Viro n += *start; 13451689c73aSAl Viro while (n > 0) { 13468cefc107SDavid Howells get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); 13478cefc107SDavid Howells iter_head++; 1348241699cdSAl Viro n -= PAGE_SIZE; 1349241699cdSAl Viro } 1350241699cdSAl Viro 1351241699cdSAl Viro return maxsize; 1352241699cdSAl Viro } 1353241699cdSAl Viro 1354241699cdSAl Viro static ssize_t pipe_get_pages(struct iov_iter *i, 1355241699cdSAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1356241699cdSAl Viro size_t *start) 1357241699cdSAl Viro { 13588cefc107SDavid Howells unsigned int iter_head, npages; 1359241699cdSAl Viro size_t capacity; 1360241699cdSAl Viro 1361241699cdSAl Viro if (!sanity(i)) 1362241699cdSAl Viro return -EFAULT; 1363241699cdSAl Viro 13648cefc107SDavid Howells data_start(i, &iter_head, start); 13658cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 13668cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1367241699cdSAl Viro capacity = min(npages, maxpages) * PAGE_SIZE - *start; 1368241699cdSAl Viro 13698cefc107SDavid Howells return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); 1370241699cdSAl Viro } 1371241699cdSAl Viro 13727ff50620SDavid Howells static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, 13737ff50620SDavid Howells pgoff_t index, unsigned int nr_pages) 13747ff50620SDavid Howells { 13757ff50620SDavid Howells XA_STATE(xas, xa, index); 13767ff50620SDavid Howells struct page *page; 13777ff50620SDavid Howells unsigned int ret = 0; 13787ff50620SDavid Howells 13797ff50620SDavid Howells rcu_read_lock(); 13807ff50620SDavid Howells for (page = xas_load(&xas); page; page = xas_next(&xas)) { 13817ff50620SDavid Howells if (xas_retry(&xas, page)) 13827ff50620SDavid Howells continue; 13837ff50620SDavid Howells 13847ff50620SDavid Howells /* Has the page moved or been split? */ 13857ff50620SDavid Howells if (unlikely(page != xas_reload(&xas))) { 13867ff50620SDavid Howells xas_reset(&xas); 13877ff50620SDavid Howells continue; 13887ff50620SDavid Howells } 13897ff50620SDavid Howells 13907ff50620SDavid Howells pages[ret] = find_subpage(page, xas.xa_index); 13917ff50620SDavid Howells get_page(pages[ret]); 13927ff50620SDavid Howells if (++ret == nr_pages) 13937ff50620SDavid Howells break; 13947ff50620SDavid Howells } 13957ff50620SDavid Howells rcu_read_unlock(); 13967ff50620SDavid Howells return ret; 13977ff50620SDavid Howells } 13987ff50620SDavid Howells 13997ff50620SDavid Howells static ssize_t iter_xarray_get_pages(struct iov_iter *i, 14007ff50620SDavid Howells struct page **pages, size_t maxsize, 14017ff50620SDavid Howells unsigned maxpages, size_t *_start_offset) 14027ff50620SDavid Howells { 14037ff50620SDavid Howells unsigned nr, offset; 14047ff50620SDavid Howells pgoff_t index, count; 14057ff50620SDavid Howells size_t size = maxsize, actual; 14067ff50620SDavid Howells loff_t pos; 14077ff50620SDavid Howells 14087ff50620SDavid Howells if (!size || !maxpages) 14097ff50620SDavid Howells return 0; 14107ff50620SDavid Howells 14117ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 14127ff50620SDavid Howells index = pos >> PAGE_SHIFT; 14137ff50620SDavid Howells offset = pos & ~PAGE_MASK; 14147ff50620SDavid Howells *_start_offset = offset; 14157ff50620SDavid Howells 14167ff50620SDavid Howells count = 1; 14177ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 14187ff50620SDavid Howells size -= PAGE_SIZE - offset; 14197ff50620SDavid Howells count += size >> PAGE_SHIFT; 14207ff50620SDavid Howells size &= ~PAGE_MASK; 14217ff50620SDavid Howells if (size) 14227ff50620SDavid Howells count++; 14237ff50620SDavid Howells } 14247ff50620SDavid Howells 14257ff50620SDavid Howells if (count > maxpages) 14267ff50620SDavid Howells count = maxpages; 14277ff50620SDavid Howells 14287ff50620SDavid Howells nr = iter_xarray_populate_pages(pages, i->xarray, index, count); 14297ff50620SDavid Howells if (nr == 0) 14307ff50620SDavid Howells return 0; 14317ff50620SDavid Howells 14327ff50620SDavid Howells actual = PAGE_SIZE * nr; 14337ff50620SDavid Howells actual -= offset; 14347ff50620SDavid Howells if (nr == count && size > 0) { 14357ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 14367ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 14377ff50620SDavid Howells } 14387ff50620SDavid Howells return actual; 14397ff50620SDavid Howells } 14407ff50620SDavid Howells 14413d671ca6SAl Viro /* must be done on non-empty ITER_IOVEC one */ 14423d671ca6SAl Viro static unsigned long first_iovec_segment(const struct iov_iter *i, 14433d671ca6SAl Viro size_t *size, size_t *start, 14443d671ca6SAl Viro size_t maxsize, unsigned maxpages) 14453d671ca6SAl Viro { 14463d671ca6SAl Viro size_t skip; 14473d671ca6SAl Viro long k; 14483d671ca6SAl Viro 14493d671ca6SAl Viro for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { 14503d671ca6SAl Viro unsigned long addr = (unsigned long)i->iov[k].iov_base + skip; 14513d671ca6SAl Viro size_t len = i->iov[k].iov_len - skip; 14523d671ca6SAl Viro 14533d671ca6SAl Viro if (unlikely(!len)) 14543d671ca6SAl Viro continue; 14553d671ca6SAl Viro if (len > maxsize) 14563d671ca6SAl Viro len = maxsize; 14573d671ca6SAl Viro len += (*start = addr % PAGE_SIZE); 14583d671ca6SAl Viro if (len > maxpages * PAGE_SIZE) 14593d671ca6SAl Viro len = maxpages * PAGE_SIZE; 14603d671ca6SAl Viro *size = len; 14613d671ca6SAl Viro return addr & PAGE_MASK; 14623d671ca6SAl Viro } 14633d671ca6SAl Viro BUG(); // if it had been empty, we wouldn't get called 14643d671ca6SAl Viro } 14653d671ca6SAl Viro 14663d671ca6SAl Viro /* must be done on non-empty ITER_BVEC one */ 14673d671ca6SAl Viro static struct page *first_bvec_segment(const struct iov_iter *i, 14683d671ca6SAl Viro size_t *size, size_t *start, 14693d671ca6SAl Viro size_t maxsize, unsigned maxpages) 14703d671ca6SAl Viro { 14713d671ca6SAl Viro struct page *page; 14723d671ca6SAl Viro size_t skip = i->iov_offset, len; 14733d671ca6SAl Viro 14743d671ca6SAl Viro len = i->bvec->bv_len - skip; 14753d671ca6SAl Viro if (len > maxsize) 14763d671ca6SAl Viro len = maxsize; 14773d671ca6SAl Viro skip += i->bvec->bv_offset; 14783d671ca6SAl Viro page = i->bvec->bv_page + skip / PAGE_SIZE; 14793d671ca6SAl Viro len += (*start = skip % PAGE_SIZE); 14803d671ca6SAl Viro if (len > maxpages * PAGE_SIZE) 14813d671ca6SAl Viro len = maxpages * PAGE_SIZE; 14823d671ca6SAl Viro *size = len; 14833d671ca6SAl Viro return page; 14843d671ca6SAl Viro } 14853d671ca6SAl Viro 1486d879cb83SAl Viro ssize_t iov_iter_get_pages(struct iov_iter *i, 1487d879cb83SAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1488d879cb83SAl Viro size_t *start) 1489d879cb83SAl Viro { 14903d671ca6SAl Viro size_t len; 14913d671ca6SAl Viro int n, res; 14923d671ca6SAl Viro 1493d879cb83SAl Viro if (maxsize > i->count) 1494d879cb83SAl Viro maxsize = i->count; 14953d671ca6SAl Viro if (!maxsize) 14963d671ca6SAl Viro return 0; 1497d879cb83SAl Viro 14983d671ca6SAl Viro if (likely(iter_is_iovec(i))) { 14993d671ca6SAl Viro unsigned long addr; 15009ea9ce04SDavid Howells 15013d671ca6SAl Viro addr = first_iovec_segment(i, &len, start, maxsize, maxpages); 1502d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 150373b0140bSIra Weiny res = get_user_pages_fast(addr, n, 150473b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, 150573b0140bSIra Weiny pages); 1506d879cb83SAl Viro if (unlikely(res < 0)) 1507d879cb83SAl Viro return res; 1508d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 15093d671ca6SAl Viro } 15103d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 15113d671ca6SAl Viro struct page *page; 15123d671ca6SAl Viro 15133d671ca6SAl Viro page = first_bvec_segment(i, &len, start, maxsize, maxpages); 15143d671ca6SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 15153d671ca6SAl Viro while (n--) 15163d671ca6SAl Viro get_page(*pages++ = page++); 15173d671ca6SAl Viro return len - *start; 15183d671ca6SAl Viro } 15193d671ca6SAl Viro if (iov_iter_is_pipe(i)) 15203d671ca6SAl Viro return pipe_get_pages(i, pages, maxsize, maxpages, start); 15213d671ca6SAl Viro if (iov_iter_is_xarray(i)) 15223d671ca6SAl Viro return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); 1523d879cb83SAl Viro return -EFAULT; 1524d879cb83SAl Viro } 1525d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages); 1526d879cb83SAl Viro 1527d879cb83SAl Viro static struct page **get_pages_array(size_t n) 1528d879cb83SAl Viro { 1529752ade68SMichal Hocko return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); 1530d879cb83SAl Viro } 1531d879cb83SAl Viro 1532241699cdSAl Viro static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 1533241699cdSAl Viro struct page ***pages, size_t maxsize, 1534241699cdSAl Viro size_t *start) 1535241699cdSAl Viro { 1536241699cdSAl Viro struct page **p; 15378cefc107SDavid Howells unsigned int iter_head, npages; 1538d7760d63SIlya Dryomov ssize_t n; 1539241699cdSAl Viro 1540241699cdSAl Viro if (!sanity(i)) 1541241699cdSAl Viro return -EFAULT; 1542241699cdSAl Viro 15438cefc107SDavid Howells data_start(i, &iter_head, start); 15448cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 15458cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1546241699cdSAl Viro n = npages * PAGE_SIZE - *start; 1547241699cdSAl Viro if (maxsize > n) 1548241699cdSAl Viro maxsize = n; 1549241699cdSAl Viro else 1550241699cdSAl Viro npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1551241699cdSAl Viro p = get_pages_array(npages); 1552241699cdSAl Viro if (!p) 1553241699cdSAl Viro return -ENOMEM; 15548cefc107SDavid Howells n = __pipe_get_pages(i, maxsize, p, iter_head, start); 1555241699cdSAl Viro if (n > 0) 1556241699cdSAl Viro *pages = p; 1557241699cdSAl Viro else 1558241699cdSAl Viro kvfree(p); 1559241699cdSAl Viro return n; 1560241699cdSAl Viro } 1561241699cdSAl Viro 15627ff50620SDavid Howells static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, 15637ff50620SDavid Howells struct page ***pages, size_t maxsize, 15647ff50620SDavid Howells size_t *_start_offset) 15657ff50620SDavid Howells { 15667ff50620SDavid Howells struct page **p; 15677ff50620SDavid Howells unsigned nr, offset; 15687ff50620SDavid Howells pgoff_t index, count; 15697ff50620SDavid Howells size_t size = maxsize, actual; 15707ff50620SDavid Howells loff_t pos; 15717ff50620SDavid Howells 15727ff50620SDavid Howells if (!size) 15737ff50620SDavid Howells return 0; 15747ff50620SDavid Howells 15757ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 15767ff50620SDavid Howells index = pos >> PAGE_SHIFT; 15777ff50620SDavid Howells offset = pos & ~PAGE_MASK; 15787ff50620SDavid Howells *_start_offset = offset; 15797ff50620SDavid Howells 15807ff50620SDavid Howells count = 1; 15817ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 15827ff50620SDavid Howells size -= PAGE_SIZE - offset; 15837ff50620SDavid Howells count += size >> PAGE_SHIFT; 15847ff50620SDavid Howells size &= ~PAGE_MASK; 15857ff50620SDavid Howells if (size) 15867ff50620SDavid Howells count++; 15877ff50620SDavid Howells } 15887ff50620SDavid Howells 15897ff50620SDavid Howells p = get_pages_array(count); 15907ff50620SDavid Howells if (!p) 15917ff50620SDavid Howells return -ENOMEM; 15927ff50620SDavid Howells *pages = p; 15937ff50620SDavid Howells 15947ff50620SDavid Howells nr = iter_xarray_populate_pages(p, i->xarray, index, count); 15957ff50620SDavid Howells if (nr == 0) 15967ff50620SDavid Howells return 0; 15977ff50620SDavid Howells 15987ff50620SDavid Howells actual = PAGE_SIZE * nr; 15997ff50620SDavid Howells actual -= offset; 16007ff50620SDavid Howells if (nr == count && size > 0) { 16017ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 16027ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 16037ff50620SDavid Howells } 16047ff50620SDavid Howells return actual; 16057ff50620SDavid Howells } 16067ff50620SDavid Howells 1607d879cb83SAl Viro ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 1608d879cb83SAl Viro struct page ***pages, size_t maxsize, 1609d879cb83SAl Viro size_t *start) 1610d879cb83SAl Viro { 1611d879cb83SAl Viro struct page **p; 16123d671ca6SAl Viro size_t len; 16133d671ca6SAl Viro int n, res; 1614d879cb83SAl Viro 1615d879cb83SAl Viro if (maxsize > i->count) 1616d879cb83SAl Viro maxsize = i->count; 16173d671ca6SAl Viro if (!maxsize) 16183d671ca6SAl Viro return 0; 1619d879cb83SAl Viro 16203d671ca6SAl Viro if (likely(iter_is_iovec(i))) { 16213d671ca6SAl Viro unsigned long addr; 16229ea9ce04SDavid Howells 16233d671ca6SAl Viro addr = first_iovec_segment(i, &len, start, maxsize, ~0U); 1624d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 1625d879cb83SAl Viro p = get_pages_array(n); 1626d879cb83SAl Viro if (!p) 1627d879cb83SAl Viro return -ENOMEM; 162873b0140bSIra Weiny res = get_user_pages_fast(addr, n, 162973b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); 1630d879cb83SAl Viro if (unlikely(res < 0)) { 1631d879cb83SAl Viro kvfree(p); 1632d879cb83SAl Viro return res; 1633d879cb83SAl Viro } 1634d879cb83SAl Viro *pages = p; 1635d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 16363d671ca6SAl Viro } 16373d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 16383d671ca6SAl Viro struct page *page; 16393d671ca6SAl Viro 16403d671ca6SAl Viro page = first_bvec_segment(i, &len, start, maxsize, ~0U); 16413d671ca6SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 16423d671ca6SAl Viro *pages = p = get_pages_array(n); 1643d879cb83SAl Viro if (!p) 1644d879cb83SAl Viro return -ENOMEM; 16453d671ca6SAl Viro while (n--) 16463d671ca6SAl Viro get_page(*p++ = page++); 16473d671ca6SAl Viro return len - *start; 16483d671ca6SAl Viro } 16493d671ca6SAl Viro if (iov_iter_is_pipe(i)) 16503d671ca6SAl Viro return pipe_get_pages_alloc(i, pages, maxsize, start); 16513d671ca6SAl Viro if (iov_iter_is_xarray(i)) 16523d671ca6SAl Viro return iter_xarray_get_pages_alloc(i, pages, maxsize, start); 1653d879cb83SAl Viro return -EFAULT; 1654d879cb83SAl Viro } 1655d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages_alloc); 1656d879cb83SAl Viro 1657d879cb83SAl Viro size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 1658d879cb83SAl Viro struct iov_iter *i) 1659d879cb83SAl Viro { 1660d879cb83SAl Viro __wsum sum, next; 1661d879cb83SAl Viro sum = *csum; 16629ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1663241699cdSAl Viro WARN_ON(1); 1664241699cdSAl Viro return 0; 1665241699cdSAl Viro } 16667baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, ({ 16677baa5099SAl Viro next = csum_and_copy_from_user(base, addr + off, len); 1668622838f3SAl Viro if (next) 1669d879cb83SAl Viro sum = csum_block_add(sum, next, off); 16707baa5099SAl Viro next ? 0 : len; 1671d879cb83SAl Viro }), ({ 16727baa5099SAl Viro sum = csum_and_memcpy(addr + off, base, len, sum, off); 1673d879cb83SAl Viro }) 1674d879cb83SAl Viro ) 1675d879cb83SAl Viro *csum = sum; 1676d879cb83SAl Viro return bytes; 1677d879cb83SAl Viro } 1678d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter); 1679d879cb83SAl Viro 168052cbd23aSWillem de Bruijn size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 1681d879cb83SAl Viro struct iov_iter *i) 1682d879cb83SAl Viro { 168352cbd23aSWillem de Bruijn struct csum_state *csstate = _csstate; 1684d879cb83SAl Viro __wsum sum, next; 168578e1f386SAl Viro 168678e1f386SAl Viro if (unlikely(iov_iter_is_pipe(i))) 168752cbd23aSWillem de Bruijn return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); 168878e1f386SAl Viro 1689594e450bSAl Viro sum = csum_shift(csstate->csum, csstate->off); 169078e1f386SAl Viro if (unlikely(iov_iter_is_discard(i))) { 1691241699cdSAl Viro WARN_ON(1); /* for now */ 1692241699cdSAl Viro return 0; 1693241699cdSAl Viro } 16947baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, ({ 16957baa5099SAl Viro next = csum_and_copy_to_user(addr + off, base, len); 1696622838f3SAl Viro if (next) 1697d879cb83SAl Viro sum = csum_block_add(sum, next, off); 16987baa5099SAl Viro next ? 0 : len; 1699d879cb83SAl Viro }), ({ 17007baa5099SAl Viro sum = csum_and_memcpy(base, addr + off, len, sum, off); 1701d879cb83SAl Viro }) 1702d879cb83SAl Viro ) 1703594e450bSAl Viro csstate->csum = csum_shift(sum, csstate->off); 1704594e450bSAl Viro csstate->off += bytes; 1705d879cb83SAl Viro return bytes; 1706d879cb83SAl Viro } 1707d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_to_iter); 1708d879cb83SAl Viro 1709d05f4435SSagi Grimberg size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, 1710d05f4435SSagi Grimberg struct iov_iter *i) 1711d05f4435SSagi Grimberg { 17127999096fSHerbert Xu #ifdef CONFIG_CRYPTO_HASH 1713d05f4435SSagi Grimberg struct ahash_request *hash = hashp; 1714d05f4435SSagi Grimberg struct scatterlist sg; 1715d05f4435SSagi Grimberg size_t copied; 1716d05f4435SSagi Grimberg 1717d05f4435SSagi Grimberg copied = copy_to_iter(addr, bytes, i); 1718d05f4435SSagi Grimberg sg_init_one(&sg, addr, copied); 1719d05f4435SSagi Grimberg ahash_request_set_crypt(hash, &sg, NULL, copied); 1720d05f4435SSagi Grimberg crypto_ahash_update(hash); 1721d05f4435SSagi Grimberg return copied; 172227fad74aSYueHaibing #else 172327fad74aSYueHaibing return 0; 172427fad74aSYueHaibing #endif 1725d05f4435SSagi Grimberg } 1726d05f4435SSagi Grimberg EXPORT_SYMBOL(hash_and_copy_to_iter); 1727d05f4435SSagi Grimberg 172866531c65SAl Viro static int iov_npages(const struct iov_iter *i, int maxpages) 1729d879cb83SAl Viro { 173066531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 173166531c65SAl Viro const struct iovec *p; 1732d879cb83SAl Viro int npages = 0; 1733d879cb83SAl Viro 173466531c65SAl Viro for (p = i->iov; size; skip = 0, p++) { 173566531c65SAl Viro unsigned offs = offset_in_page(p->iov_base + skip); 173666531c65SAl Viro size_t len = min(p->iov_len - skip, size); 1737d879cb83SAl Viro 173866531c65SAl Viro if (len) { 173966531c65SAl Viro size -= len; 174066531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 174166531c65SAl Viro if (unlikely(npages > maxpages)) 174266531c65SAl Viro return maxpages; 174366531c65SAl Viro } 174466531c65SAl Viro } 174566531c65SAl Viro return npages; 174666531c65SAl Viro } 174766531c65SAl Viro 174866531c65SAl Viro static int bvec_npages(const struct iov_iter *i, int maxpages) 174966531c65SAl Viro { 175066531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 175166531c65SAl Viro const struct bio_vec *p; 175266531c65SAl Viro int npages = 0; 175366531c65SAl Viro 175466531c65SAl Viro for (p = i->bvec; size; skip = 0, p++) { 175566531c65SAl Viro unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; 175666531c65SAl Viro size_t len = min(p->bv_len - skip, size); 175766531c65SAl Viro 175866531c65SAl Viro size -= len; 175966531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 176066531c65SAl Viro if (unlikely(npages > maxpages)) 176166531c65SAl Viro return maxpages; 176266531c65SAl Viro } 176366531c65SAl Viro return npages; 176466531c65SAl Viro } 176566531c65SAl Viro 176666531c65SAl Viro int iov_iter_npages(const struct iov_iter *i, int maxpages) 176766531c65SAl Viro { 176866531c65SAl Viro if (unlikely(!i->count)) 176966531c65SAl Viro return 0; 177066531c65SAl Viro /* iovec and kvec have identical layouts */ 177166531c65SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 177266531c65SAl Viro return iov_npages(i, maxpages); 177366531c65SAl Viro if (iov_iter_is_bvec(i)) 177466531c65SAl Viro return bvec_npages(i, maxpages); 177566531c65SAl Viro if (iov_iter_is_pipe(i)) { 17768cefc107SDavid Howells unsigned int iter_head; 177766531c65SAl Viro int npages; 1778241699cdSAl Viro size_t off; 1779241699cdSAl Viro 1780241699cdSAl Viro if (!sanity(i)) 1781241699cdSAl Viro return 0; 1782241699cdSAl Viro 17838cefc107SDavid Howells data_start(i, &iter_head, &off); 1784241699cdSAl Viro /* some of this one + all after this one */ 178566531c65SAl Viro npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 178666531c65SAl Viro return min(npages, maxpages); 178766531c65SAl Viro } 178866531c65SAl Viro if (iov_iter_is_xarray(i)) { 1789e4f8df86SAl Viro unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; 1790e4f8df86SAl Viro int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); 179166531c65SAl Viro return min(npages, maxpages); 179266531c65SAl Viro } 179366531c65SAl Viro return 0; 1794d879cb83SAl Viro } 1795d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_npages); 1796d879cb83SAl Viro 1797d879cb83SAl Viro const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) 1798d879cb83SAl Viro { 1799d879cb83SAl Viro *new = *old; 180000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(new))) { 1801241699cdSAl Viro WARN_ON(1); 1802241699cdSAl Viro return NULL; 1803241699cdSAl Viro } 18047ff50620SDavid Howells if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) 18059ea9ce04SDavid Howells return NULL; 180600e23707SDavid Howells if (iov_iter_is_bvec(new)) 1807d879cb83SAl Viro return new->bvec = kmemdup(new->bvec, 1808d879cb83SAl Viro new->nr_segs * sizeof(struct bio_vec), 1809d879cb83SAl Viro flags); 1810d879cb83SAl Viro else 1811d879cb83SAl Viro /* iovec and kvec have identical layout */ 1812d879cb83SAl Viro return new->iov = kmemdup(new->iov, 1813d879cb83SAl Viro new->nr_segs * sizeof(struct iovec), 1814d879cb83SAl Viro flags); 1815d879cb83SAl Viro } 1816d879cb83SAl Viro EXPORT_SYMBOL(dup_iter); 1817bc917be8SAl Viro 1818bfdc5970SChristoph Hellwig static int copy_compat_iovec_from_user(struct iovec *iov, 1819bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1820bfdc5970SChristoph Hellwig { 1821bfdc5970SChristoph Hellwig const struct compat_iovec __user *uiov = 1822bfdc5970SChristoph Hellwig (const struct compat_iovec __user *)uvec; 1823bfdc5970SChristoph Hellwig int ret = -EFAULT, i; 1824bfdc5970SChristoph Hellwig 1825a959a978SChristoph Hellwig if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) 1826bfdc5970SChristoph Hellwig return -EFAULT; 1827bfdc5970SChristoph Hellwig 1828bfdc5970SChristoph Hellwig for (i = 0; i < nr_segs; i++) { 1829bfdc5970SChristoph Hellwig compat_uptr_t buf; 1830bfdc5970SChristoph Hellwig compat_ssize_t len; 1831bfdc5970SChristoph Hellwig 1832bfdc5970SChristoph Hellwig unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); 1833bfdc5970SChristoph Hellwig unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); 1834bfdc5970SChristoph Hellwig 1835bfdc5970SChristoph Hellwig /* check for compat_size_t not fitting in compat_ssize_t .. */ 1836bfdc5970SChristoph Hellwig if (len < 0) { 1837bfdc5970SChristoph Hellwig ret = -EINVAL; 1838bfdc5970SChristoph Hellwig goto uaccess_end; 1839bfdc5970SChristoph Hellwig } 1840bfdc5970SChristoph Hellwig iov[i].iov_base = compat_ptr(buf); 1841bfdc5970SChristoph Hellwig iov[i].iov_len = len; 1842bfdc5970SChristoph Hellwig } 1843bfdc5970SChristoph Hellwig 1844bfdc5970SChristoph Hellwig ret = 0; 1845bfdc5970SChristoph Hellwig uaccess_end: 1846bfdc5970SChristoph Hellwig user_access_end(); 1847bfdc5970SChristoph Hellwig return ret; 1848bfdc5970SChristoph Hellwig } 1849bfdc5970SChristoph Hellwig 1850bfdc5970SChristoph Hellwig static int copy_iovec_from_user(struct iovec *iov, 1851bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1852fb041b59SDavid Laight { 1853fb041b59SDavid Laight unsigned long seg; 1854bfdc5970SChristoph Hellwig 1855bfdc5970SChristoph Hellwig if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) 1856bfdc5970SChristoph Hellwig return -EFAULT; 1857bfdc5970SChristoph Hellwig for (seg = 0; seg < nr_segs; seg++) { 1858bfdc5970SChristoph Hellwig if ((ssize_t)iov[seg].iov_len < 0) 1859bfdc5970SChristoph Hellwig return -EINVAL; 1860bfdc5970SChristoph Hellwig } 1861bfdc5970SChristoph Hellwig 1862bfdc5970SChristoph Hellwig return 0; 1863bfdc5970SChristoph Hellwig } 1864bfdc5970SChristoph Hellwig 1865bfdc5970SChristoph Hellwig struct iovec *iovec_from_user(const struct iovec __user *uvec, 1866bfdc5970SChristoph Hellwig unsigned long nr_segs, unsigned long fast_segs, 1867bfdc5970SChristoph Hellwig struct iovec *fast_iov, bool compat) 1868bfdc5970SChristoph Hellwig { 1869bfdc5970SChristoph Hellwig struct iovec *iov = fast_iov; 1870bfdc5970SChristoph Hellwig int ret; 1871fb041b59SDavid Laight 1872fb041b59SDavid Laight /* 1873bfdc5970SChristoph Hellwig * SuS says "The readv() function *may* fail if the iovcnt argument was 1874bfdc5970SChristoph Hellwig * less than or equal to 0, or greater than {IOV_MAX}. Linux has 1875fb041b59SDavid Laight * traditionally returned zero for zero segments, so... 1876fb041b59SDavid Laight */ 1877bfdc5970SChristoph Hellwig if (nr_segs == 0) 1878bfdc5970SChristoph Hellwig return iov; 1879bfdc5970SChristoph Hellwig if (nr_segs > UIO_MAXIOV) 1880bfdc5970SChristoph Hellwig return ERR_PTR(-EINVAL); 1881fb041b59SDavid Laight if (nr_segs > fast_segs) { 1882fb041b59SDavid Laight iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); 1883bfdc5970SChristoph Hellwig if (!iov) 1884bfdc5970SChristoph Hellwig return ERR_PTR(-ENOMEM); 1885fb041b59SDavid Laight } 1886bfdc5970SChristoph Hellwig 1887bfdc5970SChristoph Hellwig if (compat) 1888bfdc5970SChristoph Hellwig ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); 1889bfdc5970SChristoph Hellwig else 1890bfdc5970SChristoph Hellwig ret = copy_iovec_from_user(iov, uvec, nr_segs); 1891bfdc5970SChristoph Hellwig if (ret) { 1892bfdc5970SChristoph Hellwig if (iov != fast_iov) 1893bfdc5970SChristoph Hellwig kfree(iov); 1894bfdc5970SChristoph Hellwig return ERR_PTR(ret); 1895fb041b59SDavid Laight } 1896bfdc5970SChristoph Hellwig 1897bfdc5970SChristoph Hellwig return iov; 1898bfdc5970SChristoph Hellwig } 1899bfdc5970SChristoph Hellwig 1900bfdc5970SChristoph Hellwig ssize_t __import_iovec(int type, const struct iovec __user *uvec, 1901bfdc5970SChristoph Hellwig unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, 1902bfdc5970SChristoph Hellwig struct iov_iter *i, bool compat) 1903bfdc5970SChristoph Hellwig { 1904bfdc5970SChristoph Hellwig ssize_t total_len = 0; 1905bfdc5970SChristoph Hellwig unsigned long seg; 1906bfdc5970SChristoph Hellwig struct iovec *iov; 1907bfdc5970SChristoph Hellwig 1908bfdc5970SChristoph Hellwig iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); 1909bfdc5970SChristoph Hellwig if (IS_ERR(iov)) { 1910bfdc5970SChristoph Hellwig *iovp = NULL; 1911bfdc5970SChristoph Hellwig return PTR_ERR(iov); 1912fb041b59SDavid Laight } 1913fb041b59SDavid Laight 1914fb041b59SDavid Laight /* 1915bfdc5970SChristoph Hellwig * According to the Single Unix Specification we should return EINVAL if 1916bfdc5970SChristoph Hellwig * an element length is < 0 when cast to ssize_t or if the total length 1917bfdc5970SChristoph Hellwig * would overflow the ssize_t return value of the system call. 1918fb041b59SDavid Laight * 1919fb041b59SDavid Laight * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the 1920fb041b59SDavid Laight * overflow case. 1921fb041b59SDavid Laight */ 1922fb041b59SDavid Laight for (seg = 0; seg < nr_segs; seg++) { 1923fb041b59SDavid Laight ssize_t len = (ssize_t)iov[seg].iov_len; 1924fb041b59SDavid Laight 1925bfdc5970SChristoph Hellwig if (!access_ok(iov[seg].iov_base, len)) { 1926bfdc5970SChristoph Hellwig if (iov != *iovp) 1927bfdc5970SChristoph Hellwig kfree(iov); 1928bfdc5970SChristoph Hellwig *iovp = NULL; 1929bfdc5970SChristoph Hellwig return -EFAULT; 1930fb041b59SDavid Laight } 1931bfdc5970SChristoph Hellwig 1932bfdc5970SChristoph Hellwig if (len > MAX_RW_COUNT - total_len) { 1933bfdc5970SChristoph Hellwig len = MAX_RW_COUNT - total_len; 1934fb041b59SDavid Laight iov[seg].iov_len = len; 1935fb041b59SDavid Laight } 1936bfdc5970SChristoph Hellwig total_len += len; 1937fb041b59SDavid Laight } 1938bfdc5970SChristoph Hellwig 1939bfdc5970SChristoph Hellwig iov_iter_init(i, type, iov, nr_segs, total_len); 1940bfdc5970SChristoph Hellwig if (iov == *iovp) 1941bfdc5970SChristoph Hellwig *iovp = NULL; 1942bfdc5970SChristoph Hellwig else 1943bfdc5970SChristoph Hellwig *iovp = iov; 1944bfdc5970SChristoph Hellwig return total_len; 1945fb041b59SDavid Laight } 1946fb041b59SDavid Laight 1947ffecee4fSVegard Nossum /** 1948ffecee4fSVegard Nossum * import_iovec() - Copy an array of &struct iovec from userspace 1949ffecee4fSVegard Nossum * into the kernel, check that it is valid, and initialize a new 1950ffecee4fSVegard Nossum * &struct iov_iter iterator to access it. 1951ffecee4fSVegard Nossum * 1952ffecee4fSVegard Nossum * @type: One of %READ or %WRITE. 1953bfdc5970SChristoph Hellwig * @uvec: Pointer to the userspace array. 1954ffecee4fSVegard Nossum * @nr_segs: Number of elements in userspace array. 1955ffecee4fSVegard Nossum * @fast_segs: Number of elements in @iov. 1956bfdc5970SChristoph Hellwig * @iovp: (input and output parameter) Pointer to pointer to (usually small 1957ffecee4fSVegard Nossum * on-stack) kernel array. 1958ffecee4fSVegard Nossum * @i: Pointer to iterator that will be initialized on success. 1959ffecee4fSVegard Nossum * 1960ffecee4fSVegard Nossum * If the array pointed to by *@iov is large enough to hold all @nr_segs, 1961ffecee4fSVegard Nossum * then this function places %NULL in *@iov on return. Otherwise, a new 1962ffecee4fSVegard Nossum * array will be allocated and the result placed in *@iov. This means that 1963ffecee4fSVegard Nossum * the caller may call kfree() on *@iov regardless of whether the small 1964ffecee4fSVegard Nossum * on-stack array was used or not (and regardless of whether this function 1965ffecee4fSVegard Nossum * returns an error or not). 1966ffecee4fSVegard Nossum * 196787e5e6daSJens Axboe * Return: Negative error code on error, bytes imported on success 1968ffecee4fSVegard Nossum */ 1969bfdc5970SChristoph Hellwig ssize_t import_iovec(int type, const struct iovec __user *uvec, 1970bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 1971bfdc5970SChristoph Hellwig struct iovec **iovp, struct iov_iter *i) 1972bc917be8SAl Viro { 197389cd35c5SChristoph Hellwig return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, 197489cd35c5SChristoph Hellwig in_compat_syscall()); 1975bc917be8SAl Viro } 1976bc917be8SAl Viro EXPORT_SYMBOL(import_iovec); 1977bc917be8SAl Viro 1978bc917be8SAl Viro int import_single_range(int rw, void __user *buf, size_t len, 1979bc917be8SAl Viro struct iovec *iov, struct iov_iter *i) 1980bc917be8SAl Viro { 1981bc917be8SAl Viro if (len > MAX_RW_COUNT) 1982bc917be8SAl Viro len = MAX_RW_COUNT; 198396d4f267SLinus Torvalds if (unlikely(!access_ok(buf, len))) 1984bc917be8SAl Viro return -EFAULT; 1985bc917be8SAl Viro 1986bc917be8SAl Viro iov->iov_base = buf; 1987bc917be8SAl Viro iov->iov_len = len; 1988bc917be8SAl Viro iov_iter_init(i, rw, iov, 1, len); 1989bc917be8SAl Viro return 0; 1990bc917be8SAl Viro } 1991e1267585SAl Viro EXPORT_SYMBOL(import_single_range); 1992