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 *i = (struct iov_iter) { 4698cd54c1cSAl Viro .iter_type = ITER_IOVEC, 4708cd54c1cSAl Viro .data_source = direction, 4718cd54c1cSAl Viro .iov = iov, 4728cd54c1cSAl Viro .nr_segs = nr_segs, 4738cd54c1cSAl Viro .iov_offset = 0, 4748cd54c1cSAl Viro .count = count 4758cd54c1cSAl Viro }; 476d879cb83SAl Viro } 477d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_init); 478d879cb83SAl Viro 479241699cdSAl Viro static inline bool allocated(struct pipe_buffer *buf) 480241699cdSAl Viro { 481241699cdSAl Viro return buf->ops == &default_pipe_buf_ops; 482241699cdSAl Viro } 483241699cdSAl Viro 4848cefc107SDavid Howells static inline void data_start(const struct iov_iter *i, 4858cefc107SDavid Howells unsigned int *iter_headp, size_t *offp) 486241699cdSAl Viro { 4878cefc107SDavid Howells unsigned int p_mask = i->pipe->ring_size - 1; 4888cefc107SDavid Howells unsigned int iter_head = i->head; 489241699cdSAl Viro size_t off = i->iov_offset; 4908cefc107SDavid Howells 4918cefc107SDavid Howells if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || 4928cefc107SDavid Howells off == PAGE_SIZE)) { 4938cefc107SDavid Howells iter_head++; 494241699cdSAl Viro off = 0; 495241699cdSAl Viro } 4968cefc107SDavid Howells *iter_headp = iter_head; 497241699cdSAl Viro *offp = off; 498241699cdSAl Viro } 499241699cdSAl Viro 500241699cdSAl Viro static size_t push_pipe(struct iov_iter *i, size_t size, 5018cefc107SDavid Howells int *iter_headp, size_t *offp) 502241699cdSAl Viro { 503241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5048cefc107SDavid Howells unsigned int p_tail = pipe->tail; 5058cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5068cefc107SDavid Howells unsigned int iter_head; 507241699cdSAl Viro size_t off; 508241699cdSAl Viro ssize_t left; 509241699cdSAl Viro 510241699cdSAl Viro if (unlikely(size > i->count)) 511241699cdSAl Viro size = i->count; 512241699cdSAl Viro if (unlikely(!size)) 513241699cdSAl Viro return 0; 514241699cdSAl Viro 515241699cdSAl Viro left = size; 5168cefc107SDavid Howells data_start(i, &iter_head, &off); 5178cefc107SDavid Howells *iter_headp = iter_head; 518241699cdSAl Viro *offp = off; 519241699cdSAl Viro if (off) { 520241699cdSAl Viro left -= PAGE_SIZE - off; 521241699cdSAl Viro if (left <= 0) { 5228cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len += size; 523241699cdSAl Viro return size; 524241699cdSAl Viro } 5258cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; 5268cefc107SDavid Howells iter_head++; 527241699cdSAl Viro } 5286718b6f8SDavid Howells while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { 5298cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; 530241699cdSAl Viro struct page *page = alloc_page(GFP_USER); 531241699cdSAl Viro if (!page) 532241699cdSAl Viro break; 5338cefc107SDavid Howells 5348cefc107SDavid Howells buf->ops = &default_pipe_buf_ops; 5358cefc107SDavid Howells buf->page = page; 5368cefc107SDavid Howells buf->offset = 0; 5378cefc107SDavid Howells buf->len = min_t(ssize_t, left, PAGE_SIZE); 5388cefc107SDavid Howells left -= buf->len; 5398cefc107SDavid Howells iter_head++; 5408cefc107SDavid Howells pipe->head = iter_head; 5418cefc107SDavid Howells 5428cefc107SDavid Howells if (left == 0) 543241699cdSAl Viro return size; 544241699cdSAl Viro } 545241699cdSAl Viro return size - left; 546241699cdSAl Viro } 547241699cdSAl Viro 548241699cdSAl Viro static size_t copy_pipe_to_iter(const void *addr, size_t bytes, 549241699cdSAl Viro struct iov_iter *i) 550241699cdSAl Viro { 551241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5528cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5538cefc107SDavid Howells unsigned int i_head; 554241699cdSAl Viro size_t n, off; 555241699cdSAl Viro 556241699cdSAl Viro if (!sanity(i)) 557241699cdSAl Viro return 0; 558241699cdSAl Viro 5598cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 560241699cdSAl Viro if (unlikely(!n)) 561241699cdSAl Viro return 0; 5628cefc107SDavid Howells do { 563241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 5648cefc107SDavid Howells memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); 5658cefc107SDavid Howells i->head = i_head; 566241699cdSAl Viro i->iov_offset = off + chunk; 567241699cdSAl Viro n -= chunk; 568241699cdSAl Viro addr += chunk; 5698cefc107SDavid Howells off = 0; 5708cefc107SDavid Howells i_head++; 5718cefc107SDavid Howells } while (n); 572241699cdSAl Viro i->count -= bytes; 573241699cdSAl Viro return bytes; 574241699cdSAl Viro } 575241699cdSAl Viro 576f9152895SAl Viro static __wsum csum_and_memcpy(void *to, const void *from, size_t len, 577f9152895SAl Viro __wsum sum, size_t off) 578f9152895SAl Viro { 579cc44c17bSAl Viro __wsum next = csum_partial_copy_nocheck(from, to, len); 580f9152895SAl Viro return csum_block_add(sum, next, off); 581f9152895SAl Viro } 582f9152895SAl Viro 58378e1f386SAl Viro static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, 5846852df12SAl Viro struct iov_iter *i, __wsum *sump) 58578e1f386SAl Viro { 58678e1f386SAl Viro struct pipe_inode_info *pipe = i->pipe; 5878cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5886852df12SAl Viro __wsum sum = *sump; 5896852df12SAl Viro size_t off = 0; 5908cefc107SDavid Howells unsigned int i_head; 5916852df12SAl Viro size_t r; 59278e1f386SAl Viro 59378e1f386SAl Viro if (!sanity(i)) 59478e1f386SAl Viro return 0; 59578e1f386SAl Viro 5966852df12SAl Viro bytes = push_pipe(i, bytes, &i_head, &r); 5976852df12SAl Viro while (bytes) { 5986852df12SAl Viro size_t chunk = min_t(size_t, bytes, PAGE_SIZE - r); 5992495bdccSAl Viro char *p = kmap_local_page(pipe->bufs[i_head & p_mask].page); 6006852df12SAl Viro sum = csum_and_memcpy(p + r, addr + off, chunk, sum, off); 6012495bdccSAl Viro kunmap_local(p); 6028cefc107SDavid Howells i->head = i_head; 60378e1f386SAl Viro i->iov_offset = r + chunk; 6046852df12SAl Viro bytes -= chunk; 60578e1f386SAl Viro off += chunk; 6068cefc107SDavid Howells r = 0; 6078cefc107SDavid Howells i_head++; 6086852df12SAl Viro } 6096852df12SAl Viro *sump = sum; 6106852df12SAl Viro i->count -= off; 6116852df12SAl Viro return off; 61278e1f386SAl Viro } 61378e1f386SAl Viro 614aa28de27SAl Viro size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 615d879cb83SAl Viro { 61600e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 617241699cdSAl Viro return copy_pipe_to_iter(addr, bytes, i); 61809fc68dcSAl Viro if (iter_is_iovec(i)) 61909fc68dcSAl Viro might_fault(); 6207baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 6217baa5099SAl Viro copyout(base, addr + off, len), 6227baa5099SAl Viro memcpy(base, addr + off, 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 size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, 640ca146f6fSDan Williams struct iov_iter *i) 641ca146f6fSDan Williams { 642ca146f6fSDan Williams struct pipe_inode_info *pipe = i->pipe; 6438cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 6448cefc107SDavid Howells unsigned int i_head; 645ca146f6fSDan Williams size_t n, off, xfer = 0; 646ca146f6fSDan Williams 647ca146f6fSDan Williams if (!sanity(i)) 648ca146f6fSDan Williams return 0; 649ca146f6fSDan Williams 6502a510a74SAl Viro n = push_pipe(i, bytes, &i_head, &off); 6512a510a74SAl Viro while (n) { 652ca146f6fSDan Williams size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 6532a510a74SAl Viro char *p = kmap_local_page(pipe->bufs[i_head & p_mask].page); 654ca146f6fSDan Williams unsigned long rem; 6552a510a74SAl Viro rem = copy_mc_to_kernel(p + off, addr + xfer, chunk); 6562a510a74SAl Viro chunk -= rem; 6572a510a74SAl Viro kunmap_local(p); 6588cefc107SDavid Howells i->head = i_head; 6592a510a74SAl Viro i->iov_offset = off + chunk; 6602a510a74SAl Viro xfer += chunk; 661ca146f6fSDan Williams if (rem) 662ca146f6fSDan Williams break; 663ca146f6fSDan Williams n -= chunk; 6648cefc107SDavid Howells off = 0; 6658cefc107SDavid Howells i_head++; 6662a510a74SAl Viro } 667ca146f6fSDan Williams i->count -= xfer; 668ca146f6fSDan Williams return xfer; 669ca146f6fSDan Williams } 670ca146f6fSDan Williams 671bf3eeb9bSDan Williams /** 672ec6347bbSDan Williams * _copy_mc_to_iter - copy to iter with source memory error exception handling 673bf3eeb9bSDan Williams * @addr: source kernel address 674bf3eeb9bSDan Williams * @bytes: total transfer length 67544e55997SRandy Dunlap * @i: destination iterator 676bf3eeb9bSDan Williams * 677ec6347bbSDan Williams * The pmem driver deploys this for the dax operation 678ec6347bbSDan Williams * (dax_copy_to_iter()) for dax reads (bypass page-cache and the 679ec6347bbSDan Williams * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes 680ec6347bbSDan Williams * successfully copied. 681bf3eeb9bSDan Williams * 682ec6347bbSDan Williams * The main differences between this and typical _copy_to_iter(). 683bf3eeb9bSDan Williams * 684bf3eeb9bSDan Williams * * Typical tail/residue handling after a fault retries the copy 685bf3eeb9bSDan Williams * byte-by-byte until the fault happens again. Re-triggering machine 686bf3eeb9bSDan Williams * checks is potentially fatal so the implementation uses source 687bf3eeb9bSDan Williams * alignment and poison alignment assumptions to avoid re-triggering 688bf3eeb9bSDan Williams * hardware exceptions. 689bf3eeb9bSDan Williams * 690bf3eeb9bSDan Williams * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. 691bf3eeb9bSDan Williams * Compare to copy_to_iter() where only ITER_IOVEC attempts might return 692bf3eeb9bSDan Williams * a short copy. 69344e55997SRandy Dunlap * 69444e55997SRandy Dunlap * Return: number of bytes copied (may be %0) 695bf3eeb9bSDan Williams */ 696ec6347bbSDan Williams size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 6978780356eSDan Williams { 69800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 699ec6347bbSDan Williams return copy_mc_pipe_to_iter(addr, bytes, i); 7008780356eSDan Williams if (iter_is_iovec(i)) 7018780356eSDan Williams might_fault(); 7027baa5099SAl Viro __iterate_and_advance(i, bytes, base, len, off, 7037baa5099SAl Viro copyout_mc(base, addr + off, len), 7047baa5099SAl Viro copy_mc_to_kernel(base, addr + off, len) 7058780356eSDan Williams ) 7068780356eSDan Williams 7078780356eSDan Williams return bytes; 7088780356eSDan Williams } 709ec6347bbSDan Williams EXPORT_SYMBOL_GPL(_copy_mc_to_iter); 710ec6347bbSDan Williams #endif /* CONFIG_ARCH_HAS_COPY_MC */ 7118780356eSDan Williams 712aa28de27SAl Viro size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) 713d879cb83SAl Viro { 71400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 715241699cdSAl Viro WARN_ON(1); 716241699cdSAl Viro return 0; 717241699cdSAl Viro } 71809fc68dcSAl Viro if (iter_is_iovec(i)) 71909fc68dcSAl Viro might_fault(); 7207baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 7217baa5099SAl Viro copyin(addr + off, base, len), 7227baa5099SAl Viro memcpy(addr + off, base, len) 723d879cb83SAl Viro ) 724d879cb83SAl Viro 725d879cb83SAl Viro return bytes; 726d879cb83SAl Viro } 727aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter); 728d879cb83SAl Viro 729aa28de27SAl Viro size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) 730d879cb83SAl Viro { 73100e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 732241699cdSAl Viro WARN_ON(1); 733241699cdSAl Viro return 0; 734241699cdSAl Viro } 7357baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 7367baa5099SAl Viro __copy_from_user_inatomic_nocache(addr + off, base, len), 7377baa5099SAl Viro memcpy(addr + off, base, len) 738d879cb83SAl Viro ) 739d879cb83SAl Viro 740d879cb83SAl Viro return bytes; 741d879cb83SAl Viro } 742aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_nocache); 743d879cb83SAl Viro 7440aed55afSDan Williams #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE 745abd08d7dSDan Williams /** 746abd08d7dSDan Williams * _copy_from_iter_flushcache - write destination through cpu cache 747abd08d7dSDan Williams * @addr: destination kernel address 748abd08d7dSDan Williams * @bytes: total transfer length 74944e55997SRandy Dunlap * @i: source iterator 750abd08d7dSDan Williams * 751abd08d7dSDan Williams * The pmem driver arranges for filesystem-dax to use this facility via 752abd08d7dSDan Williams * dax_copy_from_iter() for ensuring that writes to persistent memory 753abd08d7dSDan Williams * are flushed through the CPU cache. It is differentiated from 754abd08d7dSDan Williams * _copy_from_iter_nocache() in that guarantees all data is flushed for 755abd08d7dSDan Williams * all iterator types. The _copy_from_iter_nocache() only attempts to 756abd08d7dSDan Williams * bypass the cache for the ITER_IOVEC case, and on some archs may use 757abd08d7dSDan Williams * instructions that strand dirty-data in the cache. 75844e55997SRandy Dunlap * 75944e55997SRandy Dunlap * Return: number of bytes copied (may be %0) 760abd08d7dSDan Williams */ 7616a37e940SLinus Torvalds size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 7620aed55afSDan Williams { 76300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 7640aed55afSDan Williams WARN_ON(1); 7650aed55afSDan Williams return 0; 7660aed55afSDan Williams } 7677baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 7687baa5099SAl Viro __copy_from_user_flushcache(addr + off, base, len), 7697baa5099SAl Viro memcpy_flushcache(addr + off, base, len) 7700aed55afSDan Williams ) 7710aed55afSDan Williams 7720aed55afSDan Williams return bytes; 7730aed55afSDan Williams } 7746a37e940SLinus Torvalds EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); 7750aed55afSDan Williams #endif 7760aed55afSDan Williams 77772e809edSAl Viro static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) 77872e809edSAl Viro { 7796daef95bSEric Dumazet struct page *head; 7806daef95bSEric Dumazet size_t v = n + offset; 7816daef95bSEric Dumazet 7826daef95bSEric Dumazet /* 7836daef95bSEric Dumazet * The general case needs to access the page order in order 7846daef95bSEric Dumazet * to compute the page size. 7856daef95bSEric Dumazet * However, we mostly deal with order-0 pages and thus can 7866daef95bSEric Dumazet * avoid a possible cache line miss for requests that fit all 7876daef95bSEric Dumazet * page orders. 7886daef95bSEric Dumazet */ 7896daef95bSEric Dumazet if (n <= v && v <= PAGE_SIZE) 7906daef95bSEric Dumazet return true; 7916daef95bSEric Dumazet 7926daef95bSEric Dumazet head = compound_head(page); 7936daef95bSEric Dumazet v += (page - head) << PAGE_SHIFT; 794a90bcb86SPetar Penkov 795a50b854eSMatthew Wilcox (Oracle) if (likely(n <= v && v <= (page_size(head)))) 79672e809edSAl Viro return true; 79772e809edSAl Viro WARN_ON(1); 79872e809edSAl Viro return false; 79972e809edSAl Viro } 800cbbd26b8SAl Viro 80108aa6479SAl Viro static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 802d879cb83SAl Viro struct iov_iter *i) 803d879cb83SAl Viro { 80428f38db7SAl Viro if (likely(iter_is_iovec(i))) 80528f38db7SAl Viro return copy_page_to_iter_iovec(page, offset, bytes, i); 80628f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 807c1d4d6a9SAl Viro void *kaddr = kmap_local_page(page); 808c1d4d6a9SAl Viro size_t wanted = _copy_to_iter(kaddr + offset, bytes, i); 809c1d4d6a9SAl Viro kunmap_local(kaddr); 810d879cb83SAl Viro return wanted; 81128f38db7SAl Viro } 81228f38db7SAl Viro if (iov_iter_is_pipe(i)) 81328f38db7SAl Viro return copy_page_to_iter_pipe(page, offset, bytes, i); 81428f38db7SAl Viro if (unlikely(iov_iter_is_discard(i))) { 815a506abc7SAl Viro if (unlikely(i->count < bytes)) 816a506abc7SAl Viro bytes = i->count; 817a506abc7SAl Viro i->count -= bytes; 8189ea9ce04SDavid Howells return bytes; 81928f38db7SAl Viro } 82028f38db7SAl Viro WARN_ON(1); 82128f38db7SAl Viro return 0; 822d879cb83SAl Viro } 82308aa6479SAl Viro 82408aa6479SAl Viro size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 82508aa6479SAl Viro struct iov_iter *i) 82608aa6479SAl Viro { 82708aa6479SAl Viro size_t res = 0; 82808aa6479SAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 82908aa6479SAl Viro return 0; 83008aa6479SAl Viro page += offset / PAGE_SIZE; // first subpage 83108aa6479SAl Viro offset %= PAGE_SIZE; 83208aa6479SAl Viro while (1) { 83308aa6479SAl Viro size_t n = __copy_page_to_iter(page, offset, 83408aa6479SAl Viro min(bytes, (size_t)PAGE_SIZE - offset), i); 83508aa6479SAl Viro res += n; 83608aa6479SAl Viro bytes -= n; 83708aa6479SAl Viro if (!bytes || !n) 83808aa6479SAl Viro break; 83908aa6479SAl Viro offset += n; 84008aa6479SAl Viro if (offset == PAGE_SIZE) { 84108aa6479SAl Viro page++; 84208aa6479SAl Viro offset = 0; 84308aa6479SAl Viro } 84408aa6479SAl Viro } 84508aa6479SAl Viro return res; 84608aa6479SAl Viro } 847d879cb83SAl Viro EXPORT_SYMBOL(copy_page_to_iter); 848d879cb83SAl Viro 849d879cb83SAl Viro size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, 850d879cb83SAl Viro struct iov_iter *i) 851d879cb83SAl Viro { 85272e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 85372e809edSAl Viro return 0; 85428f38db7SAl Viro if (likely(iter_is_iovec(i))) 85528f38db7SAl Viro return copy_page_from_iter_iovec(page, offset, bytes, i); 85628f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 85755ca375cSAl Viro void *kaddr = kmap_local_page(page); 858aa28de27SAl Viro size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); 85955ca375cSAl Viro kunmap_local(kaddr); 860d879cb83SAl Viro return wanted; 86128f38db7SAl Viro } 86228f38db7SAl Viro WARN_ON(1); 86328f38db7SAl Viro return 0; 864d879cb83SAl Viro } 865d879cb83SAl Viro EXPORT_SYMBOL(copy_page_from_iter); 866d879cb83SAl Viro 867241699cdSAl Viro static size_t pipe_zero(size_t bytes, struct iov_iter *i) 868241699cdSAl Viro { 869241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 8708cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 8718cefc107SDavid Howells unsigned int i_head; 872241699cdSAl Viro size_t n, off; 873241699cdSAl Viro 874241699cdSAl Viro if (!sanity(i)) 875241699cdSAl Viro return 0; 876241699cdSAl Viro 8778cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 878241699cdSAl Viro if (unlikely(!n)) 879241699cdSAl Viro return 0; 880241699cdSAl Viro 8818cefc107SDavid Howells do { 882241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 883893839fdSAl Viro char *p = kmap_local_page(pipe->bufs[i_head & p_mask].page); 884893839fdSAl Viro memset(p + off, 0, chunk); 885893839fdSAl Viro kunmap_local(p); 8868cefc107SDavid Howells i->head = i_head; 887241699cdSAl Viro i->iov_offset = off + chunk; 888241699cdSAl Viro n -= chunk; 8898cefc107SDavid Howells off = 0; 8908cefc107SDavid Howells i_head++; 8918cefc107SDavid Howells } while (n); 892241699cdSAl Viro i->count -= bytes; 893241699cdSAl Viro return bytes; 894241699cdSAl Viro } 895241699cdSAl Viro 896d879cb83SAl Viro size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 897d879cb83SAl Viro { 89800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 899241699cdSAl Viro return pipe_zero(bytes, i); 9007baa5099SAl Viro iterate_and_advance(i, bytes, base, len, count, 9017baa5099SAl Viro clear_user(base, len), 9027baa5099SAl Viro memset(base, 0, len) 903d879cb83SAl Viro ) 904d879cb83SAl Viro 905d879cb83SAl Viro return bytes; 906d879cb83SAl Viro } 907d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_zero); 908d879cb83SAl Viro 909f0b65f39SAl Viro size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, 910f0b65f39SAl Viro struct iov_iter *i) 911d879cb83SAl Viro { 912d879cb83SAl Viro char *kaddr = kmap_atomic(page), *p = kaddr + offset; 91372e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) { 91472e809edSAl Viro kunmap_atomic(kaddr); 91572e809edSAl Viro return 0; 91672e809edSAl Viro } 9179ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 918241699cdSAl Viro kunmap_atomic(kaddr); 919241699cdSAl Viro WARN_ON(1); 920241699cdSAl Viro return 0; 921241699cdSAl Viro } 9227baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 9237baa5099SAl Viro copyin(p + off, base, len), 9247baa5099SAl Viro memcpy(p + off, base, len) 925d879cb83SAl Viro ) 926d879cb83SAl Viro kunmap_atomic(kaddr); 927d879cb83SAl Viro return bytes; 928d879cb83SAl Viro } 929f0b65f39SAl Viro EXPORT_SYMBOL(copy_page_from_iter_atomic); 930d879cb83SAl Viro 931b9dc6f65SAl Viro static inline void pipe_truncate(struct iov_iter *i) 932241699cdSAl Viro { 933241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 9348cefc107SDavid Howells unsigned int p_tail = pipe->tail; 9358cefc107SDavid Howells unsigned int p_head = pipe->head; 9368cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9378cefc107SDavid Howells 9388cefc107SDavid Howells if (!pipe_empty(p_head, p_tail)) { 9398cefc107SDavid Howells struct pipe_buffer *buf; 9408cefc107SDavid Howells unsigned int i_head = i->head; 941b9dc6f65SAl Viro size_t off = i->iov_offset; 9428cefc107SDavid Howells 943b9dc6f65SAl Viro if (off) { 9448cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 9458cefc107SDavid Howells buf->len = off - buf->offset; 9468cefc107SDavid Howells i_head++; 947b9dc6f65SAl Viro } 9488cefc107SDavid Howells while (p_head != i_head) { 9498cefc107SDavid Howells p_head--; 9508cefc107SDavid Howells pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); 951241699cdSAl Viro } 9528cefc107SDavid Howells 9538cefc107SDavid Howells pipe->head = p_head; 954241699cdSAl Viro } 955b9dc6f65SAl Viro } 956b9dc6f65SAl Viro 957b9dc6f65SAl Viro static void pipe_advance(struct iov_iter *i, size_t size) 958b9dc6f65SAl Viro { 959b9dc6f65SAl Viro struct pipe_inode_info *pipe = i->pipe; 960b9dc6f65SAl Viro if (size) { 961b9dc6f65SAl Viro struct pipe_buffer *buf; 9628cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9638cefc107SDavid Howells unsigned int i_head = i->head; 964b9dc6f65SAl Viro size_t off = i->iov_offset, left = size; 9658cefc107SDavid Howells 966b9dc6f65SAl Viro if (off) /* make it relative to the beginning of buffer */ 9678cefc107SDavid Howells left += off - pipe->bufs[i_head & p_mask].offset; 968b9dc6f65SAl Viro while (1) { 9698cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 970b9dc6f65SAl Viro if (left <= buf->len) 971b9dc6f65SAl Viro break; 972b9dc6f65SAl Viro left -= buf->len; 9738cefc107SDavid Howells i_head++; 974b9dc6f65SAl Viro } 9758cefc107SDavid Howells i->head = i_head; 976b9dc6f65SAl Viro i->iov_offset = buf->offset + left; 977b9dc6f65SAl Viro } 978b9dc6f65SAl Viro i->count -= size; 979b9dc6f65SAl Viro /* ... and discard everything past that point */ 980b9dc6f65SAl Viro pipe_truncate(i); 981241699cdSAl Viro } 982241699cdSAl Viro 98354c8195bSPavel Begunkov static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) 98454c8195bSPavel Begunkov { 98554c8195bSPavel Begunkov struct bvec_iter bi; 98654c8195bSPavel Begunkov 98754c8195bSPavel Begunkov bi.bi_size = i->count; 98854c8195bSPavel Begunkov bi.bi_bvec_done = i->iov_offset; 98954c8195bSPavel Begunkov bi.bi_idx = 0; 99054c8195bSPavel Begunkov bvec_iter_advance(i->bvec, &bi, size); 99154c8195bSPavel Begunkov 99254c8195bSPavel Begunkov i->bvec += bi.bi_idx; 99354c8195bSPavel Begunkov i->nr_segs -= bi.bi_idx; 99454c8195bSPavel Begunkov i->count = bi.bi_size; 99554c8195bSPavel Begunkov i->iov_offset = bi.bi_bvec_done; 99654c8195bSPavel Begunkov } 99754c8195bSPavel Begunkov 998185ac4d4SAl Viro static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) 999185ac4d4SAl Viro { 1000185ac4d4SAl Viro const struct iovec *iov, *end; 1001185ac4d4SAl Viro 1002185ac4d4SAl Viro if (!i->count) 1003185ac4d4SAl Viro return; 1004185ac4d4SAl Viro i->count -= size; 1005185ac4d4SAl Viro 1006185ac4d4SAl Viro size += i->iov_offset; // from beginning of current segment 1007185ac4d4SAl Viro for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { 1008185ac4d4SAl Viro if (likely(size < iov->iov_len)) 1009185ac4d4SAl Viro break; 1010185ac4d4SAl Viro size -= iov->iov_len; 1011185ac4d4SAl Viro } 1012185ac4d4SAl Viro i->iov_offset = size; 1013185ac4d4SAl Viro i->nr_segs -= iov - i->iov; 1014185ac4d4SAl Viro i->iov = iov; 1015185ac4d4SAl Viro } 1016185ac4d4SAl Viro 1017d879cb83SAl Viro void iov_iter_advance(struct iov_iter *i, size_t size) 1018d879cb83SAl Viro { 10193b3fc051SAl Viro if (unlikely(i->count < size)) 10203b3fc051SAl Viro size = i->count; 1021185ac4d4SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { 1022185ac4d4SAl Viro /* iovec and kvec have identical layouts */ 1023185ac4d4SAl Viro iov_iter_iovec_advance(i, size); 1024185ac4d4SAl Viro } else if (iov_iter_is_bvec(i)) { 1025185ac4d4SAl Viro iov_iter_bvec_advance(i, size); 1026185ac4d4SAl Viro } else if (iov_iter_is_pipe(i)) { 1027241699cdSAl Viro pipe_advance(i, size); 1028185ac4d4SAl Viro } else if (unlikely(iov_iter_is_xarray(i))) { 10297ff50620SDavid Howells i->iov_offset += size; 10307ff50620SDavid Howells i->count -= size; 1031185ac4d4SAl Viro } else if (iov_iter_is_discard(i)) { 1032185ac4d4SAl Viro i->count -= size; 10337ff50620SDavid Howells } 1034d879cb83SAl Viro } 1035d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_advance); 1036d879cb83SAl Viro 103727c0e374SAl Viro void iov_iter_revert(struct iov_iter *i, size_t unroll) 103827c0e374SAl Viro { 103927c0e374SAl Viro if (!unroll) 104027c0e374SAl Viro return; 10415b47d59aSAl Viro if (WARN_ON(unroll > MAX_RW_COUNT)) 10425b47d59aSAl Viro return; 104327c0e374SAl Viro i->count += unroll; 104400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 104527c0e374SAl Viro struct pipe_inode_info *pipe = i->pipe; 10468cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10478cefc107SDavid Howells unsigned int i_head = i->head; 104827c0e374SAl Viro size_t off = i->iov_offset; 104927c0e374SAl Viro while (1) { 10508cefc107SDavid Howells struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; 10518cefc107SDavid Howells size_t n = off - b->offset; 105227c0e374SAl Viro if (unroll < n) { 10534fa55cefSAl Viro off -= unroll; 105427c0e374SAl Viro break; 105527c0e374SAl Viro } 105627c0e374SAl Viro unroll -= n; 10578cefc107SDavid Howells if (!unroll && i_head == i->start_head) { 105827c0e374SAl Viro off = 0; 105927c0e374SAl Viro break; 106027c0e374SAl Viro } 10618cefc107SDavid Howells i_head--; 10628cefc107SDavid Howells b = &pipe->bufs[i_head & p_mask]; 10638cefc107SDavid Howells off = b->offset + b->len; 106427c0e374SAl Viro } 106527c0e374SAl Viro i->iov_offset = off; 10668cefc107SDavid Howells i->head = i_head; 106727c0e374SAl Viro pipe_truncate(i); 106827c0e374SAl Viro return; 106927c0e374SAl Viro } 10709ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 10719ea9ce04SDavid Howells return; 107227c0e374SAl Viro if (unroll <= i->iov_offset) { 107327c0e374SAl Viro i->iov_offset -= unroll; 107427c0e374SAl Viro return; 107527c0e374SAl Viro } 107627c0e374SAl Viro unroll -= i->iov_offset; 10777ff50620SDavid Howells if (iov_iter_is_xarray(i)) { 10787ff50620SDavid Howells BUG(); /* We should never go beyond the start of the specified 10797ff50620SDavid Howells * range since we might then be straying into pages that 10807ff50620SDavid Howells * aren't pinned. 10817ff50620SDavid Howells */ 10827ff50620SDavid Howells } else if (iov_iter_is_bvec(i)) { 108327c0e374SAl Viro const struct bio_vec *bvec = i->bvec; 108427c0e374SAl Viro while (1) { 108527c0e374SAl Viro size_t n = (--bvec)->bv_len; 108627c0e374SAl Viro i->nr_segs++; 108727c0e374SAl Viro if (unroll <= n) { 108827c0e374SAl Viro i->bvec = bvec; 108927c0e374SAl Viro i->iov_offset = n - unroll; 109027c0e374SAl Viro return; 109127c0e374SAl Viro } 109227c0e374SAl Viro unroll -= n; 109327c0e374SAl Viro } 109427c0e374SAl Viro } else { /* same logics for iovec and kvec */ 109527c0e374SAl Viro const struct iovec *iov = i->iov; 109627c0e374SAl Viro while (1) { 109727c0e374SAl Viro size_t n = (--iov)->iov_len; 109827c0e374SAl Viro i->nr_segs++; 109927c0e374SAl Viro if (unroll <= n) { 110027c0e374SAl Viro i->iov = iov; 110127c0e374SAl Viro i->iov_offset = n - unroll; 110227c0e374SAl Viro return; 110327c0e374SAl Viro } 110427c0e374SAl Viro unroll -= n; 110527c0e374SAl Viro } 110627c0e374SAl Viro } 110727c0e374SAl Viro } 110827c0e374SAl Viro EXPORT_SYMBOL(iov_iter_revert); 110927c0e374SAl Viro 1110d879cb83SAl Viro /* 1111d879cb83SAl Viro * Return the count of just the current iov_iter segment. 1112d879cb83SAl Viro */ 1113d879cb83SAl Viro size_t iov_iter_single_seg_count(const struct iov_iter *i) 1114d879cb83SAl Viro { 111528f38db7SAl Viro if (i->nr_segs > 1) { 111628f38db7SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 111728f38db7SAl Viro return min(i->count, i->iov->iov_len - i->iov_offset); 11187ff50620SDavid Howells if (iov_iter_is_bvec(i)) 1119d879cb83SAl Viro return min(i->count, i->bvec->bv_len - i->iov_offset); 112028f38db7SAl Viro } 112128f38db7SAl Viro return i->count; 1122d879cb83SAl Viro } 1123d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_single_seg_count); 1124d879cb83SAl Viro 1125aa563d7bSDavid Howells void iov_iter_kvec(struct iov_iter *i, unsigned int direction, 1126d879cb83SAl Viro const struct kvec *kvec, unsigned long nr_segs, 1127d879cb83SAl Viro size_t count) 1128d879cb83SAl Viro { 1129aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 11308cd54c1cSAl Viro *i = (struct iov_iter){ 11318cd54c1cSAl Viro .iter_type = ITER_KVEC, 11328cd54c1cSAl Viro .data_source = direction, 11338cd54c1cSAl Viro .kvec = kvec, 11348cd54c1cSAl Viro .nr_segs = nr_segs, 11358cd54c1cSAl Viro .iov_offset = 0, 11368cd54c1cSAl Viro .count = count 11378cd54c1cSAl Viro }; 1138d879cb83SAl Viro } 1139d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_kvec); 1140d879cb83SAl Viro 1141aa563d7bSDavid Howells void iov_iter_bvec(struct iov_iter *i, unsigned int direction, 1142d879cb83SAl Viro const struct bio_vec *bvec, unsigned long nr_segs, 1143d879cb83SAl Viro size_t count) 1144d879cb83SAl Viro { 1145aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 11468cd54c1cSAl Viro *i = (struct iov_iter){ 11478cd54c1cSAl Viro .iter_type = ITER_BVEC, 11488cd54c1cSAl Viro .data_source = direction, 11498cd54c1cSAl Viro .bvec = bvec, 11508cd54c1cSAl Viro .nr_segs = nr_segs, 11518cd54c1cSAl Viro .iov_offset = 0, 11528cd54c1cSAl Viro .count = count 11538cd54c1cSAl Viro }; 1154d879cb83SAl Viro } 1155d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_bvec); 1156d879cb83SAl Viro 1157aa563d7bSDavid Howells void iov_iter_pipe(struct iov_iter *i, unsigned int direction, 1158241699cdSAl Viro struct pipe_inode_info *pipe, 1159241699cdSAl Viro size_t count) 1160241699cdSAl Viro { 1161aa563d7bSDavid Howells BUG_ON(direction != READ); 11628cefc107SDavid Howells WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); 11638cd54c1cSAl Viro *i = (struct iov_iter){ 11648cd54c1cSAl Viro .iter_type = ITER_PIPE, 11658cd54c1cSAl Viro .data_source = false, 11668cd54c1cSAl Viro .pipe = pipe, 11678cd54c1cSAl Viro .head = pipe->head, 11688cd54c1cSAl Viro .start_head = pipe->head, 11698cd54c1cSAl Viro .iov_offset = 0, 11708cd54c1cSAl Viro .count = count 11718cd54c1cSAl Viro }; 1172241699cdSAl Viro } 1173241699cdSAl Viro EXPORT_SYMBOL(iov_iter_pipe); 1174241699cdSAl Viro 11759ea9ce04SDavid Howells /** 11767ff50620SDavid Howells * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray 11777ff50620SDavid Howells * @i: The iterator to initialise. 11787ff50620SDavid Howells * @direction: The direction of the transfer. 11797ff50620SDavid Howells * @xarray: The xarray to access. 11807ff50620SDavid Howells * @start: The start file position. 11817ff50620SDavid Howells * @count: The size of the I/O buffer in bytes. 11827ff50620SDavid Howells * 11837ff50620SDavid Howells * Set up an I/O iterator to either draw data out of the pages attached to an 11847ff50620SDavid Howells * inode or to inject data into those pages. The pages *must* be prevented 11857ff50620SDavid Howells * from evaporation, either by taking a ref on them or locking them by the 11867ff50620SDavid Howells * caller. 11877ff50620SDavid Howells */ 11887ff50620SDavid Howells void iov_iter_xarray(struct iov_iter *i, unsigned int direction, 11897ff50620SDavid Howells struct xarray *xarray, loff_t start, size_t count) 11907ff50620SDavid Howells { 11917ff50620SDavid Howells BUG_ON(direction & ~1); 11928cd54c1cSAl Viro *i = (struct iov_iter) { 11938cd54c1cSAl Viro .iter_type = ITER_XARRAY, 11948cd54c1cSAl Viro .data_source = direction, 11958cd54c1cSAl Viro .xarray = xarray, 11968cd54c1cSAl Viro .xarray_start = start, 11978cd54c1cSAl Viro .count = count, 11988cd54c1cSAl Viro .iov_offset = 0 11998cd54c1cSAl Viro }; 12007ff50620SDavid Howells } 12017ff50620SDavid Howells EXPORT_SYMBOL(iov_iter_xarray); 12027ff50620SDavid Howells 12037ff50620SDavid Howells /** 12049ea9ce04SDavid Howells * iov_iter_discard - Initialise an I/O iterator that discards data 12059ea9ce04SDavid Howells * @i: The iterator to initialise. 12069ea9ce04SDavid Howells * @direction: The direction of the transfer. 12079ea9ce04SDavid Howells * @count: The size of the I/O buffer in bytes. 12089ea9ce04SDavid Howells * 12099ea9ce04SDavid Howells * Set up an I/O iterator that just discards everything that's written to it. 12109ea9ce04SDavid Howells * It's only available as a READ iterator. 12119ea9ce04SDavid Howells */ 12129ea9ce04SDavid Howells void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) 12139ea9ce04SDavid Howells { 12149ea9ce04SDavid Howells BUG_ON(direction != READ); 12158cd54c1cSAl Viro *i = (struct iov_iter){ 12168cd54c1cSAl Viro .iter_type = ITER_DISCARD, 12178cd54c1cSAl Viro .data_source = false, 12188cd54c1cSAl Viro .count = count, 12198cd54c1cSAl Viro .iov_offset = 0 12208cd54c1cSAl Viro }; 12219ea9ce04SDavid Howells } 12229ea9ce04SDavid Howells EXPORT_SYMBOL(iov_iter_discard); 12239ea9ce04SDavid Howells 12249221d2e3SAl Viro static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) 1225d879cb83SAl Viro { 1226d879cb83SAl Viro unsigned long res = 0; 1227d879cb83SAl Viro size_t size = i->count; 12289221d2e3SAl Viro size_t skip = i->iov_offset; 12299221d2e3SAl Viro unsigned k; 1230d879cb83SAl Viro 12319221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 12329221d2e3SAl Viro size_t len = i->iov[k].iov_len - skip; 12339221d2e3SAl Viro if (len) { 12349221d2e3SAl Viro res |= (unsigned long)i->iov[k].iov_base + skip; 12359221d2e3SAl Viro if (len > size) 12369221d2e3SAl Viro len = size; 12379221d2e3SAl Viro res |= len; 12389221d2e3SAl Viro size -= len; 12399221d2e3SAl Viro if (!size) 12409221d2e3SAl Viro break; 12419221d2e3SAl Viro } 12429221d2e3SAl Viro } 12439221d2e3SAl Viro return res; 12449221d2e3SAl Viro } 12459221d2e3SAl Viro 12469221d2e3SAl Viro static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) 12479221d2e3SAl Viro { 12489221d2e3SAl Viro unsigned res = 0; 12499221d2e3SAl Viro size_t size = i->count; 12509221d2e3SAl Viro unsigned skip = i->iov_offset; 12519221d2e3SAl Viro unsigned k; 12529221d2e3SAl Viro 12539221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 12549221d2e3SAl Viro size_t len = i->bvec[k].bv_len - skip; 12559221d2e3SAl Viro res |= (unsigned long)i->bvec[k].bv_offset + skip; 12569221d2e3SAl Viro if (len > size) 12579221d2e3SAl Viro len = size; 12589221d2e3SAl Viro res |= len; 12599221d2e3SAl Viro size -= len; 12609221d2e3SAl Viro if (!size) 12619221d2e3SAl Viro break; 12629221d2e3SAl Viro } 12639221d2e3SAl Viro return res; 12649221d2e3SAl Viro } 12659221d2e3SAl Viro 12669221d2e3SAl Viro unsigned long iov_iter_alignment(const struct iov_iter *i) 12679221d2e3SAl Viro { 12689221d2e3SAl Viro /* iovec and kvec have identical layouts */ 12699221d2e3SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 12709221d2e3SAl Viro return iov_iter_alignment_iovec(i); 12719221d2e3SAl Viro 12729221d2e3SAl Viro if (iov_iter_is_bvec(i)) 12739221d2e3SAl Viro return iov_iter_alignment_bvec(i); 12749221d2e3SAl Viro 12759221d2e3SAl Viro if (iov_iter_is_pipe(i)) { 1276e0ff126eSJan Kara unsigned int p_mask = i->pipe->ring_size - 1; 12779221d2e3SAl Viro size_t size = i->count; 1278e0ff126eSJan Kara 12798cefc107SDavid Howells if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) 1280241699cdSAl Viro return size | i->iov_offset; 1281241699cdSAl Viro return size; 1282241699cdSAl Viro } 12839221d2e3SAl Viro 12849221d2e3SAl Viro if (iov_iter_is_xarray(i)) 12853d14ec1fSDavid Howells return (i->xarray_start + i->iov_offset) | i->count; 12869221d2e3SAl Viro 12879221d2e3SAl Viro return 0; 1288d879cb83SAl Viro } 1289d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_alignment); 1290d879cb83SAl Viro 1291357f435dSAl Viro unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 1292357f435dSAl Viro { 1293357f435dSAl Viro unsigned long res = 0; 1294610c7a71SAl Viro unsigned long v = 0; 1295357f435dSAl Viro size_t size = i->count; 1296610c7a71SAl Viro unsigned k; 1297357f435dSAl Viro 1298610c7a71SAl Viro if (WARN_ON(!iter_is_iovec(i))) 1299241699cdSAl Viro return ~0U; 1300241699cdSAl Viro 1301610c7a71SAl Viro for (k = 0; k < i->nr_segs; k++) { 1302610c7a71SAl Viro if (i->iov[k].iov_len) { 1303610c7a71SAl Viro unsigned long base = (unsigned long)i->iov[k].iov_base; 1304610c7a71SAl Viro if (v) // if not the first one 1305610c7a71SAl Viro res |= base | v; // this start | previous end 1306610c7a71SAl Viro v = base + i->iov[k].iov_len; 1307610c7a71SAl Viro if (size <= i->iov[k].iov_len) 1308610c7a71SAl Viro break; 1309610c7a71SAl Viro size -= i->iov[k].iov_len; 1310610c7a71SAl Viro } 1311610c7a71SAl Viro } 1312357f435dSAl Viro return res; 1313357f435dSAl Viro } 1314357f435dSAl Viro EXPORT_SYMBOL(iov_iter_gap_alignment); 1315357f435dSAl Viro 1316e76b6312SIlya Dryomov static inline ssize_t __pipe_get_pages(struct iov_iter *i, 1317241699cdSAl Viro size_t maxsize, 1318241699cdSAl Viro struct page **pages, 13198cefc107SDavid Howells int iter_head, 1320241699cdSAl Viro size_t *start) 1321241699cdSAl Viro { 1322241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 13238cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 13248cefc107SDavid Howells ssize_t n = push_pipe(i, maxsize, &iter_head, start); 1325241699cdSAl Viro if (!n) 1326241699cdSAl Viro return -EFAULT; 1327241699cdSAl Viro 1328241699cdSAl Viro maxsize = n; 1329241699cdSAl Viro n += *start; 13301689c73aSAl Viro while (n > 0) { 13318cefc107SDavid Howells get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); 13328cefc107SDavid Howells iter_head++; 1333241699cdSAl Viro n -= PAGE_SIZE; 1334241699cdSAl Viro } 1335241699cdSAl Viro 1336241699cdSAl Viro return maxsize; 1337241699cdSAl Viro } 1338241699cdSAl Viro 1339241699cdSAl Viro static ssize_t pipe_get_pages(struct iov_iter *i, 1340241699cdSAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1341241699cdSAl Viro size_t *start) 1342241699cdSAl Viro { 13438cefc107SDavid Howells unsigned int iter_head, npages; 1344241699cdSAl Viro size_t capacity; 1345241699cdSAl Viro 1346241699cdSAl Viro if (!sanity(i)) 1347241699cdSAl Viro return -EFAULT; 1348241699cdSAl Viro 13498cefc107SDavid Howells data_start(i, &iter_head, start); 13508cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 13518cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1352241699cdSAl Viro capacity = min(npages, maxpages) * PAGE_SIZE - *start; 1353241699cdSAl Viro 13548cefc107SDavid Howells return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); 1355241699cdSAl Viro } 1356241699cdSAl Viro 13577ff50620SDavid Howells static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, 13587ff50620SDavid Howells pgoff_t index, unsigned int nr_pages) 13597ff50620SDavid Howells { 13607ff50620SDavid Howells XA_STATE(xas, xa, index); 13617ff50620SDavid Howells struct page *page; 13627ff50620SDavid Howells unsigned int ret = 0; 13637ff50620SDavid Howells 13647ff50620SDavid Howells rcu_read_lock(); 13657ff50620SDavid Howells for (page = xas_load(&xas); page; page = xas_next(&xas)) { 13667ff50620SDavid Howells if (xas_retry(&xas, page)) 13677ff50620SDavid Howells continue; 13687ff50620SDavid Howells 13697ff50620SDavid Howells /* Has the page moved or been split? */ 13707ff50620SDavid Howells if (unlikely(page != xas_reload(&xas))) { 13717ff50620SDavid Howells xas_reset(&xas); 13727ff50620SDavid Howells continue; 13737ff50620SDavid Howells } 13747ff50620SDavid Howells 13757ff50620SDavid Howells pages[ret] = find_subpage(page, xas.xa_index); 13767ff50620SDavid Howells get_page(pages[ret]); 13777ff50620SDavid Howells if (++ret == nr_pages) 13787ff50620SDavid Howells break; 13797ff50620SDavid Howells } 13807ff50620SDavid Howells rcu_read_unlock(); 13817ff50620SDavid Howells return ret; 13827ff50620SDavid Howells } 13837ff50620SDavid Howells 13847ff50620SDavid Howells static ssize_t iter_xarray_get_pages(struct iov_iter *i, 13857ff50620SDavid Howells struct page **pages, size_t maxsize, 13867ff50620SDavid Howells unsigned maxpages, size_t *_start_offset) 13877ff50620SDavid Howells { 13887ff50620SDavid Howells unsigned nr, offset; 13897ff50620SDavid Howells pgoff_t index, count; 13907ff50620SDavid Howells size_t size = maxsize, actual; 13917ff50620SDavid Howells loff_t pos; 13927ff50620SDavid Howells 13937ff50620SDavid Howells if (!size || !maxpages) 13947ff50620SDavid Howells return 0; 13957ff50620SDavid Howells 13967ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 13977ff50620SDavid Howells index = pos >> PAGE_SHIFT; 13987ff50620SDavid Howells offset = pos & ~PAGE_MASK; 13997ff50620SDavid Howells *_start_offset = offset; 14007ff50620SDavid Howells 14017ff50620SDavid Howells count = 1; 14027ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 14037ff50620SDavid Howells size -= PAGE_SIZE - offset; 14047ff50620SDavid Howells count += size >> PAGE_SHIFT; 14057ff50620SDavid Howells size &= ~PAGE_MASK; 14067ff50620SDavid Howells if (size) 14077ff50620SDavid Howells count++; 14087ff50620SDavid Howells } 14097ff50620SDavid Howells 14107ff50620SDavid Howells if (count > maxpages) 14117ff50620SDavid Howells count = maxpages; 14127ff50620SDavid Howells 14137ff50620SDavid Howells nr = iter_xarray_populate_pages(pages, i->xarray, index, count); 14147ff50620SDavid Howells if (nr == 0) 14157ff50620SDavid Howells return 0; 14167ff50620SDavid Howells 14177ff50620SDavid Howells actual = PAGE_SIZE * nr; 14187ff50620SDavid Howells actual -= offset; 14197ff50620SDavid Howells if (nr == count && size > 0) { 14207ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 14217ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 14227ff50620SDavid Howells } 14237ff50620SDavid Howells return actual; 14247ff50620SDavid Howells } 14257ff50620SDavid Howells 14263d671ca6SAl Viro /* must be done on non-empty ITER_IOVEC one */ 14273d671ca6SAl Viro static unsigned long first_iovec_segment(const struct iov_iter *i, 14283d671ca6SAl Viro size_t *size, size_t *start, 14293d671ca6SAl Viro size_t maxsize, unsigned maxpages) 14303d671ca6SAl Viro { 14313d671ca6SAl Viro size_t skip; 14323d671ca6SAl Viro long k; 14333d671ca6SAl Viro 14343d671ca6SAl Viro for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { 14353d671ca6SAl Viro unsigned long addr = (unsigned long)i->iov[k].iov_base + skip; 14363d671ca6SAl Viro size_t len = i->iov[k].iov_len - skip; 14373d671ca6SAl Viro 14383d671ca6SAl Viro if (unlikely(!len)) 14393d671ca6SAl Viro continue; 14403d671ca6SAl Viro if (len > maxsize) 14413d671ca6SAl Viro len = maxsize; 14423d671ca6SAl Viro len += (*start = addr % PAGE_SIZE); 14433d671ca6SAl Viro if (len > maxpages * PAGE_SIZE) 14443d671ca6SAl Viro len = maxpages * PAGE_SIZE; 14453d671ca6SAl Viro *size = len; 14463d671ca6SAl Viro return addr & PAGE_MASK; 14473d671ca6SAl Viro } 14483d671ca6SAl Viro BUG(); // if it had been empty, we wouldn't get called 14493d671ca6SAl Viro } 14503d671ca6SAl Viro 14513d671ca6SAl Viro /* must be done on non-empty ITER_BVEC one */ 14523d671ca6SAl Viro static struct page *first_bvec_segment(const struct iov_iter *i, 14533d671ca6SAl Viro size_t *size, size_t *start, 14543d671ca6SAl Viro size_t maxsize, unsigned maxpages) 14553d671ca6SAl Viro { 14563d671ca6SAl Viro struct page *page; 14573d671ca6SAl Viro size_t skip = i->iov_offset, len; 14583d671ca6SAl Viro 14593d671ca6SAl Viro len = i->bvec->bv_len - skip; 14603d671ca6SAl Viro if (len > maxsize) 14613d671ca6SAl Viro len = maxsize; 14623d671ca6SAl Viro skip += i->bvec->bv_offset; 14633d671ca6SAl Viro page = i->bvec->bv_page + skip / PAGE_SIZE; 14643d671ca6SAl Viro len += (*start = skip % PAGE_SIZE); 14653d671ca6SAl Viro if (len > maxpages * PAGE_SIZE) 14663d671ca6SAl Viro len = maxpages * PAGE_SIZE; 14673d671ca6SAl Viro *size = len; 14683d671ca6SAl Viro return page; 14693d671ca6SAl Viro } 14703d671ca6SAl Viro 1471d879cb83SAl Viro ssize_t iov_iter_get_pages(struct iov_iter *i, 1472d879cb83SAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1473d879cb83SAl Viro size_t *start) 1474d879cb83SAl Viro { 14753d671ca6SAl Viro size_t len; 14763d671ca6SAl Viro int n, res; 14773d671ca6SAl Viro 1478d879cb83SAl Viro if (maxsize > i->count) 1479d879cb83SAl Viro maxsize = i->count; 14803d671ca6SAl Viro if (!maxsize) 14813d671ca6SAl Viro return 0; 1482d879cb83SAl Viro 14833d671ca6SAl Viro if (likely(iter_is_iovec(i))) { 14843d671ca6SAl Viro unsigned long addr; 14859ea9ce04SDavid Howells 14863d671ca6SAl Viro addr = first_iovec_segment(i, &len, start, maxsize, maxpages); 1487d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 148873b0140bSIra Weiny res = get_user_pages_fast(addr, n, 148973b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, 149073b0140bSIra Weiny pages); 1491*814a6674SAndreas Gruenbacher if (unlikely(res <= 0)) 1492d879cb83SAl Viro return res; 1493d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 14943d671ca6SAl Viro } 14953d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 14963d671ca6SAl Viro struct page *page; 14973d671ca6SAl Viro 14983d671ca6SAl Viro page = first_bvec_segment(i, &len, start, maxsize, maxpages); 14993d671ca6SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 15003d671ca6SAl Viro while (n--) 15013d671ca6SAl Viro get_page(*pages++ = page++); 15023d671ca6SAl Viro return len - *start; 15033d671ca6SAl Viro } 15043d671ca6SAl Viro if (iov_iter_is_pipe(i)) 15053d671ca6SAl Viro return pipe_get_pages(i, pages, maxsize, maxpages, start); 15063d671ca6SAl Viro if (iov_iter_is_xarray(i)) 15073d671ca6SAl Viro return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); 1508d879cb83SAl Viro return -EFAULT; 1509d879cb83SAl Viro } 1510d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages); 1511d879cb83SAl Viro 1512d879cb83SAl Viro static struct page **get_pages_array(size_t n) 1513d879cb83SAl Viro { 1514752ade68SMichal Hocko return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); 1515d879cb83SAl Viro } 1516d879cb83SAl Viro 1517241699cdSAl Viro static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 1518241699cdSAl Viro struct page ***pages, size_t maxsize, 1519241699cdSAl Viro size_t *start) 1520241699cdSAl Viro { 1521241699cdSAl Viro struct page **p; 15228cefc107SDavid Howells unsigned int iter_head, npages; 1523d7760d63SIlya Dryomov ssize_t n; 1524241699cdSAl Viro 1525241699cdSAl Viro if (!sanity(i)) 1526241699cdSAl Viro return -EFAULT; 1527241699cdSAl Viro 15288cefc107SDavid Howells data_start(i, &iter_head, start); 15298cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 15308cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1531241699cdSAl Viro n = npages * PAGE_SIZE - *start; 1532241699cdSAl Viro if (maxsize > n) 1533241699cdSAl Viro maxsize = n; 1534241699cdSAl Viro else 1535241699cdSAl Viro npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1536241699cdSAl Viro p = get_pages_array(npages); 1537241699cdSAl Viro if (!p) 1538241699cdSAl Viro return -ENOMEM; 15398cefc107SDavid Howells n = __pipe_get_pages(i, maxsize, p, iter_head, start); 1540241699cdSAl Viro if (n > 0) 1541241699cdSAl Viro *pages = p; 1542241699cdSAl Viro else 1543241699cdSAl Viro kvfree(p); 1544241699cdSAl Viro return n; 1545241699cdSAl Viro } 1546241699cdSAl Viro 15477ff50620SDavid Howells static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, 15487ff50620SDavid Howells struct page ***pages, size_t maxsize, 15497ff50620SDavid Howells size_t *_start_offset) 15507ff50620SDavid Howells { 15517ff50620SDavid Howells struct page **p; 15527ff50620SDavid Howells unsigned nr, offset; 15537ff50620SDavid Howells pgoff_t index, count; 15547ff50620SDavid Howells size_t size = maxsize, actual; 15557ff50620SDavid Howells loff_t pos; 15567ff50620SDavid Howells 15577ff50620SDavid Howells if (!size) 15587ff50620SDavid Howells return 0; 15597ff50620SDavid Howells 15607ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 15617ff50620SDavid Howells index = pos >> PAGE_SHIFT; 15627ff50620SDavid Howells offset = pos & ~PAGE_MASK; 15637ff50620SDavid Howells *_start_offset = offset; 15647ff50620SDavid Howells 15657ff50620SDavid Howells count = 1; 15667ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 15677ff50620SDavid Howells size -= PAGE_SIZE - offset; 15687ff50620SDavid Howells count += size >> PAGE_SHIFT; 15697ff50620SDavid Howells size &= ~PAGE_MASK; 15707ff50620SDavid Howells if (size) 15717ff50620SDavid Howells count++; 15727ff50620SDavid Howells } 15737ff50620SDavid Howells 15747ff50620SDavid Howells p = get_pages_array(count); 15757ff50620SDavid Howells if (!p) 15767ff50620SDavid Howells return -ENOMEM; 15777ff50620SDavid Howells *pages = p; 15787ff50620SDavid Howells 15797ff50620SDavid Howells nr = iter_xarray_populate_pages(p, i->xarray, index, count); 15807ff50620SDavid Howells if (nr == 0) 15817ff50620SDavid Howells return 0; 15827ff50620SDavid Howells 15837ff50620SDavid Howells actual = PAGE_SIZE * nr; 15847ff50620SDavid Howells actual -= offset; 15857ff50620SDavid Howells if (nr == count && size > 0) { 15867ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 15877ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 15887ff50620SDavid Howells } 15897ff50620SDavid Howells return actual; 15907ff50620SDavid Howells } 15917ff50620SDavid Howells 1592d879cb83SAl Viro ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 1593d879cb83SAl Viro struct page ***pages, size_t maxsize, 1594d879cb83SAl Viro size_t *start) 1595d879cb83SAl Viro { 1596d879cb83SAl Viro struct page **p; 15973d671ca6SAl Viro size_t len; 15983d671ca6SAl Viro int n, res; 1599d879cb83SAl Viro 1600d879cb83SAl Viro if (maxsize > i->count) 1601d879cb83SAl Viro maxsize = i->count; 16023d671ca6SAl Viro if (!maxsize) 16033d671ca6SAl Viro return 0; 1604d879cb83SAl Viro 16053d671ca6SAl Viro if (likely(iter_is_iovec(i))) { 16063d671ca6SAl Viro unsigned long addr; 16079ea9ce04SDavid Howells 16083d671ca6SAl Viro addr = first_iovec_segment(i, &len, start, maxsize, ~0U); 1609d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 1610d879cb83SAl Viro p = get_pages_array(n); 1611d879cb83SAl Viro if (!p) 1612d879cb83SAl Viro return -ENOMEM; 161373b0140bSIra Weiny res = get_user_pages_fast(addr, n, 161473b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); 1615*814a6674SAndreas Gruenbacher if (unlikely(res <= 0)) { 1616d879cb83SAl Viro kvfree(p); 1617*814a6674SAndreas Gruenbacher *pages = NULL; 1618d879cb83SAl Viro return res; 1619d879cb83SAl Viro } 1620d879cb83SAl Viro *pages = p; 1621d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 16223d671ca6SAl Viro } 16233d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 16243d671ca6SAl Viro struct page *page; 16253d671ca6SAl Viro 16263d671ca6SAl Viro page = first_bvec_segment(i, &len, start, maxsize, ~0U); 16273d671ca6SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 16283d671ca6SAl Viro *pages = p = get_pages_array(n); 1629d879cb83SAl Viro if (!p) 1630d879cb83SAl Viro return -ENOMEM; 16313d671ca6SAl Viro while (n--) 16323d671ca6SAl Viro get_page(*p++ = page++); 16333d671ca6SAl Viro return len - *start; 16343d671ca6SAl Viro } 16353d671ca6SAl Viro if (iov_iter_is_pipe(i)) 16363d671ca6SAl Viro return pipe_get_pages_alloc(i, pages, maxsize, start); 16373d671ca6SAl Viro if (iov_iter_is_xarray(i)) 16383d671ca6SAl Viro return iter_xarray_get_pages_alloc(i, pages, maxsize, start); 1639d879cb83SAl Viro return -EFAULT; 1640d879cb83SAl Viro } 1641d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages_alloc); 1642d879cb83SAl Viro 1643d879cb83SAl Viro size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 1644d879cb83SAl Viro struct iov_iter *i) 1645d879cb83SAl Viro { 1646d879cb83SAl Viro __wsum sum, next; 1647d879cb83SAl Viro sum = *csum; 16489ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1649241699cdSAl Viro WARN_ON(1); 1650241699cdSAl Viro return 0; 1651241699cdSAl Viro } 16527baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, ({ 16537baa5099SAl Viro next = csum_and_copy_from_user(base, addr + off, len); 1654d879cb83SAl Viro sum = csum_block_add(sum, next, off); 16557baa5099SAl Viro next ? 0 : len; 1656d879cb83SAl Viro }), ({ 16577baa5099SAl Viro sum = csum_and_memcpy(addr + off, base, len, sum, off); 1658d879cb83SAl Viro }) 1659d879cb83SAl Viro ) 1660d879cb83SAl Viro *csum = sum; 1661d879cb83SAl Viro return bytes; 1662d879cb83SAl Viro } 1663d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter); 1664d879cb83SAl Viro 166552cbd23aSWillem de Bruijn size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 1666d879cb83SAl Viro struct iov_iter *i) 1667d879cb83SAl Viro { 166852cbd23aSWillem de Bruijn struct csum_state *csstate = _csstate; 1669d879cb83SAl Viro __wsum sum, next; 167078e1f386SAl Viro 167178e1f386SAl Viro if (unlikely(iov_iter_is_discard(i))) { 1672241699cdSAl Viro WARN_ON(1); /* for now */ 1673241699cdSAl Viro return 0; 1674241699cdSAl Viro } 16756852df12SAl Viro 16766852df12SAl Viro sum = csum_shift(csstate->csum, csstate->off); 16776852df12SAl Viro if (unlikely(iov_iter_is_pipe(i))) 16786852df12SAl Viro bytes = csum_and_copy_to_pipe_iter(addr, bytes, i, &sum); 16796852df12SAl Viro else iterate_and_advance(i, bytes, base, len, off, ({ 16807baa5099SAl Viro next = csum_and_copy_to_user(addr + off, base, len); 1681d879cb83SAl Viro sum = csum_block_add(sum, next, off); 16827baa5099SAl Viro next ? 0 : len; 1683d879cb83SAl Viro }), ({ 16847baa5099SAl Viro sum = csum_and_memcpy(base, addr + off, len, sum, off); 1685d879cb83SAl Viro }) 1686d879cb83SAl Viro ) 1687594e450bSAl Viro csstate->csum = csum_shift(sum, csstate->off); 1688594e450bSAl Viro csstate->off += bytes; 1689d879cb83SAl Viro return bytes; 1690d879cb83SAl Viro } 1691d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_to_iter); 1692d879cb83SAl Viro 1693d05f4435SSagi Grimberg size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, 1694d05f4435SSagi Grimberg struct iov_iter *i) 1695d05f4435SSagi Grimberg { 16967999096fSHerbert Xu #ifdef CONFIG_CRYPTO_HASH 1697d05f4435SSagi Grimberg struct ahash_request *hash = hashp; 1698d05f4435SSagi Grimberg struct scatterlist sg; 1699d05f4435SSagi Grimberg size_t copied; 1700d05f4435SSagi Grimberg 1701d05f4435SSagi Grimberg copied = copy_to_iter(addr, bytes, i); 1702d05f4435SSagi Grimberg sg_init_one(&sg, addr, copied); 1703d05f4435SSagi Grimberg ahash_request_set_crypt(hash, &sg, NULL, copied); 1704d05f4435SSagi Grimberg crypto_ahash_update(hash); 1705d05f4435SSagi Grimberg return copied; 170627fad74aSYueHaibing #else 170727fad74aSYueHaibing return 0; 170827fad74aSYueHaibing #endif 1709d05f4435SSagi Grimberg } 1710d05f4435SSagi Grimberg EXPORT_SYMBOL(hash_and_copy_to_iter); 1711d05f4435SSagi Grimberg 171266531c65SAl Viro static int iov_npages(const struct iov_iter *i, int maxpages) 1713d879cb83SAl Viro { 171466531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 171566531c65SAl Viro const struct iovec *p; 1716d879cb83SAl Viro int npages = 0; 1717d879cb83SAl Viro 171866531c65SAl Viro for (p = i->iov; size; skip = 0, p++) { 171966531c65SAl Viro unsigned offs = offset_in_page(p->iov_base + skip); 172066531c65SAl Viro size_t len = min(p->iov_len - skip, size); 1721d879cb83SAl Viro 172266531c65SAl Viro if (len) { 172366531c65SAl Viro size -= len; 172466531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 172566531c65SAl Viro if (unlikely(npages > maxpages)) 172666531c65SAl Viro return maxpages; 172766531c65SAl Viro } 172866531c65SAl Viro } 172966531c65SAl Viro return npages; 173066531c65SAl Viro } 173166531c65SAl Viro 173266531c65SAl Viro static int bvec_npages(const struct iov_iter *i, int maxpages) 173366531c65SAl Viro { 173466531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 173566531c65SAl Viro const struct bio_vec *p; 173666531c65SAl Viro int npages = 0; 173766531c65SAl Viro 173866531c65SAl Viro for (p = i->bvec; size; skip = 0, p++) { 173966531c65SAl Viro unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; 174066531c65SAl Viro size_t len = min(p->bv_len - skip, size); 174166531c65SAl Viro 174266531c65SAl Viro size -= len; 174366531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 174466531c65SAl Viro if (unlikely(npages > maxpages)) 174566531c65SAl Viro return maxpages; 174666531c65SAl Viro } 174766531c65SAl Viro return npages; 174866531c65SAl Viro } 174966531c65SAl Viro 175066531c65SAl Viro int iov_iter_npages(const struct iov_iter *i, int maxpages) 175166531c65SAl Viro { 175266531c65SAl Viro if (unlikely(!i->count)) 175366531c65SAl Viro return 0; 175466531c65SAl Viro /* iovec and kvec have identical layouts */ 175566531c65SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 175666531c65SAl Viro return iov_npages(i, maxpages); 175766531c65SAl Viro if (iov_iter_is_bvec(i)) 175866531c65SAl Viro return bvec_npages(i, maxpages); 175966531c65SAl Viro if (iov_iter_is_pipe(i)) { 17608cefc107SDavid Howells unsigned int iter_head; 176166531c65SAl Viro int npages; 1762241699cdSAl Viro size_t off; 1763241699cdSAl Viro 1764241699cdSAl Viro if (!sanity(i)) 1765241699cdSAl Viro return 0; 1766241699cdSAl Viro 17678cefc107SDavid Howells data_start(i, &iter_head, &off); 1768241699cdSAl Viro /* some of this one + all after this one */ 176966531c65SAl Viro npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 177066531c65SAl Viro return min(npages, maxpages); 177166531c65SAl Viro } 177266531c65SAl Viro if (iov_iter_is_xarray(i)) { 1773e4f8df86SAl Viro unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; 1774e4f8df86SAl Viro int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); 177566531c65SAl Viro return min(npages, maxpages); 177666531c65SAl Viro } 177766531c65SAl Viro return 0; 1778d879cb83SAl Viro } 1779d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_npages); 1780d879cb83SAl Viro 1781d879cb83SAl Viro const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) 1782d879cb83SAl Viro { 1783d879cb83SAl Viro *new = *old; 178400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(new))) { 1785241699cdSAl Viro WARN_ON(1); 1786241699cdSAl Viro return NULL; 1787241699cdSAl Viro } 17887ff50620SDavid Howells if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) 17899ea9ce04SDavid Howells return NULL; 179000e23707SDavid Howells if (iov_iter_is_bvec(new)) 1791d879cb83SAl Viro return new->bvec = kmemdup(new->bvec, 1792d879cb83SAl Viro new->nr_segs * sizeof(struct bio_vec), 1793d879cb83SAl Viro flags); 1794d879cb83SAl Viro else 1795d879cb83SAl Viro /* iovec and kvec have identical layout */ 1796d879cb83SAl Viro return new->iov = kmemdup(new->iov, 1797d879cb83SAl Viro new->nr_segs * sizeof(struct iovec), 1798d879cb83SAl Viro flags); 1799d879cb83SAl Viro } 1800d879cb83SAl Viro EXPORT_SYMBOL(dup_iter); 1801bc917be8SAl Viro 1802bfdc5970SChristoph Hellwig static int copy_compat_iovec_from_user(struct iovec *iov, 1803bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1804bfdc5970SChristoph Hellwig { 1805bfdc5970SChristoph Hellwig const struct compat_iovec __user *uiov = 1806bfdc5970SChristoph Hellwig (const struct compat_iovec __user *)uvec; 1807bfdc5970SChristoph Hellwig int ret = -EFAULT, i; 1808bfdc5970SChristoph Hellwig 1809a959a978SChristoph Hellwig if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) 1810bfdc5970SChristoph Hellwig return -EFAULT; 1811bfdc5970SChristoph Hellwig 1812bfdc5970SChristoph Hellwig for (i = 0; i < nr_segs; i++) { 1813bfdc5970SChristoph Hellwig compat_uptr_t buf; 1814bfdc5970SChristoph Hellwig compat_ssize_t len; 1815bfdc5970SChristoph Hellwig 1816bfdc5970SChristoph Hellwig unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); 1817bfdc5970SChristoph Hellwig unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); 1818bfdc5970SChristoph Hellwig 1819bfdc5970SChristoph Hellwig /* check for compat_size_t not fitting in compat_ssize_t .. */ 1820bfdc5970SChristoph Hellwig if (len < 0) { 1821bfdc5970SChristoph Hellwig ret = -EINVAL; 1822bfdc5970SChristoph Hellwig goto uaccess_end; 1823bfdc5970SChristoph Hellwig } 1824bfdc5970SChristoph Hellwig iov[i].iov_base = compat_ptr(buf); 1825bfdc5970SChristoph Hellwig iov[i].iov_len = len; 1826bfdc5970SChristoph Hellwig } 1827bfdc5970SChristoph Hellwig 1828bfdc5970SChristoph Hellwig ret = 0; 1829bfdc5970SChristoph Hellwig uaccess_end: 1830bfdc5970SChristoph Hellwig user_access_end(); 1831bfdc5970SChristoph Hellwig return ret; 1832bfdc5970SChristoph Hellwig } 1833bfdc5970SChristoph Hellwig 1834bfdc5970SChristoph Hellwig static int copy_iovec_from_user(struct iovec *iov, 1835bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1836fb041b59SDavid Laight { 1837fb041b59SDavid Laight unsigned long seg; 1838bfdc5970SChristoph Hellwig 1839bfdc5970SChristoph Hellwig if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) 1840bfdc5970SChristoph Hellwig return -EFAULT; 1841bfdc5970SChristoph Hellwig for (seg = 0; seg < nr_segs; seg++) { 1842bfdc5970SChristoph Hellwig if ((ssize_t)iov[seg].iov_len < 0) 1843bfdc5970SChristoph Hellwig return -EINVAL; 1844bfdc5970SChristoph Hellwig } 1845bfdc5970SChristoph Hellwig 1846bfdc5970SChristoph Hellwig return 0; 1847bfdc5970SChristoph Hellwig } 1848bfdc5970SChristoph Hellwig 1849bfdc5970SChristoph Hellwig struct iovec *iovec_from_user(const struct iovec __user *uvec, 1850bfdc5970SChristoph Hellwig unsigned long nr_segs, unsigned long fast_segs, 1851bfdc5970SChristoph Hellwig struct iovec *fast_iov, bool compat) 1852bfdc5970SChristoph Hellwig { 1853bfdc5970SChristoph Hellwig struct iovec *iov = fast_iov; 1854bfdc5970SChristoph Hellwig int ret; 1855fb041b59SDavid Laight 1856fb041b59SDavid Laight /* 1857bfdc5970SChristoph Hellwig * SuS says "The readv() function *may* fail if the iovcnt argument was 1858bfdc5970SChristoph Hellwig * less than or equal to 0, or greater than {IOV_MAX}. Linux has 1859fb041b59SDavid Laight * traditionally returned zero for zero segments, so... 1860fb041b59SDavid Laight */ 1861bfdc5970SChristoph Hellwig if (nr_segs == 0) 1862bfdc5970SChristoph Hellwig return iov; 1863bfdc5970SChristoph Hellwig if (nr_segs > UIO_MAXIOV) 1864bfdc5970SChristoph Hellwig return ERR_PTR(-EINVAL); 1865fb041b59SDavid Laight if (nr_segs > fast_segs) { 1866fb041b59SDavid Laight iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); 1867bfdc5970SChristoph Hellwig if (!iov) 1868bfdc5970SChristoph Hellwig return ERR_PTR(-ENOMEM); 1869fb041b59SDavid Laight } 1870bfdc5970SChristoph Hellwig 1871bfdc5970SChristoph Hellwig if (compat) 1872bfdc5970SChristoph Hellwig ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); 1873bfdc5970SChristoph Hellwig else 1874bfdc5970SChristoph Hellwig ret = copy_iovec_from_user(iov, uvec, nr_segs); 1875bfdc5970SChristoph Hellwig if (ret) { 1876bfdc5970SChristoph Hellwig if (iov != fast_iov) 1877bfdc5970SChristoph Hellwig kfree(iov); 1878bfdc5970SChristoph Hellwig return ERR_PTR(ret); 1879fb041b59SDavid Laight } 1880bfdc5970SChristoph Hellwig 1881bfdc5970SChristoph Hellwig return iov; 1882bfdc5970SChristoph Hellwig } 1883bfdc5970SChristoph Hellwig 1884bfdc5970SChristoph Hellwig ssize_t __import_iovec(int type, const struct iovec __user *uvec, 1885bfdc5970SChristoph Hellwig unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, 1886bfdc5970SChristoph Hellwig struct iov_iter *i, bool compat) 1887bfdc5970SChristoph Hellwig { 1888bfdc5970SChristoph Hellwig ssize_t total_len = 0; 1889bfdc5970SChristoph Hellwig unsigned long seg; 1890bfdc5970SChristoph Hellwig struct iovec *iov; 1891bfdc5970SChristoph Hellwig 1892bfdc5970SChristoph Hellwig iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); 1893bfdc5970SChristoph Hellwig if (IS_ERR(iov)) { 1894bfdc5970SChristoph Hellwig *iovp = NULL; 1895bfdc5970SChristoph Hellwig return PTR_ERR(iov); 1896fb041b59SDavid Laight } 1897fb041b59SDavid Laight 1898fb041b59SDavid Laight /* 1899bfdc5970SChristoph Hellwig * According to the Single Unix Specification we should return EINVAL if 1900bfdc5970SChristoph Hellwig * an element length is < 0 when cast to ssize_t or if the total length 1901bfdc5970SChristoph Hellwig * would overflow the ssize_t return value of the system call. 1902fb041b59SDavid Laight * 1903fb041b59SDavid Laight * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the 1904fb041b59SDavid Laight * overflow case. 1905fb041b59SDavid Laight */ 1906fb041b59SDavid Laight for (seg = 0; seg < nr_segs; seg++) { 1907fb041b59SDavid Laight ssize_t len = (ssize_t)iov[seg].iov_len; 1908fb041b59SDavid Laight 1909bfdc5970SChristoph Hellwig if (!access_ok(iov[seg].iov_base, len)) { 1910bfdc5970SChristoph Hellwig if (iov != *iovp) 1911bfdc5970SChristoph Hellwig kfree(iov); 1912bfdc5970SChristoph Hellwig *iovp = NULL; 1913bfdc5970SChristoph Hellwig return -EFAULT; 1914fb041b59SDavid Laight } 1915bfdc5970SChristoph Hellwig 1916bfdc5970SChristoph Hellwig if (len > MAX_RW_COUNT - total_len) { 1917bfdc5970SChristoph Hellwig len = MAX_RW_COUNT - total_len; 1918fb041b59SDavid Laight iov[seg].iov_len = len; 1919fb041b59SDavid Laight } 1920bfdc5970SChristoph Hellwig total_len += len; 1921fb041b59SDavid Laight } 1922bfdc5970SChristoph Hellwig 1923bfdc5970SChristoph Hellwig iov_iter_init(i, type, iov, nr_segs, total_len); 1924bfdc5970SChristoph Hellwig if (iov == *iovp) 1925bfdc5970SChristoph Hellwig *iovp = NULL; 1926bfdc5970SChristoph Hellwig else 1927bfdc5970SChristoph Hellwig *iovp = iov; 1928bfdc5970SChristoph Hellwig return total_len; 1929fb041b59SDavid Laight } 1930fb041b59SDavid Laight 1931ffecee4fSVegard Nossum /** 1932ffecee4fSVegard Nossum * import_iovec() - Copy an array of &struct iovec from userspace 1933ffecee4fSVegard Nossum * into the kernel, check that it is valid, and initialize a new 1934ffecee4fSVegard Nossum * &struct iov_iter iterator to access it. 1935ffecee4fSVegard Nossum * 1936ffecee4fSVegard Nossum * @type: One of %READ or %WRITE. 1937bfdc5970SChristoph Hellwig * @uvec: Pointer to the userspace array. 1938ffecee4fSVegard Nossum * @nr_segs: Number of elements in userspace array. 1939ffecee4fSVegard Nossum * @fast_segs: Number of elements in @iov. 1940bfdc5970SChristoph Hellwig * @iovp: (input and output parameter) Pointer to pointer to (usually small 1941ffecee4fSVegard Nossum * on-stack) kernel array. 1942ffecee4fSVegard Nossum * @i: Pointer to iterator that will be initialized on success. 1943ffecee4fSVegard Nossum * 1944ffecee4fSVegard Nossum * If the array pointed to by *@iov is large enough to hold all @nr_segs, 1945ffecee4fSVegard Nossum * then this function places %NULL in *@iov on return. Otherwise, a new 1946ffecee4fSVegard Nossum * array will be allocated and the result placed in *@iov. This means that 1947ffecee4fSVegard Nossum * the caller may call kfree() on *@iov regardless of whether the small 1948ffecee4fSVegard Nossum * on-stack array was used or not (and regardless of whether this function 1949ffecee4fSVegard Nossum * returns an error or not). 1950ffecee4fSVegard Nossum * 195187e5e6daSJens Axboe * Return: Negative error code on error, bytes imported on success 1952ffecee4fSVegard Nossum */ 1953bfdc5970SChristoph Hellwig ssize_t import_iovec(int type, const struct iovec __user *uvec, 1954bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 1955bfdc5970SChristoph Hellwig struct iovec **iovp, struct iov_iter *i) 1956bc917be8SAl Viro { 195789cd35c5SChristoph Hellwig return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, 195889cd35c5SChristoph Hellwig in_compat_syscall()); 1959bc917be8SAl Viro } 1960bc917be8SAl Viro EXPORT_SYMBOL(import_iovec); 1961bc917be8SAl Viro 1962bc917be8SAl Viro int import_single_range(int rw, void __user *buf, size_t len, 1963bc917be8SAl Viro struct iovec *iov, struct iov_iter *i) 1964bc917be8SAl Viro { 1965bc917be8SAl Viro if (len > MAX_RW_COUNT) 1966bc917be8SAl Viro len = MAX_RW_COUNT; 196796d4f267SLinus Torvalds if (unlikely(!access_ok(buf, len))) 1968bc917be8SAl Viro return -EFAULT; 1969bc917be8SAl Viro 1970bc917be8SAl Viro iov->iov_base = buf; 1971bc917be8SAl Viro iov->iov_len = len; 1972bc917be8SAl Viro iov_iter_init(i, rw, iov, 1, len); 1973bc917be8SAl Viro return 0; 1974bc917be8SAl Viro } 1975e1267585SAl Viro EXPORT_SYMBOL(import_single_range); 19768fb0f47aSJens Axboe 19778fb0f47aSJens Axboe /** 19788fb0f47aSJens Axboe * iov_iter_restore() - Restore a &struct iov_iter to the same state as when 19798fb0f47aSJens Axboe * iov_iter_save_state() was called. 19808fb0f47aSJens Axboe * 19818fb0f47aSJens Axboe * @i: &struct iov_iter to restore 19828fb0f47aSJens Axboe * @state: state to restore from 19838fb0f47aSJens Axboe * 19848fb0f47aSJens Axboe * Used after iov_iter_save_state() to bring restore @i, if operations may 19858fb0f47aSJens Axboe * have advanced it. 19868fb0f47aSJens Axboe * 19878fb0f47aSJens Axboe * Note: only works on ITER_IOVEC, ITER_BVEC, and ITER_KVEC 19888fb0f47aSJens Axboe */ 19898fb0f47aSJens Axboe void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state) 19908fb0f47aSJens Axboe { 19918fb0f47aSJens Axboe if (WARN_ON_ONCE(!iov_iter_is_bvec(i) && !iter_is_iovec(i)) && 19928fb0f47aSJens Axboe !iov_iter_is_kvec(i)) 19938fb0f47aSJens Axboe return; 19948fb0f47aSJens Axboe i->iov_offset = state->iov_offset; 19958fb0f47aSJens Axboe i->count = state->count; 19968fb0f47aSJens Axboe /* 19978fb0f47aSJens Axboe * For the *vec iters, nr_segs + iov is constant - if we increment 19988fb0f47aSJens Axboe * the vec, then we also decrement the nr_segs count. Hence we don't 19998fb0f47aSJens Axboe * need to track both of these, just one is enough and we can deduct 20008fb0f47aSJens Axboe * the other from that. ITER_KVEC and ITER_IOVEC are the same struct 20018fb0f47aSJens Axboe * size, so we can just increment the iov pointer as they are unionzed. 20028fb0f47aSJens Axboe * ITER_BVEC _may_ be the same size on some archs, but on others it is 20038fb0f47aSJens Axboe * not. Be safe and handle it separately. 20048fb0f47aSJens Axboe */ 20058fb0f47aSJens Axboe BUILD_BUG_ON(sizeof(struct iovec) != sizeof(struct kvec)); 20068fb0f47aSJens Axboe if (iov_iter_is_bvec(i)) 20078fb0f47aSJens Axboe i->bvec -= state->nr_segs - i->nr_segs; 20088fb0f47aSJens Axboe else 20098fb0f47aSJens Axboe i->iov -= state->nr_segs - i->nr_segs; 20108fb0f47aSJens Axboe i->nr_segs = state->nr_segs; 20118fb0f47aSJens Axboe } 2012