1457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 27999096fSHerbert Xu #include <crypto/hash.h> 3d879cb83SAl Viro #include <linux/export.h> 42f8b5444SChristoph Hellwig #include <linux/bvec.h> 54d0e9df5SAlbert van der Linde #include <linux/fault-inject-usercopy.h> 6d879cb83SAl Viro #include <linux/uio.h> 7d879cb83SAl Viro #include <linux/pagemap.h> 828961998SIra Weiny #include <linux/highmem.h> 9d879cb83SAl Viro #include <linux/slab.h> 10d879cb83SAl Viro #include <linux/vmalloc.h> 11241699cdSAl Viro #include <linux/splice.h> 12bfdc5970SChristoph Hellwig #include <linux/compat.h> 13d879cb83SAl Viro #include <net/checksum.h> 14d05f4435SSagi Grimberg #include <linux/scatterlist.h> 15d0ef4c36SMarco Elver #include <linux/instrumented.h> 16d879cb83SAl Viro 17241699cdSAl Viro #define PIPE_PARANOIA /* for now */ 18241699cdSAl Viro 19d879cb83SAl Viro #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ 20d879cb83SAl Viro size_t left; \ 21d879cb83SAl Viro size_t wanted = n; \ 22d879cb83SAl Viro __p = i->iov; \ 23d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len - skip); \ 24d879cb83SAl Viro if (likely(__v.iov_len)) { \ 25d879cb83SAl Viro __v.iov_base = __p->iov_base + skip; \ 26d879cb83SAl Viro left = (STEP); \ 27d879cb83SAl Viro __v.iov_len -= left; \ 28d879cb83SAl Viro skip += __v.iov_len; \ 29d879cb83SAl Viro n -= __v.iov_len; \ 30d879cb83SAl Viro } else { \ 31d879cb83SAl Viro left = 0; \ 32d879cb83SAl Viro } \ 33d879cb83SAl Viro while (unlikely(!left && n)) { \ 34d879cb83SAl Viro __p++; \ 35d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len); \ 36d879cb83SAl Viro if (unlikely(!__v.iov_len)) \ 37d879cb83SAl Viro continue; \ 38d879cb83SAl Viro __v.iov_base = __p->iov_base; \ 39d879cb83SAl Viro left = (STEP); \ 40d879cb83SAl Viro __v.iov_len -= left; \ 41d879cb83SAl Viro skip = __v.iov_len; \ 42d879cb83SAl Viro n -= __v.iov_len; \ 43d879cb83SAl Viro } \ 44d879cb83SAl Viro n = wanted - n; \ 45d879cb83SAl Viro } 46d879cb83SAl Viro 47d879cb83SAl Viro #define iterate_kvec(i, n, __v, __p, skip, STEP) { \ 48d879cb83SAl Viro size_t wanted = n; \ 49d879cb83SAl Viro __p = i->kvec; \ 50d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len - skip); \ 51d879cb83SAl Viro if (likely(__v.iov_len)) { \ 52d879cb83SAl Viro __v.iov_base = __p->iov_base + skip; \ 53d879cb83SAl Viro (void)(STEP); \ 54d879cb83SAl Viro skip += __v.iov_len; \ 55d879cb83SAl Viro n -= __v.iov_len; \ 56d879cb83SAl Viro } \ 57d879cb83SAl Viro while (unlikely(n)) { \ 58d879cb83SAl Viro __p++; \ 59d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len); \ 60d879cb83SAl Viro if (unlikely(!__v.iov_len)) \ 61d879cb83SAl Viro continue; \ 62d879cb83SAl Viro __v.iov_base = __p->iov_base; \ 63d879cb83SAl Viro (void)(STEP); \ 64d879cb83SAl Viro skip = __v.iov_len; \ 65d879cb83SAl Viro n -= __v.iov_len; \ 66d879cb83SAl Viro } \ 67d879cb83SAl Viro n = wanted; \ 68d879cb83SAl Viro } 69d879cb83SAl Viro 701bdc76aeSMing Lei #define iterate_bvec(i, n, __v, __bi, skip, STEP) { \ 711bdc76aeSMing Lei struct bvec_iter __start; \ 721bdc76aeSMing Lei __start.bi_size = n; \ 731bdc76aeSMing Lei __start.bi_bvec_done = skip; \ 741bdc76aeSMing Lei __start.bi_idx = 0; \ 751bdc76aeSMing Lei for_each_bvec(__v, i->bvec, __bi, __start) { \ 76d879cb83SAl Viro (void)(STEP); \ 77d879cb83SAl Viro } \ 78d879cb83SAl Viro } 79d879cb83SAl Viro 807ff50620SDavid Howells #define iterate_xarray(i, n, __v, skip, STEP) { \ 817ff50620SDavid Howells struct page *head = NULL; \ 827ff50620SDavid Howells size_t wanted = n, seg, offset; \ 837ff50620SDavid Howells loff_t start = i->xarray_start + skip; \ 847ff50620SDavid Howells pgoff_t index = start >> PAGE_SHIFT; \ 857ff50620SDavid Howells int j; \ 867ff50620SDavid Howells \ 877ff50620SDavid Howells XA_STATE(xas, i->xarray, index); \ 887ff50620SDavid Howells \ 897ff50620SDavid Howells rcu_read_lock(); \ 907ff50620SDavid Howells xas_for_each(&xas, head, ULONG_MAX) { \ 917ff50620SDavid Howells if (xas_retry(&xas, head)) \ 927ff50620SDavid Howells continue; \ 937ff50620SDavid Howells if (WARN_ON(xa_is_value(head))) \ 947ff50620SDavid Howells break; \ 957ff50620SDavid Howells if (WARN_ON(PageHuge(head))) \ 967ff50620SDavid Howells break; \ 977ff50620SDavid Howells for (j = (head->index < index) ? index - head->index : 0; \ 987ff50620SDavid Howells j < thp_nr_pages(head); j++) { \ 997ff50620SDavid Howells __v.bv_page = head + j; \ 1007ff50620SDavid Howells offset = (i->xarray_start + skip) & ~PAGE_MASK; \ 1017ff50620SDavid Howells seg = PAGE_SIZE - offset; \ 1027ff50620SDavid Howells __v.bv_offset = offset; \ 1037ff50620SDavid Howells __v.bv_len = min(n, seg); \ 1047ff50620SDavid Howells (void)(STEP); \ 1057ff50620SDavid Howells n -= __v.bv_len; \ 1067ff50620SDavid Howells skip += __v.bv_len; \ 1077ff50620SDavid Howells if (n == 0) \ 1087ff50620SDavid Howells break; \ 1097ff50620SDavid Howells } \ 1107ff50620SDavid Howells if (n == 0) \ 1117ff50620SDavid Howells break; \ 1127ff50620SDavid Howells } \ 1137ff50620SDavid Howells rcu_read_unlock(); \ 1147ff50620SDavid Howells n = wanted - n; \ 1157ff50620SDavid Howells } 1167ff50620SDavid Howells 1177ff50620SDavid Howells #define iterate_all_kinds(i, n, v, I, B, K, X) { \ 11833844e66SAl Viro if (likely(n)) { \ 119d879cb83SAl Viro size_t skip = i->iov_offset; \ 120*28f38db7SAl Viro if (likely(iter_is_iovec(i))) { \ 121d879cb83SAl Viro const struct iovec *iov; \ 122d879cb83SAl Viro struct iovec v; \ 123d879cb83SAl Viro iterate_iovec(i, n, v, iov, skip, (I)) \ 124*28f38db7SAl Viro } else if (iov_iter_is_bvec(i)) { \ 125*28f38db7SAl Viro struct bio_vec v; \ 126*28f38db7SAl Viro struct bvec_iter __bi; \ 127*28f38db7SAl Viro iterate_bvec(i, n, v, __bi, skip, (B)) \ 128*28f38db7SAl Viro } else if (iov_iter_is_kvec(i)) { \ 129*28f38db7SAl Viro const struct kvec *kvec; \ 130*28f38db7SAl Viro struct kvec v; \ 131*28f38db7SAl Viro iterate_kvec(i, n, v, kvec, skip, (K)) \ 132*28f38db7SAl Viro } else if (iov_iter_is_xarray(i)) { \ 133*28f38db7SAl Viro struct bio_vec v; \ 134*28f38db7SAl Viro iterate_xarray(i, n, v, skip, (X)); \ 135d879cb83SAl Viro } \ 13633844e66SAl Viro } \ 137d879cb83SAl Viro } 138d879cb83SAl Viro 1397ff50620SDavid Howells #define iterate_and_advance(i, n, v, I, B, K, X) { \ 140dd254f5aSAl Viro if (unlikely(i->count < n)) \ 141dd254f5aSAl Viro n = i->count; \ 14219f18459SAl Viro if (i->count) { \ 143d879cb83SAl Viro size_t skip = i->iov_offset; \ 144*28f38db7SAl Viro if (likely(iter_is_iovec(i))) { \ 145d879cb83SAl Viro const struct iovec *iov; \ 146d879cb83SAl Viro struct iovec v; \ 147d879cb83SAl Viro iterate_iovec(i, n, v, iov, skip, (I)) \ 148d879cb83SAl Viro if (skip == iov->iov_len) { \ 149d879cb83SAl Viro iov++; \ 150d879cb83SAl Viro skip = 0; \ 151d879cb83SAl Viro } \ 152d879cb83SAl Viro i->nr_segs -= iov - i->iov; \ 153d879cb83SAl Viro i->iov = iov; \ 154*28f38db7SAl Viro } else if (iov_iter_is_bvec(i)) { \ 155*28f38db7SAl Viro const struct bio_vec *bvec = i->bvec; \ 156*28f38db7SAl Viro struct bio_vec v; \ 157*28f38db7SAl Viro struct bvec_iter __bi; \ 158*28f38db7SAl Viro iterate_bvec(i, n, v, __bi, skip, (B)) \ 159*28f38db7SAl Viro i->bvec = __bvec_iter_bvec(i->bvec, __bi); \ 160*28f38db7SAl Viro i->nr_segs -= i->bvec - bvec; \ 161*28f38db7SAl Viro skip = __bi.bi_bvec_done; \ 162*28f38db7SAl Viro } else if (iov_iter_is_kvec(i)) { \ 163*28f38db7SAl Viro const struct kvec *kvec; \ 164*28f38db7SAl Viro struct kvec v; \ 165*28f38db7SAl Viro iterate_kvec(i, n, v, kvec, skip, (K)) \ 166*28f38db7SAl Viro if (skip == kvec->iov_len) { \ 167*28f38db7SAl Viro kvec++; \ 168*28f38db7SAl Viro skip = 0; \ 169*28f38db7SAl Viro } \ 170*28f38db7SAl Viro i->nr_segs -= kvec - i->kvec; \ 171*28f38db7SAl Viro i->kvec = kvec; \ 172*28f38db7SAl Viro } else if (iov_iter_is_xarray(i)) { \ 173*28f38db7SAl Viro struct bio_vec v; \ 174*28f38db7SAl Viro iterate_xarray(i, n, v, skip, (X)) \ 175*28f38db7SAl Viro } else if (iov_iter_is_discard(i)) { \ 176*28f38db7SAl Viro skip += n; \ 177d879cb83SAl Viro } \ 178d879cb83SAl Viro i->count -= n; \ 179d879cb83SAl Viro i->iov_offset = skip; \ 180dd254f5aSAl Viro } \ 181d879cb83SAl Viro } 182d879cb83SAl Viro 18309fc68dcSAl Viro static int copyout(void __user *to, const void *from, size_t n) 18409fc68dcSAl Viro { 1854d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1864d0e9df5SAlbert van der Linde return n; 18796d4f267SLinus Torvalds if (access_ok(to, n)) { 188d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 18909fc68dcSAl Viro n = raw_copy_to_user(to, from, n); 19009fc68dcSAl Viro } 19109fc68dcSAl Viro return n; 19209fc68dcSAl Viro } 19309fc68dcSAl Viro 19409fc68dcSAl Viro static int copyin(void *to, const void __user *from, size_t n) 19509fc68dcSAl Viro { 1964d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1974d0e9df5SAlbert van der Linde return n; 19896d4f267SLinus Torvalds if (access_ok(from, n)) { 199d0ef4c36SMarco Elver instrument_copy_from_user(to, from, n); 20009fc68dcSAl Viro n = raw_copy_from_user(to, from, n); 20109fc68dcSAl Viro } 20209fc68dcSAl Viro return n; 20309fc68dcSAl Viro } 20409fc68dcSAl Viro 205d879cb83SAl Viro static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, 206d879cb83SAl Viro struct iov_iter *i) 207d879cb83SAl Viro { 208d879cb83SAl Viro size_t skip, copy, left, wanted; 209d879cb83SAl Viro const struct iovec *iov; 210d879cb83SAl Viro char __user *buf; 211d879cb83SAl Viro void *kaddr, *from; 212d879cb83SAl Viro 213d879cb83SAl Viro if (unlikely(bytes > i->count)) 214d879cb83SAl Viro bytes = i->count; 215d879cb83SAl Viro 216d879cb83SAl Viro if (unlikely(!bytes)) 217d879cb83SAl Viro return 0; 218d879cb83SAl Viro 21909fc68dcSAl Viro might_fault(); 220d879cb83SAl Viro wanted = bytes; 221d879cb83SAl Viro iov = i->iov; 222d879cb83SAl Viro skip = i->iov_offset; 223d879cb83SAl Viro buf = iov->iov_base + skip; 224d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 225d879cb83SAl Viro 2263fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { 227d879cb83SAl Viro kaddr = kmap_atomic(page); 228d879cb83SAl Viro from = kaddr + offset; 229d879cb83SAl Viro 230d879cb83SAl Viro /* first chunk, usually the only one */ 23109fc68dcSAl Viro left = copyout(buf, from, copy); 232d879cb83SAl Viro copy -= left; 233d879cb83SAl Viro skip += copy; 234d879cb83SAl Viro from += copy; 235d879cb83SAl Viro bytes -= copy; 236d879cb83SAl Viro 237d879cb83SAl Viro while (unlikely(!left && bytes)) { 238d879cb83SAl Viro iov++; 239d879cb83SAl Viro buf = iov->iov_base; 240d879cb83SAl Viro copy = min(bytes, iov->iov_len); 24109fc68dcSAl Viro left = copyout(buf, from, copy); 242d879cb83SAl Viro copy -= left; 243d879cb83SAl Viro skip = copy; 244d879cb83SAl Viro from += copy; 245d879cb83SAl Viro bytes -= copy; 246d879cb83SAl Viro } 247d879cb83SAl Viro if (likely(!bytes)) { 248d879cb83SAl Viro kunmap_atomic(kaddr); 249d879cb83SAl Viro goto done; 250d879cb83SAl Viro } 251d879cb83SAl Viro offset = from - kaddr; 252d879cb83SAl Viro buf += copy; 253d879cb83SAl Viro kunmap_atomic(kaddr); 254d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 255d879cb83SAl Viro } 256d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 2573fa6c507SMikulas Patocka 258d879cb83SAl Viro kaddr = kmap(page); 259d879cb83SAl Viro from = kaddr + offset; 26009fc68dcSAl Viro left = copyout(buf, from, copy); 261d879cb83SAl Viro copy -= left; 262d879cb83SAl Viro skip += copy; 263d879cb83SAl Viro from += copy; 264d879cb83SAl Viro bytes -= copy; 265d879cb83SAl Viro while (unlikely(!left && bytes)) { 266d879cb83SAl Viro iov++; 267d879cb83SAl Viro buf = iov->iov_base; 268d879cb83SAl Viro copy = min(bytes, iov->iov_len); 26909fc68dcSAl Viro left = copyout(buf, from, copy); 270d879cb83SAl Viro copy -= left; 271d879cb83SAl Viro skip = copy; 272d879cb83SAl Viro from += copy; 273d879cb83SAl Viro bytes -= copy; 274d879cb83SAl Viro } 275d879cb83SAl Viro kunmap(page); 2763fa6c507SMikulas Patocka 277d879cb83SAl Viro done: 278d879cb83SAl Viro if (skip == iov->iov_len) { 279d879cb83SAl Viro iov++; 280d879cb83SAl Viro skip = 0; 281d879cb83SAl Viro } 282d879cb83SAl Viro i->count -= wanted - bytes; 283d879cb83SAl Viro i->nr_segs -= iov - i->iov; 284d879cb83SAl Viro i->iov = iov; 285d879cb83SAl Viro i->iov_offset = skip; 286d879cb83SAl Viro return wanted - bytes; 287d879cb83SAl Viro } 288d879cb83SAl Viro 289d879cb83SAl Viro static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, 290d879cb83SAl Viro struct iov_iter *i) 291d879cb83SAl Viro { 292d879cb83SAl Viro size_t skip, copy, left, wanted; 293d879cb83SAl Viro const struct iovec *iov; 294d879cb83SAl Viro char __user *buf; 295d879cb83SAl Viro void *kaddr, *to; 296d879cb83SAl Viro 297d879cb83SAl Viro if (unlikely(bytes > i->count)) 298d879cb83SAl Viro bytes = i->count; 299d879cb83SAl Viro 300d879cb83SAl Viro if (unlikely(!bytes)) 301d879cb83SAl Viro return 0; 302d879cb83SAl Viro 30309fc68dcSAl Viro might_fault(); 304d879cb83SAl Viro wanted = bytes; 305d879cb83SAl Viro iov = i->iov; 306d879cb83SAl Viro skip = i->iov_offset; 307d879cb83SAl Viro buf = iov->iov_base + skip; 308d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 309d879cb83SAl Viro 3103fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { 311d879cb83SAl Viro kaddr = kmap_atomic(page); 312d879cb83SAl Viro to = kaddr + offset; 313d879cb83SAl Viro 314d879cb83SAl Viro /* first chunk, usually the only one */ 31509fc68dcSAl Viro left = copyin(to, buf, copy); 316d879cb83SAl Viro copy -= left; 317d879cb83SAl Viro skip += copy; 318d879cb83SAl Viro to += copy; 319d879cb83SAl Viro bytes -= copy; 320d879cb83SAl Viro 321d879cb83SAl Viro while (unlikely(!left && bytes)) { 322d879cb83SAl Viro iov++; 323d879cb83SAl Viro buf = iov->iov_base; 324d879cb83SAl Viro copy = min(bytes, iov->iov_len); 32509fc68dcSAl Viro left = copyin(to, buf, copy); 326d879cb83SAl Viro copy -= left; 327d879cb83SAl Viro skip = copy; 328d879cb83SAl Viro to += copy; 329d879cb83SAl Viro bytes -= copy; 330d879cb83SAl Viro } 331d879cb83SAl Viro if (likely(!bytes)) { 332d879cb83SAl Viro kunmap_atomic(kaddr); 333d879cb83SAl Viro goto done; 334d879cb83SAl Viro } 335d879cb83SAl Viro offset = to - kaddr; 336d879cb83SAl Viro buf += copy; 337d879cb83SAl Viro kunmap_atomic(kaddr); 338d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 339d879cb83SAl Viro } 340d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 3413fa6c507SMikulas Patocka 342d879cb83SAl Viro kaddr = kmap(page); 343d879cb83SAl Viro to = kaddr + offset; 34409fc68dcSAl Viro left = copyin(to, buf, copy); 345d879cb83SAl Viro copy -= left; 346d879cb83SAl Viro skip += copy; 347d879cb83SAl Viro to += copy; 348d879cb83SAl Viro bytes -= copy; 349d879cb83SAl Viro while (unlikely(!left && bytes)) { 350d879cb83SAl Viro iov++; 351d879cb83SAl Viro buf = iov->iov_base; 352d879cb83SAl Viro copy = min(bytes, iov->iov_len); 35309fc68dcSAl Viro left = copyin(to, buf, copy); 354d879cb83SAl Viro copy -= left; 355d879cb83SAl Viro skip = copy; 356d879cb83SAl Viro to += copy; 357d879cb83SAl Viro bytes -= copy; 358d879cb83SAl Viro } 359d879cb83SAl Viro kunmap(page); 3603fa6c507SMikulas Patocka 361d879cb83SAl Viro done: 362d879cb83SAl Viro if (skip == iov->iov_len) { 363d879cb83SAl Viro iov++; 364d879cb83SAl Viro skip = 0; 365d879cb83SAl Viro } 366d879cb83SAl Viro i->count -= wanted - bytes; 367d879cb83SAl Viro i->nr_segs -= iov - i->iov; 368d879cb83SAl Viro i->iov = iov; 369d879cb83SAl Viro i->iov_offset = skip; 370d879cb83SAl Viro return wanted - bytes; 371d879cb83SAl Viro } 372d879cb83SAl Viro 373241699cdSAl Viro #ifdef PIPE_PARANOIA 374241699cdSAl Viro static bool sanity(const struct iov_iter *i) 375241699cdSAl Viro { 376241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 3778cefc107SDavid Howells unsigned int p_head = pipe->head; 3788cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3798cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3808cefc107SDavid Howells unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); 3818cefc107SDavid Howells unsigned int i_head = i->head; 3828cefc107SDavid Howells unsigned int idx; 3838cefc107SDavid Howells 384241699cdSAl Viro if (i->iov_offset) { 385241699cdSAl Viro struct pipe_buffer *p; 3868cefc107SDavid Howells if (unlikely(p_occupancy == 0)) 387241699cdSAl Viro goto Bad; // pipe must be non-empty 3888cefc107SDavid Howells if (unlikely(i_head != p_head - 1)) 389241699cdSAl Viro goto Bad; // must be at the last buffer... 390241699cdSAl Viro 3918cefc107SDavid Howells p = &pipe->bufs[i_head & p_mask]; 392241699cdSAl Viro if (unlikely(p->offset + p->len != i->iov_offset)) 393241699cdSAl Viro goto Bad; // ... at the end of segment 394241699cdSAl Viro } else { 3958cefc107SDavid Howells if (i_head != p_head) 396241699cdSAl Viro goto Bad; // must be right after the last buffer 397241699cdSAl Viro } 398241699cdSAl Viro return true; 399241699cdSAl Viro Bad: 4008cefc107SDavid Howells printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); 4018cefc107SDavid Howells printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", 4028cefc107SDavid Howells p_head, p_tail, pipe->ring_size); 4038cefc107SDavid Howells for (idx = 0; idx < pipe->ring_size; idx++) 404241699cdSAl Viro printk(KERN_ERR "[%p %p %d %d]\n", 405241699cdSAl Viro pipe->bufs[idx].ops, 406241699cdSAl Viro pipe->bufs[idx].page, 407241699cdSAl Viro pipe->bufs[idx].offset, 408241699cdSAl Viro pipe->bufs[idx].len); 409241699cdSAl Viro WARN_ON(1); 410241699cdSAl Viro return false; 411241699cdSAl Viro } 412241699cdSAl Viro #else 413241699cdSAl Viro #define sanity(i) true 414241699cdSAl Viro #endif 415241699cdSAl Viro 416241699cdSAl Viro static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, 417241699cdSAl Viro struct iov_iter *i) 418241699cdSAl Viro { 419241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 420241699cdSAl Viro struct pipe_buffer *buf; 4218cefc107SDavid Howells unsigned int p_tail = pipe->tail; 4228cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 4238cefc107SDavid Howells unsigned int i_head = i->head; 424241699cdSAl Viro size_t off; 425241699cdSAl Viro 426241699cdSAl Viro if (unlikely(bytes > i->count)) 427241699cdSAl Viro bytes = i->count; 428241699cdSAl Viro 429241699cdSAl Viro if (unlikely(!bytes)) 430241699cdSAl Viro return 0; 431241699cdSAl Viro 432241699cdSAl Viro if (!sanity(i)) 433241699cdSAl Viro return 0; 434241699cdSAl Viro 435241699cdSAl Viro off = i->iov_offset; 4368cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 437241699cdSAl Viro if (off) { 438241699cdSAl Viro if (offset == off && buf->page == page) { 439241699cdSAl Viro /* merge with the last one */ 440241699cdSAl Viro buf->len += bytes; 441241699cdSAl Viro i->iov_offset += bytes; 442241699cdSAl Viro goto out; 443241699cdSAl Viro } 4448cefc107SDavid Howells i_head++; 4458cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 446241699cdSAl Viro } 4476718b6f8SDavid Howells if (pipe_full(i_head, p_tail, pipe->max_usage)) 448241699cdSAl Viro return 0; 4498cefc107SDavid Howells 450241699cdSAl Viro buf->ops = &page_cache_pipe_buf_ops; 4518cefc107SDavid Howells get_page(page); 4528cefc107SDavid Howells buf->page = page; 453241699cdSAl Viro buf->offset = offset; 454241699cdSAl Viro buf->len = bytes; 4558cefc107SDavid Howells 4568cefc107SDavid Howells pipe->head = i_head + 1; 457241699cdSAl Viro i->iov_offset = offset + bytes; 4588cefc107SDavid Howells i->head = i_head; 459241699cdSAl Viro out: 460241699cdSAl Viro i->count -= bytes; 461241699cdSAl Viro return bytes; 462241699cdSAl Viro } 463241699cdSAl Viro 464d879cb83SAl Viro /* 465171a0203SAnton Altaparmakov * Fault in one or more iovecs of the given iov_iter, to a maximum length of 466171a0203SAnton Altaparmakov * bytes. For each iovec, fault in each page that constitutes the iovec. 467171a0203SAnton Altaparmakov * 468171a0203SAnton Altaparmakov * Return 0 on success, or non-zero if the memory could not be accessed (i.e. 469171a0203SAnton Altaparmakov * because it is an invalid address). 470171a0203SAnton Altaparmakov */ 471d4690f1eSAl Viro int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) 472171a0203SAnton Altaparmakov { 473171a0203SAnton Altaparmakov size_t skip = i->iov_offset; 474171a0203SAnton Altaparmakov const struct iovec *iov; 475171a0203SAnton Altaparmakov int err; 476171a0203SAnton Altaparmakov struct iovec v; 477171a0203SAnton Altaparmakov 4780e8f0d67SAl Viro if (iter_is_iovec(i)) { 479171a0203SAnton Altaparmakov iterate_iovec(i, bytes, v, iov, skip, ({ 4804bce9f6eSAl Viro err = fault_in_pages_readable(v.iov_base, v.iov_len); 481171a0203SAnton Altaparmakov if (unlikely(err)) 482171a0203SAnton Altaparmakov return err; 483171a0203SAnton Altaparmakov 0;})) 484171a0203SAnton Altaparmakov } 485171a0203SAnton Altaparmakov return 0; 486171a0203SAnton Altaparmakov } 487d4690f1eSAl Viro EXPORT_SYMBOL(iov_iter_fault_in_readable); 488171a0203SAnton Altaparmakov 489aa563d7bSDavid Howells void iov_iter_init(struct iov_iter *i, unsigned int direction, 490d879cb83SAl Viro const struct iovec *iov, unsigned long nr_segs, 491d879cb83SAl Viro size_t count) 492d879cb83SAl Viro { 493aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 494aa563d7bSDavid Howells direction &= READ | WRITE; 495aa563d7bSDavid Howells 496d879cb83SAl Viro /* It will get better. Eventually... */ 497db68ce10SAl Viro if (uaccess_kernel()) { 498aa563d7bSDavid Howells i->type = ITER_KVEC | direction; 499d879cb83SAl Viro i->kvec = (struct kvec *)iov; 500d879cb83SAl Viro } else { 501aa563d7bSDavid Howells i->type = ITER_IOVEC | direction; 502d879cb83SAl Viro i->iov = iov; 503d879cb83SAl Viro } 504d879cb83SAl Viro i->nr_segs = nr_segs; 505d879cb83SAl Viro i->iov_offset = 0; 506d879cb83SAl Viro i->count = count; 507d879cb83SAl Viro } 508d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_init); 509d879cb83SAl Viro 510241699cdSAl Viro static inline bool allocated(struct pipe_buffer *buf) 511241699cdSAl Viro { 512241699cdSAl Viro return buf->ops == &default_pipe_buf_ops; 513241699cdSAl Viro } 514241699cdSAl Viro 5158cefc107SDavid Howells static inline void data_start(const struct iov_iter *i, 5168cefc107SDavid Howells unsigned int *iter_headp, size_t *offp) 517241699cdSAl Viro { 5188cefc107SDavid Howells unsigned int p_mask = i->pipe->ring_size - 1; 5198cefc107SDavid Howells unsigned int iter_head = i->head; 520241699cdSAl Viro size_t off = i->iov_offset; 5218cefc107SDavid Howells 5228cefc107SDavid Howells if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || 5238cefc107SDavid Howells off == PAGE_SIZE)) { 5248cefc107SDavid Howells iter_head++; 525241699cdSAl Viro off = 0; 526241699cdSAl Viro } 5278cefc107SDavid Howells *iter_headp = iter_head; 528241699cdSAl Viro *offp = off; 529241699cdSAl Viro } 530241699cdSAl Viro 531241699cdSAl Viro static size_t push_pipe(struct iov_iter *i, size_t size, 5328cefc107SDavid Howells int *iter_headp, size_t *offp) 533241699cdSAl Viro { 534241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5358cefc107SDavid Howells unsigned int p_tail = pipe->tail; 5368cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5378cefc107SDavid Howells unsigned int iter_head; 538241699cdSAl Viro size_t off; 539241699cdSAl Viro ssize_t left; 540241699cdSAl Viro 541241699cdSAl Viro if (unlikely(size > i->count)) 542241699cdSAl Viro size = i->count; 543241699cdSAl Viro if (unlikely(!size)) 544241699cdSAl Viro return 0; 545241699cdSAl Viro 546241699cdSAl Viro left = size; 5478cefc107SDavid Howells data_start(i, &iter_head, &off); 5488cefc107SDavid Howells *iter_headp = iter_head; 549241699cdSAl Viro *offp = off; 550241699cdSAl Viro if (off) { 551241699cdSAl Viro left -= PAGE_SIZE - off; 552241699cdSAl Viro if (left <= 0) { 5538cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len += size; 554241699cdSAl Viro return size; 555241699cdSAl Viro } 5568cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; 5578cefc107SDavid Howells iter_head++; 558241699cdSAl Viro } 5596718b6f8SDavid Howells while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { 5608cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; 561241699cdSAl Viro struct page *page = alloc_page(GFP_USER); 562241699cdSAl Viro if (!page) 563241699cdSAl Viro break; 5648cefc107SDavid Howells 5658cefc107SDavid Howells buf->ops = &default_pipe_buf_ops; 5668cefc107SDavid Howells buf->page = page; 5678cefc107SDavid Howells buf->offset = 0; 5688cefc107SDavid Howells buf->len = min_t(ssize_t, left, PAGE_SIZE); 5698cefc107SDavid Howells left -= buf->len; 5708cefc107SDavid Howells iter_head++; 5718cefc107SDavid Howells pipe->head = iter_head; 5728cefc107SDavid Howells 5738cefc107SDavid Howells if (left == 0) 574241699cdSAl Viro return size; 575241699cdSAl Viro } 576241699cdSAl Viro return size - left; 577241699cdSAl Viro } 578241699cdSAl Viro 579241699cdSAl Viro static size_t copy_pipe_to_iter(const void *addr, size_t bytes, 580241699cdSAl Viro struct iov_iter *i) 581241699cdSAl Viro { 582241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5838cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5848cefc107SDavid Howells unsigned int i_head; 585241699cdSAl Viro size_t n, off; 586241699cdSAl Viro 587241699cdSAl Viro if (!sanity(i)) 588241699cdSAl Viro return 0; 589241699cdSAl Viro 5908cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 591241699cdSAl Viro if (unlikely(!n)) 592241699cdSAl Viro return 0; 5938cefc107SDavid Howells do { 594241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 5958cefc107SDavid Howells memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); 5968cefc107SDavid Howells i->head = i_head; 597241699cdSAl Viro i->iov_offset = off + chunk; 598241699cdSAl Viro n -= chunk; 599241699cdSAl Viro addr += chunk; 6008cefc107SDavid Howells off = 0; 6018cefc107SDavid Howells i_head++; 6028cefc107SDavid Howells } while (n); 603241699cdSAl Viro i->count -= bytes; 604241699cdSAl Viro return bytes; 605241699cdSAl Viro } 606241699cdSAl Viro 607f9152895SAl Viro static __wsum csum_and_memcpy(void *to, const void *from, size_t len, 608f9152895SAl Viro __wsum sum, size_t off) 609f9152895SAl Viro { 610cc44c17bSAl Viro __wsum next = csum_partial_copy_nocheck(from, to, len); 611f9152895SAl Viro return csum_block_add(sum, next, off); 612f9152895SAl Viro } 613f9152895SAl Viro 61478e1f386SAl Viro static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, 61552cbd23aSWillem de Bruijn struct csum_state *csstate, 61652cbd23aSWillem de Bruijn struct iov_iter *i) 61778e1f386SAl Viro { 61878e1f386SAl Viro struct pipe_inode_info *pipe = i->pipe; 6198cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 62052cbd23aSWillem de Bruijn __wsum sum = csstate->csum; 62152cbd23aSWillem de Bruijn size_t off = csstate->off; 6228cefc107SDavid Howells unsigned int i_head; 62378e1f386SAl Viro size_t n, r; 62478e1f386SAl Viro 62578e1f386SAl Viro if (!sanity(i)) 62678e1f386SAl Viro return 0; 62778e1f386SAl Viro 6288cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &r); 62978e1f386SAl Viro if (unlikely(!n)) 63078e1f386SAl Viro return 0; 6318cefc107SDavid Howells do { 63278e1f386SAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - r); 6338cefc107SDavid Howells char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); 634f9152895SAl Viro sum = csum_and_memcpy(p + r, addr, chunk, sum, off); 63578e1f386SAl Viro kunmap_atomic(p); 6368cefc107SDavid Howells i->head = i_head; 63778e1f386SAl Viro i->iov_offset = r + chunk; 63878e1f386SAl Viro n -= chunk; 63978e1f386SAl Viro off += chunk; 64078e1f386SAl Viro addr += chunk; 6418cefc107SDavid Howells r = 0; 6428cefc107SDavid Howells i_head++; 6438cefc107SDavid Howells } while (n); 64478e1f386SAl Viro i->count -= bytes; 64552cbd23aSWillem de Bruijn csstate->csum = sum; 64652cbd23aSWillem de Bruijn csstate->off = off; 64778e1f386SAl Viro return bytes; 64878e1f386SAl Viro } 64978e1f386SAl Viro 650aa28de27SAl Viro size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 651d879cb83SAl Viro { 65236f7a8a4SAl Viro const char *from = addr; 65300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 654241699cdSAl Viro return copy_pipe_to_iter(addr, bytes, i); 65509fc68dcSAl Viro if (iter_is_iovec(i)) 65609fc68dcSAl Viro might_fault(); 657d879cb83SAl Viro iterate_and_advance(i, bytes, v, 65809fc68dcSAl Viro copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 659d879cb83SAl Viro memcpy_to_page(v.bv_page, v.bv_offset, 660d879cb83SAl Viro (from += v.bv_len) - v.bv_len, v.bv_len), 6617ff50620SDavid Howells memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 6627ff50620SDavid Howells memcpy_to_page(v.bv_page, v.bv_offset, 6637ff50620SDavid Howells (from += v.bv_len) - v.bv_len, v.bv_len) 664d879cb83SAl Viro ) 665d879cb83SAl Viro 666d879cb83SAl Viro return bytes; 667d879cb83SAl Viro } 668aa28de27SAl Viro EXPORT_SYMBOL(_copy_to_iter); 669d879cb83SAl Viro 670ec6347bbSDan Williams #ifdef CONFIG_ARCH_HAS_COPY_MC 671ec6347bbSDan Williams static int copyout_mc(void __user *to, const void *from, size_t n) 6728780356eSDan Williams { 67396d4f267SLinus Torvalds if (access_ok(to, n)) { 674d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 675ec6347bbSDan Williams n = copy_mc_to_user((__force void *) to, from, n); 6768780356eSDan Williams } 6778780356eSDan Williams return n; 6788780356eSDan Williams } 6798780356eSDan Williams 680ec6347bbSDan Williams static unsigned long copy_mc_to_page(struct page *page, size_t offset, 6818780356eSDan Williams const char *from, size_t len) 6828780356eSDan Williams { 6838780356eSDan Williams unsigned long ret; 6848780356eSDan Williams char *to; 6858780356eSDan Williams 6868780356eSDan Williams to = kmap_atomic(page); 687ec6347bbSDan Williams ret = copy_mc_to_kernel(to + offset, from, len); 6888780356eSDan Williams kunmap_atomic(to); 6898780356eSDan Williams 6908780356eSDan Williams return ret; 6918780356eSDan Williams } 6928780356eSDan Williams 693ec6347bbSDan Williams static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, 694ca146f6fSDan Williams struct iov_iter *i) 695ca146f6fSDan Williams { 696ca146f6fSDan Williams struct pipe_inode_info *pipe = i->pipe; 6978cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 6988cefc107SDavid Howells unsigned int i_head; 699ca146f6fSDan Williams size_t n, off, xfer = 0; 700ca146f6fSDan Williams 701ca146f6fSDan Williams if (!sanity(i)) 702ca146f6fSDan Williams return 0; 703ca146f6fSDan Williams 7048cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 705ca146f6fSDan Williams if (unlikely(!n)) 706ca146f6fSDan Williams return 0; 7078cefc107SDavid Howells do { 708ca146f6fSDan Williams size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 709ca146f6fSDan Williams unsigned long rem; 710ca146f6fSDan Williams 711ec6347bbSDan Williams rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, 7128cefc107SDavid Howells off, addr, chunk); 7138cefc107SDavid Howells i->head = i_head; 714ca146f6fSDan Williams i->iov_offset = off + chunk - rem; 715ca146f6fSDan Williams xfer += chunk - rem; 716ca146f6fSDan Williams if (rem) 717ca146f6fSDan Williams break; 718ca146f6fSDan Williams n -= chunk; 719ca146f6fSDan Williams addr += chunk; 7208cefc107SDavid Howells off = 0; 7218cefc107SDavid Howells i_head++; 7228cefc107SDavid Howells } while (n); 723ca146f6fSDan Williams i->count -= xfer; 724ca146f6fSDan Williams return xfer; 725ca146f6fSDan Williams } 726ca146f6fSDan Williams 727bf3eeb9bSDan Williams /** 728ec6347bbSDan Williams * _copy_mc_to_iter - copy to iter with source memory error exception handling 729bf3eeb9bSDan Williams * @addr: source kernel address 730bf3eeb9bSDan Williams * @bytes: total transfer length 731bf3eeb9bSDan Williams * @iter: destination iterator 732bf3eeb9bSDan Williams * 733ec6347bbSDan Williams * The pmem driver deploys this for the dax operation 734ec6347bbSDan Williams * (dax_copy_to_iter()) for dax reads (bypass page-cache and the 735ec6347bbSDan Williams * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes 736ec6347bbSDan Williams * successfully copied. 737bf3eeb9bSDan Williams * 738ec6347bbSDan Williams * The main differences between this and typical _copy_to_iter(). 739bf3eeb9bSDan Williams * 740bf3eeb9bSDan Williams * * Typical tail/residue handling after a fault retries the copy 741bf3eeb9bSDan Williams * byte-by-byte until the fault happens again. Re-triggering machine 742bf3eeb9bSDan Williams * checks is potentially fatal so the implementation uses source 743bf3eeb9bSDan Williams * alignment and poison alignment assumptions to avoid re-triggering 744bf3eeb9bSDan Williams * hardware exceptions. 745bf3eeb9bSDan Williams * 746bf3eeb9bSDan Williams * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. 747bf3eeb9bSDan Williams * Compare to copy_to_iter() where only ITER_IOVEC attempts might return 748bf3eeb9bSDan Williams * a short copy. 749bf3eeb9bSDan Williams */ 750ec6347bbSDan Williams size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 7518780356eSDan Williams { 7528780356eSDan Williams const char *from = addr; 7538780356eSDan Williams unsigned long rem, curr_addr, s_addr = (unsigned long) addr; 7548780356eSDan Williams 75500e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 756ec6347bbSDan Williams return copy_mc_pipe_to_iter(addr, bytes, i); 7578780356eSDan Williams if (iter_is_iovec(i)) 7588780356eSDan Williams might_fault(); 7598780356eSDan Williams iterate_and_advance(i, bytes, v, 760ec6347bbSDan Williams copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len, 761ec6347bbSDan Williams v.iov_len), 7628780356eSDan Williams ({ 763ec6347bbSDan Williams rem = copy_mc_to_page(v.bv_page, v.bv_offset, 7648780356eSDan Williams (from += v.bv_len) - v.bv_len, v.bv_len); 7658780356eSDan Williams if (rem) { 7668780356eSDan Williams curr_addr = (unsigned long) from; 7678780356eSDan Williams bytes = curr_addr - s_addr - rem; 7688780356eSDan Williams return bytes; 7698780356eSDan Williams } 7708780356eSDan Williams }), 7718780356eSDan Williams ({ 772ec6347bbSDan Williams rem = copy_mc_to_kernel(v.iov_base, (from += v.iov_len) 773ec6347bbSDan Williams - v.iov_len, v.iov_len); 7748780356eSDan Williams if (rem) { 7758780356eSDan Williams curr_addr = (unsigned long) from; 7768780356eSDan Williams bytes = curr_addr - s_addr - rem; 7778780356eSDan Williams return bytes; 7788780356eSDan Williams } 7797ff50620SDavid Howells }), 7807ff50620SDavid Howells ({ 7817ff50620SDavid Howells rem = copy_mc_to_page(v.bv_page, v.bv_offset, 7827ff50620SDavid Howells (from += v.bv_len) - v.bv_len, v.bv_len); 7837ff50620SDavid Howells if (rem) { 7847ff50620SDavid Howells curr_addr = (unsigned long) from; 7857ff50620SDavid Howells bytes = curr_addr - s_addr - rem; 7867ff50620SDavid Howells rcu_read_unlock(); 7873d14ec1fSDavid Howells i->iov_offset += bytes; 7883d14ec1fSDavid Howells i->count -= bytes; 7897ff50620SDavid Howells return bytes; 7907ff50620SDavid Howells } 7918780356eSDan Williams }) 7928780356eSDan Williams ) 7938780356eSDan Williams 7948780356eSDan Williams return bytes; 7958780356eSDan Williams } 796ec6347bbSDan Williams EXPORT_SYMBOL_GPL(_copy_mc_to_iter); 797ec6347bbSDan Williams #endif /* CONFIG_ARCH_HAS_COPY_MC */ 7988780356eSDan Williams 799aa28de27SAl Viro size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) 800d879cb83SAl Viro { 801d879cb83SAl Viro char *to = addr; 80200e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 803241699cdSAl Viro WARN_ON(1); 804241699cdSAl Viro return 0; 805241699cdSAl Viro } 80609fc68dcSAl Viro if (iter_is_iovec(i)) 80709fc68dcSAl Viro might_fault(); 808d879cb83SAl Viro iterate_and_advance(i, bytes, v, 80909fc68dcSAl Viro copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 810d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 811d879cb83SAl Viro v.bv_offset, v.bv_len), 8127ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 8137ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 8147ff50620SDavid Howells v.bv_offset, v.bv_len) 815d879cb83SAl Viro ) 816d879cb83SAl Viro 817d879cb83SAl Viro return bytes; 818d879cb83SAl Viro } 819aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter); 820d879cb83SAl Viro 821aa28de27SAl Viro size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) 822d879cb83SAl Viro { 823d879cb83SAl Viro char *to = addr; 82400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 825241699cdSAl Viro WARN_ON(1); 826241699cdSAl Viro return 0; 827241699cdSAl Viro } 828d879cb83SAl Viro iterate_and_advance(i, bytes, v, 8293f763453SAl Viro __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, 830d879cb83SAl Viro v.iov_base, v.iov_len), 831d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 832d879cb83SAl Viro v.bv_offset, v.bv_len), 8337ff50620SDavid Howells memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 8347ff50620SDavid Howells memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 8357ff50620SDavid Howells v.bv_offset, v.bv_len) 836d879cb83SAl Viro ) 837d879cb83SAl Viro 838d879cb83SAl Viro return bytes; 839d879cb83SAl Viro } 840aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_nocache); 841d879cb83SAl Viro 8420aed55afSDan Williams #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE 843abd08d7dSDan Williams /** 844abd08d7dSDan Williams * _copy_from_iter_flushcache - write destination through cpu cache 845abd08d7dSDan Williams * @addr: destination kernel address 846abd08d7dSDan Williams * @bytes: total transfer length 847abd08d7dSDan Williams * @iter: source iterator 848abd08d7dSDan Williams * 849abd08d7dSDan Williams * The pmem driver arranges for filesystem-dax to use this facility via 850abd08d7dSDan Williams * dax_copy_from_iter() for ensuring that writes to persistent memory 851abd08d7dSDan Williams * are flushed through the CPU cache. It is differentiated from 852abd08d7dSDan Williams * _copy_from_iter_nocache() in that guarantees all data is flushed for 853abd08d7dSDan Williams * all iterator types. The _copy_from_iter_nocache() only attempts to 854abd08d7dSDan Williams * bypass the cache for the ITER_IOVEC case, and on some archs may use 855abd08d7dSDan Williams * instructions that strand dirty-data in the cache. 856abd08d7dSDan Williams */ 8576a37e940SLinus Torvalds size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 8580aed55afSDan Williams { 8590aed55afSDan Williams char *to = addr; 86000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 8610aed55afSDan Williams WARN_ON(1); 8620aed55afSDan Williams return 0; 8630aed55afSDan Williams } 8640aed55afSDan Williams iterate_and_advance(i, bytes, v, 8650aed55afSDan Williams __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, 8660aed55afSDan Williams v.iov_base, v.iov_len), 8670aed55afSDan Williams memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 8680aed55afSDan Williams v.bv_offset, v.bv_len), 8690aed55afSDan Williams memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, 8707ff50620SDavid Howells v.iov_len), 8717ff50620SDavid Howells memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 8727ff50620SDavid Howells v.bv_offset, v.bv_len) 8730aed55afSDan Williams ) 8740aed55afSDan Williams 8750aed55afSDan Williams return bytes; 8760aed55afSDan Williams } 8776a37e940SLinus Torvalds EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); 8780aed55afSDan Williams #endif 8790aed55afSDan Williams 88072e809edSAl Viro static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) 88172e809edSAl Viro { 8826daef95bSEric Dumazet struct page *head; 8836daef95bSEric Dumazet size_t v = n + offset; 8846daef95bSEric Dumazet 8856daef95bSEric Dumazet /* 8866daef95bSEric Dumazet * The general case needs to access the page order in order 8876daef95bSEric Dumazet * to compute the page size. 8886daef95bSEric Dumazet * However, we mostly deal with order-0 pages and thus can 8896daef95bSEric Dumazet * avoid a possible cache line miss for requests that fit all 8906daef95bSEric Dumazet * page orders. 8916daef95bSEric Dumazet */ 8926daef95bSEric Dumazet if (n <= v && v <= PAGE_SIZE) 8936daef95bSEric Dumazet return true; 8946daef95bSEric Dumazet 8956daef95bSEric Dumazet head = compound_head(page); 8966daef95bSEric Dumazet v += (page - head) << PAGE_SHIFT; 897a90bcb86SPetar Penkov 898a50b854eSMatthew Wilcox (Oracle) if (likely(n <= v && v <= (page_size(head)))) 89972e809edSAl Viro return true; 90072e809edSAl Viro WARN_ON(1); 90172e809edSAl Viro return false; 90272e809edSAl Viro } 903cbbd26b8SAl Viro 90408aa6479SAl Viro static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 905d879cb83SAl Viro struct iov_iter *i) 906d879cb83SAl Viro { 907*28f38db7SAl Viro if (likely(iter_is_iovec(i))) 908*28f38db7SAl Viro return copy_page_to_iter_iovec(page, offset, bytes, i); 909*28f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 910d879cb83SAl Viro void *kaddr = kmap_atomic(page); 911d879cb83SAl Viro size_t wanted = copy_to_iter(kaddr + offset, bytes, i); 912d879cb83SAl Viro kunmap_atomic(kaddr); 913d879cb83SAl Viro return wanted; 914*28f38db7SAl Viro } 915*28f38db7SAl Viro if (iov_iter_is_pipe(i)) 916*28f38db7SAl Viro return copy_page_to_iter_pipe(page, offset, bytes, i); 917*28f38db7SAl Viro if (unlikely(iov_iter_is_discard(i))) { 918a506abc7SAl Viro if (unlikely(i->count < bytes)) 919a506abc7SAl Viro bytes = i->count; 920a506abc7SAl Viro i->count -= bytes; 9219ea9ce04SDavid Howells return bytes; 922*28f38db7SAl Viro } 923*28f38db7SAl Viro WARN_ON(1); 924*28f38db7SAl Viro return 0; 925d879cb83SAl Viro } 92608aa6479SAl Viro 92708aa6479SAl Viro size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 92808aa6479SAl Viro struct iov_iter *i) 92908aa6479SAl Viro { 93008aa6479SAl Viro size_t res = 0; 93108aa6479SAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 93208aa6479SAl Viro return 0; 93308aa6479SAl Viro page += offset / PAGE_SIZE; // first subpage 93408aa6479SAl Viro offset %= PAGE_SIZE; 93508aa6479SAl Viro while (1) { 93608aa6479SAl Viro size_t n = __copy_page_to_iter(page, offset, 93708aa6479SAl Viro min(bytes, (size_t)PAGE_SIZE - offset), i); 93808aa6479SAl Viro res += n; 93908aa6479SAl Viro bytes -= n; 94008aa6479SAl Viro if (!bytes || !n) 94108aa6479SAl Viro break; 94208aa6479SAl Viro offset += n; 94308aa6479SAl Viro if (offset == PAGE_SIZE) { 94408aa6479SAl Viro page++; 94508aa6479SAl Viro offset = 0; 94608aa6479SAl Viro } 94708aa6479SAl Viro } 94808aa6479SAl Viro return res; 94908aa6479SAl Viro } 950d879cb83SAl Viro EXPORT_SYMBOL(copy_page_to_iter); 951d879cb83SAl Viro 952d879cb83SAl Viro size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, 953d879cb83SAl Viro struct iov_iter *i) 954d879cb83SAl Viro { 95572e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 95672e809edSAl Viro return 0; 957*28f38db7SAl Viro if (likely(iter_is_iovec(i))) 958*28f38db7SAl Viro return copy_page_from_iter_iovec(page, offset, bytes, i); 959*28f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 960d879cb83SAl Viro void *kaddr = kmap_atomic(page); 961aa28de27SAl Viro size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); 962d879cb83SAl Viro kunmap_atomic(kaddr); 963d879cb83SAl Viro return wanted; 964*28f38db7SAl Viro } 965*28f38db7SAl Viro WARN_ON(1); 966*28f38db7SAl Viro return 0; 967d879cb83SAl Viro } 968d879cb83SAl Viro EXPORT_SYMBOL(copy_page_from_iter); 969d879cb83SAl Viro 970241699cdSAl Viro static size_t pipe_zero(size_t bytes, struct iov_iter *i) 971241699cdSAl Viro { 972241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 9738cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9748cefc107SDavid Howells unsigned int i_head; 975241699cdSAl Viro size_t n, off; 976241699cdSAl Viro 977241699cdSAl Viro if (!sanity(i)) 978241699cdSAl Viro return 0; 979241699cdSAl Viro 9808cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 981241699cdSAl Viro if (unlikely(!n)) 982241699cdSAl Viro return 0; 983241699cdSAl Viro 9848cefc107SDavid Howells do { 985241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 9868cefc107SDavid Howells memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); 9878cefc107SDavid Howells i->head = i_head; 988241699cdSAl Viro i->iov_offset = off + chunk; 989241699cdSAl Viro n -= chunk; 9908cefc107SDavid Howells off = 0; 9918cefc107SDavid Howells i_head++; 9928cefc107SDavid Howells } while (n); 993241699cdSAl Viro i->count -= bytes; 994241699cdSAl Viro return bytes; 995241699cdSAl Viro } 996241699cdSAl Viro 997d879cb83SAl Viro size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 998d879cb83SAl Viro { 99900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1000241699cdSAl Viro return pipe_zero(bytes, i); 1001d879cb83SAl Viro iterate_and_advance(i, bytes, v, 100209fc68dcSAl Viro clear_user(v.iov_base, v.iov_len), 1003d879cb83SAl Viro memzero_page(v.bv_page, v.bv_offset, v.bv_len), 10047ff50620SDavid Howells memset(v.iov_base, 0, v.iov_len), 10057ff50620SDavid Howells memzero_page(v.bv_page, v.bv_offset, v.bv_len) 1006d879cb83SAl Viro ) 1007d879cb83SAl Viro 1008d879cb83SAl Viro return bytes; 1009d879cb83SAl Viro } 1010d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_zero); 1011d879cb83SAl Viro 1012d879cb83SAl Viro size_t iov_iter_copy_from_user_atomic(struct page *page, 1013d879cb83SAl Viro struct iov_iter *i, unsigned long offset, size_t bytes) 1014d879cb83SAl Viro { 1015d879cb83SAl Viro char *kaddr = kmap_atomic(page), *p = kaddr + offset; 101672e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) { 101772e809edSAl Viro kunmap_atomic(kaddr); 101872e809edSAl Viro return 0; 101972e809edSAl Viro } 10209ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1021241699cdSAl Viro kunmap_atomic(kaddr); 1022241699cdSAl Viro WARN_ON(1); 1023241699cdSAl Viro return 0; 1024241699cdSAl Viro } 1025d879cb83SAl Viro iterate_all_kinds(i, bytes, v, 102609fc68dcSAl Viro copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 1027d879cb83SAl Viro memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 1028d879cb83SAl Viro v.bv_offset, v.bv_len), 10297ff50620SDavid Howells memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 10307ff50620SDavid Howells memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 10317ff50620SDavid Howells v.bv_offset, v.bv_len) 1032d879cb83SAl Viro ) 1033d879cb83SAl Viro kunmap_atomic(kaddr); 1034d879cb83SAl Viro return bytes; 1035d879cb83SAl Viro } 1036d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); 1037d879cb83SAl Viro 1038b9dc6f65SAl Viro static inline void pipe_truncate(struct iov_iter *i) 1039241699cdSAl Viro { 1040241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 10418cefc107SDavid Howells unsigned int p_tail = pipe->tail; 10428cefc107SDavid Howells unsigned int p_head = pipe->head; 10438cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10448cefc107SDavid Howells 10458cefc107SDavid Howells if (!pipe_empty(p_head, p_tail)) { 10468cefc107SDavid Howells struct pipe_buffer *buf; 10478cefc107SDavid Howells unsigned int i_head = i->head; 1048b9dc6f65SAl Viro size_t off = i->iov_offset; 10498cefc107SDavid Howells 1050b9dc6f65SAl Viro if (off) { 10518cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 10528cefc107SDavid Howells buf->len = off - buf->offset; 10538cefc107SDavid Howells i_head++; 1054b9dc6f65SAl Viro } 10558cefc107SDavid Howells while (p_head != i_head) { 10568cefc107SDavid Howells p_head--; 10578cefc107SDavid Howells pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); 1058241699cdSAl Viro } 10598cefc107SDavid Howells 10608cefc107SDavid Howells pipe->head = p_head; 1061241699cdSAl Viro } 1062b9dc6f65SAl Viro } 1063b9dc6f65SAl Viro 1064b9dc6f65SAl Viro static void pipe_advance(struct iov_iter *i, size_t size) 1065b9dc6f65SAl Viro { 1066b9dc6f65SAl Viro struct pipe_inode_info *pipe = i->pipe; 1067b9dc6f65SAl Viro if (size) { 1068b9dc6f65SAl Viro struct pipe_buffer *buf; 10698cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10708cefc107SDavid Howells unsigned int i_head = i->head; 1071b9dc6f65SAl Viro size_t off = i->iov_offset, left = size; 10728cefc107SDavid Howells 1073b9dc6f65SAl Viro if (off) /* make it relative to the beginning of buffer */ 10748cefc107SDavid Howells left += off - pipe->bufs[i_head & p_mask].offset; 1075b9dc6f65SAl Viro while (1) { 10768cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 1077b9dc6f65SAl Viro if (left <= buf->len) 1078b9dc6f65SAl Viro break; 1079b9dc6f65SAl Viro left -= buf->len; 10808cefc107SDavid Howells i_head++; 1081b9dc6f65SAl Viro } 10828cefc107SDavid Howells i->head = i_head; 1083b9dc6f65SAl Viro i->iov_offset = buf->offset + left; 1084b9dc6f65SAl Viro } 1085b9dc6f65SAl Viro i->count -= size; 1086b9dc6f65SAl Viro /* ... and discard everything past that point */ 1087b9dc6f65SAl Viro pipe_truncate(i); 1088241699cdSAl Viro } 1089241699cdSAl Viro 109054c8195bSPavel Begunkov static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) 109154c8195bSPavel Begunkov { 109254c8195bSPavel Begunkov struct bvec_iter bi; 109354c8195bSPavel Begunkov 109454c8195bSPavel Begunkov bi.bi_size = i->count; 109554c8195bSPavel Begunkov bi.bi_bvec_done = i->iov_offset; 109654c8195bSPavel Begunkov bi.bi_idx = 0; 109754c8195bSPavel Begunkov bvec_iter_advance(i->bvec, &bi, size); 109854c8195bSPavel Begunkov 109954c8195bSPavel Begunkov i->bvec += bi.bi_idx; 110054c8195bSPavel Begunkov i->nr_segs -= bi.bi_idx; 110154c8195bSPavel Begunkov i->count = bi.bi_size; 110254c8195bSPavel Begunkov i->iov_offset = bi.bi_bvec_done; 110354c8195bSPavel Begunkov } 110454c8195bSPavel Begunkov 1105d879cb83SAl Viro void iov_iter_advance(struct iov_iter *i, size_t size) 1106d879cb83SAl Viro { 11073b3fc051SAl Viro if (unlikely(i->count < size)) 11083b3fc051SAl Viro size = i->count; 110900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 1110241699cdSAl Viro pipe_advance(i, size); 1111241699cdSAl Viro return; 1112241699cdSAl Viro } 11139ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) { 11149ea9ce04SDavid Howells i->count -= size; 11159ea9ce04SDavid Howells return; 11169ea9ce04SDavid Howells } 11177ff50620SDavid Howells if (unlikely(iov_iter_is_xarray(i))) { 11187ff50620SDavid Howells i->iov_offset += size; 11197ff50620SDavid Howells i->count -= size; 11207ff50620SDavid Howells return; 11217ff50620SDavid Howells } 112254c8195bSPavel Begunkov if (iov_iter_is_bvec(i)) { 112354c8195bSPavel Begunkov iov_iter_bvec_advance(i, size); 112454c8195bSPavel Begunkov return; 112554c8195bSPavel Begunkov } 11267ff50620SDavid Howells iterate_and_advance(i, size, v, 0, 0, 0, 0) 1127d879cb83SAl Viro } 1128d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_advance); 1129d879cb83SAl Viro 113027c0e374SAl Viro void iov_iter_revert(struct iov_iter *i, size_t unroll) 113127c0e374SAl Viro { 113227c0e374SAl Viro if (!unroll) 113327c0e374SAl Viro return; 11345b47d59aSAl Viro if (WARN_ON(unroll > MAX_RW_COUNT)) 11355b47d59aSAl Viro return; 113627c0e374SAl Viro i->count += unroll; 113700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 113827c0e374SAl Viro struct pipe_inode_info *pipe = i->pipe; 11398cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 11408cefc107SDavid Howells unsigned int i_head = i->head; 114127c0e374SAl Viro size_t off = i->iov_offset; 114227c0e374SAl Viro while (1) { 11438cefc107SDavid Howells struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; 11448cefc107SDavid Howells size_t n = off - b->offset; 114527c0e374SAl Viro if (unroll < n) { 11464fa55cefSAl Viro off -= unroll; 114727c0e374SAl Viro break; 114827c0e374SAl Viro } 114927c0e374SAl Viro unroll -= n; 11508cefc107SDavid Howells if (!unroll && i_head == i->start_head) { 115127c0e374SAl Viro off = 0; 115227c0e374SAl Viro break; 115327c0e374SAl Viro } 11548cefc107SDavid Howells i_head--; 11558cefc107SDavid Howells b = &pipe->bufs[i_head & p_mask]; 11568cefc107SDavid Howells off = b->offset + b->len; 115727c0e374SAl Viro } 115827c0e374SAl Viro i->iov_offset = off; 11598cefc107SDavid Howells i->head = i_head; 116027c0e374SAl Viro pipe_truncate(i); 116127c0e374SAl Viro return; 116227c0e374SAl Viro } 11639ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 11649ea9ce04SDavid Howells return; 116527c0e374SAl Viro if (unroll <= i->iov_offset) { 116627c0e374SAl Viro i->iov_offset -= unroll; 116727c0e374SAl Viro return; 116827c0e374SAl Viro } 116927c0e374SAl Viro unroll -= i->iov_offset; 11707ff50620SDavid Howells if (iov_iter_is_xarray(i)) { 11717ff50620SDavid Howells BUG(); /* We should never go beyond the start of the specified 11727ff50620SDavid Howells * range since we might then be straying into pages that 11737ff50620SDavid Howells * aren't pinned. 11747ff50620SDavid Howells */ 11757ff50620SDavid Howells } else if (iov_iter_is_bvec(i)) { 117627c0e374SAl Viro const struct bio_vec *bvec = i->bvec; 117727c0e374SAl Viro while (1) { 117827c0e374SAl Viro size_t n = (--bvec)->bv_len; 117927c0e374SAl Viro i->nr_segs++; 118027c0e374SAl Viro if (unroll <= n) { 118127c0e374SAl Viro i->bvec = bvec; 118227c0e374SAl Viro i->iov_offset = n - unroll; 118327c0e374SAl Viro return; 118427c0e374SAl Viro } 118527c0e374SAl Viro unroll -= n; 118627c0e374SAl Viro } 118727c0e374SAl Viro } else { /* same logics for iovec and kvec */ 118827c0e374SAl Viro const struct iovec *iov = i->iov; 118927c0e374SAl Viro while (1) { 119027c0e374SAl Viro size_t n = (--iov)->iov_len; 119127c0e374SAl Viro i->nr_segs++; 119227c0e374SAl Viro if (unroll <= n) { 119327c0e374SAl Viro i->iov = iov; 119427c0e374SAl Viro i->iov_offset = n - unroll; 119527c0e374SAl Viro return; 119627c0e374SAl Viro } 119727c0e374SAl Viro unroll -= n; 119827c0e374SAl Viro } 119927c0e374SAl Viro } 120027c0e374SAl Viro } 120127c0e374SAl Viro EXPORT_SYMBOL(iov_iter_revert); 120227c0e374SAl Viro 1203d879cb83SAl Viro /* 1204d879cb83SAl Viro * Return the count of just the current iov_iter segment. 1205d879cb83SAl Viro */ 1206d879cb83SAl Viro size_t iov_iter_single_seg_count(const struct iov_iter *i) 1207d879cb83SAl Viro { 1208*28f38db7SAl Viro if (i->nr_segs > 1) { 1209*28f38db7SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 1210*28f38db7SAl Viro return min(i->count, i->iov->iov_len - i->iov_offset); 12117ff50620SDavid Howells if (iov_iter_is_bvec(i)) 1212d879cb83SAl Viro return min(i->count, i->bvec->bv_len - i->iov_offset); 1213*28f38db7SAl Viro } 1214*28f38db7SAl Viro return i->count; 1215d879cb83SAl Viro } 1216d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_single_seg_count); 1217d879cb83SAl Viro 1218aa563d7bSDavid Howells void iov_iter_kvec(struct iov_iter *i, unsigned int direction, 1219d879cb83SAl Viro const struct kvec *kvec, unsigned long nr_segs, 1220d879cb83SAl Viro size_t count) 1221d879cb83SAl Viro { 1222aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 1223aa563d7bSDavid Howells i->type = ITER_KVEC | (direction & (READ | WRITE)); 1224d879cb83SAl Viro i->kvec = kvec; 1225d879cb83SAl Viro i->nr_segs = nr_segs; 1226d879cb83SAl Viro i->iov_offset = 0; 1227d879cb83SAl Viro i->count = count; 1228d879cb83SAl Viro } 1229d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_kvec); 1230d879cb83SAl Viro 1231aa563d7bSDavid Howells void iov_iter_bvec(struct iov_iter *i, unsigned int direction, 1232d879cb83SAl Viro const struct bio_vec *bvec, unsigned long nr_segs, 1233d879cb83SAl Viro size_t count) 1234d879cb83SAl Viro { 1235aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 1236aa563d7bSDavid Howells i->type = ITER_BVEC | (direction & (READ | WRITE)); 1237d879cb83SAl Viro i->bvec = bvec; 1238d879cb83SAl Viro i->nr_segs = nr_segs; 1239d879cb83SAl Viro i->iov_offset = 0; 1240d879cb83SAl Viro i->count = count; 1241d879cb83SAl Viro } 1242d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_bvec); 1243d879cb83SAl Viro 1244aa563d7bSDavid Howells void iov_iter_pipe(struct iov_iter *i, unsigned int direction, 1245241699cdSAl Viro struct pipe_inode_info *pipe, 1246241699cdSAl Viro size_t count) 1247241699cdSAl Viro { 1248aa563d7bSDavid Howells BUG_ON(direction != READ); 12498cefc107SDavid Howells WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); 1250aa563d7bSDavid Howells i->type = ITER_PIPE | READ; 1251241699cdSAl Viro i->pipe = pipe; 12528cefc107SDavid Howells i->head = pipe->head; 1253241699cdSAl Viro i->iov_offset = 0; 1254241699cdSAl Viro i->count = count; 12558cefc107SDavid Howells i->start_head = i->head; 1256241699cdSAl Viro } 1257241699cdSAl Viro EXPORT_SYMBOL(iov_iter_pipe); 1258241699cdSAl Viro 12599ea9ce04SDavid Howells /** 12607ff50620SDavid Howells * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray 12617ff50620SDavid Howells * @i: The iterator to initialise. 12627ff50620SDavid Howells * @direction: The direction of the transfer. 12637ff50620SDavid Howells * @xarray: The xarray to access. 12647ff50620SDavid Howells * @start: The start file position. 12657ff50620SDavid Howells * @count: The size of the I/O buffer in bytes. 12667ff50620SDavid Howells * 12677ff50620SDavid Howells * Set up an I/O iterator to either draw data out of the pages attached to an 12687ff50620SDavid Howells * inode or to inject data into those pages. The pages *must* be prevented 12697ff50620SDavid Howells * from evaporation, either by taking a ref on them or locking them by the 12707ff50620SDavid Howells * caller. 12717ff50620SDavid Howells */ 12727ff50620SDavid Howells void iov_iter_xarray(struct iov_iter *i, unsigned int direction, 12737ff50620SDavid Howells struct xarray *xarray, loff_t start, size_t count) 12747ff50620SDavid Howells { 12757ff50620SDavid Howells BUG_ON(direction & ~1); 12767ff50620SDavid Howells i->type = ITER_XARRAY | (direction & (READ | WRITE)); 12777ff50620SDavid Howells i->xarray = xarray; 12787ff50620SDavid Howells i->xarray_start = start; 12797ff50620SDavid Howells i->count = count; 12807ff50620SDavid Howells i->iov_offset = 0; 12817ff50620SDavid Howells } 12827ff50620SDavid Howells EXPORT_SYMBOL(iov_iter_xarray); 12837ff50620SDavid Howells 12847ff50620SDavid Howells /** 12859ea9ce04SDavid Howells * iov_iter_discard - Initialise an I/O iterator that discards data 12869ea9ce04SDavid Howells * @i: The iterator to initialise. 12879ea9ce04SDavid Howells * @direction: The direction of the transfer. 12889ea9ce04SDavid Howells * @count: The size of the I/O buffer in bytes. 12899ea9ce04SDavid Howells * 12909ea9ce04SDavid Howells * Set up an I/O iterator that just discards everything that's written to it. 12919ea9ce04SDavid Howells * It's only available as a READ iterator. 12929ea9ce04SDavid Howells */ 12939ea9ce04SDavid Howells void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) 12949ea9ce04SDavid Howells { 12959ea9ce04SDavid Howells BUG_ON(direction != READ); 12969ea9ce04SDavid Howells i->type = ITER_DISCARD | READ; 12979ea9ce04SDavid Howells i->count = count; 12989ea9ce04SDavid Howells i->iov_offset = 0; 12999ea9ce04SDavid Howells } 13009ea9ce04SDavid Howells EXPORT_SYMBOL(iov_iter_discard); 13019ea9ce04SDavid Howells 1302d879cb83SAl Viro unsigned long iov_iter_alignment(const struct iov_iter *i) 1303d879cb83SAl Viro { 1304d879cb83SAl Viro unsigned long res = 0; 1305d879cb83SAl Viro size_t size = i->count; 1306d879cb83SAl Viro 130700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 1308e0ff126eSJan Kara unsigned int p_mask = i->pipe->ring_size - 1; 1309e0ff126eSJan Kara 13108cefc107SDavid Howells if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) 1311241699cdSAl Viro return size | i->iov_offset; 1312241699cdSAl Viro return size; 1313241699cdSAl Viro } 13143d14ec1fSDavid Howells if (unlikely(iov_iter_is_xarray(i))) 13153d14ec1fSDavid Howells return (i->xarray_start + i->iov_offset) | i->count; 1316d879cb83SAl Viro iterate_all_kinds(i, size, v, 1317d879cb83SAl Viro (res |= (unsigned long)v.iov_base | v.iov_len, 0), 1318d879cb83SAl Viro res |= v.bv_offset | v.bv_len, 13197ff50620SDavid Howells res |= (unsigned long)v.iov_base | v.iov_len, 13207ff50620SDavid Howells res |= v.bv_offset | v.bv_len 1321d879cb83SAl Viro ) 1322d879cb83SAl Viro return res; 1323d879cb83SAl Viro } 1324d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_alignment); 1325d879cb83SAl Viro 1326357f435dSAl Viro unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 1327357f435dSAl Viro { 1328357f435dSAl Viro unsigned long res = 0; 1329357f435dSAl Viro size_t size = i->count; 1330357f435dSAl Viro 13319ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1332241699cdSAl Viro WARN_ON(1); 1333241699cdSAl Viro return ~0U; 1334241699cdSAl Viro } 1335241699cdSAl Viro 1336357f435dSAl Viro iterate_all_kinds(i, size, v, 1337357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.iov_base) | 1338357f435dSAl Viro (size != v.iov_len ? size : 0), 0), 1339357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.bv_offset) | 1340357f435dSAl Viro (size != v.bv_len ? size : 0)), 1341357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.iov_base) | 13427ff50620SDavid Howells (size != v.iov_len ? size : 0)), 13437ff50620SDavid Howells (res |= (!res ? 0 : (unsigned long)v.bv_offset) | 13447ff50620SDavid Howells (size != v.bv_len ? size : 0)) 1345357f435dSAl Viro ); 1346357f435dSAl Viro return res; 1347357f435dSAl Viro } 1348357f435dSAl Viro EXPORT_SYMBOL(iov_iter_gap_alignment); 1349357f435dSAl Viro 1350e76b6312SIlya Dryomov static inline ssize_t __pipe_get_pages(struct iov_iter *i, 1351241699cdSAl Viro size_t maxsize, 1352241699cdSAl Viro struct page **pages, 13538cefc107SDavid Howells int iter_head, 1354241699cdSAl Viro size_t *start) 1355241699cdSAl Viro { 1356241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 13578cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 13588cefc107SDavid Howells ssize_t n = push_pipe(i, maxsize, &iter_head, start); 1359241699cdSAl Viro if (!n) 1360241699cdSAl Viro return -EFAULT; 1361241699cdSAl Viro 1362241699cdSAl Viro maxsize = n; 1363241699cdSAl Viro n += *start; 13641689c73aSAl Viro while (n > 0) { 13658cefc107SDavid Howells get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); 13668cefc107SDavid Howells iter_head++; 1367241699cdSAl Viro n -= PAGE_SIZE; 1368241699cdSAl Viro } 1369241699cdSAl Viro 1370241699cdSAl Viro return maxsize; 1371241699cdSAl Viro } 1372241699cdSAl Viro 1373241699cdSAl Viro static ssize_t pipe_get_pages(struct iov_iter *i, 1374241699cdSAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1375241699cdSAl Viro size_t *start) 1376241699cdSAl Viro { 13778cefc107SDavid Howells unsigned int iter_head, npages; 1378241699cdSAl Viro size_t capacity; 1379241699cdSAl Viro 138033844e66SAl Viro if (!maxsize) 138133844e66SAl Viro return 0; 138233844e66SAl Viro 1383241699cdSAl Viro if (!sanity(i)) 1384241699cdSAl Viro return -EFAULT; 1385241699cdSAl Viro 13868cefc107SDavid Howells data_start(i, &iter_head, start); 13878cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 13888cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1389241699cdSAl Viro capacity = min(npages, maxpages) * PAGE_SIZE - *start; 1390241699cdSAl Viro 13918cefc107SDavid Howells return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); 1392241699cdSAl Viro } 1393241699cdSAl Viro 13947ff50620SDavid Howells static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, 13957ff50620SDavid Howells pgoff_t index, unsigned int nr_pages) 13967ff50620SDavid Howells { 13977ff50620SDavid Howells XA_STATE(xas, xa, index); 13987ff50620SDavid Howells struct page *page; 13997ff50620SDavid Howells unsigned int ret = 0; 14007ff50620SDavid Howells 14017ff50620SDavid Howells rcu_read_lock(); 14027ff50620SDavid Howells for (page = xas_load(&xas); page; page = xas_next(&xas)) { 14037ff50620SDavid Howells if (xas_retry(&xas, page)) 14047ff50620SDavid Howells continue; 14057ff50620SDavid Howells 14067ff50620SDavid Howells /* Has the page moved or been split? */ 14077ff50620SDavid Howells if (unlikely(page != xas_reload(&xas))) { 14087ff50620SDavid Howells xas_reset(&xas); 14097ff50620SDavid Howells continue; 14107ff50620SDavid Howells } 14117ff50620SDavid Howells 14127ff50620SDavid Howells pages[ret] = find_subpage(page, xas.xa_index); 14137ff50620SDavid Howells get_page(pages[ret]); 14147ff50620SDavid Howells if (++ret == nr_pages) 14157ff50620SDavid Howells break; 14167ff50620SDavid Howells } 14177ff50620SDavid Howells rcu_read_unlock(); 14187ff50620SDavid Howells return ret; 14197ff50620SDavid Howells } 14207ff50620SDavid Howells 14217ff50620SDavid Howells static ssize_t iter_xarray_get_pages(struct iov_iter *i, 14227ff50620SDavid Howells struct page **pages, size_t maxsize, 14237ff50620SDavid Howells unsigned maxpages, size_t *_start_offset) 14247ff50620SDavid Howells { 14257ff50620SDavid Howells unsigned nr, offset; 14267ff50620SDavid Howells pgoff_t index, count; 14277ff50620SDavid Howells size_t size = maxsize, actual; 14287ff50620SDavid Howells loff_t pos; 14297ff50620SDavid Howells 14307ff50620SDavid Howells if (!size || !maxpages) 14317ff50620SDavid Howells return 0; 14327ff50620SDavid Howells 14337ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 14347ff50620SDavid Howells index = pos >> PAGE_SHIFT; 14357ff50620SDavid Howells offset = pos & ~PAGE_MASK; 14367ff50620SDavid Howells *_start_offset = offset; 14377ff50620SDavid Howells 14387ff50620SDavid Howells count = 1; 14397ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 14407ff50620SDavid Howells size -= PAGE_SIZE - offset; 14417ff50620SDavid Howells count += size >> PAGE_SHIFT; 14427ff50620SDavid Howells size &= ~PAGE_MASK; 14437ff50620SDavid Howells if (size) 14447ff50620SDavid Howells count++; 14457ff50620SDavid Howells } 14467ff50620SDavid Howells 14477ff50620SDavid Howells if (count > maxpages) 14487ff50620SDavid Howells count = maxpages; 14497ff50620SDavid Howells 14507ff50620SDavid Howells nr = iter_xarray_populate_pages(pages, i->xarray, index, count); 14517ff50620SDavid Howells if (nr == 0) 14527ff50620SDavid Howells return 0; 14537ff50620SDavid Howells 14547ff50620SDavid Howells actual = PAGE_SIZE * nr; 14557ff50620SDavid Howells actual -= offset; 14567ff50620SDavid Howells if (nr == count && size > 0) { 14577ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 14587ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 14597ff50620SDavid Howells } 14607ff50620SDavid Howells return actual; 14617ff50620SDavid Howells } 14627ff50620SDavid Howells 1463d879cb83SAl Viro ssize_t iov_iter_get_pages(struct iov_iter *i, 1464d879cb83SAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1465d879cb83SAl Viro size_t *start) 1466d879cb83SAl Viro { 1467d879cb83SAl Viro if (maxsize > i->count) 1468d879cb83SAl Viro maxsize = i->count; 1469d879cb83SAl Viro 147000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1471241699cdSAl Viro return pipe_get_pages(i, pages, maxsize, maxpages, start); 14727ff50620SDavid Howells if (unlikely(iov_iter_is_xarray(i))) 14737ff50620SDavid Howells return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); 14749ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 14759ea9ce04SDavid Howells return -EFAULT; 14769ea9ce04SDavid Howells 1477d879cb83SAl Viro iterate_all_kinds(i, maxsize, v, ({ 1478d879cb83SAl Viro unsigned long addr = (unsigned long)v.iov_base; 1479d879cb83SAl Viro size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); 1480d879cb83SAl Viro int n; 1481d879cb83SAl Viro int res; 1482d879cb83SAl Viro 1483d879cb83SAl Viro if (len > maxpages * PAGE_SIZE) 1484d879cb83SAl Viro len = maxpages * PAGE_SIZE; 1485d879cb83SAl Viro addr &= ~(PAGE_SIZE - 1); 1486d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 148773b0140bSIra Weiny res = get_user_pages_fast(addr, n, 148873b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, 148973b0140bSIra Weiny pages); 1490d879cb83SAl Viro if (unlikely(res < 0)) 1491d879cb83SAl Viro return res; 1492d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 1493d879cb83SAl Viro 0;}),({ 1494d879cb83SAl Viro /* can't be more than PAGE_SIZE */ 1495d879cb83SAl Viro *start = v.bv_offset; 1496d879cb83SAl Viro get_page(*pages = v.bv_page); 1497d879cb83SAl Viro return v.bv_len; 1498d879cb83SAl Viro }),({ 1499d879cb83SAl Viro return -EFAULT; 15007ff50620SDavid Howells }), 15017ff50620SDavid Howells 0 1502d879cb83SAl Viro ) 1503d879cb83SAl Viro return 0; 1504d879cb83SAl Viro } 1505d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages); 1506d879cb83SAl Viro 1507d879cb83SAl Viro static struct page **get_pages_array(size_t n) 1508d879cb83SAl Viro { 1509752ade68SMichal Hocko return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); 1510d879cb83SAl Viro } 1511d879cb83SAl Viro 1512241699cdSAl Viro static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 1513241699cdSAl Viro struct page ***pages, size_t maxsize, 1514241699cdSAl Viro size_t *start) 1515241699cdSAl Viro { 1516241699cdSAl Viro struct page **p; 15178cefc107SDavid Howells unsigned int iter_head, npages; 1518d7760d63SIlya Dryomov ssize_t n; 1519241699cdSAl Viro 152033844e66SAl Viro if (!maxsize) 152133844e66SAl Viro return 0; 152233844e66SAl Viro 1523241699cdSAl Viro if (!sanity(i)) 1524241699cdSAl Viro return -EFAULT; 1525241699cdSAl Viro 15268cefc107SDavid Howells data_start(i, &iter_head, start); 15278cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 15288cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1529241699cdSAl Viro n = npages * PAGE_SIZE - *start; 1530241699cdSAl Viro if (maxsize > n) 1531241699cdSAl Viro maxsize = n; 1532241699cdSAl Viro else 1533241699cdSAl Viro npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1534241699cdSAl Viro p = get_pages_array(npages); 1535241699cdSAl Viro if (!p) 1536241699cdSAl Viro return -ENOMEM; 15378cefc107SDavid Howells n = __pipe_get_pages(i, maxsize, p, iter_head, start); 1538241699cdSAl Viro if (n > 0) 1539241699cdSAl Viro *pages = p; 1540241699cdSAl Viro else 1541241699cdSAl Viro kvfree(p); 1542241699cdSAl Viro return n; 1543241699cdSAl Viro } 1544241699cdSAl Viro 15457ff50620SDavid Howells static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, 15467ff50620SDavid Howells struct page ***pages, size_t maxsize, 15477ff50620SDavid Howells size_t *_start_offset) 15487ff50620SDavid Howells { 15497ff50620SDavid Howells struct page **p; 15507ff50620SDavid Howells unsigned nr, offset; 15517ff50620SDavid Howells pgoff_t index, count; 15527ff50620SDavid Howells size_t size = maxsize, actual; 15537ff50620SDavid Howells loff_t pos; 15547ff50620SDavid Howells 15557ff50620SDavid Howells if (!size) 15567ff50620SDavid Howells return 0; 15577ff50620SDavid Howells 15587ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 15597ff50620SDavid Howells index = pos >> PAGE_SHIFT; 15607ff50620SDavid Howells offset = pos & ~PAGE_MASK; 15617ff50620SDavid Howells *_start_offset = offset; 15627ff50620SDavid Howells 15637ff50620SDavid Howells count = 1; 15647ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 15657ff50620SDavid Howells size -= PAGE_SIZE - offset; 15667ff50620SDavid Howells count += size >> PAGE_SHIFT; 15677ff50620SDavid Howells size &= ~PAGE_MASK; 15687ff50620SDavid Howells if (size) 15697ff50620SDavid Howells count++; 15707ff50620SDavid Howells } 15717ff50620SDavid Howells 15727ff50620SDavid Howells p = get_pages_array(count); 15737ff50620SDavid Howells if (!p) 15747ff50620SDavid Howells return -ENOMEM; 15757ff50620SDavid Howells *pages = p; 15767ff50620SDavid Howells 15777ff50620SDavid Howells nr = iter_xarray_populate_pages(p, i->xarray, index, count); 15787ff50620SDavid Howells if (nr == 0) 15797ff50620SDavid Howells return 0; 15807ff50620SDavid Howells 15817ff50620SDavid Howells actual = PAGE_SIZE * nr; 15827ff50620SDavid Howells actual -= offset; 15837ff50620SDavid Howells if (nr == count && size > 0) { 15847ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 15857ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 15867ff50620SDavid Howells } 15877ff50620SDavid Howells return actual; 15887ff50620SDavid Howells } 15897ff50620SDavid Howells 1590d879cb83SAl Viro ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 1591d879cb83SAl Viro struct page ***pages, size_t maxsize, 1592d879cb83SAl Viro size_t *start) 1593d879cb83SAl Viro { 1594d879cb83SAl Viro struct page **p; 1595d879cb83SAl Viro 1596d879cb83SAl Viro if (maxsize > i->count) 1597d879cb83SAl Viro maxsize = i->count; 1598d879cb83SAl Viro 159900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1600241699cdSAl Viro return pipe_get_pages_alloc(i, pages, maxsize, start); 16017ff50620SDavid Howells if (unlikely(iov_iter_is_xarray(i))) 16027ff50620SDavid Howells return iter_xarray_get_pages_alloc(i, pages, maxsize, start); 16039ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 16049ea9ce04SDavid Howells return -EFAULT; 16059ea9ce04SDavid Howells 1606d879cb83SAl Viro iterate_all_kinds(i, maxsize, v, ({ 1607d879cb83SAl Viro unsigned long addr = (unsigned long)v.iov_base; 1608d879cb83SAl Viro size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); 1609d879cb83SAl Viro int n; 1610d879cb83SAl Viro int res; 1611d879cb83SAl Viro 1612d879cb83SAl Viro addr &= ~(PAGE_SIZE - 1); 1613d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 1614d879cb83SAl Viro p = get_pages_array(n); 1615d879cb83SAl Viro if (!p) 1616d879cb83SAl Viro return -ENOMEM; 161773b0140bSIra Weiny res = get_user_pages_fast(addr, n, 161873b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); 1619d879cb83SAl Viro if (unlikely(res < 0)) { 1620d879cb83SAl Viro kvfree(p); 1621d879cb83SAl Viro return res; 1622d879cb83SAl Viro } 1623d879cb83SAl Viro *pages = p; 1624d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 1625d879cb83SAl Viro 0;}),({ 1626d879cb83SAl Viro /* can't be more than PAGE_SIZE */ 1627d879cb83SAl Viro *start = v.bv_offset; 1628d879cb83SAl Viro *pages = p = get_pages_array(1); 1629d879cb83SAl Viro if (!p) 1630d879cb83SAl Viro return -ENOMEM; 1631d879cb83SAl Viro get_page(*p = v.bv_page); 1632d879cb83SAl Viro return v.bv_len; 1633d879cb83SAl Viro }),({ 1634d879cb83SAl Viro return -EFAULT; 16357ff50620SDavid Howells }), 0 1636d879cb83SAl Viro ) 1637d879cb83SAl Viro return 0; 1638d879cb83SAl Viro } 1639d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages_alloc); 1640d879cb83SAl Viro 1641d879cb83SAl Viro size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 1642d879cb83SAl Viro struct iov_iter *i) 1643d879cb83SAl Viro { 1644d879cb83SAl Viro char *to = addr; 1645d879cb83SAl Viro __wsum sum, next; 1646d879cb83SAl Viro size_t off = 0; 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 } 1652d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1653d879cb83SAl Viro next = csum_and_copy_from_user(v.iov_base, 1654d879cb83SAl Viro (to += v.iov_len) - v.iov_len, 1655c693cc46SAl Viro v.iov_len); 1656c693cc46SAl Viro if (next) { 1657d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1658d879cb83SAl Viro off += v.iov_len; 1659d879cb83SAl Viro } 1660c693cc46SAl Viro next ? 0 : v.iov_len; 1661d879cb83SAl Viro }), ({ 1662d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1663f9152895SAl Viro sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 1664f9152895SAl Viro p + v.bv_offset, v.bv_len, 1665f9152895SAl Viro sum, off); 1666d879cb83SAl Viro kunmap_atomic(p); 1667d879cb83SAl Viro off += v.bv_len; 1668d879cb83SAl Viro }),({ 1669f9152895SAl Viro sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, 1670f9152895SAl Viro v.iov_base, v.iov_len, 1671f9152895SAl Viro sum, off); 1672d879cb83SAl Viro off += v.iov_len; 16737ff50620SDavid Howells }), ({ 16747ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 16757ff50620SDavid Howells sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, 16767ff50620SDavid Howells p + v.bv_offset, v.bv_len, 16777ff50620SDavid Howells sum, off); 16787ff50620SDavid Howells kunmap_atomic(p); 16797ff50620SDavid Howells off += v.bv_len; 1680d879cb83SAl Viro }) 1681d879cb83SAl Viro ) 1682d879cb83SAl Viro *csum = sum; 1683d879cb83SAl Viro return bytes; 1684d879cb83SAl Viro } 1685d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter); 1686d879cb83SAl Viro 168752cbd23aSWillem de Bruijn size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 1688d879cb83SAl Viro struct iov_iter *i) 1689d879cb83SAl Viro { 169052cbd23aSWillem de Bruijn struct csum_state *csstate = _csstate; 169136f7a8a4SAl Viro const char *from = addr; 1692d879cb83SAl Viro __wsum sum, next; 169352cbd23aSWillem de Bruijn size_t off; 169478e1f386SAl Viro 169578e1f386SAl Viro if (unlikely(iov_iter_is_pipe(i))) 169652cbd23aSWillem de Bruijn return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); 169778e1f386SAl Viro 169852cbd23aSWillem de Bruijn sum = csstate->csum; 169952cbd23aSWillem de Bruijn off = csstate->off; 170078e1f386SAl Viro if (unlikely(iov_iter_is_discard(i))) { 1701241699cdSAl Viro WARN_ON(1); /* for now */ 1702241699cdSAl Viro return 0; 1703241699cdSAl Viro } 1704d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1705d879cb83SAl Viro next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, 1706d879cb83SAl Viro v.iov_base, 1707c693cc46SAl Viro v.iov_len); 1708c693cc46SAl Viro if (next) { 1709d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1710d879cb83SAl Viro off += v.iov_len; 1711d879cb83SAl Viro } 1712c693cc46SAl Viro next ? 0 : v.iov_len; 1713d879cb83SAl Viro }), ({ 1714d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1715f9152895SAl Viro sum = csum_and_memcpy(p + v.bv_offset, 1716f9152895SAl Viro (from += v.bv_len) - v.bv_len, 1717f9152895SAl Viro v.bv_len, sum, off); 1718d879cb83SAl Viro kunmap_atomic(p); 1719d879cb83SAl Viro off += v.bv_len; 1720d879cb83SAl Viro }),({ 1721f9152895SAl Viro sum = csum_and_memcpy(v.iov_base, 1722f9152895SAl Viro (from += v.iov_len) - v.iov_len, 1723f9152895SAl Viro v.iov_len, sum, off); 1724d879cb83SAl Viro off += v.iov_len; 17257ff50620SDavid Howells }), ({ 17267ff50620SDavid Howells char *p = kmap_atomic(v.bv_page); 17277ff50620SDavid Howells sum = csum_and_memcpy(p + v.bv_offset, 17287ff50620SDavid Howells (from += v.bv_len) - v.bv_len, 17297ff50620SDavid Howells v.bv_len, sum, off); 17307ff50620SDavid Howells kunmap_atomic(p); 17317ff50620SDavid Howells off += v.bv_len; 1732d879cb83SAl Viro }) 1733d879cb83SAl Viro ) 173452cbd23aSWillem de Bruijn csstate->csum = sum; 173552cbd23aSWillem de Bruijn csstate->off = off; 1736d879cb83SAl Viro return bytes; 1737d879cb83SAl Viro } 1738d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_to_iter); 1739d879cb83SAl Viro 1740d05f4435SSagi Grimberg size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, 1741d05f4435SSagi Grimberg struct iov_iter *i) 1742d05f4435SSagi Grimberg { 17437999096fSHerbert Xu #ifdef CONFIG_CRYPTO_HASH 1744d05f4435SSagi Grimberg struct ahash_request *hash = hashp; 1745d05f4435SSagi Grimberg struct scatterlist sg; 1746d05f4435SSagi Grimberg size_t copied; 1747d05f4435SSagi Grimberg 1748d05f4435SSagi Grimberg copied = copy_to_iter(addr, bytes, i); 1749d05f4435SSagi Grimberg sg_init_one(&sg, addr, copied); 1750d05f4435SSagi Grimberg ahash_request_set_crypt(hash, &sg, NULL, copied); 1751d05f4435SSagi Grimberg crypto_ahash_update(hash); 1752d05f4435SSagi Grimberg return copied; 175327fad74aSYueHaibing #else 175427fad74aSYueHaibing return 0; 175527fad74aSYueHaibing #endif 1756d05f4435SSagi Grimberg } 1757d05f4435SSagi Grimberg EXPORT_SYMBOL(hash_and_copy_to_iter); 1758d05f4435SSagi Grimberg 1759d879cb83SAl Viro int iov_iter_npages(const struct iov_iter *i, int maxpages) 1760d879cb83SAl Viro { 1761d879cb83SAl Viro size_t size = i->count; 1762d879cb83SAl Viro int npages = 0; 1763d879cb83SAl Viro 1764d879cb83SAl Viro if (!size) 1765d879cb83SAl Viro return 0; 17669ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 17679ea9ce04SDavid Howells return 0; 1768d879cb83SAl Viro 176900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 1770241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 17718cefc107SDavid Howells unsigned int iter_head; 1772241699cdSAl Viro size_t off; 1773241699cdSAl Viro 1774241699cdSAl Viro if (!sanity(i)) 1775241699cdSAl Viro return 0; 1776241699cdSAl Viro 17778cefc107SDavid Howells data_start(i, &iter_head, &off); 1778241699cdSAl Viro /* some of this one + all after this one */ 17798cefc107SDavid Howells npages = pipe_space_for_user(iter_head, pipe->tail, pipe); 1780241699cdSAl Viro if (npages >= maxpages) 1781241699cdSAl Viro return maxpages; 17827ff50620SDavid Howells } else if (unlikely(iov_iter_is_xarray(i))) { 17837ff50620SDavid Howells unsigned offset; 17847ff50620SDavid Howells 17857ff50620SDavid Howells offset = (i->xarray_start + i->iov_offset) & ~PAGE_MASK; 17867ff50620SDavid Howells 17877ff50620SDavid Howells npages = 1; 17887ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 17897ff50620SDavid Howells size -= PAGE_SIZE - offset; 17907ff50620SDavid Howells npages += size >> PAGE_SHIFT; 17917ff50620SDavid Howells size &= ~PAGE_MASK; 17927ff50620SDavid Howells if (size) 17937ff50620SDavid Howells npages++; 17947ff50620SDavid Howells } 17957ff50620SDavid Howells if (npages >= maxpages) 17967ff50620SDavid Howells return maxpages; 1797241699cdSAl Viro } else iterate_all_kinds(i, size, v, ({ 1798d879cb83SAl Viro unsigned long p = (unsigned long)v.iov_base; 1799d879cb83SAl Viro npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) 1800d879cb83SAl Viro - p / PAGE_SIZE; 1801d879cb83SAl Viro if (npages >= maxpages) 1802d879cb83SAl Viro return maxpages; 1803d879cb83SAl Viro 0;}),({ 1804d879cb83SAl Viro npages++; 1805d879cb83SAl Viro if (npages >= maxpages) 1806d879cb83SAl Viro return maxpages; 1807d879cb83SAl Viro }),({ 1808d879cb83SAl Viro unsigned long p = (unsigned long)v.iov_base; 1809d879cb83SAl Viro npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) 1810d879cb83SAl Viro - p / PAGE_SIZE; 1811d879cb83SAl Viro if (npages >= maxpages) 1812d879cb83SAl Viro return maxpages; 18137ff50620SDavid Howells }), 18147ff50620SDavid Howells 0 1815d879cb83SAl Viro ) 1816d879cb83SAl Viro return npages; 1817d879cb83SAl Viro } 1818d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_npages); 1819d879cb83SAl Viro 1820d879cb83SAl Viro const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) 1821d879cb83SAl Viro { 1822d879cb83SAl Viro *new = *old; 182300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(new))) { 1824241699cdSAl Viro WARN_ON(1); 1825241699cdSAl Viro return NULL; 1826241699cdSAl Viro } 18277ff50620SDavid Howells if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) 18289ea9ce04SDavid Howells return NULL; 182900e23707SDavid Howells if (iov_iter_is_bvec(new)) 1830d879cb83SAl Viro return new->bvec = kmemdup(new->bvec, 1831d879cb83SAl Viro new->nr_segs * sizeof(struct bio_vec), 1832d879cb83SAl Viro flags); 1833d879cb83SAl Viro else 1834d879cb83SAl Viro /* iovec and kvec have identical layout */ 1835d879cb83SAl Viro return new->iov = kmemdup(new->iov, 1836d879cb83SAl Viro new->nr_segs * sizeof(struct iovec), 1837d879cb83SAl Viro flags); 1838d879cb83SAl Viro } 1839d879cb83SAl Viro EXPORT_SYMBOL(dup_iter); 1840bc917be8SAl Viro 1841bfdc5970SChristoph Hellwig static int copy_compat_iovec_from_user(struct iovec *iov, 1842bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1843bfdc5970SChristoph Hellwig { 1844bfdc5970SChristoph Hellwig const struct compat_iovec __user *uiov = 1845bfdc5970SChristoph Hellwig (const struct compat_iovec __user *)uvec; 1846bfdc5970SChristoph Hellwig int ret = -EFAULT, i; 1847bfdc5970SChristoph Hellwig 1848a959a978SChristoph Hellwig if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) 1849bfdc5970SChristoph Hellwig return -EFAULT; 1850bfdc5970SChristoph Hellwig 1851bfdc5970SChristoph Hellwig for (i = 0; i < nr_segs; i++) { 1852bfdc5970SChristoph Hellwig compat_uptr_t buf; 1853bfdc5970SChristoph Hellwig compat_ssize_t len; 1854bfdc5970SChristoph Hellwig 1855bfdc5970SChristoph Hellwig unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); 1856bfdc5970SChristoph Hellwig unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); 1857bfdc5970SChristoph Hellwig 1858bfdc5970SChristoph Hellwig /* check for compat_size_t not fitting in compat_ssize_t .. */ 1859bfdc5970SChristoph Hellwig if (len < 0) { 1860bfdc5970SChristoph Hellwig ret = -EINVAL; 1861bfdc5970SChristoph Hellwig goto uaccess_end; 1862bfdc5970SChristoph Hellwig } 1863bfdc5970SChristoph Hellwig iov[i].iov_base = compat_ptr(buf); 1864bfdc5970SChristoph Hellwig iov[i].iov_len = len; 1865bfdc5970SChristoph Hellwig } 1866bfdc5970SChristoph Hellwig 1867bfdc5970SChristoph Hellwig ret = 0; 1868bfdc5970SChristoph Hellwig uaccess_end: 1869bfdc5970SChristoph Hellwig user_access_end(); 1870bfdc5970SChristoph Hellwig return ret; 1871bfdc5970SChristoph Hellwig } 1872bfdc5970SChristoph Hellwig 1873bfdc5970SChristoph Hellwig static int copy_iovec_from_user(struct iovec *iov, 1874bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1875fb041b59SDavid Laight { 1876fb041b59SDavid Laight unsigned long seg; 1877bfdc5970SChristoph Hellwig 1878bfdc5970SChristoph Hellwig if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) 1879bfdc5970SChristoph Hellwig return -EFAULT; 1880bfdc5970SChristoph Hellwig for (seg = 0; seg < nr_segs; seg++) { 1881bfdc5970SChristoph Hellwig if ((ssize_t)iov[seg].iov_len < 0) 1882bfdc5970SChristoph Hellwig return -EINVAL; 1883bfdc5970SChristoph Hellwig } 1884bfdc5970SChristoph Hellwig 1885bfdc5970SChristoph Hellwig return 0; 1886bfdc5970SChristoph Hellwig } 1887bfdc5970SChristoph Hellwig 1888bfdc5970SChristoph Hellwig struct iovec *iovec_from_user(const struct iovec __user *uvec, 1889bfdc5970SChristoph Hellwig unsigned long nr_segs, unsigned long fast_segs, 1890bfdc5970SChristoph Hellwig struct iovec *fast_iov, bool compat) 1891bfdc5970SChristoph Hellwig { 1892bfdc5970SChristoph Hellwig struct iovec *iov = fast_iov; 1893bfdc5970SChristoph Hellwig int ret; 1894fb041b59SDavid Laight 1895fb041b59SDavid Laight /* 1896bfdc5970SChristoph Hellwig * SuS says "The readv() function *may* fail if the iovcnt argument was 1897bfdc5970SChristoph Hellwig * less than or equal to 0, or greater than {IOV_MAX}. Linux has 1898fb041b59SDavid Laight * traditionally returned zero for zero segments, so... 1899fb041b59SDavid Laight */ 1900bfdc5970SChristoph Hellwig if (nr_segs == 0) 1901bfdc5970SChristoph Hellwig return iov; 1902bfdc5970SChristoph Hellwig if (nr_segs > UIO_MAXIOV) 1903bfdc5970SChristoph Hellwig return ERR_PTR(-EINVAL); 1904fb041b59SDavid Laight if (nr_segs > fast_segs) { 1905fb041b59SDavid Laight iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); 1906bfdc5970SChristoph Hellwig if (!iov) 1907bfdc5970SChristoph Hellwig return ERR_PTR(-ENOMEM); 1908fb041b59SDavid Laight } 1909bfdc5970SChristoph Hellwig 1910bfdc5970SChristoph Hellwig if (compat) 1911bfdc5970SChristoph Hellwig ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); 1912bfdc5970SChristoph Hellwig else 1913bfdc5970SChristoph Hellwig ret = copy_iovec_from_user(iov, uvec, nr_segs); 1914bfdc5970SChristoph Hellwig if (ret) { 1915bfdc5970SChristoph Hellwig if (iov != fast_iov) 1916bfdc5970SChristoph Hellwig kfree(iov); 1917bfdc5970SChristoph Hellwig return ERR_PTR(ret); 1918fb041b59SDavid Laight } 1919bfdc5970SChristoph Hellwig 1920bfdc5970SChristoph Hellwig return iov; 1921bfdc5970SChristoph Hellwig } 1922bfdc5970SChristoph Hellwig 1923bfdc5970SChristoph Hellwig ssize_t __import_iovec(int type, const struct iovec __user *uvec, 1924bfdc5970SChristoph Hellwig unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, 1925bfdc5970SChristoph Hellwig struct iov_iter *i, bool compat) 1926bfdc5970SChristoph Hellwig { 1927bfdc5970SChristoph Hellwig ssize_t total_len = 0; 1928bfdc5970SChristoph Hellwig unsigned long seg; 1929bfdc5970SChristoph Hellwig struct iovec *iov; 1930bfdc5970SChristoph Hellwig 1931bfdc5970SChristoph Hellwig iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); 1932bfdc5970SChristoph Hellwig if (IS_ERR(iov)) { 1933bfdc5970SChristoph Hellwig *iovp = NULL; 1934bfdc5970SChristoph Hellwig return PTR_ERR(iov); 1935fb041b59SDavid Laight } 1936fb041b59SDavid Laight 1937fb041b59SDavid Laight /* 1938bfdc5970SChristoph Hellwig * According to the Single Unix Specification we should return EINVAL if 1939bfdc5970SChristoph Hellwig * an element length is < 0 when cast to ssize_t or if the total length 1940bfdc5970SChristoph Hellwig * would overflow the ssize_t return value of the system call. 1941fb041b59SDavid Laight * 1942fb041b59SDavid Laight * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the 1943fb041b59SDavid Laight * overflow case. 1944fb041b59SDavid Laight */ 1945fb041b59SDavid Laight for (seg = 0; seg < nr_segs; seg++) { 1946fb041b59SDavid Laight ssize_t len = (ssize_t)iov[seg].iov_len; 1947fb041b59SDavid Laight 1948bfdc5970SChristoph Hellwig if (!access_ok(iov[seg].iov_base, len)) { 1949bfdc5970SChristoph Hellwig if (iov != *iovp) 1950bfdc5970SChristoph Hellwig kfree(iov); 1951bfdc5970SChristoph Hellwig *iovp = NULL; 1952bfdc5970SChristoph Hellwig return -EFAULT; 1953fb041b59SDavid Laight } 1954bfdc5970SChristoph Hellwig 1955bfdc5970SChristoph Hellwig if (len > MAX_RW_COUNT - total_len) { 1956bfdc5970SChristoph Hellwig len = MAX_RW_COUNT - total_len; 1957fb041b59SDavid Laight iov[seg].iov_len = len; 1958fb041b59SDavid Laight } 1959bfdc5970SChristoph Hellwig total_len += len; 1960fb041b59SDavid Laight } 1961bfdc5970SChristoph Hellwig 1962bfdc5970SChristoph Hellwig iov_iter_init(i, type, iov, nr_segs, total_len); 1963bfdc5970SChristoph Hellwig if (iov == *iovp) 1964bfdc5970SChristoph Hellwig *iovp = NULL; 1965bfdc5970SChristoph Hellwig else 1966bfdc5970SChristoph Hellwig *iovp = iov; 1967bfdc5970SChristoph Hellwig return total_len; 1968fb041b59SDavid Laight } 1969fb041b59SDavid Laight 1970ffecee4fSVegard Nossum /** 1971ffecee4fSVegard Nossum * import_iovec() - Copy an array of &struct iovec from userspace 1972ffecee4fSVegard Nossum * into the kernel, check that it is valid, and initialize a new 1973ffecee4fSVegard Nossum * &struct iov_iter iterator to access it. 1974ffecee4fSVegard Nossum * 1975ffecee4fSVegard Nossum * @type: One of %READ or %WRITE. 1976bfdc5970SChristoph Hellwig * @uvec: Pointer to the userspace array. 1977ffecee4fSVegard Nossum * @nr_segs: Number of elements in userspace array. 1978ffecee4fSVegard Nossum * @fast_segs: Number of elements in @iov. 1979bfdc5970SChristoph Hellwig * @iovp: (input and output parameter) Pointer to pointer to (usually small 1980ffecee4fSVegard Nossum * on-stack) kernel array. 1981ffecee4fSVegard Nossum * @i: Pointer to iterator that will be initialized on success. 1982ffecee4fSVegard Nossum * 1983ffecee4fSVegard Nossum * If the array pointed to by *@iov is large enough to hold all @nr_segs, 1984ffecee4fSVegard Nossum * then this function places %NULL in *@iov on return. Otherwise, a new 1985ffecee4fSVegard Nossum * array will be allocated and the result placed in *@iov. This means that 1986ffecee4fSVegard Nossum * the caller may call kfree() on *@iov regardless of whether the small 1987ffecee4fSVegard Nossum * on-stack array was used or not (and regardless of whether this function 1988ffecee4fSVegard Nossum * returns an error or not). 1989ffecee4fSVegard Nossum * 199087e5e6daSJens Axboe * Return: Negative error code on error, bytes imported on success 1991ffecee4fSVegard Nossum */ 1992bfdc5970SChristoph Hellwig ssize_t import_iovec(int type, const struct iovec __user *uvec, 1993bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 1994bfdc5970SChristoph Hellwig struct iovec **iovp, struct iov_iter *i) 1995bc917be8SAl Viro { 199689cd35c5SChristoph Hellwig return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, 199789cd35c5SChristoph Hellwig in_compat_syscall()); 1998bc917be8SAl Viro } 1999bc917be8SAl Viro EXPORT_SYMBOL(import_iovec); 2000bc917be8SAl Viro 2001bc917be8SAl Viro int import_single_range(int rw, void __user *buf, size_t len, 2002bc917be8SAl Viro struct iovec *iov, struct iov_iter *i) 2003bc917be8SAl Viro { 2004bc917be8SAl Viro if (len > MAX_RW_COUNT) 2005bc917be8SAl Viro len = MAX_RW_COUNT; 200696d4f267SLinus Torvalds if (unlikely(!access_ok(buf, len))) 2007bc917be8SAl Viro return -EFAULT; 2008bc917be8SAl Viro 2009bc917be8SAl Viro iov->iov_base = buf; 2010bc917be8SAl Viro iov->iov_len = len; 2011bc917be8SAl Viro iov_iter_init(i, rw, iov, 1, len); 2012bc917be8SAl Viro return 0; 2013bc917be8SAl Viro } 2014e1267585SAl Viro EXPORT_SYMBOL(import_single_range); 2015