1d879cb83SAl Viro #include <linux/export.h> 22f8b5444SChristoph Hellwig #include <linux/bvec.h> 3d879cb83SAl Viro #include <linux/uio.h> 4d879cb83SAl Viro #include <linux/pagemap.h> 5d879cb83SAl Viro #include <linux/slab.h> 6d879cb83SAl Viro #include <linux/vmalloc.h> 7241699cdSAl Viro #include <linux/splice.h> 8d879cb83SAl Viro #include <net/checksum.h> 9d879cb83SAl Viro 10241699cdSAl Viro #define PIPE_PARANOIA /* for now */ 11241699cdSAl Viro 12d879cb83SAl Viro #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ 13d879cb83SAl Viro size_t left; \ 14d879cb83SAl Viro size_t wanted = n; \ 15d879cb83SAl Viro __p = i->iov; \ 16d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len - skip); \ 17d879cb83SAl Viro if (likely(__v.iov_len)) { \ 18d879cb83SAl Viro __v.iov_base = __p->iov_base + skip; \ 19d879cb83SAl Viro left = (STEP); \ 20d879cb83SAl Viro __v.iov_len -= left; \ 21d879cb83SAl Viro skip += __v.iov_len; \ 22d879cb83SAl Viro n -= __v.iov_len; \ 23d879cb83SAl Viro } else { \ 24d879cb83SAl Viro left = 0; \ 25d879cb83SAl Viro } \ 26d879cb83SAl Viro while (unlikely(!left && n)) { \ 27d879cb83SAl Viro __p++; \ 28d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len); \ 29d879cb83SAl Viro if (unlikely(!__v.iov_len)) \ 30d879cb83SAl Viro continue; \ 31d879cb83SAl Viro __v.iov_base = __p->iov_base; \ 32d879cb83SAl Viro left = (STEP); \ 33d879cb83SAl Viro __v.iov_len -= left; \ 34d879cb83SAl Viro skip = __v.iov_len; \ 35d879cb83SAl Viro n -= __v.iov_len; \ 36d879cb83SAl Viro } \ 37d879cb83SAl Viro n = wanted - n; \ 38d879cb83SAl Viro } 39d879cb83SAl Viro 40d879cb83SAl Viro #define iterate_kvec(i, n, __v, __p, skip, STEP) { \ 41d879cb83SAl Viro size_t wanted = n; \ 42d879cb83SAl Viro __p = i->kvec; \ 43d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len - skip); \ 44d879cb83SAl Viro if (likely(__v.iov_len)) { \ 45d879cb83SAl Viro __v.iov_base = __p->iov_base + skip; \ 46d879cb83SAl Viro (void)(STEP); \ 47d879cb83SAl Viro skip += __v.iov_len; \ 48d879cb83SAl Viro n -= __v.iov_len; \ 49d879cb83SAl Viro } \ 50d879cb83SAl Viro while (unlikely(n)) { \ 51d879cb83SAl Viro __p++; \ 52d879cb83SAl Viro __v.iov_len = min(n, __p->iov_len); \ 53d879cb83SAl Viro if (unlikely(!__v.iov_len)) \ 54d879cb83SAl Viro continue; \ 55d879cb83SAl Viro __v.iov_base = __p->iov_base; \ 56d879cb83SAl Viro (void)(STEP); \ 57d879cb83SAl Viro skip = __v.iov_len; \ 58d879cb83SAl Viro n -= __v.iov_len; \ 59d879cb83SAl Viro } \ 60d879cb83SAl Viro n = wanted; \ 61d879cb83SAl Viro } 62d879cb83SAl Viro 631bdc76aeSMing Lei #define iterate_bvec(i, n, __v, __bi, skip, STEP) { \ 641bdc76aeSMing Lei struct bvec_iter __start; \ 651bdc76aeSMing Lei __start.bi_size = n; \ 661bdc76aeSMing Lei __start.bi_bvec_done = skip; \ 671bdc76aeSMing Lei __start.bi_idx = 0; \ 681bdc76aeSMing Lei for_each_bvec(__v, i->bvec, __bi, __start) { \ 691bdc76aeSMing Lei if (!__v.bv_len) \ 70d879cb83SAl Viro continue; \ 71d879cb83SAl Viro (void)(STEP); \ 72d879cb83SAl Viro } \ 73d879cb83SAl Viro } 74d879cb83SAl Viro 75d879cb83SAl Viro #define iterate_all_kinds(i, n, v, I, B, K) { \ 7633844e66SAl Viro if (likely(n)) { \ 77d879cb83SAl Viro size_t skip = i->iov_offset; \ 78d879cb83SAl Viro if (unlikely(i->type & ITER_BVEC)) { \ 79d879cb83SAl Viro struct bio_vec v; \ 801bdc76aeSMing Lei struct bvec_iter __bi; \ 811bdc76aeSMing Lei iterate_bvec(i, n, v, __bi, skip, (B)) \ 82d879cb83SAl Viro } else if (unlikely(i->type & ITER_KVEC)) { \ 83d879cb83SAl Viro const struct kvec *kvec; \ 84d879cb83SAl Viro struct kvec v; \ 85d879cb83SAl Viro iterate_kvec(i, n, v, kvec, skip, (K)) \ 869ea9ce04SDavid Howells } else if (unlikely(i->type & ITER_DISCARD)) { \ 87d879cb83SAl Viro } else { \ 88d879cb83SAl Viro const struct iovec *iov; \ 89d879cb83SAl Viro struct iovec v; \ 90d879cb83SAl Viro iterate_iovec(i, n, v, iov, skip, (I)) \ 91d879cb83SAl Viro } \ 9233844e66SAl Viro } \ 93d879cb83SAl Viro } 94d879cb83SAl Viro 95d879cb83SAl Viro #define iterate_and_advance(i, n, v, I, B, K) { \ 96dd254f5aSAl Viro if (unlikely(i->count < n)) \ 97dd254f5aSAl Viro n = i->count; \ 9819f18459SAl Viro if (i->count) { \ 99d879cb83SAl Viro size_t skip = i->iov_offset; \ 100d879cb83SAl Viro if (unlikely(i->type & ITER_BVEC)) { \ 1011bdc76aeSMing Lei const struct bio_vec *bvec = i->bvec; \ 102d879cb83SAl Viro struct bio_vec v; \ 1031bdc76aeSMing Lei struct bvec_iter __bi; \ 1041bdc76aeSMing Lei iterate_bvec(i, n, v, __bi, skip, (B)) \ 1051bdc76aeSMing Lei i->bvec = __bvec_iter_bvec(i->bvec, __bi); \ 1061bdc76aeSMing Lei i->nr_segs -= i->bvec - bvec; \ 1071bdc76aeSMing Lei skip = __bi.bi_bvec_done; \ 108d879cb83SAl Viro } else if (unlikely(i->type & ITER_KVEC)) { \ 109d879cb83SAl Viro const struct kvec *kvec; \ 110d879cb83SAl Viro struct kvec v; \ 111d879cb83SAl Viro iterate_kvec(i, n, v, kvec, skip, (K)) \ 112d879cb83SAl Viro if (skip == kvec->iov_len) { \ 113d879cb83SAl Viro kvec++; \ 114d879cb83SAl Viro skip = 0; \ 115d879cb83SAl Viro } \ 116d879cb83SAl Viro i->nr_segs -= kvec - i->kvec; \ 117d879cb83SAl Viro i->kvec = kvec; \ 1189ea9ce04SDavid Howells } else if (unlikely(i->type & ITER_DISCARD)) { \ 1199ea9ce04SDavid Howells skip += n; \ 120d879cb83SAl Viro } else { \ 121d879cb83SAl Viro const struct iovec *iov; \ 122d879cb83SAl Viro struct iovec v; \ 123d879cb83SAl Viro iterate_iovec(i, n, v, iov, skip, (I)) \ 124d879cb83SAl Viro if (skip == iov->iov_len) { \ 125d879cb83SAl Viro iov++; \ 126d879cb83SAl Viro skip = 0; \ 127d879cb83SAl Viro } \ 128d879cb83SAl Viro i->nr_segs -= iov - i->iov; \ 129d879cb83SAl Viro i->iov = iov; \ 130d879cb83SAl Viro } \ 131d879cb83SAl Viro i->count -= n; \ 132d879cb83SAl Viro i->iov_offset = skip; \ 133dd254f5aSAl Viro } \ 134d879cb83SAl Viro } 135d879cb83SAl Viro 13609fc68dcSAl Viro static int copyout(void __user *to, const void *from, size_t n) 13709fc68dcSAl Viro { 13809fc68dcSAl Viro if (access_ok(VERIFY_WRITE, to, n)) { 13909fc68dcSAl Viro kasan_check_read(from, n); 14009fc68dcSAl Viro n = raw_copy_to_user(to, from, n); 14109fc68dcSAl Viro } 14209fc68dcSAl Viro return n; 14309fc68dcSAl Viro } 14409fc68dcSAl Viro 14509fc68dcSAl Viro static int copyin(void *to, const void __user *from, size_t n) 14609fc68dcSAl Viro { 14709fc68dcSAl Viro if (access_ok(VERIFY_READ, from, n)) { 14809fc68dcSAl Viro kasan_check_write(to, n); 14909fc68dcSAl Viro n = raw_copy_from_user(to, from, n); 15009fc68dcSAl Viro } 15109fc68dcSAl Viro return n; 15209fc68dcSAl Viro } 15309fc68dcSAl Viro 154d879cb83SAl Viro static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, 155d879cb83SAl Viro struct iov_iter *i) 156d879cb83SAl Viro { 157d879cb83SAl Viro size_t skip, copy, left, wanted; 158d879cb83SAl Viro const struct iovec *iov; 159d879cb83SAl Viro char __user *buf; 160d879cb83SAl Viro void *kaddr, *from; 161d879cb83SAl Viro 162d879cb83SAl Viro if (unlikely(bytes > i->count)) 163d879cb83SAl Viro bytes = i->count; 164d879cb83SAl Viro 165d879cb83SAl Viro if (unlikely(!bytes)) 166d879cb83SAl Viro return 0; 167d879cb83SAl Viro 16809fc68dcSAl Viro might_fault(); 169d879cb83SAl Viro wanted = bytes; 170d879cb83SAl Viro iov = i->iov; 171d879cb83SAl Viro skip = i->iov_offset; 172d879cb83SAl Viro buf = iov->iov_base + skip; 173d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 174d879cb83SAl Viro 1753fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { 176d879cb83SAl Viro kaddr = kmap_atomic(page); 177d879cb83SAl Viro from = kaddr + offset; 178d879cb83SAl Viro 179d879cb83SAl Viro /* first chunk, usually the only one */ 18009fc68dcSAl Viro left = copyout(buf, from, copy); 181d879cb83SAl Viro copy -= left; 182d879cb83SAl Viro skip += copy; 183d879cb83SAl Viro from += copy; 184d879cb83SAl Viro bytes -= copy; 185d879cb83SAl Viro 186d879cb83SAl Viro while (unlikely(!left && bytes)) { 187d879cb83SAl Viro iov++; 188d879cb83SAl Viro buf = iov->iov_base; 189d879cb83SAl Viro copy = min(bytes, iov->iov_len); 19009fc68dcSAl Viro left = copyout(buf, from, copy); 191d879cb83SAl Viro copy -= left; 192d879cb83SAl Viro skip = copy; 193d879cb83SAl Viro from += copy; 194d879cb83SAl Viro bytes -= copy; 195d879cb83SAl Viro } 196d879cb83SAl Viro if (likely(!bytes)) { 197d879cb83SAl Viro kunmap_atomic(kaddr); 198d879cb83SAl Viro goto done; 199d879cb83SAl Viro } 200d879cb83SAl Viro offset = from - kaddr; 201d879cb83SAl Viro buf += copy; 202d879cb83SAl Viro kunmap_atomic(kaddr); 203d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 204d879cb83SAl Viro } 205d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 2063fa6c507SMikulas Patocka 207d879cb83SAl Viro kaddr = kmap(page); 208d879cb83SAl Viro from = kaddr + offset; 20909fc68dcSAl Viro left = copyout(buf, from, copy); 210d879cb83SAl Viro copy -= left; 211d879cb83SAl Viro skip += copy; 212d879cb83SAl Viro from += copy; 213d879cb83SAl Viro bytes -= copy; 214d879cb83SAl Viro while (unlikely(!left && bytes)) { 215d879cb83SAl Viro iov++; 216d879cb83SAl Viro buf = iov->iov_base; 217d879cb83SAl Viro copy = min(bytes, iov->iov_len); 21809fc68dcSAl Viro left = copyout(buf, from, copy); 219d879cb83SAl Viro copy -= left; 220d879cb83SAl Viro skip = copy; 221d879cb83SAl Viro from += copy; 222d879cb83SAl Viro bytes -= copy; 223d879cb83SAl Viro } 224d879cb83SAl Viro kunmap(page); 2253fa6c507SMikulas Patocka 226d879cb83SAl Viro done: 227d879cb83SAl Viro if (skip == iov->iov_len) { 228d879cb83SAl Viro iov++; 229d879cb83SAl Viro skip = 0; 230d879cb83SAl Viro } 231d879cb83SAl Viro i->count -= wanted - bytes; 232d879cb83SAl Viro i->nr_segs -= iov - i->iov; 233d879cb83SAl Viro i->iov = iov; 234d879cb83SAl Viro i->iov_offset = skip; 235d879cb83SAl Viro return wanted - bytes; 236d879cb83SAl Viro } 237d879cb83SAl Viro 238d879cb83SAl Viro static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, 239d879cb83SAl Viro struct iov_iter *i) 240d879cb83SAl Viro { 241d879cb83SAl Viro size_t skip, copy, left, wanted; 242d879cb83SAl Viro const struct iovec *iov; 243d879cb83SAl Viro char __user *buf; 244d879cb83SAl Viro void *kaddr, *to; 245d879cb83SAl Viro 246d879cb83SAl Viro if (unlikely(bytes > i->count)) 247d879cb83SAl Viro bytes = i->count; 248d879cb83SAl Viro 249d879cb83SAl Viro if (unlikely(!bytes)) 250d879cb83SAl Viro return 0; 251d879cb83SAl Viro 25209fc68dcSAl Viro might_fault(); 253d879cb83SAl Viro wanted = bytes; 254d879cb83SAl Viro iov = i->iov; 255d879cb83SAl Viro skip = i->iov_offset; 256d879cb83SAl Viro buf = iov->iov_base + skip; 257d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 258d879cb83SAl Viro 2593fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { 260d879cb83SAl Viro kaddr = kmap_atomic(page); 261d879cb83SAl Viro to = kaddr + offset; 262d879cb83SAl Viro 263d879cb83SAl Viro /* first chunk, usually the only one */ 26409fc68dcSAl Viro left = copyin(to, buf, copy); 265d879cb83SAl Viro copy -= left; 266d879cb83SAl Viro skip += copy; 267d879cb83SAl Viro to += copy; 268d879cb83SAl Viro bytes -= copy; 269d879cb83SAl Viro 270d879cb83SAl Viro while (unlikely(!left && bytes)) { 271d879cb83SAl Viro iov++; 272d879cb83SAl Viro buf = iov->iov_base; 273d879cb83SAl Viro copy = min(bytes, iov->iov_len); 27409fc68dcSAl Viro left = copyin(to, buf, copy); 275d879cb83SAl Viro copy -= left; 276d879cb83SAl Viro skip = copy; 277d879cb83SAl Viro to += copy; 278d879cb83SAl Viro bytes -= copy; 279d879cb83SAl Viro } 280d879cb83SAl Viro if (likely(!bytes)) { 281d879cb83SAl Viro kunmap_atomic(kaddr); 282d879cb83SAl Viro goto done; 283d879cb83SAl Viro } 284d879cb83SAl Viro offset = to - kaddr; 285d879cb83SAl Viro buf += copy; 286d879cb83SAl Viro kunmap_atomic(kaddr); 287d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 288d879cb83SAl Viro } 289d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 2903fa6c507SMikulas Patocka 291d879cb83SAl Viro kaddr = kmap(page); 292d879cb83SAl Viro to = kaddr + offset; 29309fc68dcSAl Viro left = copyin(to, buf, copy); 294d879cb83SAl Viro copy -= left; 295d879cb83SAl Viro skip += copy; 296d879cb83SAl Viro to += copy; 297d879cb83SAl Viro bytes -= copy; 298d879cb83SAl Viro while (unlikely(!left && bytes)) { 299d879cb83SAl Viro iov++; 300d879cb83SAl Viro buf = iov->iov_base; 301d879cb83SAl Viro copy = min(bytes, iov->iov_len); 30209fc68dcSAl Viro left = copyin(to, buf, copy); 303d879cb83SAl Viro copy -= left; 304d879cb83SAl Viro skip = copy; 305d879cb83SAl Viro to += copy; 306d879cb83SAl Viro bytes -= copy; 307d879cb83SAl Viro } 308d879cb83SAl Viro kunmap(page); 3093fa6c507SMikulas Patocka 310d879cb83SAl Viro done: 311d879cb83SAl Viro if (skip == iov->iov_len) { 312d879cb83SAl Viro iov++; 313d879cb83SAl Viro skip = 0; 314d879cb83SAl Viro } 315d879cb83SAl Viro i->count -= wanted - bytes; 316d879cb83SAl Viro i->nr_segs -= iov - i->iov; 317d879cb83SAl Viro i->iov = iov; 318d879cb83SAl Viro i->iov_offset = skip; 319d879cb83SAl Viro return wanted - bytes; 320d879cb83SAl Viro } 321d879cb83SAl Viro 322241699cdSAl Viro #ifdef PIPE_PARANOIA 323241699cdSAl Viro static bool sanity(const struct iov_iter *i) 324241699cdSAl Viro { 325241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 326241699cdSAl Viro int idx = i->idx; 327241699cdSAl Viro int next = pipe->curbuf + pipe->nrbufs; 328241699cdSAl Viro if (i->iov_offset) { 329241699cdSAl Viro struct pipe_buffer *p; 330241699cdSAl Viro if (unlikely(!pipe->nrbufs)) 331241699cdSAl Viro goto Bad; // pipe must be non-empty 332241699cdSAl Viro if (unlikely(idx != ((next - 1) & (pipe->buffers - 1)))) 333241699cdSAl Viro goto Bad; // must be at the last buffer... 334241699cdSAl Viro 335241699cdSAl Viro p = &pipe->bufs[idx]; 336241699cdSAl Viro if (unlikely(p->offset + p->len != i->iov_offset)) 337241699cdSAl Viro goto Bad; // ... at the end of segment 338241699cdSAl Viro } else { 339241699cdSAl Viro if (idx != (next & (pipe->buffers - 1))) 340241699cdSAl Viro goto Bad; // must be right after the last buffer 341241699cdSAl Viro } 342241699cdSAl Viro return true; 343241699cdSAl Viro Bad: 344241699cdSAl Viro printk(KERN_ERR "idx = %d, offset = %zd\n", i->idx, i->iov_offset); 345241699cdSAl Viro printk(KERN_ERR "curbuf = %d, nrbufs = %d, buffers = %d\n", 346241699cdSAl Viro pipe->curbuf, pipe->nrbufs, pipe->buffers); 347241699cdSAl Viro for (idx = 0; idx < pipe->buffers; idx++) 348241699cdSAl Viro printk(KERN_ERR "[%p %p %d %d]\n", 349241699cdSAl Viro pipe->bufs[idx].ops, 350241699cdSAl Viro pipe->bufs[idx].page, 351241699cdSAl Viro pipe->bufs[idx].offset, 352241699cdSAl Viro pipe->bufs[idx].len); 353241699cdSAl Viro WARN_ON(1); 354241699cdSAl Viro return false; 355241699cdSAl Viro } 356241699cdSAl Viro #else 357241699cdSAl Viro #define sanity(i) true 358241699cdSAl Viro #endif 359241699cdSAl Viro 360241699cdSAl Viro static inline int next_idx(int idx, struct pipe_inode_info *pipe) 361241699cdSAl Viro { 362241699cdSAl Viro return (idx + 1) & (pipe->buffers - 1); 363241699cdSAl Viro } 364241699cdSAl Viro 365241699cdSAl Viro static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, 366241699cdSAl Viro struct iov_iter *i) 367241699cdSAl Viro { 368241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 369241699cdSAl Viro struct pipe_buffer *buf; 370241699cdSAl Viro size_t off; 371241699cdSAl Viro int idx; 372241699cdSAl Viro 373241699cdSAl Viro if (unlikely(bytes > i->count)) 374241699cdSAl Viro bytes = i->count; 375241699cdSAl Viro 376241699cdSAl Viro if (unlikely(!bytes)) 377241699cdSAl Viro return 0; 378241699cdSAl Viro 379241699cdSAl Viro if (!sanity(i)) 380241699cdSAl Viro return 0; 381241699cdSAl Viro 382241699cdSAl Viro off = i->iov_offset; 383241699cdSAl Viro idx = i->idx; 384241699cdSAl Viro buf = &pipe->bufs[idx]; 385241699cdSAl Viro if (off) { 386241699cdSAl Viro if (offset == off && buf->page == page) { 387241699cdSAl Viro /* merge with the last one */ 388241699cdSAl Viro buf->len += bytes; 389241699cdSAl Viro i->iov_offset += bytes; 390241699cdSAl Viro goto out; 391241699cdSAl Viro } 392241699cdSAl Viro idx = next_idx(idx, pipe); 393241699cdSAl Viro buf = &pipe->bufs[idx]; 394241699cdSAl Viro } 395241699cdSAl Viro if (idx == pipe->curbuf && pipe->nrbufs) 396241699cdSAl Viro return 0; 397241699cdSAl Viro pipe->nrbufs++; 398241699cdSAl Viro buf->ops = &page_cache_pipe_buf_ops; 399241699cdSAl Viro get_page(buf->page = page); 400241699cdSAl Viro buf->offset = offset; 401241699cdSAl Viro buf->len = bytes; 402241699cdSAl Viro i->iov_offset = offset + bytes; 403241699cdSAl Viro i->idx = idx; 404241699cdSAl Viro out: 405241699cdSAl Viro i->count -= bytes; 406241699cdSAl Viro return bytes; 407241699cdSAl Viro } 408241699cdSAl Viro 409d879cb83SAl Viro /* 410171a0203SAnton Altaparmakov * Fault in one or more iovecs of the given iov_iter, to a maximum length of 411171a0203SAnton Altaparmakov * bytes. For each iovec, fault in each page that constitutes the iovec. 412171a0203SAnton Altaparmakov * 413171a0203SAnton Altaparmakov * Return 0 on success, or non-zero if the memory could not be accessed (i.e. 414171a0203SAnton Altaparmakov * because it is an invalid address). 415171a0203SAnton Altaparmakov */ 416d4690f1eSAl Viro int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) 417171a0203SAnton Altaparmakov { 418171a0203SAnton Altaparmakov size_t skip = i->iov_offset; 419171a0203SAnton Altaparmakov const struct iovec *iov; 420171a0203SAnton Altaparmakov int err; 421171a0203SAnton Altaparmakov struct iovec v; 422171a0203SAnton Altaparmakov 423171a0203SAnton Altaparmakov if (!(i->type & (ITER_BVEC|ITER_KVEC))) { 424171a0203SAnton Altaparmakov iterate_iovec(i, bytes, v, iov, skip, ({ 4254bce9f6eSAl Viro err = fault_in_pages_readable(v.iov_base, v.iov_len); 426171a0203SAnton Altaparmakov if (unlikely(err)) 427171a0203SAnton Altaparmakov return err; 428171a0203SAnton Altaparmakov 0;})) 429171a0203SAnton Altaparmakov } 430171a0203SAnton Altaparmakov return 0; 431171a0203SAnton Altaparmakov } 432d4690f1eSAl Viro EXPORT_SYMBOL(iov_iter_fault_in_readable); 433171a0203SAnton Altaparmakov 434aa563d7bSDavid Howells void iov_iter_init(struct iov_iter *i, unsigned int direction, 435d879cb83SAl Viro const struct iovec *iov, unsigned long nr_segs, 436d879cb83SAl Viro size_t count) 437d879cb83SAl Viro { 438aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 439aa563d7bSDavid Howells direction &= READ | WRITE; 440aa563d7bSDavid Howells 441d879cb83SAl Viro /* It will get better. Eventually... */ 442db68ce10SAl Viro if (uaccess_kernel()) { 443aa563d7bSDavid Howells i->type = ITER_KVEC | direction; 444d879cb83SAl Viro i->kvec = (struct kvec *)iov; 445d879cb83SAl Viro } else { 446aa563d7bSDavid Howells i->type = ITER_IOVEC | direction; 447d879cb83SAl Viro i->iov = iov; 448d879cb83SAl Viro } 449d879cb83SAl Viro i->nr_segs = nr_segs; 450d879cb83SAl Viro i->iov_offset = 0; 451d879cb83SAl Viro i->count = count; 452d879cb83SAl Viro } 453d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_init); 454d879cb83SAl Viro 455d879cb83SAl Viro static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len) 456d879cb83SAl Viro { 457d879cb83SAl Viro char *from = kmap_atomic(page); 458d879cb83SAl Viro memcpy(to, from + offset, len); 459d879cb83SAl Viro kunmap_atomic(from); 460d879cb83SAl Viro } 461d879cb83SAl Viro 46236f7a8a4SAl Viro static void memcpy_to_page(struct page *page, size_t offset, const char *from, size_t len) 463d879cb83SAl Viro { 464d879cb83SAl Viro char *to = kmap_atomic(page); 465d879cb83SAl Viro memcpy(to + offset, from, len); 466d879cb83SAl Viro kunmap_atomic(to); 467d879cb83SAl Viro } 468d879cb83SAl Viro 469d879cb83SAl Viro static void memzero_page(struct page *page, size_t offset, size_t len) 470d879cb83SAl Viro { 471d879cb83SAl Viro char *addr = kmap_atomic(page); 472d879cb83SAl Viro memset(addr + offset, 0, len); 473d879cb83SAl Viro kunmap_atomic(addr); 474d879cb83SAl Viro } 475d879cb83SAl Viro 476241699cdSAl Viro static inline bool allocated(struct pipe_buffer *buf) 477241699cdSAl Viro { 478241699cdSAl Viro return buf->ops == &default_pipe_buf_ops; 479241699cdSAl Viro } 480241699cdSAl Viro 481241699cdSAl Viro static inline void data_start(const struct iov_iter *i, int *idxp, size_t *offp) 482241699cdSAl Viro { 483241699cdSAl Viro size_t off = i->iov_offset; 484241699cdSAl Viro int idx = i->idx; 485241699cdSAl Viro if (off && (!allocated(&i->pipe->bufs[idx]) || off == PAGE_SIZE)) { 486241699cdSAl Viro idx = next_idx(idx, i->pipe); 487241699cdSAl Viro off = 0; 488241699cdSAl Viro } 489241699cdSAl Viro *idxp = idx; 490241699cdSAl Viro *offp = off; 491241699cdSAl Viro } 492241699cdSAl Viro 493241699cdSAl Viro static size_t push_pipe(struct iov_iter *i, size_t size, 494241699cdSAl Viro int *idxp, size_t *offp) 495241699cdSAl Viro { 496241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 497241699cdSAl Viro size_t off; 498241699cdSAl Viro int idx; 499241699cdSAl Viro ssize_t left; 500241699cdSAl Viro 501241699cdSAl Viro if (unlikely(size > i->count)) 502241699cdSAl Viro size = i->count; 503241699cdSAl Viro if (unlikely(!size)) 504241699cdSAl Viro return 0; 505241699cdSAl Viro 506241699cdSAl Viro left = size; 507241699cdSAl Viro data_start(i, &idx, &off); 508241699cdSAl Viro *idxp = idx; 509241699cdSAl Viro *offp = off; 510241699cdSAl Viro if (off) { 511241699cdSAl Viro left -= PAGE_SIZE - off; 512241699cdSAl Viro if (left <= 0) { 513241699cdSAl Viro pipe->bufs[idx].len += size; 514241699cdSAl Viro return size; 515241699cdSAl Viro } 516241699cdSAl Viro pipe->bufs[idx].len = PAGE_SIZE; 517241699cdSAl Viro idx = next_idx(idx, pipe); 518241699cdSAl Viro } 519241699cdSAl Viro while (idx != pipe->curbuf || !pipe->nrbufs) { 520241699cdSAl Viro struct page *page = alloc_page(GFP_USER); 521241699cdSAl Viro if (!page) 522241699cdSAl Viro break; 523241699cdSAl Viro pipe->nrbufs++; 524241699cdSAl Viro pipe->bufs[idx].ops = &default_pipe_buf_ops; 525241699cdSAl Viro pipe->bufs[idx].page = page; 526241699cdSAl Viro pipe->bufs[idx].offset = 0; 527241699cdSAl Viro if (left <= PAGE_SIZE) { 528241699cdSAl Viro pipe->bufs[idx].len = left; 529241699cdSAl Viro return size; 530241699cdSAl Viro } 531241699cdSAl Viro pipe->bufs[idx].len = PAGE_SIZE; 532241699cdSAl Viro left -= PAGE_SIZE; 533241699cdSAl Viro idx = next_idx(idx, pipe); 534241699cdSAl Viro } 535241699cdSAl Viro return size - left; 536241699cdSAl Viro } 537241699cdSAl Viro 538241699cdSAl Viro static size_t copy_pipe_to_iter(const void *addr, size_t bytes, 539241699cdSAl Viro struct iov_iter *i) 540241699cdSAl Viro { 541241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 542241699cdSAl Viro size_t n, off; 543241699cdSAl Viro int idx; 544241699cdSAl Viro 545241699cdSAl Viro if (!sanity(i)) 546241699cdSAl Viro return 0; 547241699cdSAl Viro 548241699cdSAl Viro bytes = n = push_pipe(i, bytes, &idx, &off); 549241699cdSAl Viro if (unlikely(!n)) 550241699cdSAl Viro return 0; 551241699cdSAl Viro for ( ; n; idx = next_idx(idx, pipe), off = 0) { 552241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 553241699cdSAl Viro memcpy_to_page(pipe->bufs[idx].page, off, addr, chunk); 554241699cdSAl Viro i->idx = idx; 555241699cdSAl Viro i->iov_offset = off + chunk; 556241699cdSAl Viro n -= chunk; 557241699cdSAl Viro addr += chunk; 558241699cdSAl Viro } 559241699cdSAl Viro i->count -= bytes; 560241699cdSAl Viro return bytes; 561241699cdSAl Viro } 562241699cdSAl Viro 56378e1f386SAl Viro static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, 56478e1f386SAl Viro __wsum *csum, struct iov_iter *i) 56578e1f386SAl Viro { 56678e1f386SAl Viro struct pipe_inode_info *pipe = i->pipe; 56778e1f386SAl Viro size_t n, r; 56878e1f386SAl Viro size_t off = 0; 56978e1f386SAl Viro __wsum sum = *csum, next; 57078e1f386SAl Viro int idx; 57178e1f386SAl Viro 57278e1f386SAl Viro if (!sanity(i)) 57378e1f386SAl Viro return 0; 57478e1f386SAl Viro 57578e1f386SAl Viro bytes = n = push_pipe(i, bytes, &idx, &r); 57678e1f386SAl Viro if (unlikely(!n)) 57778e1f386SAl Viro return 0; 57878e1f386SAl Viro for ( ; n; idx = next_idx(idx, pipe), r = 0) { 57978e1f386SAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - r); 58078e1f386SAl Viro char *p = kmap_atomic(pipe->bufs[idx].page); 58178e1f386SAl Viro next = csum_partial_copy_nocheck(addr, p + r, chunk, 0); 58278e1f386SAl Viro sum = csum_block_add(sum, next, off); 58378e1f386SAl Viro kunmap_atomic(p); 58478e1f386SAl Viro i->idx = idx; 58578e1f386SAl Viro i->iov_offset = r + chunk; 58678e1f386SAl Viro n -= chunk; 58778e1f386SAl Viro off += chunk; 58878e1f386SAl Viro addr += chunk; 58978e1f386SAl Viro } 59078e1f386SAl Viro i->count -= bytes; 59178e1f386SAl Viro *csum = sum; 59278e1f386SAl Viro return bytes; 59378e1f386SAl Viro } 59478e1f386SAl Viro 595aa28de27SAl Viro size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 596d879cb83SAl Viro { 59736f7a8a4SAl Viro const char *from = addr; 59800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 599241699cdSAl Viro return copy_pipe_to_iter(addr, bytes, i); 60009fc68dcSAl Viro if (iter_is_iovec(i)) 60109fc68dcSAl Viro might_fault(); 602d879cb83SAl Viro iterate_and_advance(i, bytes, v, 60309fc68dcSAl Viro copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 604d879cb83SAl Viro memcpy_to_page(v.bv_page, v.bv_offset, 605d879cb83SAl Viro (from += v.bv_len) - v.bv_len, v.bv_len), 606d879cb83SAl Viro memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len) 607d879cb83SAl Viro ) 608d879cb83SAl Viro 609d879cb83SAl Viro return bytes; 610d879cb83SAl Viro } 611aa28de27SAl Viro EXPORT_SYMBOL(_copy_to_iter); 612d879cb83SAl Viro 6138780356eSDan Williams #ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE 6148780356eSDan Williams static int copyout_mcsafe(void __user *to, const void *from, size_t n) 6158780356eSDan Williams { 6168780356eSDan Williams if (access_ok(VERIFY_WRITE, to, n)) { 6178780356eSDan Williams kasan_check_read(from, n); 6188780356eSDan Williams n = copy_to_user_mcsafe((__force void *) to, from, n); 6198780356eSDan Williams } 6208780356eSDan Williams return n; 6218780356eSDan Williams } 6228780356eSDan Williams 6238780356eSDan Williams static unsigned long memcpy_mcsafe_to_page(struct page *page, size_t offset, 6248780356eSDan Williams const char *from, size_t len) 6258780356eSDan Williams { 6268780356eSDan Williams unsigned long ret; 6278780356eSDan Williams char *to; 6288780356eSDan Williams 6298780356eSDan Williams to = kmap_atomic(page); 6308780356eSDan Williams ret = memcpy_mcsafe(to + offset, from, len); 6318780356eSDan Williams kunmap_atomic(to); 6328780356eSDan Williams 6338780356eSDan Williams return ret; 6348780356eSDan Williams } 6358780356eSDan Williams 636ca146f6fSDan Williams static size_t copy_pipe_to_iter_mcsafe(const void *addr, size_t bytes, 637ca146f6fSDan Williams struct iov_iter *i) 638ca146f6fSDan Williams { 639ca146f6fSDan Williams struct pipe_inode_info *pipe = i->pipe; 640ca146f6fSDan Williams size_t n, off, xfer = 0; 641ca146f6fSDan Williams int idx; 642ca146f6fSDan Williams 643ca146f6fSDan Williams if (!sanity(i)) 644ca146f6fSDan Williams return 0; 645ca146f6fSDan Williams 646ca146f6fSDan Williams bytes = n = push_pipe(i, bytes, &idx, &off); 647ca146f6fSDan Williams if (unlikely(!n)) 648ca146f6fSDan Williams return 0; 649ca146f6fSDan Williams for ( ; n; idx = next_idx(idx, pipe), off = 0) { 650ca146f6fSDan Williams size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 651ca146f6fSDan Williams unsigned long rem; 652ca146f6fSDan Williams 653ca146f6fSDan Williams rem = memcpy_mcsafe_to_page(pipe->bufs[idx].page, off, addr, 654ca146f6fSDan Williams chunk); 655ca146f6fSDan Williams i->idx = idx; 656ca146f6fSDan Williams i->iov_offset = off + chunk - rem; 657ca146f6fSDan Williams xfer += chunk - rem; 658ca146f6fSDan Williams if (rem) 659ca146f6fSDan Williams break; 660ca146f6fSDan Williams n -= chunk; 661ca146f6fSDan Williams addr += chunk; 662ca146f6fSDan Williams } 663ca146f6fSDan Williams i->count -= xfer; 664ca146f6fSDan Williams return xfer; 665ca146f6fSDan Williams } 666ca146f6fSDan Williams 667bf3eeb9bSDan Williams /** 668bf3eeb9bSDan Williams * _copy_to_iter_mcsafe - copy to user with source-read error exception handling 669bf3eeb9bSDan Williams * @addr: source kernel address 670bf3eeb9bSDan Williams * @bytes: total transfer length 671bf3eeb9bSDan Williams * @iter: destination iterator 672bf3eeb9bSDan Williams * 673bf3eeb9bSDan Williams * The pmem driver arranges for filesystem-dax to use this facility via 674bf3eeb9bSDan Williams * dax_copy_to_iter() for protecting read/write to persistent memory. 675bf3eeb9bSDan Williams * Unless / until an architecture can guarantee identical performance 676bf3eeb9bSDan Williams * between _copy_to_iter_mcsafe() and _copy_to_iter() it would be a 677bf3eeb9bSDan Williams * performance regression to switch more users to the mcsafe version. 678bf3eeb9bSDan Williams * 679bf3eeb9bSDan Williams * Otherwise, the main differences between this and typical _copy_to_iter(). 680bf3eeb9bSDan Williams * 681bf3eeb9bSDan Williams * * Typical tail/residue handling after a fault retries the copy 682bf3eeb9bSDan Williams * byte-by-byte until the fault happens again. Re-triggering machine 683bf3eeb9bSDan Williams * checks is potentially fatal so the implementation uses source 684bf3eeb9bSDan Williams * alignment and poison alignment assumptions to avoid re-triggering 685bf3eeb9bSDan Williams * hardware exceptions. 686bf3eeb9bSDan Williams * 687bf3eeb9bSDan Williams * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. 688bf3eeb9bSDan Williams * Compare to copy_to_iter() where only ITER_IOVEC attempts might return 689bf3eeb9bSDan Williams * a short copy. 690bf3eeb9bSDan Williams * 691bf3eeb9bSDan Williams * See MCSAFE_TEST for self-test. 692bf3eeb9bSDan Williams */ 6938780356eSDan Williams size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i) 6948780356eSDan Williams { 6958780356eSDan Williams const char *from = addr; 6968780356eSDan Williams unsigned long rem, curr_addr, s_addr = (unsigned long) addr; 6978780356eSDan Williams 69800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 699ca146f6fSDan Williams return copy_pipe_to_iter_mcsafe(addr, bytes, i); 7008780356eSDan Williams if (iter_is_iovec(i)) 7018780356eSDan Williams might_fault(); 7028780356eSDan Williams iterate_and_advance(i, bytes, v, 7038780356eSDan Williams copyout_mcsafe(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), 7048780356eSDan Williams ({ 7058780356eSDan Williams rem = memcpy_mcsafe_to_page(v.bv_page, v.bv_offset, 7068780356eSDan Williams (from += v.bv_len) - v.bv_len, v.bv_len); 7078780356eSDan Williams if (rem) { 7088780356eSDan Williams curr_addr = (unsigned long) from; 7098780356eSDan Williams bytes = curr_addr - s_addr - rem; 7108780356eSDan Williams return bytes; 7118780356eSDan Williams } 7128780356eSDan Williams }), 7138780356eSDan Williams ({ 7148780356eSDan Williams rem = memcpy_mcsafe(v.iov_base, (from += v.iov_len) - v.iov_len, 7158780356eSDan Williams v.iov_len); 7168780356eSDan Williams if (rem) { 7178780356eSDan Williams curr_addr = (unsigned long) from; 7188780356eSDan Williams bytes = curr_addr - s_addr - rem; 7198780356eSDan Williams return bytes; 7208780356eSDan Williams } 7218780356eSDan Williams }) 7228780356eSDan Williams ) 7238780356eSDan Williams 7248780356eSDan Williams return bytes; 7258780356eSDan Williams } 7268780356eSDan Williams EXPORT_SYMBOL_GPL(_copy_to_iter_mcsafe); 7278780356eSDan Williams #endif /* CONFIG_ARCH_HAS_UACCESS_MCSAFE */ 7288780356eSDan Williams 729aa28de27SAl Viro size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) 730d879cb83SAl Viro { 731d879cb83SAl Viro char *to = addr; 73200e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 733241699cdSAl Viro WARN_ON(1); 734241699cdSAl Viro return 0; 735241699cdSAl Viro } 73609fc68dcSAl Viro if (iter_is_iovec(i)) 73709fc68dcSAl Viro might_fault(); 738d879cb83SAl Viro iterate_and_advance(i, bytes, v, 73909fc68dcSAl Viro copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 740d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 741d879cb83SAl Viro v.bv_offset, v.bv_len), 742d879cb83SAl Viro memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) 743d879cb83SAl Viro ) 744d879cb83SAl Viro 745d879cb83SAl Viro return bytes; 746d879cb83SAl Viro } 747aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter); 748d879cb83SAl Viro 749aa28de27SAl Viro bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i) 750cbbd26b8SAl Viro { 751cbbd26b8SAl Viro char *to = addr; 75200e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 753cbbd26b8SAl Viro WARN_ON(1); 754cbbd26b8SAl Viro return false; 755cbbd26b8SAl Viro } 75633844e66SAl Viro if (unlikely(i->count < bytes)) 757cbbd26b8SAl Viro return false; 758cbbd26b8SAl Viro 75909fc68dcSAl Viro if (iter_is_iovec(i)) 76009fc68dcSAl Viro might_fault(); 761cbbd26b8SAl Viro iterate_all_kinds(i, bytes, v, ({ 76209fc68dcSAl Viro if (copyin((to += v.iov_len) - v.iov_len, 763cbbd26b8SAl Viro v.iov_base, v.iov_len)) 764cbbd26b8SAl Viro return false; 765cbbd26b8SAl Viro 0;}), 766cbbd26b8SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 767cbbd26b8SAl Viro v.bv_offset, v.bv_len), 768cbbd26b8SAl Viro memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) 769cbbd26b8SAl Viro ) 770cbbd26b8SAl Viro 771cbbd26b8SAl Viro iov_iter_advance(i, bytes); 772cbbd26b8SAl Viro return true; 773cbbd26b8SAl Viro } 774aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_full); 775cbbd26b8SAl Viro 776aa28de27SAl Viro size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) 777d879cb83SAl Viro { 778d879cb83SAl Viro char *to = addr; 77900e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 780241699cdSAl Viro WARN_ON(1); 781241699cdSAl Viro return 0; 782241699cdSAl Viro } 783d879cb83SAl Viro iterate_and_advance(i, bytes, v, 7843f763453SAl Viro __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, 785d879cb83SAl Viro v.iov_base, v.iov_len), 786d879cb83SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 787d879cb83SAl Viro v.bv_offset, v.bv_len), 788d879cb83SAl Viro memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) 789d879cb83SAl Viro ) 790d879cb83SAl Viro 791d879cb83SAl Viro return bytes; 792d879cb83SAl Viro } 793aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_nocache); 794d879cb83SAl Viro 7950aed55afSDan Williams #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE 796abd08d7dSDan Williams /** 797abd08d7dSDan Williams * _copy_from_iter_flushcache - write destination through cpu cache 798abd08d7dSDan Williams * @addr: destination kernel address 799abd08d7dSDan Williams * @bytes: total transfer length 800abd08d7dSDan Williams * @iter: source iterator 801abd08d7dSDan Williams * 802abd08d7dSDan Williams * The pmem driver arranges for filesystem-dax to use this facility via 803abd08d7dSDan Williams * dax_copy_from_iter() for ensuring that writes to persistent memory 804abd08d7dSDan Williams * are flushed through the CPU cache. It is differentiated from 805abd08d7dSDan Williams * _copy_from_iter_nocache() in that guarantees all data is flushed for 806abd08d7dSDan Williams * all iterator types. The _copy_from_iter_nocache() only attempts to 807abd08d7dSDan Williams * bypass the cache for the ITER_IOVEC case, and on some archs may use 808abd08d7dSDan Williams * instructions that strand dirty-data in the cache. 809abd08d7dSDan Williams */ 8106a37e940SLinus Torvalds size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 8110aed55afSDan Williams { 8120aed55afSDan Williams char *to = addr; 81300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 8140aed55afSDan Williams WARN_ON(1); 8150aed55afSDan Williams return 0; 8160aed55afSDan Williams } 8170aed55afSDan Williams iterate_and_advance(i, bytes, v, 8180aed55afSDan Williams __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, 8190aed55afSDan Williams v.iov_base, v.iov_len), 8200aed55afSDan Williams memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, 8210aed55afSDan Williams v.bv_offset, v.bv_len), 8220aed55afSDan Williams memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, 8230aed55afSDan Williams v.iov_len) 8240aed55afSDan Williams ) 8250aed55afSDan Williams 8260aed55afSDan Williams return bytes; 8270aed55afSDan Williams } 8286a37e940SLinus Torvalds EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); 8290aed55afSDan Williams #endif 8300aed55afSDan Williams 831aa28de27SAl Viro bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i) 832cbbd26b8SAl Viro { 833cbbd26b8SAl Viro char *to = addr; 83400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 835cbbd26b8SAl Viro WARN_ON(1); 836cbbd26b8SAl Viro return false; 837cbbd26b8SAl Viro } 83833844e66SAl Viro if (unlikely(i->count < bytes)) 839cbbd26b8SAl Viro return false; 840cbbd26b8SAl Viro iterate_all_kinds(i, bytes, v, ({ 8413f763453SAl Viro if (__copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, 842cbbd26b8SAl Viro v.iov_base, v.iov_len)) 843cbbd26b8SAl Viro return false; 844cbbd26b8SAl Viro 0;}), 845cbbd26b8SAl Viro memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, 846cbbd26b8SAl Viro v.bv_offset, v.bv_len), 847cbbd26b8SAl Viro memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) 848cbbd26b8SAl Viro ) 849cbbd26b8SAl Viro 850cbbd26b8SAl Viro iov_iter_advance(i, bytes); 851cbbd26b8SAl Viro return true; 852cbbd26b8SAl Viro } 853aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_full_nocache); 854cbbd26b8SAl Viro 85572e809edSAl Viro static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) 85672e809edSAl Viro { 857a90bcb86SPetar Penkov struct page *head = compound_head(page); 858a90bcb86SPetar Penkov size_t v = n + offset + page_address(page) - page_address(head); 859a90bcb86SPetar Penkov 860a90bcb86SPetar Penkov if (likely(n <= v && v <= (PAGE_SIZE << compound_order(head)))) 86172e809edSAl Viro return true; 86272e809edSAl Viro WARN_ON(1); 86372e809edSAl Viro return false; 86472e809edSAl Viro } 865d879cb83SAl Viro 866d879cb83SAl Viro size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 867d879cb83SAl Viro struct iov_iter *i) 868d879cb83SAl Viro { 86972e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 87072e809edSAl Viro return 0; 871d879cb83SAl Viro if (i->type & (ITER_BVEC|ITER_KVEC)) { 872d879cb83SAl Viro void *kaddr = kmap_atomic(page); 873d879cb83SAl Viro size_t wanted = copy_to_iter(kaddr + offset, bytes, i); 874d879cb83SAl Viro kunmap_atomic(kaddr); 875d879cb83SAl Viro return wanted; 8769ea9ce04SDavid Howells } else if (unlikely(iov_iter_is_discard(i))) 8779ea9ce04SDavid Howells return bytes; 8789ea9ce04SDavid Howells else if (likely(!iov_iter_is_pipe(i))) 879d879cb83SAl Viro return copy_page_to_iter_iovec(page, offset, bytes, i); 880241699cdSAl Viro else 881241699cdSAl Viro return copy_page_to_iter_pipe(page, offset, bytes, i); 882d879cb83SAl Viro } 883d879cb83SAl Viro EXPORT_SYMBOL(copy_page_to_iter); 884d879cb83SAl Viro 885d879cb83SAl Viro size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, 886d879cb83SAl Viro struct iov_iter *i) 887d879cb83SAl Viro { 88872e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 88972e809edSAl Viro return 0; 8909ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 891241699cdSAl Viro WARN_ON(1); 892241699cdSAl Viro return 0; 893241699cdSAl Viro } 894d879cb83SAl Viro if (i->type & (ITER_BVEC|ITER_KVEC)) { 895d879cb83SAl Viro void *kaddr = kmap_atomic(page); 896aa28de27SAl Viro size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); 897d879cb83SAl Viro kunmap_atomic(kaddr); 898d879cb83SAl Viro return wanted; 899d879cb83SAl Viro } else 900d879cb83SAl Viro return copy_page_from_iter_iovec(page, offset, bytes, i); 901d879cb83SAl Viro } 902d879cb83SAl Viro EXPORT_SYMBOL(copy_page_from_iter); 903d879cb83SAl Viro 904241699cdSAl Viro static size_t pipe_zero(size_t bytes, struct iov_iter *i) 905241699cdSAl Viro { 906241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 907241699cdSAl Viro size_t n, off; 908241699cdSAl Viro int idx; 909241699cdSAl Viro 910241699cdSAl Viro if (!sanity(i)) 911241699cdSAl Viro return 0; 912241699cdSAl Viro 913241699cdSAl Viro bytes = n = push_pipe(i, bytes, &idx, &off); 914241699cdSAl Viro if (unlikely(!n)) 915241699cdSAl Viro return 0; 916241699cdSAl Viro 917241699cdSAl Viro for ( ; n; idx = next_idx(idx, pipe), off = 0) { 918241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 919241699cdSAl Viro memzero_page(pipe->bufs[idx].page, off, chunk); 920241699cdSAl Viro i->idx = idx; 921241699cdSAl Viro i->iov_offset = off + chunk; 922241699cdSAl Viro n -= chunk; 923241699cdSAl Viro } 924241699cdSAl Viro i->count -= bytes; 925241699cdSAl Viro return bytes; 926241699cdSAl Viro } 927241699cdSAl Viro 928d879cb83SAl Viro size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 929d879cb83SAl Viro { 93000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 931241699cdSAl Viro return pipe_zero(bytes, i); 932d879cb83SAl Viro iterate_and_advance(i, bytes, v, 93309fc68dcSAl Viro clear_user(v.iov_base, v.iov_len), 934d879cb83SAl Viro memzero_page(v.bv_page, v.bv_offset, v.bv_len), 935d879cb83SAl Viro memset(v.iov_base, 0, v.iov_len) 936d879cb83SAl Viro ) 937d879cb83SAl Viro 938d879cb83SAl Viro return bytes; 939d879cb83SAl Viro } 940d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_zero); 941d879cb83SAl Viro 942d879cb83SAl Viro size_t iov_iter_copy_from_user_atomic(struct page *page, 943d879cb83SAl Viro struct iov_iter *i, unsigned long offset, size_t bytes) 944d879cb83SAl Viro { 945d879cb83SAl Viro char *kaddr = kmap_atomic(page), *p = kaddr + offset; 94672e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) { 94772e809edSAl Viro kunmap_atomic(kaddr); 94872e809edSAl Viro return 0; 94972e809edSAl Viro } 9509ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 951241699cdSAl Viro kunmap_atomic(kaddr); 952241699cdSAl Viro WARN_ON(1); 953241699cdSAl Viro return 0; 954241699cdSAl Viro } 955d879cb83SAl Viro iterate_all_kinds(i, bytes, v, 95609fc68dcSAl Viro copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), 957d879cb83SAl Viro memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, 958d879cb83SAl Viro v.bv_offset, v.bv_len), 959d879cb83SAl Viro memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) 960d879cb83SAl Viro ) 961d879cb83SAl Viro kunmap_atomic(kaddr); 962d879cb83SAl Viro return bytes; 963d879cb83SAl Viro } 964d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); 965d879cb83SAl Viro 966b9dc6f65SAl Viro static inline void pipe_truncate(struct iov_iter *i) 967241699cdSAl Viro { 968241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 969241699cdSAl Viro if (pipe->nrbufs) { 970b9dc6f65SAl Viro size_t off = i->iov_offset; 971b9dc6f65SAl Viro int idx = i->idx; 972b9dc6f65SAl Viro int nrbufs = (idx - pipe->curbuf) & (pipe->buffers - 1); 973b9dc6f65SAl Viro if (off) { 974b9dc6f65SAl Viro pipe->bufs[idx].len = off - pipe->bufs[idx].offset; 975b9dc6f65SAl Viro idx = next_idx(idx, pipe); 976b9dc6f65SAl Viro nrbufs++; 977b9dc6f65SAl Viro } 978b9dc6f65SAl Viro while (pipe->nrbufs > nrbufs) { 979a779638cSMiklos Szeredi pipe_buf_release(pipe, &pipe->bufs[idx]); 980241699cdSAl Viro idx = next_idx(idx, pipe); 981241699cdSAl Viro pipe->nrbufs--; 982241699cdSAl Viro } 983241699cdSAl Viro } 984b9dc6f65SAl Viro } 985b9dc6f65SAl Viro 986b9dc6f65SAl Viro static void pipe_advance(struct iov_iter *i, size_t size) 987b9dc6f65SAl Viro { 988b9dc6f65SAl Viro struct pipe_inode_info *pipe = i->pipe; 989b9dc6f65SAl Viro if (unlikely(i->count < size)) 990b9dc6f65SAl Viro size = i->count; 991b9dc6f65SAl Viro if (size) { 992b9dc6f65SAl Viro struct pipe_buffer *buf; 993b9dc6f65SAl Viro size_t off = i->iov_offset, left = size; 994b9dc6f65SAl Viro int idx = i->idx; 995b9dc6f65SAl Viro if (off) /* make it relative to the beginning of buffer */ 996b9dc6f65SAl Viro left += off - pipe->bufs[idx].offset; 997b9dc6f65SAl Viro while (1) { 998b9dc6f65SAl Viro buf = &pipe->bufs[idx]; 999b9dc6f65SAl Viro if (left <= buf->len) 1000b9dc6f65SAl Viro break; 1001b9dc6f65SAl Viro left -= buf->len; 1002b9dc6f65SAl Viro idx = next_idx(idx, pipe); 1003b9dc6f65SAl Viro } 1004b9dc6f65SAl Viro i->idx = idx; 1005b9dc6f65SAl Viro i->iov_offset = buf->offset + left; 1006b9dc6f65SAl Viro } 1007b9dc6f65SAl Viro i->count -= size; 1008b9dc6f65SAl Viro /* ... and discard everything past that point */ 1009b9dc6f65SAl Viro pipe_truncate(i); 1010241699cdSAl Viro } 1011241699cdSAl Viro 1012d879cb83SAl Viro void iov_iter_advance(struct iov_iter *i, size_t size) 1013d879cb83SAl Viro { 101400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 1015241699cdSAl Viro pipe_advance(i, size); 1016241699cdSAl Viro return; 1017241699cdSAl Viro } 10189ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) { 10199ea9ce04SDavid Howells i->count -= size; 10209ea9ce04SDavid Howells return; 10219ea9ce04SDavid Howells } 1022d879cb83SAl Viro iterate_and_advance(i, size, v, 0, 0, 0) 1023d879cb83SAl Viro } 1024d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_advance); 1025d879cb83SAl Viro 102627c0e374SAl Viro void iov_iter_revert(struct iov_iter *i, size_t unroll) 102727c0e374SAl Viro { 102827c0e374SAl Viro if (!unroll) 102927c0e374SAl Viro return; 10305b47d59aSAl Viro if (WARN_ON(unroll > MAX_RW_COUNT)) 10315b47d59aSAl Viro return; 103227c0e374SAl Viro i->count += unroll; 103300e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 103427c0e374SAl Viro struct pipe_inode_info *pipe = i->pipe; 103527c0e374SAl Viro int idx = i->idx; 103627c0e374SAl Viro size_t off = i->iov_offset; 103727c0e374SAl Viro while (1) { 103827c0e374SAl Viro size_t n = off - pipe->bufs[idx].offset; 103927c0e374SAl Viro if (unroll < n) { 10404fa55cefSAl Viro off -= unroll; 104127c0e374SAl Viro break; 104227c0e374SAl Viro } 104327c0e374SAl Viro unroll -= n; 104427c0e374SAl Viro if (!unroll && idx == i->start_idx) { 104527c0e374SAl Viro off = 0; 104627c0e374SAl Viro break; 104727c0e374SAl Viro } 104827c0e374SAl Viro if (!idx--) 104927c0e374SAl Viro idx = pipe->buffers - 1; 105027c0e374SAl Viro off = pipe->bufs[idx].offset + pipe->bufs[idx].len; 105127c0e374SAl Viro } 105227c0e374SAl Viro i->iov_offset = off; 105327c0e374SAl Viro i->idx = idx; 105427c0e374SAl Viro pipe_truncate(i); 105527c0e374SAl Viro return; 105627c0e374SAl Viro } 10579ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 10589ea9ce04SDavid Howells return; 105927c0e374SAl Viro if (unroll <= i->iov_offset) { 106027c0e374SAl Viro i->iov_offset -= unroll; 106127c0e374SAl Viro return; 106227c0e374SAl Viro } 106327c0e374SAl Viro unroll -= i->iov_offset; 106400e23707SDavid Howells if (iov_iter_is_bvec(i)) { 106527c0e374SAl Viro const struct bio_vec *bvec = i->bvec; 106627c0e374SAl Viro while (1) { 106727c0e374SAl Viro size_t n = (--bvec)->bv_len; 106827c0e374SAl Viro i->nr_segs++; 106927c0e374SAl Viro if (unroll <= n) { 107027c0e374SAl Viro i->bvec = bvec; 107127c0e374SAl Viro i->iov_offset = n - unroll; 107227c0e374SAl Viro return; 107327c0e374SAl Viro } 107427c0e374SAl Viro unroll -= n; 107527c0e374SAl Viro } 107627c0e374SAl Viro } else { /* same logics for iovec and kvec */ 107727c0e374SAl Viro const struct iovec *iov = i->iov; 107827c0e374SAl Viro while (1) { 107927c0e374SAl Viro size_t n = (--iov)->iov_len; 108027c0e374SAl Viro i->nr_segs++; 108127c0e374SAl Viro if (unroll <= n) { 108227c0e374SAl Viro i->iov = iov; 108327c0e374SAl Viro i->iov_offset = n - unroll; 108427c0e374SAl Viro return; 108527c0e374SAl Viro } 108627c0e374SAl Viro unroll -= n; 108727c0e374SAl Viro } 108827c0e374SAl Viro } 108927c0e374SAl Viro } 109027c0e374SAl Viro EXPORT_SYMBOL(iov_iter_revert); 109127c0e374SAl Viro 1092d879cb83SAl Viro /* 1093d879cb83SAl Viro * Return the count of just the current iov_iter segment. 1094d879cb83SAl Viro */ 1095d879cb83SAl Viro size_t iov_iter_single_seg_count(const struct iov_iter *i) 1096d879cb83SAl Viro { 109700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1098241699cdSAl Viro return i->count; // it is a silly place, anyway 1099d879cb83SAl Viro if (i->nr_segs == 1) 1100d879cb83SAl Viro return i->count; 11019ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 11029ea9ce04SDavid Howells return i->count; 110300e23707SDavid Howells else if (iov_iter_is_bvec(i)) 1104d879cb83SAl Viro return min(i->count, i->bvec->bv_len - i->iov_offset); 1105d879cb83SAl Viro else 1106d879cb83SAl Viro return min(i->count, i->iov->iov_len - i->iov_offset); 1107d879cb83SAl Viro } 1108d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_single_seg_count); 1109d879cb83SAl Viro 1110aa563d7bSDavid Howells void iov_iter_kvec(struct iov_iter *i, unsigned int direction, 1111d879cb83SAl Viro const struct kvec *kvec, unsigned long nr_segs, 1112d879cb83SAl Viro size_t count) 1113d879cb83SAl Viro { 1114aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 1115aa563d7bSDavid Howells i->type = ITER_KVEC | (direction & (READ | WRITE)); 1116d879cb83SAl Viro i->kvec = kvec; 1117d879cb83SAl Viro i->nr_segs = nr_segs; 1118d879cb83SAl Viro i->iov_offset = 0; 1119d879cb83SAl Viro i->count = count; 1120d879cb83SAl Viro } 1121d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_kvec); 1122d879cb83SAl Viro 1123aa563d7bSDavid Howells void iov_iter_bvec(struct iov_iter *i, unsigned int direction, 1124d879cb83SAl Viro const struct bio_vec *bvec, unsigned long nr_segs, 1125d879cb83SAl Viro size_t count) 1126d879cb83SAl Viro { 1127aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 1128aa563d7bSDavid Howells i->type = ITER_BVEC | (direction & (READ | WRITE)); 1129d879cb83SAl Viro i->bvec = bvec; 1130d879cb83SAl Viro i->nr_segs = nr_segs; 1131d879cb83SAl Viro i->iov_offset = 0; 1132d879cb83SAl Viro i->count = count; 1133d879cb83SAl Viro } 1134d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_bvec); 1135d879cb83SAl Viro 1136aa563d7bSDavid Howells void iov_iter_pipe(struct iov_iter *i, unsigned int direction, 1137241699cdSAl Viro struct pipe_inode_info *pipe, 1138241699cdSAl Viro size_t count) 1139241699cdSAl Viro { 1140aa563d7bSDavid Howells BUG_ON(direction != READ); 1141b9dc6f65SAl Viro WARN_ON(pipe->nrbufs == pipe->buffers); 1142aa563d7bSDavid Howells i->type = ITER_PIPE | READ; 1143241699cdSAl Viro i->pipe = pipe; 1144241699cdSAl Viro i->idx = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1); 1145241699cdSAl Viro i->iov_offset = 0; 1146241699cdSAl Viro i->count = count; 114727c0e374SAl Viro i->start_idx = i->idx; 1148241699cdSAl Viro } 1149241699cdSAl Viro EXPORT_SYMBOL(iov_iter_pipe); 1150241699cdSAl Viro 11519ea9ce04SDavid Howells /** 11529ea9ce04SDavid Howells * iov_iter_discard - Initialise an I/O iterator that discards data 11539ea9ce04SDavid Howells * @i: The iterator to initialise. 11549ea9ce04SDavid Howells * @direction: The direction of the transfer. 11559ea9ce04SDavid Howells * @count: The size of the I/O buffer in bytes. 11569ea9ce04SDavid Howells * 11579ea9ce04SDavid Howells * Set up an I/O iterator that just discards everything that's written to it. 11589ea9ce04SDavid Howells * It's only available as a READ iterator. 11599ea9ce04SDavid Howells */ 11609ea9ce04SDavid Howells void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) 11619ea9ce04SDavid Howells { 11629ea9ce04SDavid Howells BUG_ON(direction != READ); 11639ea9ce04SDavid Howells i->type = ITER_DISCARD | READ; 11649ea9ce04SDavid Howells i->count = count; 11659ea9ce04SDavid Howells i->iov_offset = 0; 11669ea9ce04SDavid Howells } 11679ea9ce04SDavid Howells EXPORT_SYMBOL(iov_iter_discard); 11689ea9ce04SDavid Howells 1169d879cb83SAl Viro unsigned long iov_iter_alignment(const struct iov_iter *i) 1170d879cb83SAl Viro { 1171d879cb83SAl Viro unsigned long res = 0; 1172d879cb83SAl Viro size_t size = i->count; 1173d879cb83SAl Viro 117400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 117533844e66SAl Viro if (size && i->iov_offset && allocated(&i->pipe->bufs[i->idx])) 1176241699cdSAl Viro return size | i->iov_offset; 1177241699cdSAl Viro return size; 1178241699cdSAl Viro } 1179d879cb83SAl Viro iterate_all_kinds(i, size, v, 1180d879cb83SAl Viro (res |= (unsigned long)v.iov_base | v.iov_len, 0), 1181d879cb83SAl Viro res |= v.bv_offset | v.bv_len, 1182d879cb83SAl Viro res |= (unsigned long)v.iov_base | v.iov_len 1183d879cb83SAl Viro ) 1184d879cb83SAl Viro return res; 1185d879cb83SAl Viro } 1186d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_alignment); 1187d879cb83SAl Viro 1188357f435dSAl Viro unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 1189357f435dSAl Viro { 1190357f435dSAl Viro unsigned long res = 0; 1191357f435dSAl Viro size_t size = i->count; 1192357f435dSAl Viro 11939ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1194241699cdSAl Viro WARN_ON(1); 1195241699cdSAl Viro return ~0U; 1196241699cdSAl Viro } 1197241699cdSAl Viro 1198357f435dSAl Viro iterate_all_kinds(i, size, v, 1199357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.iov_base) | 1200357f435dSAl Viro (size != v.iov_len ? size : 0), 0), 1201357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.bv_offset) | 1202357f435dSAl Viro (size != v.bv_len ? size : 0)), 1203357f435dSAl Viro (res |= (!res ? 0 : (unsigned long)v.iov_base) | 1204357f435dSAl Viro (size != v.iov_len ? size : 0)) 1205357f435dSAl Viro ); 1206357f435dSAl Viro return res; 1207357f435dSAl Viro } 1208357f435dSAl Viro EXPORT_SYMBOL(iov_iter_gap_alignment); 1209357f435dSAl Viro 1210e76b6312SIlya Dryomov static inline ssize_t __pipe_get_pages(struct iov_iter *i, 1211241699cdSAl Viro size_t maxsize, 1212241699cdSAl Viro struct page **pages, 1213241699cdSAl Viro int idx, 1214241699cdSAl Viro size_t *start) 1215241699cdSAl Viro { 1216241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 12171689c73aSAl Viro ssize_t n = push_pipe(i, maxsize, &idx, start); 1218241699cdSAl Viro if (!n) 1219241699cdSAl Viro return -EFAULT; 1220241699cdSAl Viro 1221241699cdSAl Viro maxsize = n; 1222241699cdSAl Viro n += *start; 12231689c73aSAl Viro while (n > 0) { 1224241699cdSAl Viro get_page(*pages++ = pipe->bufs[idx].page); 1225241699cdSAl Viro idx = next_idx(idx, pipe); 1226241699cdSAl Viro n -= PAGE_SIZE; 1227241699cdSAl Viro } 1228241699cdSAl Viro 1229241699cdSAl Viro return maxsize; 1230241699cdSAl Viro } 1231241699cdSAl Viro 1232241699cdSAl Viro static ssize_t pipe_get_pages(struct iov_iter *i, 1233241699cdSAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1234241699cdSAl Viro size_t *start) 1235241699cdSAl Viro { 1236241699cdSAl Viro unsigned npages; 1237241699cdSAl Viro size_t capacity; 1238241699cdSAl Viro int idx; 1239241699cdSAl Viro 124033844e66SAl Viro if (!maxsize) 124133844e66SAl Viro return 0; 124233844e66SAl Viro 1243241699cdSAl Viro if (!sanity(i)) 1244241699cdSAl Viro return -EFAULT; 1245241699cdSAl Viro 1246241699cdSAl Viro data_start(i, &idx, start); 1247241699cdSAl Viro /* some of this one + all after this one */ 1248241699cdSAl Viro npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1; 1249241699cdSAl Viro capacity = min(npages,maxpages) * PAGE_SIZE - *start; 1250241699cdSAl Viro 1251241699cdSAl Viro return __pipe_get_pages(i, min(maxsize, capacity), pages, idx, start); 1252241699cdSAl Viro } 1253241699cdSAl Viro 1254d879cb83SAl Viro ssize_t iov_iter_get_pages(struct iov_iter *i, 1255d879cb83SAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1256d879cb83SAl Viro size_t *start) 1257d879cb83SAl Viro { 1258d879cb83SAl Viro if (maxsize > i->count) 1259d879cb83SAl Viro maxsize = i->count; 1260d879cb83SAl Viro 126100e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1262241699cdSAl Viro return pipe_get_pages(i, pages, maxsize, maxpages, start); 12639ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 12649ea9ce04SDavid Howells return -EFAULT; 12659ea9ce04SDavid Howells 1266d879cb83SAl Viro iterate_all_kinds(i, maxsize, v, ({ 1267d879cb83SAl Viro unsigned long addr = (unsigned long)v.iov_base; 1268d879cb83SAl Viro size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); 1269d879cb83SAl Viro int n; 1270d879cb83SAl Viro int res; 1271d879cb83SAl Viro 1272d879cb83SAl Viro if (len > maxpages * PAGE_SIZE) 1273d879cb83SAl Viro len = maxpages * PAGE_SIZE; 1274d879cb83SAl Viro addr &= ~(PAGE_SIZE - 1); 1275d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 127600e23707SDavid Howells res = get_user_pages_fast(addr, n, iov_iter_rw(i) != WRITE, pages); 1277d879cb83SAl Viro if (unlikely(res < 0)) 1278d879cb83SAl Viro return res; 1279d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 1280d879cb83SAl Viro 0;}),({ 1281d879cb83SAl Viro /* can't be more than PAGE_SIZE */ 1282d879cb83SAl Viro *start = v.bv_offset; 1283d879cb83SAl Viro get_page(*pages = v.bv_page); 1284d879cb83SAl Viro return v.bv_len; 1285d879cb83SAl Viro }),({ 1286d879cb83SAl Viro return -EFAULT; 1287d879cb83SAl Viro }) 1288d879cb83SAl Viro ) 1289d879cb83SAl Viro return 0; 1290d879cb83SAl Viro } 1291d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages); 1292d879cb83SAl Viro 1293d879cb83SAl Viro static struct page **get_pages_array(size_t n) 1294d879cb83SAl Viro { 1295752ade68SMichal Hocko return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); 1296d879cb83SAl Viro } 1297d879cb83SAl Viro 1298241699cdSAl Viro static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 1299241699cdSAl Viro struct page ***pages, size_t maxsize, 1300241699cdSAl Viro size_t *start) 1301241699cdSAl Viro { 1302241699cdSAl Viro struct page **p; 1303d7760d63SIlya Dryomov ssize_t n; 1304241699cdSAl Viro int idx; 1305241699cdSAl Viro int npages; 1306241699cdSAl Viro 130733844e66SAl Viro if (!maxsize) 130833844e66SAl Viro return 0; 130933844e66SAl Viro 1310241699cdSAl Viro if (!sanity(i)) 1311241699cdSAl Viro return -EFAULT; 1312241699cdSAl Viro 1313241699cdSAl Viro data_start(i, &idx, start); 1314241699cdSAl Viro /* some of this one + all after this one */ 1315241699cdSAl Viro npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1; 1316241699cdSAl Viro n = npages * PAGE_SIZE - *start; 1317241699cdSAl Viro if (maxsize > n) 1318241699cdSAl Viro maxsize = n; 1319241699cdSAl Viro else 1320241699cdSAl Viro npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1321241699cdSAl Viro p = get_pages_array(npages); 1322241699cdSAl Viro if (!p) 1323241699cdSAl Viro return -ENOMEM; 1324241699cdSAl Viro n = __pipe_get_pages(i, maxsize, p, idx, start); 1325241699cdSAl Viro if (n > 0) 1326241699cdSAl Viro *pages = p; 1327241699cdSAl Viro else 1328241699cdSAl Viro kvfree(p); 1329241699cdSAl Viro return n; 1330241699cdSAl Viro } 1331241699cdSAl Viro 1332d879cb83SAl Viro ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 1333d879cb83SAl Viro struct page ***pages, size_t maxsize, 1334d879cb83SAl Viro size_t *start) 1335d879cb83SAl Viro { 1336d879cb83SAl Viro struct page **p; 1337d879cb83SAl Viro 1338d879cb83SAl Viro if (maxsize > i->count) 1339d879cb83SAl Viro maxsize = i->count; 1340d879cb83SAl Viro 134100e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 1342241699cdSAl Viro return pipe_get_pages_alloc(i, pages, maxsize, start); 13439ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 13449ea9ce04SDavid Howells return -EFAULT; 13459ea9ce04SDavid Howells 1346d879cb83SAl Viro iterate_all_kinds(i, maxsize, v, ({ 1347d879cb83SAl Viro unsigned long addr = (unsigned long)v.iov_base; 1348d879cb83SAl Viro size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); 1349d879cb83SAl Viro int n; 1350d879cb83SAl Viro int res; 1351d879cb83SAl Viro 1352d879cb83SAl Viro addr &= ~(PAGE_SIZE - 1); 1353d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 1354d879cb83SAl Viro p = get_pages_array(n); 1355d879cb83SAl Viro if (!p) 1356d879cb83SAl Viro return -ENOMEM; 135700e23707SDavid Howells res = get_user_pages_fast(addr, n, iov_iter_rw(i) != WRITE, p); 1358d879cb83SAl Viro if (unlikely(res < 0)) { 1359d879cb83SAl Viro kvfree(p); 1360d879cb83SAl Viro return res; 1361d879cb83SAl Viro } 1362d879cb83SAl Viro *pages = p; 1363d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 1364d879cb83SAl Viro 0;}),({ 1365d879cb83SAl Viro /* can't be more than PAGE_SIZE */ 1366d879cb83SAl Viro *start = v.bv_offset; 1367d879cb83SAl Viro *pages = p = get_pages_array(1); 1368d879cb83SAl Viro if (!p) 1369d879cb83SAl Viro return -ENOMEM; 1370d879cb83SAl Viro get_page(*p = v.bv_page); 1371d879cb83SAl Viro return v.bv_len; 1372d879cb83SAl Viro }),({ 1373d879cb83SAl Viro return -EFAULT; 1374d879cb83SAl Viro }) 1375d879cb83SAl Viro ) 1376d879cb83SAl Viro return 0; 1377d879cb83SAl Viro } 1378d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages_alloc); 1379d879cb83SAl Viro 1380d879cb83SAl Viro size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 1381d879cb83SAl Viro struct iov_iter *i) 1382d879cb83SAl Viro { 1383d879cb83SAl Viro char *to = addr; 1384d879cb83SAl Viro __wsum sum, next; 1385d879cb83SAl Viro size_t off = 0; 1386d879cb83SAl Viro sum = *csum; 13879ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1388241699cdSAl Viro WARN_ON(1); 1389241699cdSAl Viro return 0; 1390241699cdSAl Viro } 1391d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1392d879cb83SAl Viro int err = 0; 1393d879cb83SAl Viro next = csum_and_copy_from_user(v.iov_base, 1394d879cb83SAl Viro (to += v.iov_len) - v.iov_len, 1395d879cb83SAl Viro v.iov_len, 0, &err); 1396d879cb83SAl Viro if (!err) { 1397d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1398d879cb83SAl Viro off += v.iov_len; 1399d879cb83SAl Viro } 1400d879cb83SAl Viro err ? v.iov_len : 0; 1401d879cb83SAl Viro }), ({ 1402d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1403d879cb83SAl Viro next = csum_partial_copy_nocheck(p + v.bv_offset, 1404d879cb83SAl Viro (to += v.bv_len) - v.bv_len, 1405d879cb83SAl Viro v.bv_len, 0); 1406d879cb83SAl Viro kunmap_atomic(p); 1407d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1408d879cb83SAl Viro off += v.bv_len; 1409d879cb83SAl Viro }),({ 1410d879cb83SAl Viro next = csum_partial_copy_nocheck(v.iov_base, 1411d879cb83SAl Viro (to += v.iov_len) - v.iov_len, 1412d879cb83SAl Viro v.iov_len, 0); 1413d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1414d879cb83SAl Viro off += v.iov_len; 1415d879cb83SAl Viro }) 1416d879cb83SAl Viro ) 1417d879cb83SAl Viro *csum = sum; 1418d879cb83SAl Viro return bytes; 1419d879cb83SAl Viro } 1420d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter); 1421d879cb83SAl Viro 1422cbbd26b8SAl Viro bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, 1423cbbd26b8SAl Viro struct iov_iter *i) 1424cbbd26b8SAl Viro { 1425cbbd26b8SAl Viro char *to = addr; 1426cbbd26b8SAl Viro __wsum sum, next; 1427cbbd26b8SAl Viro size_t off = 0; 1428cbbd26b8SAl Viro sum = *csum; 14299ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1430cbbd26b8SAl Viro WARN_ON(1); 1431cbbd26b8SAl Viro return false; 1432cbbd26b8SAl Viro } 1433cbbd26b8SAl Viro if (unlikely(i->count < bytes)) 1434cbbd26b8SAl Viro return false; 1435cbbd26b8SAl Viro iterate_all_kinds(i, bytes, v, ({ 1436cbbd26b8SAl Viro int err = 0; 1437cbbd26b8SAl Viro next = csum_and_copy_from_user(v.iov_base, 1438cbbd26b8SAl Viro (to += v.iov_len) - v.iov_len, 1439cbbd26b8SAl Viro v.iov_len, 0, &err); 1440cbbd26b8SAl Viro if (err) 1441cbbd26b8SAl Viro return false; 1442cbbd26b8SAl Viro sum = csum_block_add(sum, next, off); 1443cbbd26b8SAl Viro off += v.iov_len; 1444cbbd26b8SAl Viro 0; 1445cbbd26b8SAl Viro }), ({ 1446cbbd26b8SAl Viro char *p = kmap_atomic(v.bv_page); 1447cbbd26b8SAl Viro next = csum_partial_copy_nocheck(p + v.bv_offset, 1448cbbd26b8SAl Viro (to += v.bv_len) - v.bv_len, 1449cbbd26b8SAl Viro v.bv_len, 0); 1450cbbd26b8SAl Viro kunmap_atomic(p); 1451cbbd26b8SAl Viro sum = csum_block_add(sum, next, off); 1452cbbd26b8SAl Viro off += v.bv_len; 1453cbbd26b8SAl Viro }),({ 1454cbbd26b8SAl Viro next = csum_partial_copy_nocheck(v.iov_base, 1455cbbd26b8SAl Viro (to += v.iov_len) - v.iov_len, 1456cbbd26b8SAl Viro v.iov_len, 0); 1457cbbd26b8SAl Viro sum = csum_block_add(sum, next, off); 1458cbbd26b8SAl Viro off += v.iov_len; 1459cbbd26b8SAl Viro }) 1460cbbd26b8SAl Viro ) 1461cbbd26b8SAl Viro *csum = sum; 1462cbbd26b8SAl Viro iov_iter_advance(i, bytes); 1463cbbd26b8SAl Viro return true; 1464cbbd26b8SAl Viro } 1465cbbd26b8SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter_full); 1466cbbd26b8SAl Viro 1467cb002d07SSagi Grimberg size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csump, 1468d879cb83SAl Viro struct iov_iter *i) 1469d879cb83SAl Viro { 147036f7a8a4SAl Viro const char *from = addr; 1471cb002d07SSagi Grimberg __wsum *csum = csump; 1472d879cb83SAl Viro __wsum sum, next; 1473d879cb83SAl Viro size_t off = 0; 147478e1f386SAl Viro 147578e1f386SAl Viro if (unlikely(iov_iter_is_pipe(i))) 147678e1f386SAl Viro return csum_and_copy_to_pipe_iter(addr, bytes, csum, i); 147778e1f386SAl Viro 1478d879cb83SAl Viro sum = *csum; 147978e1f386SAl Viro if (unlikely(iov_iter_is_discard(i))) { 1480241699cdSAl Viro WARN_ON(1); /* for now */ 1481241699cdSAl Viro return 0; 1482241699cdSAl Viro } 1483d879cb83SAl Viro iterate_and_advance(i, bytes, v, ({ 1484d879cb83SAl Viro int err = 0; 1485d879cb83SAl Viro next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, 1486d879cb83SAl Viro v.iov_base, 1487d879cb83SAl Viro v.iov_len, 0, &err); 1488d879cb83SAl Viro if (!err) { 1489d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1490d879cb83SAl Viro off += v.iov_len; 1491d879cb83SAl Viro } 1492d879cb83SAl Viro err ? v.iov_len : 0; 1493d879cb83SAl Viro }), ({ 1494d879cb83SAl Viro char *p = kmap_atomic(v.bv_page); 1495d879cb83SAl Viro next = csum_partial_copy_nocheck((from += v.bv_len) - v.bv_len, 1496d879cb83SAl Viro p + v.bv_offset, 1497d879cb83SAl Viro v.bv_len, 0); 1498d879cb83SAl Viro kunmap_atomic(p); 1499d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1500d879cb83SAl Viro off += v.bv_len; 1501d879cb83SAl Viro }),({ 1502d879cb83SAl Viro next = csum_partial_copy_nocheck((from += v.iov_len) - v.iov_len, 1503d879cb83SAl Viro v.iov_base, 1504d879cb83SAl Viro v.iov_len, 0); 1505d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1506d879cb83SAl Viro off += v.iov_len; 1507d879cb83SAl Viro }) 1508d879cb83SAl Viro ) 1509d879cb83SAl Viro *csum = sum; 1510d879cb83SAl Viro return bytes; 1511d879cb83SAl Viro } 1512d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_to_iter); 1513d879cb83SAl Viro 1514d879cb83SAl Viro int iov_iter_npages(const struct iov_iter *i, int maxpages) 1515d879cb83SAl Viro { 1516d879cb83SAl Viro size_t size = i->count; 1517d879cb83SAl Viro int npages = 0; 1518d879cb83SAl Viro 1519d879cb83SAl Viro if (!size) 1520d879cb83SAl Viro return 0; 15219ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 15229ea9ce04SDavid Howells return 0; 1523d879cb83SAl Viro 152400e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 1525241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 1526241699cdSAl Viro size_t off; 1527241699cdSAl Viro int idx; 1528241699cdSAl Viro 1529241699cdSAl Viro if (!sanity(i)) 1530241699cdSAl Viro return 0; 1531241699cdSAl Viro 1532241699cdSAl Viro data_start(i, &idx, &off); 1533241699cdSAl Viro /* some of this one + all after this one */ 1534241699cdSAl Viro npages = ((pipe->curbuf - idx - 1) & (pipe->buffers - 1)) + 1; 1535241699cdSAl Viro if (npages >= maxpages) 1536241699cdSAl Viro return maxpages; 1537241699cdSAl Viro } else iterate_all_kinds(i, size, v, ({ 1538d879cb83SAl Viro unsigned long p = (unsigned long)v.iov_base; 1539d879cb83SAl Viro npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) 1540d879cb83SAl Viro - p / PAGE_SIZE; 1541d879cb83SAl Viro if (npages >= maxpages) 1542d879cb83SAl Viro return maxpages; 1543d879cb83SAl Viro 0;}),({ 1544d879cb83SAl Viro npages++; 1545d879cb83SAl Viro if (npages >= maxpages) 1546d879cb83SAl Viro return maxpages; 1547d879cb83SAl Viro }),({ 1548d879cb83SAl Viro unsigned long p = (unsigned long)v.iov_base; 1549d879cb83SAl Viro npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) 1550d879cb83SAl Viro - p / PAGE_SIZE; 1551d879cb83SAl Viro if (npages >= maxpages) 1552d879cb83SAl Viro return maxpages; 1553d879cb83SAl Viro }) 1554d879cb83SAl Viro ) 1555d879cb83SAl Viro return npages; 1556d879cb83SAl Viro } 1557d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_npages); 1558d879cb83SAl Viro 1559d879cb83SAl Viro const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) 1560d879cb83SAl Viro { 1561d879cb83SAl Viro *new = *old; 156200e23707SDavid Howells if (unlikely(iov_iter_is_pipe(new))) { 1563241699cdSAl Viro WARN_ON(1); 1564241699cdSAl Viro return NULL; 1565241699cdSAl Viro } 15669ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(new))) 15679ea9ce04SDavid Howells return NULL; 156800e23707SDavid Howells if (iov_iter_is_bvec(new)) 1569d879cb83SAl Viro return new->bvec = kmemdup(new->bvec, 1570d879cb83SAl Viro new->nr_segs * sizeof(struct bio_vec), 1571d879cb83SAl Viro flags); 1572d879cb83SAl Viro else 1573d879cb83SAl Viro /* iovec and kvec have identical layout */ 1574d879cb83SAl Viro return new->iov = kmemdup(new->iov, 1575d879cb83SAl Viro new->nr_segs * sizeof(struct iovec), 1576d879cb83SAl Viro flags); 1577d879cb83SAl Viro } 1578d879cb83SAl Viro EXPORT_SYMBOL(dup_iter); 1579bc917be8SAl Viro 1580ffecee4fSVegard Nossum /** 1581ffecee4fSVegard Nossum * import_iovec() - Copy an array of &struct iovec from userspace 1582ffecee4fSVegard Nossum * into the kernel, check that it is valid, and initialize a new 1583ffecee4fSVegard Nossum * &struct iov_iter iterator to access it. 1584ffecee4fSVegard Nossum * 1585ffecee4fSVegard Nossum * @type: One of %READ or %WRITE. 1586ffecee4fSVegard Nossum * @uvector: Pointer to the userspace array. 1587ffecee4fSVegard Nossum * @nr_segs: Number of elements in userspace array. 1588ffecee4fSVegard Nossum * @fast_segs: Number of elements in @iov. 1589ffecee4fSVegard Nossum * @iov: (input and output parameter) Pointer to pointer to (usually small 1590ffecee4fSVegard Nossum * on-stack) kernel array. 1591ffecee4fSVegard Nossum * @i: Pointer to iterator that will be initialized on success. 1592ffecee4fSVegard Nossum * 1593ffecee4fSVegard Nossum * If the array pointed to by *@iov is large enough to hold all @nr_segs, 1594ffecee4fSVegard Nossum * then this function places %NULL in *@iov on return. Otherwise, a new 1595ffecee4fSVegard Nossum * array will be allocated and the result placed in *@iov. This means that 1596ffecee4fSVegard Nossum * the caller may call kfree() on *@iov regardless of whether the small 1597ffecee4fSVegard Nossum * on-stack array was used or not (and regardless of whether this function 1598ffecee4fSVegard Nossum * returns an error or not). 1599ffecee4fSVegard Nossum * 1600ffecee4fSVegard Nossum * Return: 0 on success or negative error code on error. 1601ffecee4fSVegard Nossum */ 1602bc917be8SAl Viro int import_iovec(int type, const struct iovec __user * uvector, 1603bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 1604bc917be8SAl Viro struct iovec **iov, struct iov_iter *i) 1605bc917be8SAl Viro { 1606bc917be8SAl Viro ssize_t n; 1607bc917be8SAl Viro struct iovec *p; 1608bc917be8SAl Viro n = rw_copy_check_uvector(type, uvector, nr_segs, fast_segs, 1609bc917be8SAl Viro *iov, &p); 1610bc917be8SAl Viro if (n < 0) { 1611bc917be8SAl Viro if (p != *iov) 1612bc917be8SAl Viro kfree(p); 1613bc917be8SAl Viro *iov = NULL; 1614bc917be8SAl Viro return n; 1615bc917be8SAl Viro } 1616bc917be8SAl Viro iov_iter_init(i, type, p, nr_segs, n); 1617bc917be8SAl Viro *iov = p == *iov ? NULL : p; 1618bc917be8SAl Viro return 0; 1619bc917be8SAl Viro } 1620bc917be8SAl Viro EXPORT_SYMBOL(import_iovec); 1621bc917be8SAl Viro 1622bc917be8SAl Viro #ifdef CONFIG_COMPAT 1623bc917be8SAl Viro #include <linux/compat.h> 1624bc917be8SAl Viro 1625bc917be8SAl Viro int compat_import_iovec(int type, const struct compat_iovec __user * uvector, 1626bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 1627bc917be8SAl Viro struct iovec **iov, struct iov_iter *i) 1628bc917be8SAl Viro { 1629bc917be8SAl Viro ssize_t n; 1630bc917be8SAl Viro struct iovec *p; 1631bc917be8SAl Viro n = compat_rw_copy_check_uvector(type, uvector, nr_segs, fast_segs, 1632bc917be8SAl Viro *iov, &p); 1633bc917be8SAl Viro if (n < 0) { 1634bc917be8SAl Viro if (p != *iov) 1635bc917be8SAl Viro kfree(p); 1636bc917be8SAl Viro *iov = NULL; 1637bc917be8SAl Viro return n; 1638bc917be8SAl Viro } 1639bc917be8SAl Viro iov_iter_init(i, type, p, nr_segs, n); 1640bc917be8SAl Viro *iov = p == *iov ? NULL : p; 1641bc917be8SAl Viro return 0; 1642bc917be8SAl Viro } 1643bc917be8SAl Viro #endif 1644bc917be8SAl Viro 1645bc917be8SAl Viro int import_single_range(int rw, void __user *buf, size_t len, 1646bc917be8SAl Viro struct iovec *iov, struct iov_iter *i) 1647bc917be8SAl Viro { 1648bc917be8SAl Viro if (len > MAX_RW_COUNT) 1649bc917be8SAl Viro len = MAX_RW_COUNT; 1650bc917be8SAl Viro if (unlikely(!access_ok(!rw, buf, len))) 1651bc917be8SAl Viro return -EFAULT; 1652bc917be8SAl Viro 1653bc917be8SAl Viro iov->iov_base = buf; 1654bc917be8SAl Viro iov->iov_len = len; 1655bc917be8SAl Viro iov_iter_init(i, rw, iov, 1, len); 1656bc917be8SAl Viro return 0; 1657bc917be8SAl Viro } 1658e1267585SAl Viro EXPORT_SYMBOL(import_single_range); 165909cf698aSAl Viro 166009cf698aSAl Viro int iov_iter_for_each_range(struct iov_iter *i, size_t bytes, 166109cf698aSAl Viro int (*f)(struct kvec *vec, void *context), 166209cf698aSAl Viro void *context) 166309cf698aSAl Viro { 166409cf698aSAl Viro struct kvec w; 166509cf698aSAl Viro int err = -EINVAL; 166609cf698aSAl Viro if (!bytes) 166709cf698aSAl Viro return 0; 166809cf698aSAl Viro 166909cf698aSAl Viro iterate_all_kinds(i, bytes, v, -EINVAL, ({ 167009cf698aSAl Viro w.iov_base = kmap(v.bv_page) + v.bv_offset; 167109cf698aSAl Viro w.iov_len = v.bv_len; 167209cf698aSAl Viro err = f(&w, context); 167309cf698aSAl Viro kunmap(v.bv_page); 167409cf698aSAl Viro err;}), ({ 167509cf698aSAl Viro w = v; 167609cf698aSAl Viro err = f(&w, context);}) 167709cf698aSAl Viro ) 167809cf698aSAl Viro return err; 167909cf698aSAl Viro } 168009cf698aSAl Viro EXPORT_SYMBOL(iov_iter_for_each_range); 1681