1457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 27999096fSHerbert Xu #include <crypto/hash.h> 3d879cb83SAl Viro #include <linux/export.h> 42f8b5444SChristoph Hellwig #include <linux/bvec.h> 54d0e9df5SAlbert van der Linde #include <linux/fault-inject-usercopy.h> 6d879cb83SAl Viro #include <linux/uio.h> 7d879cb83SAl Viro #include <linux/pagemap.h> 828961998SIra Weiny #include <linux/highmem.h> 9d879cb83SAl Viro #include <linux/slab.h> 10d879cb83SAl Viro #include <linux/vmalloc.h> 11241699cdSAl Viro #include <linux/splice.h> 12bfdc5970SChristoph Hellwig #include <linux/compat.h> 13d879cb83SAl Viro #include <net/checksum.h> 14d05f4435SSagi Grimberg #include <linux/scatterlist.h> 15d0ef4c36SMarco Elver #include <linux/instrumented.h> 16d879cb83SAl Viro 17241699cdSAl Viro #define PIPE_PARANOIA /* for now */ 18241699cdSAl Viro 195c67aa90SAl Viro /* covers iovec and kvec alike */ 20*7baa5099SAl Viro #define iterate_iovec(i, n, base, len, off, __p, skip, STEP) { \ 21*7baa5099SAl Viro size_t off = 0; \ 227a1bcb5dSAl Viro do { \ 23*7baa5099SAl Viro len = min(n, __p->iov_len - skip); \ 24*7baa5099SAl Viro if (likely(len)) { \ 25*7baa5099SAl Viro base = __p->iov_base + skip; \ 26*7baa5099SAl Viro len -= (STEP); \ 27*7baa5099SAl Viro off += len; \ 28*7baa5099SAl Viro skip += len; \ 29*7baa5099SAl Viro n -= len; \ 307a1bcb5dSAl Viro if (skip < __p->iov_len) \ 317a1bcb5dSAl Viro break; \ 32d879cb83SAl Viro } \ 33d879cb83SAl Viro __p++; \ 347a1bcb5dSAl Viro skip = 0; \ 357a1bcb5dSAl Viro } while (n); \ 36*7baa5099SAl Viro n = off; \ 37d879cb83SAl Viro } 38d879cb83SAl Viro 39*7baa5099SAl Viro #define iterate_bvec(i, n, base, len, off, p, skip, STEP) { \ 40*7baa5099SAl Viro size_t off = 0; \ 417491a2bfSAl Viro while (n) { \ 427491a2bfSAl Viro unsigned offset = p->bv_offset + skip; \ 431b4fb5ffSAl Viro unsigned left; \ 4421b56c84SAl Viro void *kaddr = kmap_local_page(p->bv_page + \ 4521b56c84SAl Viro offset / PAGE_SIZE); \ 46*7baa5099SAl Viro base = kaddr + offset % PAGE_SIZE; \ 47*7baa5099SAl Viro len = min(min(n, p->bv_len - skip), \ 487491a2bfSAl Viro (size_t)(PAGE_SIZE - offset % PAGE_SIZE)); \ 491b4fb5ffSAl Viro left = (STEP); \ 5021b56c84SAl Viro kunmap_local(kaddr); \ 51*7baa5099SAl Viro len -= left; \ 52*7baa5099SAl Viro off += len; \ 53*7baa5099SAl Viro skip += len; \ 547491a2bfSAl Viro if (skip == p->bv_len) { \ 557491a2bfSAl Viro skip = 0; \ 567491a2bfSAl Viro p++; \ 57d879cb83SAl Viro } \ 58*7baa5099SAl Viro n -= len; \ 591b4fb5ffSAl Viro if (left) \ 601b4fb5ffSAl Viro break; \ 617491a2bfSAl Viro } \ 62*7baa5099SAl Viro n = off; \ 63d879cb83SAl Viro } 64d879cb83SAl Viro 65*7baa5099SAl Viro #define iterate_xarray(i, n, base, len, __off, skip, STEP) { \ 661b4fb5ffSAl Viro __label__ __out; \ 67622838f3SAl Viro size_t __off = 0; \ 687ff50620SDavid Howells struct page *head = NULL; \ 69*7baa5099SAl Viro size_t offset; \ 707ff50620SDavid Howells loff_t start = i->xarray_start + skip; \ 717ff50620SDavid Howells pgoff_t index = start >> PAGE_SHIFT; \ 727ff50620SDavid Howells int j; \ 737ff50620SDavid Howells \ 747ff50620SDavid Howells XA_STATE(xas, i->xarray, index); \ 757ff50620SDavid Howells \ 767ff50620SDavid Howells rcu_read_lock(); \ 777ff50620SDavid Howells xas_for_each(&xas, head, ULONG_MAX) { \ 781b4fb5ffSAl Viro unsigned left; \ 797ff50620SDavid Howells if (xas_retry(&xas, head)) \ 807ff50620SDavid Howells continue; \ 817ff50620SDavid Howells if (WARN_ON(xa_is_value(head))) \ 827ff50620SDavid Howells break; \ 837ff50620SDavid Howells if (WARN_ON(PageHuge(head))) \ 847ff50620SDavid Howells break; \ 857ff50620SDavid Howells for (j = (head->index < index) ? index - head->index : 0; \ 867ff50620SDavid Howells j < thp_nr_pages(head); j++) { \ 8721b56c84SAl Viro void *kaddr = kmap_local_page(head + j); \ 88622838f3SAl Viro offset = (start + __off) % PAGE_SIZE; \ 89*7baa5099SAl Viro base = kaddr + offset; \ 90*7baa5099SAl Viro len = PAGE_SIZE - offset; \ 91*7baa5099SAl Viro len = min(n, len); \ 921b4fb5ffSAl Viro left = (STEP); \ 9321b56c84SAl Viro kunmap_local(kaddr); \ 94*7baa5099SAl Viro len -= left; \ 95*7baa5099SAl Viro __off += len; \ 96*7baa5099SAl Viro n -= len; \ 971b4fb5ffSAl Viro if (left || n == 0) \ 981b4fb5ffSAl Viro goto __out; \ 997ff50620SDavid Howells } \ 1007ff50620SDavid Howells } \ 1011b4fb5ffSAl Viro __out: \ 1027ff50620SDavid Howells rcu_read_unlock(); \ 103622838f3SAl Viro skip += __off; \ 104622838f3SAl Viro n = __off; \ 1057ff50620SDavid Howells } 1067ff50620SDavid Howells 107*7baa5099SAl Viro #define __iterate_and_advance(i, n, base, len, off, I, K) { \ 108dd254f5aSAl Viro if (unlikely(i->count < n)) \ 109dd254f5aSAl Viro n = i->count; \ 110f5da8354SAl Viro if (likely(n)) { \ 111d879cb83SAl Viro size_t skip = i->iov_offset; \ 11228f38db7SAl Viro if (likely(iter_is_iovec(i))) { \ 1135c67aa90SAl Viro const struct iovec *iov = i->iov; \ 114*7baa5099SAl Viro void __user *base; \ 115*7baa5099SAl Viro size_t len; \ 116*7baa5099SAl Viro iterate_iovec(i, n, base, len, off, \ 117*7baa5099SAl Viro iov, skip, (I)) \ 118d879cb83SAl Viro i->nr_segs -= iov - i->iov; \ 119d879cb83SAl Viro i->iov = iov; \ 12028f38db7SAl Viro } else if (iov_iter_is_bvec(i)) { \ 12128f38db7SAl Viro const struct bio_vec *bvec = i->bvec; \ 122*7baa5099SAl Viro void *base; \ 123*7baa5099SAl Viro size_t len; \ 124*7baa5099SAl Viro iterate_bvec(i, n, base, len, off, \ 125*7baa5099SAl Viro bvec, skip, (K)) \ 1267491a2bfSAl Viro i->nr_segs -= bvec - i->bvec; \ 1277491a2bfSAl Viro i->bvec = bvec; \ 12828f38db7SAl Viro } else if (iov_iter_is_kvec(i)) { \ 1295c67aa90SAl Viro const struct kvec *kvec = i->kvec; \ 130*7baa5099SAl Viro void *base; \ 131*7baa5099SAl Viro size_t len; \ 132*7baa5099SAl Viro iterate_iovec(i, n, base, len, off, \ 133*7baa5099SAl Viro kvec, skip, (K)) \ 13428f38db7SAl Viro i->nr_segs -= kvec - i->kvec; \ 13528f38db7SAl Viro i->kvec = kvec; \ 13628f38db7SAl Viro } else if (iov_iter_is_xarray(i)) { \ 137*7baa5099SAl Viro void *base; \ 138*7baa5099SAl Viro size_t len; \ 139*7baa5099SAl Viro iterate_xarray(i, n, base, len, off, \ 140*7baa5099SAl Viro skip, (K)) \ 141d879cb83SAl Viro } \ 142d879cb83SAl Viro i->count -= n; \ 143d879cb83SAl Viro i->iov_offset = skip; \ 144dd254f5aSAl Viro } \ 145d879cb83SAl Viro } 146*7baa5099SAl Viro #define iterate_and_advance(i, n, base, len, off, I, K) \ 147*7baa5099SAl Viro __iterate_and_advance(i, n, base, len, off, I, ((void)(K),0)) 148d879cb83SAl Viro 14909fc68dcSAl Viro static int copyout(void __user *to, const void *from, size_t n) 15009fc68dcSAl Viro { 1514d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1524d0e9df5SAlbert van der Linde return n; 15396d4f267SLinus Torvalds if (access_ok(to, n)) { 154d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 15509fc68dcSAl Viro n = raw_copy_to_user(to, from, n); 15609fc68dcSAl Viro } 15709fc68dcSAl Viro return n; 15809fc68dcSAl Viro } 15909fc68dcSAl Viro 16009fc68dcSAl Viro static int copyin(void *to, const void __user *from, size_t n) 16109fc68dcSAl Viro { 1624d0e9df5SAlbert van der Linde if (should_fail_usercopy()) 1634d0e9df5SAlbert van der Linde return n; 16496d4f267SLinus Torvalds if (access_ok(from, n)) { 165d0ef4c36SMarco Elver instrument_copy_from_user(to, from, n); 16609fc68dcSAl Viro n = raw_copy_from_user(to, from, n); 16709fc68dcSAl Viro } 16809fc68dcSAl Viro return n; 16909fc68dcSAl Viro } 17009fc68dcSAl Viro 171d879cb83SAl Viro static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, 172d879cb83SAl Viro struct iov_iter *i) 173d879cb83SAl Viro { 174d879cb83SAl Viro size_t skip, copy, left, wanted; 175d879cb83SAl Viro const struct iovec *iov; 176d879cb83SAl Viro char __user *buf; 177d879cb83SAl Viro void *kaddr, *from; 178d879cb83SAl Viro 179d879cb83SAl Viro if (unlikely(bytes > i->count)) 180d879cb83SAl Viro bytes = i->count; 181d879cb83SAl Viro 182d879cb83SAl Viro if (unlikely(!bytes)) 183d879cb83SAl Viro return 0; 184d879cb83SAl Viro 18509fc68dcSAl Viro might_fault(); 186d879cb83SAl Viro wanted = bytes; 187d879cb83SAl Viro iov = i->iov; 188d879cb83SAl Viro skip = i->iov_offset; 189d879cb83SAl Viro buf = iov->iov_base + skip; 190d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 191d879cb83SAl Viro 1923fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { 193d879cb83SAl Viro kaddr = kmap_atomic(page); 194d879cb83SAl Viro from = kaddr + offset; 195d879cb83SAl Viro 196d879cb83SAl Viro /* first chunk, usually the only one */ 19709fc68dcSAl Viro left = copyout(buf, from, copy); 198d879cb83SAl Viro copy -= left; 199d879cb83SAl Viro skip += copy; 200d879cb83SAl Viro from += copy; 201d879cb83SAl Viro bytes -= copy; 202d879cb83SAl Viro 203d879cb83SAl Viro while (unlikely(!left && bytes)) { 204d879cb83SAl Viro iov++; 205d879cb83SAl Viro buf = iov->iov_base; 206d879cb83SAl Viro copy = min(bytes, iov->iov_len); 20709fc68dcSAl Viro left = copyout(buf, from, copy); 208d879cb83SAl Viro copy -= left; 209d879cb83SAl Viro skip = copy; 210d879cb83SAl Viro from += copy; 211d879cb83SAl Viro bytes -= copy; 212d879cb83SAl Viro } 213d879cb83SAl Viro if (likely(!bytes)) { 214d879cb83SAl Viro kunmap_atomic(kaddr); 215d879cb83SAl Viro goto done; 216d879cb83SAl Viro } 217d879cb83SAl Viro offset = from - kaddr; 218d879cb83SAl Viro buf += copy; 219d879cb83SAl Viro kunmap_atomic(kaddr); 220d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 221d879cb83SAl Viro } 222d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 2233fa6c507SMikulas Patocka 224d879cb83SAl Viro kaddr = kmap(page); 225d879cb83SAl Viro from = kaddr + offset; 22609fc68dcSAl Viro left = copyout(buf, from, copy); 227d879cb83SAl Viro copy -= left; 228d879cb83SAl Viro skip += copy; 229d879cb83SAl Viro from += copy; 230d879cb83SAl Viro bytes -= copy; 231d879cb83SAl Viro while (unlikely(!left && bytes)) { 232d879cb83SAl Viro iov++; 233d879cb83SAl Viro buf = iov->iov_base; 234d879cb83SAl Viro copy = min(bytes, iov->iov_len); 23509fc68dcSAl Viro left = copyout(buf, from, copy); 236d879cb83SAl Viro copy -= left; 237d879cb83SAl Viro skip = copy; 238d879cb83SAl Viro from += copy; 239d879cb83SAl Viro bytes -= copy; 240d879cb83SAl Viro } 241d879cb83SAl Viro kunmap(page); 2423fa6c507SMikulas Patocka 243d879cb83SAl Viro done: 244d879cb83SAl Viro if (skip == iov->iov_len) { 245d879cb83SAl Viro iov++; 246d879cb83SAl Viro skip = 0; 247d879cb83SAl Viro } 248d879cb83SAl Viro i->count -= wanted - bytes; 249d879cb83SAl Viro i->nr_segs -= iov - i->iov; 250d879cb83SAl Viro i->iov = iov; 251d879cb83SAl Viro i->iov_offset = skip; 252d879cb83SAl Viro return wanted - bytes; 253d879cb83SAl Viro } 254d879cb83SAl Viro 255d879cb83SAl Viro static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, 256d879cb83SAl Viro struct iov_iter *i) 257d879cb83SAl Viro { 258d879cb83SAl Viro size_t skip, copy, left, wanted; 259d879cb83SAl Viro const struct iovec *iov; 260d879cb83SAl Viro char __user *buf; 261d879cb83SAl Viro void *kaddr, *to; 262d879cb83SAl Viro 263d879cb83SAl Viro if (unlikely(bytes > i->count)) 264d879cb83SAl Viro bytes = i->count; 265d879cb83SAl Viro 266d879cb83SAl Viro if (unlikely(!bytes)) 267d879cb83SAl Viro return 0; 268d879cb83SAl Viro 26909fc68dcSAl Viro might_fault(); 270d879cb83SAl Viro wanted = bytes; 271d879cb83SAl Viro iov = i->iov; 272d879cb83SAl Viro skip = i->iov_offset; 273d879cb83SAl Viro buf = iov->iov_base + skip; 274d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 275d879cb83SAl Viro 2763fa6c507SMikulas Patocka if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { 277d879cb83SAl Viro kaddr = kmap_atomic(page); 278d879cb83SAl Viro to = kaddr + offset; 279d879cb83SAl Viro 280d879cb83SAl Viro /* first chunk, usually the only one */ 28109fc68dcSAl Viro left = copyin(to, buf, copy); 282d879cb83SAl Viro copy -= left; 283d879cb83SAl Viro skip += copy; 284d879cb83SAl Viro to += copy; 285d879cb83SAl Viro bytes -= copy; 286d879cb83SAl Viro 287d879cb83SAl Viro while (unlikely(!left && bytes)) { 288d879cb83SAl Viro iov++; 289d879cb83SAl Viro buf = iov->iov_base; 290d879cb83SAl Viro copy = min(bytes, iov->iov_len); 29109fc68dcSAl Viro left = copyin(to, buf, copy); 292d879cb83SAl Viro copy -= left; 293d879cb83SAl Viro skip = copy; 294d879cb83SAl Viro to += copy; 295d879cb83SAl Viro bytes -= copy; 296d879cb83SAl Viro } 297d879cb83SAl Viro if (likely(!bytes)) { 298d879cb83SAl Viro kunmap_atomic(kaddr); 299d879cb83SAl Viro goto done; 300d879cb83SAl Viro } 301d879cb83SAl Viro offset = to - kaddr; 302d879cb83SAl Viro buf += copy; 303d879cb83SAl Viro kunmap_atomic(kaddr); 304d879cb83SAl Viro copy = min(bytes, iov->iov_len - skip); 305d879cb83SAl Viro } 306d879cb83SAl Viro /* Too bad - revert to non-atomic kmap */ 3073fa6c507SMikulas Patocka 308d879cb83SAl Viro kaddr = kmap(page); 309d879cb83SAl Viro to = kaddr + offset; 31009fc68dcSAl Viro left = copyin(to, buf, copy); 311d879cb83SAl Viro copy -= left; 312d879cb83SAl Viro skip += copy; 313d879cb83SAl Viro to += copy; 314d879cb83SAl Viro bytes -= copy; 315d879cb83SAl Viro while (unlikely(!left && bytes)) { 316d879cb83SAl Viro iov++; 317d879cb83SAl Viro buf = iov->iov_base; 318d879cb83SAl Viro copy = min(bytes, iov->iov_len); 31909fc68dcSAl Viro left = copyin(to, buf, copy); 320d879cb83SAl Viro copy -= left; 321d879cb83SAl Viro skip = copy; 322d879cb83SAl Viro to += copy; 323d879cb83SAl Viro bytes -= copy; 324d879cb83SAl Viro } 325d879cb83SAl Viro kunmap(page); 3263fa6c507SMikulas Patocka 327d879cb83SAl Viro done: 328d879cb83SAl Viro if (skip == iov->iov_len) { 329d879cb83SAl Viro iov++; 330d879cb83SAl Viro skip = 0; 331d879cb83SAl Viro } 332d879cb83SAl Viro i->count -= wanted - bytes; 333d879cb83SAl Viro i->nr_segs -= iov - i->iov; 334d879cb83SAl Viro i->iov = iov; 335d879cb83SAl Viro i->iov_offset = skip; 336d879cb83SAl Viro return wanted - bytes; 337d879cb83SAl Viro } 338d879cb83SAl Viro 339241699cdSAl Viro #ifdef PIPE_PARANOIA 340241699cdSAl Viro static bool sanity(const struct iov_iter *i) 341241699cdSAl Viro { 342241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 3438cefc107SDavid Howells unsigned int p_head = pipe->head; 3448cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3458cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3468cefc107SDavid Howells unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); 3478cefc107SDavid Howells unsigned int i_head = i->head; 3488cefc107SDavid Howells unsigned int idx; 3498cefc107SDavid Howells 350241699cdSAl Viro if (i->iov_offset) { 351241699cdSAl Viro struct pipe_buffer *p; 3528cefc107SDavid Howells if (unlikely(p_occupancy == 0)) 353241699cdSAl Viro goto Bad; // pipe must be non-empty 3548cefc107SDavid Howells if (unlikely(i_head != p_head - 1)) 355241699cdSAl Viro goto Bad; // must be at the last buffer... 356241699cdSAl Viro 3578cefc107SDavid Howells p = &pipe->bufs[i_head & p_mask]; 358241699cdSAl Viro if (unlikely(p->offset + p->len != i->iov_offset)) 359241699cdSAl Viro goto Bad; // ... at the end of segment 360241699cdSAl Viro } else { 3618cefc107SDavid Howells if (i_head != p_head) 362241699cdSAl Viro goto Bad; // must be right after the last buffer 363241699cdSAl Viro } 364241699cdSAl Viro return true; 365241699cdSAl Viro Bad: 3668cefc107SDavid Howells printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); 3678cefc107SDavid Howells printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", 3688cefc107SDavid Howells p_head, p_tail, pipe->ring_size); 3698cefc107SDavid Howells for (idx = 0; idx < pipe->ring_size; idx++) 370241699cdSAl Viro printk(KERN_ERR "[%p %p %d %d]\n", 371241699cdSAl Viro pipe->bufs[idx].ops, 372241699cdSAl Viro pipe->bufs[idx].page, 373241699cdSAl Viro pipe->bufs[idx].offset, 374241699cdSAl Viro pipe->bufs[idx].len); 375241699cdSAl Viro WARN_ON(1); 376241699cdSAl Viro return false; 377241699cdSAl Viro } 378241699cdSAl Viro #else 379241699cdSAl Viro #define sanity(i) true 380241699cdSAl Viro #endif 381241699cdSAl Viro 382241699cdSAl Viro static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, 383241699cdSAl Viro struct iov_iter *i) 384241699cdSAl Viro { 385241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 386241699cdSAl Viro struct pipe_buffer *buf; 3878cefc107SDavid Howells unsigned int p_tail = pipe->tail; 3888cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 3898cefc107SDavid Howells unsigned int i_head = i->head; 390241699cdSAl Viro size_t off; 391241699cdSAl Viro 392241699cdSAl Viro if (unlikely(bytes > i->count)) 393241699cdSAl Viro bytes = i->count; 394241699cdSAl Viro 395241699cdSAl Viro if (unlikely(!bytes)) 396241699cdSAl Viro return 0; 397241699cdSAl Viro 398241699cdSAl Viro if (!sanity(i)) 399241699cdSAl Viro return 0; 400241699cdSAl Viro 401241699cdSAl Viro off = i->iov_offset; 4028cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 403241699cdSAl Viro if (off) { 404241699cdSAl Viro if (offset == off && buf->page == page) { 405241699cdSAl Viro /* merge with the last one */ 406241699cdSAl Viro buf->len += bytes; 407241699cdSAl Viro i->iov_offset += bytes; 408241699cdSAl Viro goto out; 409241699cdSAl Viro } 4108cefc107SDavid Howells i_head++; 4118cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 412241699cdSAl Viro } 4136718b6f8SDavid Howells if (pipe_full(i_head, p_tail, pipe->max_usage)) 414241699cdSAl Viro return 0; 4158cefc107SDavid Howells 416241699cdSAl Viro buf->ops = &page_cache_pipe_buf_ops; 4178cefc107SDavid Howells get_page(page); 4188cefc107SDavid Howells buf->page = page; 419241699cdSAl Viro buf->offset = offset; 420241699cdSAl Viro buf->len = bytes; 4218cefc107SDavid Howells 4228cefc107SDavid Howells pipe->head = i_head + 1; 423241699cdSAl Viro i->iov_offset = offset + bytes; 4248cefc107SDavid Howells i->head = i_head; 425241699cdSAl Viro out: 426241699cdSAl Viro i->count -= bytes; 427241699cdSAl Viro return bytes; 428241699cdSAl Viro } 429241699cdSAl Viro 430d879cb83SAl Viro /* 431171a0203SAnton Altaparmakov * Fault in one or more iovecs of the given iov_iter, to a maximum length of 432171a0203SAnton Altaparmakov * bytes. For each iovec, fault in each page that constitutes the iovec. 433171a0203SAnton Altaparmakov * 434171a0203SAnton Altaparmakov * Return 0 on success, or non-zero if the memory could not be accessed (i.e. 435171a0203SAnton Altaparmakov * because it is an invalid address). 436171a0203SAnton Altaparmakov */ 4378409a0d2SAl Viro int iov_iter_fault_in_readable(const struct iov_iter *i, size_t bytes) 438171a0203SAnton Altaparmakov { 4390e8f0d67SAl Viro if (iter_is_iovec(i)) { 4408409a0d2SAl Viro const struct iovec *p; 4418409a0d2SAl Viro size_t skip; 4428409a0d2SAl Viro 4438409a0d2SAl Viro if (bytes > i->count) 4448409a0d2SAl Viro bytes = i->count; 4458409a0d2SAl Viro for (p = i->iov, skip = i->iov_offset; bytes; p++, skip = 0) { 4468409a0d2SAl Viro size_t len = min(bytes, p->iov_len - skip); 4478409a0d2SAl Viro int err; 4488409a0d2SAl Viro 4498409a0d2SAl Viro if (unlikely(!len)) 4508409a0d2SAl Viro continue; 4518409a0d2SAl Viro err = fault_in_pages_readable(p->iov_base + skip, len); 452171a0203SAnton Altaparmakov if (unlikely(err)) 453171a0203SAnton Altaparmakov return err; 4548409a0d2SAl Viro bytes -= len; 4558409a0d2SAl Viro } 456171a0203SAnton Altaparmakov } 457171a0203SAnton Altaparmakov return 0; 458171a0203SAnton Altaparmakov } 459d4690f1eSAl Viro EXPORT_SYMBOL(iov_iter_fault_in_readable); 460171a0203SAnton Altaparmakov 461aa563d7bSDavid Howells void iov_iter_init(struct iov_iter *i, unsigned int direction, 462d879cb83SAl Viro const struct iovec *iov, unsigned long nr_segs, 463d879cb83SAl Viro size_t count) 464d879cb83SAl Viro { 465aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 4668cd54c1cSAl Viro WARN_ON_ONCE(uaccess_kernel()); 4678cd54c1cSAl Viro *i = (struct iov_iter) { 4688cd54c1cSAl Viro .iter_type = ITER_IOVEC, 4698cd54c1cSAl Viro .data_source = direction, 4708cd54c1cSAl Viro .iov = iov, 4718cd54c1cSAl Viro .nr_segs = nr_segs, 4728cd54c1cSAl Viro .iov_offset = 0, 4738cd54c1cSAl Viro .count = count 4748cd54c1cSAl Viro }; 475d879cb83SAl Viro } 476d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_init); 477d879cb83SAl Viro 478241699cdSAl Viro static inline bool allocated(struct pipe_buffer *buf) 479241699cdSAl Viro { 480241699cdSAl Viro return buf->ops == &default_pipe_buf_ops; 481241699cdSAl Viro } 482241699cdSAl Viro 4838cefc107SDavid Howells static inline void data_start(const struct iov_iter *i, 4848cefc107SDavid Howells unsigned int *iter_headp, size_t *offp) 485241699cdSAl Viro { 4868cefc107SDavid Howells unsigned int p_mask = i->pipe->ring_size - 1; 4878cefc107SDavid Howells unsigned int iter_head = i->head; 488241699cdSAl Viro size_t off = i->iov_offset; 4898cefc107SDavid Howells 4908cefc107SDavid Howells if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || 4918cefc107SDavid Howells off == PAGE_SIZE)) { 4928cefc107SDavid Howells iter_head++; 493241699cdSAl Viro off = 0; 494241699cdSAl Viro } 4958cefc107SDavid Howells *iter_headp = iter_head; 496241699cdSAl Viro *offp = off; 497241699cdSAl Viro } 498241699cdSAl Viro 499241699cdSAl Viro static size_t push_pipe(struct iov_iter *i, size_t size, 5008cefc107SDavid Howells int *iter_headp, size_t *offp) 501241699cdSAl Viro { 502241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5038cefc107SDavid Howells unsigned int p_tail = pipe->tail; 5048cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5058cefc107SDavid Howells unsigned int iter_head; 506241699cdSAl Viro size_t off; 507241699cdSAl Viro ssize_t left; 508241699cdSAl Viro 509241699cdSAl Viro if (unlikely(size > i->count)) 510241699cdSAl Viro size = i->count; 511241699cdSAl Viro if (unlikely(!size)) 512241699cdSAl Viro return 0; 513241699cdSAl Viro 514241699cdSAl Viro left = size; 5158cefc107SDavid Howells data_start(i, &iter_head, &off); 5168cefc107SDavid Howells *iter_headp = iter_head; 517241699cdSAl Viro *offp = off; 518241699cdSAl Viro if (off) { 519241699cdSAl Viro left -= PAGE_SIZE - off; 520241699cdSAl Viro if (left <= 0) { 5218cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len += size; 522241699cdSAl Viro return size; 523241699cdSAl Viro } 5248cefc107SDavid Howells pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; 5258cefc107SDavid Howells iter_head++; 526241699cdSAl Viro } 5276718b6f8SDavid Howells while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { 5288cefc107SDavid Howells struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; 529241699cdSAl Viro struct page *page = alloc_page(GFP_USER); 530241699cdSAl Viro if (!page) 531241699cdSAl Viro break; 5328cefc107SDavid Howells 5338cefc107SDavid Howells buf->ops = &default_pipe_buf_ops; 5348cefc107SDavid Howells buf->page = page; 5358cefc107SDavid Howells buf->offset = 0; 5368cefc107SDavid Howells buf->len = min_t(ssize_t, left, PAGE_SIZE); 5378cefc107SDavid Howells left -= buf->len; 5388cefc107SDavid Howells iter_head++; 5398cefc107SDavid Howells pipe->head = iter_head; 5408cefc107SDavid Howells 5418cefc107SDavid Howells if (left == 0) 542241699cdSAl Viro return size; 543241699cdSAl Viro } 544241699cdSAl Viro return size - left; 545241699cdSAl Viro } 546241699cdSAl Viro 547241699cdSAl Viro static size_t copy_pipe_to_iter(const void *addr, size_t bytes, 548241699cdSAl Viro struct iov_iter *i) 549241699cdSAl Viro { 550241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 5518cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 5528cefc107SDavid Howells unsigned int i_head; 553241699cdSAl Viro size_t n, off; 554241699cdSAl Viro 555241699cdSAl Viro if (!sanity(i)) 556241699cdSAl Viro return 0; 557241699cdSAl Viro 5588cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 559241699cdSAl Viro if (unlikely(!n)) 560241699cdSAl Viro return 0; 5618cefc107SDavid Howells do { 562241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 5638cefc107SDavid Howells memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); 5648cefc107SDavid Howells i->head = i_head; 565241699cdSAl Viro i->iov_offset = off + chunk; 566241699cdSAl Viro n -= chunk; 567241699cdSAl Viro addr += chunk; 5688cefc107SDavid Howells off = 0; 5698cefc107SDavid Howells i_head++; 5708cefc107SDavid Howells } while (n); 571241699cdSAl Viro i->count -= bytes; 572241699cdSAl Viro return bytes; 573241699cdSAl Viro } 574241699cdSAl Viro 575f9152895SAl Viro static __wsum csum_and_memcpy(void *to, const void *from, size_t len, 576f9152895SAl Viro __wsum sum, size_t off) 577f9152895SAl Viro { 578cc44c17bSAl Viro __wsum next = csum_partial_copy_nocheck(from, to, len); 579f9152895SAl Viro return csum_block_add(sum, next, off); 580f9152895SAl Viro } 581f9152895SAl Viro 58278e1f386SAl Viro static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, 58352cbd23aSWillem de Bruijn struct csum_state *csstate, 58452cbd23aSWillem de Bruijn struct iov_iter *i) 58578e1f386SAl Viro { 58678e1f386SAl Viro struct pipe_inode_info *pipe = i->pipe; 5878cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 58852cbd23aSWillem de Bruijn __wsum sum = csstate->csum; 58952cbd23aSWillem de Bruijn size_t off = csstate->off; 5908cefc107SDavid Howells unsigned int i_head; 59178e1f386SAl Viro size_t n, r; 59278e1f386SAl Viro 59378e1f386SAl Viro if (!sanity(i)) 59478e1f386SAl Viro return 0; 59578e1f386SAl Viro 5968cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &r); 59778e1f386SAl Viro if (unlikely(!n)) 59878e1f386SAl Viro return 0; 5998cefc107SDavid Howells do { 60078e1f386SAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - r); 6018cefc107SDavid Howells char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); 602f9152895SAl Viro sum = csum_and_memcpy(p + r, addr, chunk, sum, off); 60378e1f386SAl Viro kunmap_atomic(p); 6048cefc107SDavid Howells i->head = i_head; 60578e1f386SAl Viro i->iov_offset = r + chunk; 60678e1f386SAl Viro n -= chunk; 60778e1f386SAl Viro off += chunk; 60878e1f386SAl Viro addr += chunk; 6098cefc107SDavid Howells r = 0; 6108cefc107SDavid Howells i_head++; 6118cefc107SDavid Howells } while (n); 61278e1f386SAl Viro i->count -= bytes; 61352cbd23aSWillem de Bruijn csstate->csum = sum; 61452cbd23aSWillem de Bruijn csstate->off = off; 61578e1f386SAl Viro return bytes; 61678e1f386SAl Viro } 61778e1f386SAl Viro 618aa28de27SAl Viro size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 619d879cb83SAl Viro { 62000e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 621241699cdSAl Viro return copy_pipe_to_iter(addr, bytes, i); 62209fc68dcSAl Viro if (iter_is_iovec(i)) 62309fc68dcSAl Viro might_fault(); 624*7baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 625*7baa5099SAl Viro copyout(base, addr + off, len), 626*7baa5099SAl Viro memcpy(base, addr + off, len) 627d879cb83SAl Viro ) 628d879cb83SAl Viro 629d879cb83SAl Viro return bytes; 630d879cb83SAl Viro } 631aa28de27SAl Viro EXPORT_SYMBOL(_copy_to_iter); 632d879cb83SAl Viro 633ec6347bbSDan Williams #ifdef CONFIG_ARCH_HAS_COPY_MC 634ec6347bbSDan Williams static int copyout_mc(void __user *to, const void *from, size_t n) 6358780356eSDan Williams { 63696d4f267SLinus Torvalds if (access_ok(to, n)) { 637d0ef4c36SMarco Elver instrument_copy_to_user(to, from, n); 638ec6347bbSDan Williams n = copy_mc_to_user((__force void *) to, from, n); 6398780356eSDan Williams } 6408780356eSDan Williams return n; 6418780356eSDan Williams } 6428780356eSDan Williams 643ec6347bbSDan Williams static unsigned long copy_mc_to_page(struct page *page, size_t offset, 6448780356eSDan Williams const char *from, size_t len) 6458780356eSDan Williams { 6468780356eSDan Williams unsigned long ret; 6478780356eSDan Williams char *to; 6488780356eSDan Williams 6498780356eSDan Williams to = kmap_atomic(page); 650ec6347bbSDan Williams ret = copy_mc_to_kernel(to + offset, from, len); 6518780356eSDan Williams kunmap_atomic(to); 6528780356eSDan Williams 6538780356eSDan Williams return ret; 6548780356eSDan Williams } 6558780356eSDan Williams 656ec6347bbSDan Williams static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, 657ca146f6fSDan Williams struct iov_iter *i) 658ca146f6fSDan Williams { 659ca146f6fSDan Williams struct pipe_inode_info *pipe = i->pipe; 6608cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 6618cefc107SDavid Howells unsigned int i_head; 662ca146f6fSDan Williams size_t n, off, xfer = 0; 663ca146f6fSDan Williams 664ca146f6fSDan Williams if (!sanity(i)) 665ca146f6fSDan Williams return 0; 666ca146f6fSDan Williams 6678cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 668ca146f6fSDan Williams if (unlikely(!n)) 669ca146f6fSDan Williams return 0; 6708cefc107SDavid Howells do { 671ca146f6fSDan Williams size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 672ca146f6fSDan Williams unsigned long rem; 673ca146f6fSDan Williams 674ec6347bbSDan Williams rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, 6758cefc107SDavid Howells off, addr, chunk); 6768cefc107SDavid Howells i->head = i_head; 677ca146f6fSDan Williams i->iov_offset = off + chunk - rem; 678ca146f6fSDan Williams xfer += chunk - rem; 679ca146f6fSDan Williams if (rem) 680ca146f6fSDan Williams break; 681ca146f6fSDan Williams n -= chunk; 682ca146f6fSDan Williams addr += chunk; 6838cefc107SDavid Howells off = 0; 6848cefc107SDavid Howells i_head++; 6858cefc107SDavid Howells } while (n); 686ca146f6fSDan Williams i->count -= xfer; 687ca146f6fSDan Williams return xfer; 688ca146f6fSDan Williams } 689ca146f6fSDan Williams 690bf3eeb9bSDan Williams /** 691ec6347bbSDan Williams * _copy_mc_to_iter - copy to iter with source memory error exception handling 692bf3eeb9bSDan Williams * @addr: source kernel address 693bf3eeb9bSDan Williams * @bytes: total transfer length 694bf3eeb9bSDan Williams * @iter: destination iterator 695bf3eeb9bSDan Williams * 696ec6347bbSDan Williams * The pmem driver deploys this for the dax operation 697ec6347bbSDan Williams * (dax_copy_to_iter()) for dax reads (bypass page-cache and the 698ec6347bbSDan Williams * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes 699ec6347bbSDan Williams * successfully copied. 700bf3eeb9bSDan Williams * 701ec6347bbSDan Williams * The main differences between this and typical _copy_to_iter(). 702bf3eeb9bSDan Williams * 703bf3eeb9bSDan Williams * * Typical tail/residue handling after a fault retries the copy 704bf3eeb9bSDan Williams * byte-by-byte until the fault happens again. Re-triggering machine 705bf3eeb9bSDan Williams * checks is potentially fatal so the implementation uses source 706bf3eeb9bSDan Williams * alignment and poison alignment assumptions to avoid re-triggering 707bf3eeb9bSDan Williams * hardware exceptions. 708bf3eeb9bSDan Williams * 709bf3eeb9bSDan Williams * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. 710bf3eeb9bSDan Williams * Compare to copy_to_iter() where only ITER_IOVEC attempts might return 711bf3eeb9bSDan Williams * a short copy. 712bf3eeb9bSDan Williams */ 713ec6347bbSDan Williams size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 7148780356eSDan Williams { 71500e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 716ec6347bbSDan Williams return copy_mc_pipe_to_iter(addr, bytes, i); 7178780356eSDan Williams if (iter_is_iovec(i)) 7188780356eSDan Williams might_fault(); 719*7baa5099SAl Viro __iterate_and_advance(i, bytes, base, len, off, 720*7baa5099SAl Viro copyout_mc(base, addr + off, len), 721*7baa5099SAl Viro copy_mc_to_kernel(base, addr + off, len) 7228780356eSDan Williams ) 7238780356eSDan Williams 7248780356eSDan Williams return bytes; 7258780356eSDan Williams } 726ec6347bbSDan Williams EXPORT_SYMBOL_GPL(_copy_mc_to_iter); 727ec6347bbSDan Williams #endif /* CONFIG_ARCH_HAS_COPY_MC */ 7288780356eSDan Williams 729aa28de27SAl Viro size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) 730d879cb83SAl Viro { 73100e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 732241699cdSAl Viro WARN_ON(1); 733241699cdSAl Viro return 0; 734241699cdSAl Viro } 73509fc68dcSAl Viro if (iter_is_iovec(i)) 73609fc68dcSAl Viro might_fault(); 737*7baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 738*7baa5099SAl Viro copyin(addr + off, base, len), 739*7baa5099SAl Viro memcpy(addr + off, base, len) 740d879cb83SAl Viro ) 741d879cb83SAl Viro 742d879cb83SAl Viro return bytes; 743d879cb83SAl Viro } 744aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter); 745d879cb83SAl Viro 746aa28de27SAl Viro size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) 747d879cb83SAl Viro { 74800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 749241699cdSAl Viro WARN_ON(1); 750241699cdSAl Viro return 0; 751241699cdSAl Viro } 752*7baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 753*7baa5099SAl Viro __copy_from_user_inatomic_nocache(addr + off, base, len), 754*7baa5099SAl Viro memcpy(addr + off, base, len) 755d879cb83SAl Viro ) 756d879cb83SAl Viro 757d879cb83SAl Viro return bytes; 758d879cb83SAl Viro } 759aa28de27SAl Viro EXPORT_SYMBOL(_copy_from_iter_nocache); 760d879cb83SAl Viro 7610aed55afSDan Williams #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE 762abd08d7dSDan Williams /** 763abd08d7dSDan Williams * _copy_from_iter_flushcache - write destination through cpu cache 764abd08d7dSDan Williams * @addr: destination kernel address 765abd08d7dSDan Williams * @bytes: total transfer length 766abd08d7dSDan Williams * @iter: source iterator 767abd08d7dSDan Williams * 768abd08d7dSDan Williams * The pmem driver arranges for filesystem-dax to use this facility via 769abd08d7dSDan Williams * dax_copy_from_iter() for ensuring that writes to persistent memory 770abd08d7dSDan Williams * are flushed through the CPU cache. It is differentiated from 771abd08d7dSDan Williams * _copy_from_iter_nocache() in that guarantees all data is flushed for 772abd08d7dSDan Williams * all iterator types. The _copy_from_iter_nocache() only attempts to 773abd08d7dSDan Williams * bypass the cache for the ITER_IOVEC case, and on some archs may use 774abd08d7dSDan Williams * instructions that strand dirty-data in the cache. 775abd08d7dSDan Williams */ 7766a37e940SLinus Torvalds size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 7770aed55afSDan Williams { 77800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 7790aed55afSDan Williams WARN_ON(1); 7800aed55afSDan Williams return 0; 7810aed55afSDan Williams } 782*7baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 783*7baa5099SAl Viro __copy_from_user_flushcache(addr + off, base, len), 784*7baa5099SAl Viro memcpy_flushcache(addr + off, base, len) 7850aed55afSDan Williams ) 7860aed55afSDan Williams 7870aed55afSDan Williams return bytes; 7880aed55afSDan Williams } 7896a37e940SLinus Torvalds EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); 7900aed55afSDan Williams #endif 7910aed55afSDan Williams 79272e809edSAl Viro static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) 79372e809edSAl Viro { 7946daef95bSEric Dumazet struct page *head; 7956daef95bSEric Dumazet size_t v = n + offset; 7966daef95bSEric Dumazet 7976daef95bSEric Dumazet /* 7986daef95bSEric Dumazet * The general case needs to access the page order in order 7996daef95bSEric Dumazet * to compute the page size. 8006daef95bSEric Dumazet * However, we mostly deal with order-0 pages and thus can 8016daef95bSEric Dumazet * avoid a possible cache line miss for requests that fit all 8026daef95bSEric Dumazet * page orders. 8036daef95bSEric Dumazet */ 8046daef95bSEric Dumazet if (n <= v && v <= PAGE_SIZE) 8056daef95bSEric Dumazet return true; 8066daef95bSEric Dumazet 8076daef95bSEric Dumazet head = compound_head(page); 8086daef95bSEric Dumazet v += (page - head) << PAGE_SHIFT; 809a90bcb86SPetar Penkov 810a50b854eSMatthew Wilcox (Oracle) if (likely(n <= v && v <= (page_size(head)))) 81172e809edSAl Viro return true; 81272e809edSAl Viro WARN_ON(1); 81372e809edSAl Viro return false; 81472e809edSAl Viro } 815cbbd26b8SAl Viro 81608aa6479SAl Viro static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 817d879cb83SAl Viro struct iov_iter *i) 818d879cb83SAl Viro { 81928f38db7SAl Viro if (likely(iter_is_iovec(i))) 82028f38db7SAl Viro return copy_page_to_iter_iovec(page, offset, bytes, i); 82128f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 822d879cb83SAl Viro void *kaddr = kmap_atomic(page); 823d879cb83SAl Viro size_t wanted = copy_to_iter(kaddr + offset, bytes, i); 824d879cb83SAl Viro kunmap_atomic(kaddr); 825d879cb83SAl Viro return wanted; 82628f38db7SAl Viro } 82728f38db7SAl Viro if (iov_iter_is_pipe(i)) 82828f38db7SAl Viro return copy_page_to_iter_pipe(page, offset, bytes, i); 82928f38db7SAl Viro if (unlikely(iov_iter_is_discard(i))) { 830a506abc7SAl Viro if (unlikely(i->count < bytes)) 831a506abc7SAl Viro bytes = i->count; 832a506abc7SAl Viro i->count -= bytes; 8339ea9ce04SDavid Howells return bytes; 83428f38db7SAl Viro } 83528f38db7SAl Viro WARN_ON(1); 83628f38db7SAl Viro return 0; 837d879cb83SAl Viro } 83808aa6479SAl Viro 83908aa6479SAl Viro size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, 84008aa6479SAl Viro struct iov_iter *i) 84108aa6479SAl Viro { 84208aa6479SAl Viro size_t res = 0; 84308aa6479SAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 84408aa6479SAl Viro return 0; 84508aa6479SAl Viro page += offset / PAGE_SIZE; // first subpage 84608aa6479SAl Viro offset %= PAGE_SIZE; 84708aa6479SAl Viro while (1) { 84808aa6479SAl Viro size_t n = __copy_page_to_iter(page, offset, 84908aa6479SAl Viro min(bytes, (size_t)PAGE_SIZE - offset), i); 85008aa6479SAl Viro res += n; 85108aa6479SAl Viro bytes -= n; 85208aa6479SAl Viro if (!bytes || !n) 85308aa6479SAl Viro break; 85408aa6479SAl Viro offset += n; 85508aa6479SAl Viro if (offset == PAGE_SIZE) { 85608aa6479SAl Viro page++; 85708aa6479SAl Viro offset = 0; 85808aa6479SAl Viro } 85908aa6479SAl Viro } 86008aa6479SAl Viro return res; 86108aa6479SAl Viro } 862d879cb83SAl Viro EXPORT_SYMBOL(copy_page_to_iter); 863d879cb83SAl Viro 864d879cb83SAl Viro size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, 865d879cb83SAl Viro struct iov_iter *i) 866d879cb83SAl Viro { 86772e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) 86872e809edSAl Viro return 0; 86928f38db7SAl Viro if (likely(iter_is_iovec(i))) 87028f38db7SAl Viro return copy_page_from_iter_iovec(page, offset, bytes, i); 87128f38db7SAl Viro if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) { 872d879cb83SAl Viro void *kaddr = kmap_atomic(page); 873aa28de27SAl Viro size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); 874d879cb83SAl Viro kunmap_atomic(kaddr); 875d879cb83SAl Viro return wanted; 87628f38db7SAl Viro } 87728f38db7SAl Viro WARN_ON(1); 87828f38db7SAl Viro return 0; 879d879cb83SAl Viro } 880d879cb83SAl Viro EXPORT_SYMBOL(copy_page_from_iter); 881d879cb83SAl Viro 882241699cdSAl Viro static size_t pipe_zero(size_t bytes, struct iov_iter *i) 883241699cdSAl Viro { 884241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 8858cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 8868cefc107SDavid Howells unsigned int i_head; 887241699cdSAl Viro size_t n, off; 888241699cdSAl Viro 889241699cdSAl Viro if (!sanity(i)) 890241699cdSAl Viro return 0; 891241699cdSAl Viro 8928cefc107SDavid Howells bytes = n = push_pipe(i, bytes, &i_head, &off); 893241699cdSAl Viro if (unlikely(!n)) 894241699cdSAl Viro return 0; 895241699cdSAl Viro 8968cefc107SDavid Howells do { 897241699cdSAl Viro size_t chunk = min_t(size_t, n, PAGE_SIZE - off); 8988cefc107SDavid Howells memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); 8998cefc107SDavid Howells i->head = i_head; 900241699cdSAl Viro i->iov_offset = off + chunk; 901241699cdSAl Viro n -= chunk; 9028cefc107SDavid Howells off = 0; 9038cefc107SDavid Howells i_head++; 9048cefc107SDavid Howells } while (n); 905241699cdSAl Viro i->count -= bytes; 906241699cdSAl Viro return bytes; 907241699cdSAl Viro } 908241699cdSAl Viro 909d879cb83SAl Viro size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 910d879cb83SAl Viro { 91100e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) 912241699cdSAl Viro return pipe_zero(bytes, i); 913*7baa5099SAl Viro iterate_and_advance(i, bytes, base, len, count, 914*7baa5099SAl Viro clear_user(base, len), 915*7baa5099SAl Viro memset(base, 0, len) 916d879cb83SAl Viro ) 917d879cb83SAl Viro 918d879cb83SAl Viro return bytes; 919d879cb83SAl Viro } 920d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_zero); 921d879cb83SAl Viro 922f0b65f39SAl Viro size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, 923f0b65f39SAl Viro struct iov_iter *i) 924d879cb83SAl Viro { 925d879cb83SAl Viro char *kaddr = kmap_atomic(page), *p = kaddr + offset; 92672e809edSAl Viro if (unlikely(!page_copy_sane(page, offset, bytes))) { 92772e809edSAl Viro kunmap_atomic(kaddr); 92872e809edSAl Viro return 0; 92972e809edSAl Viro } 9309ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 931241699cdSAl Viro kunmap_atomic(kaddr); 932241699cdSAl Viro WARN_ON(1); 933241699cdSAl Viro return 0; 934241699cdSAl Viro } 935*7baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, 936*7baa5099SAl Viro copyin(p + off, base, len), 937*7baa5099SAl Viro memcpy(p + off, base, len) 938d879cb83SAl Viro ) 939d879cb83SAl Viro kunmap_atomic(kaddr); 940d879cb83SAl Viro return bytes; 941d879cb83SAl Viro } 942f0b65f39SAl Viro EXPORT_SYMBOL(copy_page_from_iter_atomic); 943d879cb83SAl Viro 944b9dc6f65SAl Viro static inline void pipe_truncate(struct iov_iter *i) 945241699cdSAl Viro { 946241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 9478cefc107SDavid Howells unsigned int p_tail = pipe->tail; 9488cefc107SDavid Howells unsigned int p_head = pipe->head; 9498cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9508cefc107SDavid Howells 9518cefc107SDavid Howells if (!pipe_empty(p_head, p_tail)) { 9528cefc107SDavid Howells struct pipe_buffer *buf; 9538cefc107SDavid Howells unsigned int i_head = i->head; 954b9dc6f65SAl Viro size_t off = i->iov_offset; 9558cefc107SDavid Howells 956b9dc6f65SAl Viro if (off) { 9578cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 9588cefc107SDavid Howells buf->len = off - buf->offset; 9598cefc107SDavid Howells i_head++; 960b9dc6f65SAl Viro } 9618cefc107SDavid Howells while (p_head != i_head) { 9628cefc107SDavid Howells p_head--; 9638cefc107SDavid Howells pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); 964241699cdSAl Viro } 9658cefc107SDavid Howells 9668cefc107SDavid Howells pipe->head = p_head; 967241699cdSAl Viro } 968b9dc6f65SAl Viro } 969b9dc6f65SAl Viro 970b9dc6f65SAl Viro static void pipe_advance(struct iov_iter *i, size_t size) 971b9dc6f65SAl Viro { 972b9dc6f65SAl Viro struct pipe_inode_info *pipe = i->pipe; 973b9dc6f65SAl Viro if (size) { 974b9dc6f65SAl Viro struct pipe_buffer *buf; 9758cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 9768cefc107SDavid Howells unsigned int i_head = i->head; 977b9dc6f65SAl Viro size_t off = i->iov_offset, left = size; 9788cefc107SDavid Howells 979b9dc6f65SAl Viro if (off) /* make it relative to the beginning of buffer */ 9808cefc107SDavid Howells left += off - pipe->bufs[i_head & p_mask].offset; 981b9dc6f65SAl Viro while (1) { 9828cefc107SDavid Howells buf = &pipe->bufs[i_head & p_mask]; 983b9dc6f65SAl Viro if (left <= buf->len) 984b9dc6f65SAl Viro break; 985b9dc6f65SAl Viro left -= buf->len; 9868cefc107SDavid Howells i_head++; 987b9dc6f65SAl Viro } 9888cefc107SDavid Howells i->head = i_head; 989b9dc6f65SAl Viro i->iov_offset = buf->offset + left; 990b9dc6f65SAl Viro } 991b9dc6f65SAl Viro i->count -= size; 992b9dc6f65SAl Viro /* ... and discard everything past that point */ 993b9dc6f65SAl Viro pipe_truncate(i); 994241699cdSAl Viro } 995241699cdSAl Viro 99654c8195bSPavel Begunkov static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) 99754c8195bSPavel Begunkov { 99854c8195bSPavel Begunkov struct bvec_iter bi; 99954c8195bSPavel Begunkov 100054c8195bSPavel Begunkov bi.bi_size = i->count; 100154c8195bSPavel Begunkov bi.bi_bvec_done = i->iov_offset; 100254c8195bSPavel Begunkov bi.bi_idx = 0; 100354c8195bSPavel Begunkov bvec_iter_advance(i->bvec, &bi, size); 100454c8195bSPavel Begunkov 100554c8195bSPavel Begunkov i->bvec += bi.bi_idx; 100654c8195bSPavel Begunkov i->nr_segs -= bi.bi_idx; 100754c8195bSPavel Begunkov i->count = bi.bi_size; 100854c8195bSPavel Begunkov i->iov_offset = bi.bi_bvec_done; 100954c8195bSPavel Begunkov } 101054c8195bSPavel Begunkov 1011185ac4d4SAl Viro static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) 1012185ac4d4SAl Viro { 1013185ac4d4SAl Viro const struct iovec *iov, *end; 1014185ac4d4SAl Viro 1015185ac4d4SAl Viro if (!i->count) 1016185ac4d4SAl Viro return; 1017185ac4d4SAl Viro i->count -= size; 1018185ac4d4SAl Viro 1019185ac4d4SAl Viro size += i->iov_offset; // from beginning of current segment 1020185ac4d4SAl Viro for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) { 1021185ac4d4SAl Viro if (likely(size < iov->iov_len)) 1022185ac4d4SAl Viro break; 1023185ac4d4SAl Viro size -= iov->iov_len; 1024185ac4d4SAl Viro } 1025185ac4d4SAl Viro i->iov_offset = size; 1026185ac4d4SAl Viro i->nr_segs -= iov - i->iov; 1027185ac4d4SAl Viro i->iov = iov; 1028185ac4d4SAl Viro } 1029185ac4d4SAl Viro 1030d879cb83SAl Viro void iov_iter_advance(struct iov_iter *i, size_t size) 1031d879cb83SAl Viro { 10323b3fc051SAl Viro if (unlikely(i->count < size)) 10333b3fc051SAl Viro size = i->count; 1034185ac4d4SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { 1035185ac4d4SAl Viro /* iovec and kvec have identical layouts */ 1036185ac4d4SAl Viro iov_iter_iovec_advance(i, size); 1037185ac4d4SAl Viro } else if (iov_iter_is_bvec(i)) { 1038185ac4d4SAl Viro iov_iter_bvec_advance(i, size); 1039185ac4d4SAl Viro } else if (iov_iter_is_pipe(i)) { 1040241699cdSAl Viro pipe_advance(i, size); 1041185ac4d4SAl Viro } else if (unlikely(iov_iter_is_xarray(i))) { 10427ff50620SDavid Howells i->iov_offset += size; 10437ff50620SDavid Howells i->count -= size; 1044185ac4d4SAl Viro } else if (iov_iter_is_discard(i)) { 1045185ac4d4SAl Viro i->count -= size; 10467ff50620SDavid Howells } 1047d879cb83SAl Viro } 1048d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_advance); 1049d879cb83SAl Viro 105027c0e374SAl Viro void iov_iter_revert(struct iov_iter *i, size_t unroll) 105127c0e374SAl Viro { 105227c0e374SAl Viro if (!unroll) 105327c0e374SAl Viro return; 10545b47d59aSAl Viro if (WARN_ON(unroll > MAX_RW_COUNT)) 10555b47d59aSAl Viro return; 105627c0e374SAl Viro i->count += unroll; 105700e23707SDavid Howells if (unlikely(iov_iter_is_pipe(i))) { 105827c0e374SAl Viro struct pipe_inode_info *pipe = i->pipe; 10598cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 10608cefc107SDavid Howells unsigned int i_head = i->head; 106127c0e374SAl Viro size_t off = i->iov_offset; 106227c0e374SAl Viro while (1) { 10638cefc107SDavid Howells struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; 10648cefc107SDavid Howells size_t n = off - b->offset; 106527c0e374SAl Viro if (unroll < n) { 10664fa55cefSAl Viro off -= unroll; 106727c0e374SAl Viro break; 106827c0e374SAl Viro } 106927c0e374SAl Viro unroll -= n; 10708cefc107SDavid Howells if (!unroll && i_head == i->start_head) { 107127c0e374SAl Viro off = 0; 107227c0e374SAl Viro break; 107327c0e374SAl Viro } 10748cefc107SDavid Howells i_head--; 10758cefc107SDavid Howells b = &pipe->bufs[i_head & p_mask]; 10768cefc107SDavid Howells off = b->offset + b->len; 107727c0e374SAl Viro } 107827c0e374SAl Viro i->iov_offset = off; 10798cefc107SDavid Howells i->head = i_head; 108027c0e374SAl Viro pipe_truncate(i); 108127c0e374SAl Viro return; 108227c0e374SAl Viro } 10839ea9ce04SDavid Howells if (unlikely(iov_iter_is_discard(i))) 10849ea9ce04SDavid Howells return; 108527c0e374SAl Viro if (unroll <= i->iov_offset) { 108627c0e374SAl Viro i->iov_offset -= unroll; 108727c0e374SAl Viro return; 108827c0e374SAl Viro } 108927c0e374SAl Viro unroll -= i->iov_offset; 10907ff50620SDavid Howells if (iov_iter_is_xarray(i)) { 10917ff50620SDavid Howells BUG(); /* We should never go beyond the start of the specified 10927ff50620SDavid Howells * range since we might then be straying into pages that 10937ff50620SDavid Howells * aren't pinned. 10947ff50620SDavid Howells */ 10957ff50620SDavid Howells } else if (iov_iter_is_bvec(i)) { 109627c0e374SAl Viro const struct bio_vec *bvec = i->bvec; 109727c0e374SAl Viro while (1) { 109827c0e374SAl Viro size_t n = (--bvec)->bv_len; 109927c0e374SAl Viro i->nr_segs++; 110027c0e374SAl Viro if (unroll <= n) { 110127c0e374SAl Viro i->bvec = bvec; 110227c0e374SAl Viro i->iov_offset = n - unroll; 110327c0e374SAl Viro return; 110427c0e374SAl Viro } 110527c0e374SAl Viro unroll -= n; 110627c0e374SAl Viro } 110727c0e374SAl Viro } else { /* same logics for iovec and kvec */ 110827c0e374SAl Viro const struct iovec *iov = i->iov; 110927c0e374SAl Viro while (1) { 111027c0e374SAl Viro size_t n = (--iov)->iov_len; 111127c0e374SAl Viro i->nr_segs++; 111227c0e374SAl Viro if (unroll <= n) { 111327c0e374SAl Viro i->iov = iov; 111427c0e374SAl Viro i->iov_offset = n - unroll; 111527c0e374SAl Viro return; 111627c0e374SAl Viro } 111727c0e374SAl Viro unroll -= n; 111827c0e374SAl Viro } 111927c0e374SAl Viro } 112027c0e374SAl Viro } 112127c0e374SAl Viro EXPORT_SYMBOL(iov_iter_revert); 112227c0e374SAl Viro 1123d879cb83SAl Viro /* 1124d879cb83SAl Viro * Return the count of just the current iov_iter segment. 1125d879cb83SAl Viro */ 1126d879cb83SAl Viro size_t iov_iter_single_seg_count(const struct iov_iter *i) 1127d879cb83SAl Viro { 112828f38db7SAl Viro if (i->nr_segs > 1) { 112928f38db7SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 113028f38db7SAl Viro return min(i->count, i->iov->iov_len - i->iov_offset); 11317ff50620SDavid Howells if (iov_iter_is_bvec(i)) 1132d879cb83SAl Viro return min(i->count, i->bvec->bv_len - i->iov_offset); 113328f38db7SAl Viro } 113428f38db7SAl Viro return i->count; 1135d879cb83SAl Viro } 1136d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_single_seg_count); 1137d879cb83SAl Viro 1138aa563d7bSDavid Howells void iov_iter_kvec(struct iov_iter *i, unsigned int direction, 1139d879cb83SAl Viro const struct kvec *kvec, unsigned long nr_segs, 1140d879cb83SAl Viro size_t count) 1141d879cb83SAl Viro { 1142aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 11438cd54c1cSAl Viro *i = (struct iov_iter){ 11448cd54c1cSAl Viro .iter_type = ITER_KVEC, 11458cd54c1cSAl Viro .data_source = direction, 11468cd54c1cSAl Viro .kvec = kvec, 11478cd54c1cSAl Viro .nr_segs = nr_segs, 11488cd54c1cSAl Viro .iov_offset = 0, 11498cd54c1cSAl Viro .count = count 11508cd54c1cSAl Viro }; 1151d879cb83SAl Viro } 1152d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_kvec); 1153d879cb83SAl Viro 1154aa563d7bSDavid Howells void iov_iter_bvec(struct iov_iter *i, unsigned int direction, 1155d879cb83SAl Viro const struct bio_vec *bvec, unsigned long nr_segs, 1156d879cb83SAl Viro size_t count) 1157d879cb83SAl Viro { 1158aa563d7bSDavid Howells WARN_ON(direction & ~(READ | WRITE)); 11598cd54c1cSAl Viro *i = (struct iov_iter){ 11608cd54c1cSAl Viro .iter_type = ITER_BVEC, 11618cd54c1cSAl Viro .data_source = direction, 11628cd54c1cSAl Viro .bvec = bvec, 11638cd54c1cSAl Viro .nr_segs = nr_segs, 11648cd54c1cSAl Viro .iov_offset = 0, 11658cd54c1cSAl Viro .count = count 11668cd54c1cSAl Viro }; 1167d879cb83SAl Viro } 1168d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_bvec); 1169d879cb83SAl Viro 1170aa563d7bSDavid Howells void iov_iter_pipe(struct iov_iter *i, unsigned int direction, 1171241699cdSAl Viro struct pipe_inode_info *pipe, 1172241699cdSAl Viro size_t count) 1173241699cdSAl Viro { 1174aa563d7bSDavid Howells BUG_ON(direction != READ); 11758cefc107SDavid Howells WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); 11768cd54c1cSAl Viro *i = (struct iov_iter){ 11778cd54c1cSAl Viro .iter_type = ITER_PIPE, 11788cd54c1cSAl Viro .data_source = false, 11798cd54c1cSAl Viro .pipe = pipe, 11808cd54c1cSAl Viro .head = pipe->head, 11818cd54c1cSAl Viro .start_head = pipe->head, 11828cd54c1cSAl Viro .iov_offset = 0, 11838cd54c1cSAl Viro .count = count 11848cd54c1cSAl Viro }; 1185241699cdSAl Viro } 1186241699cdSAl Viro EXPORT_SYMBOL(iov_iter_pipe); 1187241699cdSAl Viro 11889ea9ce04SDavid Howells /** 11897ff50620SDavid Howells * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray 11907ff50620SDavid Howells * @i: The iterator to initialise. 11917ff50620SDavid Howells * @direction: The direction of the transfer. 11927ff50620SDavid Howells * @xarray: The xarray to access. 11937ff50620SDavid Howells * @start: The start file position. 11947ff50620SDavid Howells * @count: The size of the I/O buffer in bytes. 11957ff50620SDavid Howells * 11967ff50620SDavid Howells * Set up an I/O iterator to either draw data out of the pages attached to an 11977ff50620SDavid Howells * inode or to inject data into those pages. The pages *must* be prevented 11987ff50620SDavid Howells * from evaporation, either by taking a ref on them or locking them by the 11997ff50620SDavid Howells * caller. 12007ff50620SDavid Howells */ 12017ff50620SDavid Howells void iov_iter_xarray(struct iov_iter *i, unsigned int direction, 12027ff50620SDavid Howells struct xarray *xarray, loff_t start, size_t count) 12037ff50620SDavid Howells { 12047ff50620SDavid Howells BUG_ON(direction & ~1); 12058cd54c1cSAl Viro *i = (struct iov_iter) { 12068cd54c1cSAl Viro .iter_type = ITER_XARRAY, 12078cd54c1cSAl Viro .data_source = direction, 12088cd54c1cSAl Viro .xarray = xarray, 12098cd54c1cSAl Viro .xarray_start = start, 12108cd54c1cSAl Viro .count = count, 12118cd54c1cSAl Viro .iov_offset = 0 12128cd54c1cSAl Viro }; 12137ff50620SDavid Howells } 12147ff50620SDavid Howells EXPORT_SYMBOL(iov_iter_xarray); 12157ff50620SDavid Howells 12167ff50620SDavid Howells /** 12179ea9ce04SDavid Howells * iov_iter_discard - Initialise an I/O iterator that discards data 12189ea9ce04SDavid Howells * @i: The iterator to initialise. 12199ea9ce04SDavid Howells * @direction: The direction of the transfer. 12209ea9ce04SDavid Howells * @count: The size of the I/O buffer in bytes. 12219ea9ce04SDavid Howells * 12229ea9ce04SDavid Howells * Set up an I/O iterator that just discards everything that's written to it. 12239ea9ce04SDavid Howells * It's only available as a READ iterator. 12249ea9ce04SDavid Howells */ 12259ea9ce04SDavid Howells void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) 12269ea9ce04SDavid Howells { 12279ea9ce04SDavid Howells BUG_ON(direction != READ); 12288cd54c1cSAl Viro *i = (struct iov_iter){ 12298cd54c1cSAl Viro .iter_type = ITER_DISCARD, 12308cd54c1cSAl Viro .data_source = false, 12318cd54c1cSAl Viro .count = count, 12328cd54c1cSAl Viro .iov_offset = 0 12338cd54c1cSAl Viro }; 12349ea9ce04SDavid Howells } 12359ea9ce04SDavid Howells EXPORT_SYMBOL(iov_iter_discard); 12369ea9ce04SDavid Howells 12379221d2e3SAl Viro static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) 1238d879cb83SAl Viro { 1239d879cb83SAl Viro unsigned long res = 0; 1240d879cb83SAl Viro size_t size = i->count; 12419221d2e3SAl Viro size_t skip = i->iov_offset; 12429221d2e3SAl Viro unsigned k; 1243d879cb83SAl Viro 12449221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 12459221d2e3SAl Viro size_t len = i->iov[k].iov_len - skip; 12469221d2e3SAl Viro if (len) { 12479221d2e3SAl Viro res |= (unsigned long)i->iov[k].iov_base + skip; 12489221d2e3SAl Viro if (len > size) 12499221d2e3SAl Viro len = size; 12509221d2e3SAl Viro res |= len; 12519221d2e3SAl Viro size -= len; 12529221d2e3SAl Viro if (!size) 12539221d2e3SAl Viro break; 12549221d2e3SAl Viro } 12559221d2e3SAl Viro } 12569221d2e3SAl Viro return res; 12579221d2e3SAl Viro } 12589221d2e3SAl Viro 12599221d2e3SAl Viro static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) 12609221d2e3SAl Viro { 12619221d2e3SAl Viro unsigned res = 0; 12629221d2e3SAl Viro size_t size = i->count; 12639221d2e3SAl Viro unsigned skip = i->iov_offset; 12649221d2e3SAl Viro unsigned k; 12659221d2e3SAl Viro 12669221d2e3SAl Viro for (k = 0; k < i->nr_segs; k++, skip = 0) { 12679221d2e3SAl Viro size_t len = i->bvec[k].bv_len - skip; 12689221d2e3SAl Viro res |= (unsigned long)i->bvec[k].bv_offset + skip; 12699221d2e3SAl Viro if (len > size) 12709221d2e3SAl Viro len = size; 12719221d2e3SAl Viro res |= len; 12729221d2e3SAl Viro size -= len; 12739221d2e3SAl Viro if (!size) 12749221d2e3SAl Viro break; 12759221d2e3SAl Viro } 12769221d2e3SAl Viro return res; 12779221d2e3SAl Viro } 12789221d2e3SAl Viro 12799221d2e3SAl Viro unsigned long iov_iter_alignment(const struct iov_iter *i) 12809221d2e3SAl Viro { 12819221d2e3SAl Viro /* iovec and kvec have identical layouts */ 12829221d2e3SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 12839221d2e3SAl Viro return iov_iter_alignment_iovec(i); 12849221d2e3SAl Viro 12859221d2e3SAl Viro if (iov_iter_is_bvec(i)) 12869221d2e3SAl Viro return iov_iter_alignment_bvec(i); 12879221d2e3SAl Viro 12889221d2e3SAl Viro if (iov_iter_is_pipe(i)) { 1289e0ff126eSJan Kara unsigned int p_mask = i->pipe->ring_size - 1; 12909221d2e3SAl Viro size_t size = i->count; 1291e0ff126eSJan Kara 12928cefc107SDavid Howells if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) 1293241699cdSAl Viro return size | i->iov_offset; 1294241699cdSAl Viro return size; 1295241699cdSAl Viro } 12969221d2e3SAl Viro 12979221d2e3SAl Viro if (iov_iter_is_xarray(i)) 12983d14ec1fSDavid Howells return (i->xarray_start + i->iov_offset) | i->count; 12999221d2e3SAl Viro 13009221d2e3SAl Viro return 0; 1301d879cb83SAl Viro } 1302d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_alignment); 1303d879cb83SAl Viro 1304357f435dSAl Viro unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 1305357f435dSAl Viro { 1306357f435dSAl Viro unsigned long res = 0; 1307610c7a71SAl Viro unsigned long v = 0; 1308357f435dSAl Viro size_t size = i->count; 1309610c7a71SAl Viro unsigned k; 1310357f435dSAl Viro 1311610c7a71SAl Viro if (WARN_ON(!iter_is_iovec(i))) 1312241699cdSAl Viro return ~0U; 1313241699cdSAl Viro 1314610c7a71SAl Viro for (k = 0; k < i->nr_segs; k++) { 1315610c7a71SAl Viro if (i->iov[k].iov_len) { 1316610c7a71SAl Viro unsigned long base = (unsigned long)i->iov[k].iov_base; 1317610c7a71SAl Viro if (v) // if not the first one 1318610c7a71SAl Viro res |= base | v; // this start | previous end 1319610c7a71SAl Viro v = base + i->iov[k].iov_len; 1320610c7a71SAl Viro if (size <= i->iov[k].iov_len) 1321610c7a71SAl Viro break; 1322610c7a71SAl Viro size -= i->iov[k].iov_len; 1323610c7a71SAl Viro } 1324610c7a71SAl Viro } 1325357f435dSAl Viro return res; 1326357f435dSAl Viro } 1327357f435dSAl Viro EXPORT_SYMBOL(iov_iter_gap_alignment); 1328357f435dSAl Viro 1329e76b6312SIlya Dryomov static inline ssize_t __pipe_get_pages(struct iov_iter *i, 1330241699cdSAl Viro size_t maxsize, 1331241699cdSAl Viro struct page **pages, 13328cefc107SDavid Howells int iter_head, 1333241699cdSAl Viro size_t *start) 1334241699cdSAl Viro { 1335241699cdSAl Viro struct pipe_inode_info *pipe = i->pipe; 13368cefc107SDavid Howells unsigned int p_mask = pipe->ring_size - 1; 13378cefc107SDavid Howells ssize_t n = push_pipe(i, maxsize, &iter_head, start); 1338241699cdSAl Viro if (!n) 1339241699cdSAl Viro return -EFAULT; 1340241699cdSAl Viro 1341241699cdSAl Viro maxsize = n; 1342241699cdSAl Viro n += *start; 13431689c73aSAl Viro while (n > 0) { 13448cefc107SDavid Howells get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); 13458cefc107SDavid Howells iter_head++; 1346241699cdSAl Viro n -= PAGE_SIZE; 1347241699cdSAl Viro } 1348241699cdSAl Viro 1349241699cdSAl Viro return maxsize; 1350241699cdSAl Viro } 1351241699cdSAl Viro 1352241699cdSAl Viro static ssize_t pipe_get_pages(struct iov_iter *i, 1353241699cdSAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1354241699cdSAl Viro size_t *start) 1355241699cdSAl Viro { 13568cefc107SDavid Howells unsigned int iter_head, npages; 1357241699cdSAl Viro size_t capacity; 1358241699cdSAl Viro 1359241699cdSAl Viro if (!sanity(i)) 1360241699cdSAl Viro return -EFAULT; 1361241699cdSAl Viro 13628cefc107SDavid Howells data_start(i, &iter_head, start); 13638cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 13648cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1365241699cdSAl Viro capacity = min(npages, maxpages) * PAGE_SIZE - *start; 1366241699cdSAl Viro 13678cefc107SDavid Howells return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); 1368241699cdSAl Viro } 1369241699cdSAl Viro 13707ff50620SDavid Howells static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, 13717ff50620SDavid Howells pgoff_t index, unsigned int nr_pages) 13727ff50620SDavid Howells { 13737ff50620SDavid Howells XA_STATE(xas, xa, index); 13747ff50620SDavid Howells struct page *page; 13757ff50620SDavid Howells unsigned int ret = 0; 13767ff50620SDavid Howells 13777ff50620SDavid Howells rcu_read_lock(); 13787ff50620SDavid Howells for (page = xas_load(&xas); page; page = xas_next(&xas)) { 13797ff50620SDavid Howells if (xas_retry(&xas, page)) 13807ff50620SDavid Howells continue; 13817ff50620SDavid Howells 13827ff50620SDavid Howells /* Has the page moved or been split? */ 13837ff50620SDavid Howells if (unlikely(page != xas_reload(&xas))) { 13847ff50620SDavid Howells xas_reset(&xas); 13857ff50620SDavid Howells continue; 13867ff50620SDavid Howells } 13877ff50620SDavid Howells 13887ff50620SDavid Howells pages[ret] = find_subpage(page, xas.xa_index); 13897ff50620SDavid Howells get_page(pages[ret]); 13907ff50620SDavid Howells if (++ret == nr_pages) 13917ff50620SDavid Howells break; 13927ff50620SDavid Howells } 13937ff50620SDavid Howells rcu_read_unlock(); 13947ff50620SDavid Howells return ret; 13957ff50620SDavid Howells } 13967ff50620SDavid Howells 13977ff50620SDavid Howells static ssize_t iter_xarray_get_pages(struct iov_iter *i, 13987ff50620SDavid Howells struct page **pages, size_t maxsize, 13997ff50620SDavid Howells unsigned maxpages, size_t *_start_offset) 14007ff50620SDavid Howells { 14017ff50620SDavid Howells unsigned nr, offset; 14027ff50620SDavid Howells pgoff_t index, count; 14037ff50620SDavid Howells size_t size = maxsize, actual; 14047ff50620SDavid Howells loff_t pos; 14057ff50620SDavid Howells 14067ff50620SDavid Howells if (!size || !maxpages) 14077ff50620SDavid Howells return 0; 14087ff50620SDavid Howells 14097ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 14107ff50620SDavid Howells index = pos >> PAGE_SHIFT; 14117ff50620SDavid Howells offset = pos & ~PAGE_MASK; 14127ff50620SDavid Howells *_start_offset = offset; 14137ff50620SDavid Howells 14147ff50620SDavid Howells count = 1; 14157ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 14167ff50620SDavid Howells size -= PAGE_SIZE - offset; 14177ff50620SDavid Howells count += size >> PAGE_SHIFT; 14187ff50620SDavid Howells size &= ~PAGE_MASK; 14197ff50620SDavid Howells if (size) 14207ff50620SDavid Howells count++; 14217ff50620SDavid Howells } 14227ff50620SDavid Howells 14237ff50620SDavid Howells if (count > maxpages) 14247ff50620SDavid Howells count = maxpages; 14257ff50620SDavid Howells 14267ff50620SDavid Howells nr = iter_xarray_populate_pages(pages, i->xarray, index, count); 14277ff50620SDavid Howells if (nr == 0) 14287ff50620SDavid Howells return 0; 14297ff50620SDavid Howells 14307ff50620SDavid Howells actual = PAGE_SIZE * nr; 14317ff50620SDavid Howells actual -= offset; 14327ff50620SDavid Howells if (nr == count && size > 0) { 14337ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 14347ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 14357ff50620SDavid Howells } 14367ff50620SDavid Howells return actual; 14377ff50620SDavid Howells } 14387ff50620SDavid Howells 14393d671ca6SAl Viro /* must be done on non-empty ITER_IOVEC one */ 14403d671ca6SAl Viro static unsigned long first_iovec_segment(const struct iov_iter *i, 14413d671ca6SAl Viro size_t *size, size_t *start, 14423d671ca6SAl Viro size_t maxsize, unsigned maxpages) 14433d671ca6SAl Viro { 14443d671ca6SAl Viro size_t skip; 14453d671ca6SAl Viro long k; 14463d671ca6SAl Viro 14473d671ca6SAl Viro for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { 14483d671ca6SAl Viro unsigned long addr = (unsigned long)i->iov[k].iov_base + skip; 14493d671ca6SAl Viro size_t len = i->iov[k].iov_len - skip; 14503d671ca6SAl Viro 14513d671ca6SAl Viro if (unlikely(!len)) 14523d671ca6SAl Viro continue; 14533d671ca6SAl Viro if (len > maxsize) 14543d671ca6SAl Viro len = maxsize; 14553d671ca6SAl Viro len += (*start = addr % PAGE_SIZE); 14563d671ca6SAl Viro if (len > maxpages * PAGE_SIZE) 14573d671ca6SAl Viro len = maxpages * PAGE_SIZE; 14583d671ca6SAl Viro *size = len; 14593d671ca6SAl Viro return addr & PAGE_MASK; 14603d671ca6SAl Viro } 14613d671ca6SAl Viro BUG(); // if it had been empty, we wouldn't get called 14623d671ca6SAl Viro } 14633d671ca6SAl Viro 14643d671ca6SAl Viro /* must be done on non-empty ITER_BVEC one */ 14653d671ca6SAl Viro static struct page *first_bvec_segment(const struct iov_iter *i, 14663d671ca6SAl Viro size_t *size, size_t *start, 14673d671ca6SAl Viro size_t maxsize, unsigned maxpages) 14683d671ca6SAl Viro { 14693d671ca6SAl Viro struct page *page; 14703d671ca6SAl Viro size_t skip = i->iov_offset, len; 14713d671ca6SAl Viro 14723d671ca6SAl Viro len = i->bvec->bv_len - skip; 14733d671ca6SAl Viro if (len > maxsize) 14743d671ca6SAl Viro len = maxsize; 14753d671ca6SAl Viro skip += i->bvec->bv_offset; 14763d671ca6SAl Viro page = i->bvec->bv_page + skip / PAGE_SIZE; 14773d671ca6SAl Viro len += (*start = skip % PAGE_SIZE); 14783d671ca6SAl Viro if (len > maxpages * PAGE_SIZE) 14793d671ca6SAl Viro len = maxpages * PAGE_SIZE; 14803d671ca6SAl Viro *size = len; 14813d671ca6SAl Viro return page; 14823d671ca6SAl Viro } 14833d671ca6SAl Viro 1484d879cb83SAl Viro ssize_t iov_iter_get_pages(struct iov_iter *i, 1485d879cb83SAl Viro struct page **pages, size_t maxsize, unsigned maxpages, 1486d879cb83SAl Viro size_t *start) 1487d879cb83SAl Viro { 14883d671ca6SAl Viro size_t len; 14893d671ca6SAl Viro int n, res; 14903d671ca6SAl Viro 1491d879cb83SAl Viro if (maxsize > i->count) 1492d879cb83SAl Viro maxsize = i->count; 14933d671ca6SAl Viro if (!maxsize) 14943d671ca6SAl Viro return 0; 1495d879cb83SAl Viro 14963d671ca6SAl Viro if (likely(iter_is_iovec(i))) { 14973d671ca6SAl Viro unsigned long addr; 14989ea9ce04SDavid Howells 14993d671ca6SAl Viro addr = first_iovec_segment(i, &len, start, maxsize, maxpages); 1500d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 150173b0140bSIra Weiny res = get_user_pages_fast(addr, n, 150273b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, 150373b0140bSIra Weiny pages); 1504d879cb83SAl Viro if (unlikely(res < 0)) 1505d879cb83SAl Viro return res; 1506d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 15073d671ca6SAl Viro } 15083d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 15093d671ca6SAl Viro struct page *page; 15103d671ca6SAl Viro 15113d671ca6SAl Viro page = first_bvec_segment(i, &len, start, maxsize, maxpages); 15123d671ca6SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 15133d671ca6SAl Viro while (n--) 15143d671ca6SAl Viro get_page(*pages++ = page++); 15153d671ca6SAl Viro return len - *start; 15163d671ca6SAl Viro } 15173d671ca6SAl Viro if (iov_iter_is_pipe(i)) 15183d671ca6SAl Viro return pipe_get_pages(i, pages, maxsize, maxpages, start); 15193d671ca6SAl Viro if (iov_iter_is_xarray(i)) 15203d671ca6SAl Viro return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); 1521d879cb83SAl Viro return -EFAULT; 1522d879cb83SAl Viro } 1523d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages); 1524d879cb83SAl Viro 1525d879cb83SAl Viro static struct page **get_pages_array(size_t n) 1526d879cb83SAl Viro { 1527752ade68SMichal Hocko return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); 1528d879cb83SAl Viro } 1529d879cb83SAl Viro 1530241699cdSAl Viro static ssize_t pipe_get_pages_alloc(struct iov_iter *i, 1531241699cdSAl Viro struct page ***pages, size_t maxsize, 1532241699cdSAl Viro size_t *start) 1533241699cdSAl Viro { 1534241699cdSAl Viro struct page **p; 15358cefc107SDavid Howells unsigned int iter_head, npages; 1536d7760d63SIlya Dryomov ssize_t n; 1537241699cdSAl Viro 1538241699cdSAl Viro if (!sanity(i)) 1539241699cdSAl Viro return -EFAULT; 1540241699cdSAl Viro 15418cefc107SDavid Howells data_start(i, &iter_head, start); 15428cefc107SDavid Howells /* Amount of free space: some of this one + all after this one */ 15438cefc107SDavid Howells npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 1544241699cdSAl Viro n = npages * PAGE_SIZE - *start; 1545241699cdSAl Viro if (maxsize > n) 1546241699cdSAl Viro maxsize = n; 1547241699cdSAl Viro else 1548241699cdSAl Viro npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); 1549241699cdSAl Viro p = get_pages_array(npages); 1550241699cdSAl Viro if (!p) 1551241699cdSAl Viro return -ENOMEM; 15528cefc107SDavid Howells n = __pipe_get_pages(i, maxsize, p, iter_head, start); 1553241699cdSAl Viro if (n > 0) 1554241699cdSAl Viro *pages = p; 1555241699cdSAl Viro else 1556241699cdSAl Viro kvfree(p); 1557241699cdSAl Viro return n; 1558241699cdSAl Viro } 1559241699cdSAl Viro 15607ff50620SDavid Howells static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, 15617ff50620SDavid Howells struct page ***pages, size_t maxsize, 15627ff50620SDavid Howells size_t *_start_offset) 15637ff50620SDavid Howells { 15647ff50620SDavid Howells struct page **p; 15657ff50620SDavid Howells unsigned nr, offset; 15667ff50620SDavid Howells pgoff_t index, count; 15677ff50620SDavid Howells size_t size = maxsize, actual; 15687ff50620SDavid Howells loff_t pos; 15697ff50620SDavid Howells 15707ff50620SDavid Howells if (!size) 15717ff50620SDavid Howells return 0; 15727ff50620SDavid Howells 15737ff50620SDavid Howells pos = i->xarray_start + i->iov_offset; 15747ff50620SDavid Howells index = pos >> PAGE_SHIFT; 15757ff50620SDavid Howells offset = pos & ~PAGE_MASK; 15767ff50620SDavid Howells *_start_offset = offset; 15777ff50620SDavid Howells 15787ff50620SDavid Howells count = 1; 15797ff50620SDavid Howells if (size > PAGE_SIZE - offset) { 15807ff50620SDavid Howells size -= PAGE_SIZE - offset; 15817ff50620SDavid Howells count += size >> PAGE_SHIFT; 15827ff50620SDavid Howells size &= ~PAGE_MASK; 15837ff50620SDavid Howells if (size) 15847ff50620SDavid Howells count++; 15857ff50620SDavid Howells } 15867ff50620SDavid Howells 15877ff50620SDavid Howells p = get_pages_array(count); 15887ff50620SDavid Howells if (!p) 15897ff50620SDavid Howells return -ENOMEM; 15907ff50620SDavid Howells *pages = p; 15917ff50620SDavid Howells 15927ff50620SDavid Howells nr = iter_xarray_populate_pages(p, i->xarray, index, count); 15937ff50620SDavid Howells if (nr == 0) 15947ff50620SDavid Howells return 0; 15957ff50620SDavid Howells 15967ff50620SDavid Howells actual = PAGE_SIZE * nr; 15977ff50620SDavid Howells actual -= offset; 15987ff50620SDavid Howells if (nr == count && size > 0) { 15997ff50620SDavid Howells unsigned last_offset = (nr > 1) ? 0 : offset; 16007ff50620SDavid Howells actual -= PAGE_SIZE - (last_offset + size); 16017ff50620SDavid Howells } 16027ff50620SDavid Howells return actual; 16037ff50620SDavid Howells } 16047ff50620SDavid Howells 1605d879cb83SAl Viro ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 1606d879cb83SAl Viro struct page ***pages, size_t maxsize, 1607d879cb83SAl Viro size_t *start) 1608d879cb83SAl Viro { 1609d879cb83SAl Viro struct page **p; 16103d671ca6SAl Viro size_t len; 16113d671ca6SAl Viro int n, res; 1612d879cb83SAl Viro 1613d879cb83SAl Viro if (maxsize > i->count) 1614d879cb83SAl Viro maxsize = i->count; 16153d671ca6SAl Viro if (!maxsize) 16163d671ca6SAl Viro return 0; 1617d879cb83SAl Viro 16183d671ca6SAl Viro if (likely(iter_is_iovec(i))) { 16193d671ca6SAl Viro unsigned long addr; 16209ea9ce04SDavid Howells 16213d671ca6SAl Viro addr = first_iovec_segment(i, &len, start, maxsize, ~0U); 1622d879cb83SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 1623d879cb83SAl Viro p = get_pages_array(n); 1624d879cb83SAl Viro if (!p) 1625d879cb83SAl Viro return -ENOMEM; 162673b0140bSIra Weiny res = get_user_pages_fast(addr, n, 162773b0140bSIra Weiny iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); 1628d879cb83SAl Viro if (unlikely(res < 0)) { 1629d879cb83SAl Viro kvfree(p); 1630d879cb83SAl Viro return res; 1631d879cb83SAl Viro } 1632d879cb83SAl Viro *pages = p; 1633d879cb83SAl Viro return (res == n ? len : res * PAGE_SIZE) - *start; 16343d671ca6SAl Viro } 16353d671ca6SAl Viro if (iov_iter_is_bvec(i)) { 16363d671ca6SAl Viro struct page *page; 16373d671ca6SAl Viro 16383d671ca6SAl Viro page = first_bvec_segment(i, &len, start, maxsize, ~0U); 16393d671ca6SAl Viro n = DIV_ROUND_UP(len, PAGE_SIZE); 16403d671ca6SAl Viro *pages = p = get_pages_array(n); 1641d879cb83SAl Viro if (!p) 1642d879cb83SAl Viro return -ENOMEM; 16433d671ca6SAl Viro while (n--) 16443d671ca6SAl Viro get_page(*p++ = page++); 16453d671ca6SAl Viro return len - *start; 16463d671ca6SAl Viro } 16473d671ca6SAl Viro if (iov_iter_is_pipe(i)) 16483d671ca6SAl Viro return pipe_get_pages_alloc(i, pages, maxsize, start); 16493d671ca6SAl Viro if (iov_iter_is_xarray(i)) 16503d671ca6SAl Viro return iter_xarray_get_pages_alloc(i, pages, maxsize, start); 1651d879cb83SAl Viro return -EFAULT; 1652d879cb83SAl Viro } 1653d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_get_pages_alloc); 1654d879cb83SAl Viro 1655d879cb83SAl Viro size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 1656d879cb83SAl Viro struct iov_iter *i) 1657d879cb83SAl Viro { 1658d879cb83SAl Viro __wsum sum, next; 1659d879cb83SAl Viro sum = *csum; 16609ea9ce04SDavid Howells if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { 1661241699cdSAl Viro WARN_ON(1); 1662241699cdSAl Viro return 0; 1663241699cdSAl Viro } 1664*7baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, ({ 1665*7baa5099SAl Viro next = csum_and_copy_from_user(base, addr + off, len); 1666622838f3SAl Viro if (next) 1667d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1668*7baa5099SAl Viro next ? 0 : len; 1669d879cb83SAl Viro }), ({ 1670*7baa5099SAl Viro sum = csum_and_memcpy(addr + off, base, len, sum, off); 1671d879cb83SAl Viro }) 1672d879cb83SAl Viro ) 1673d879cb83SAl Viro *csum = sum; 1674d879cb83SAl Viro return bytes; 1675d879cb83SAl Viro } 1676d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_from_iter); 1677d879cb83SAl Viro 167852cbd23aSWillem de Bruijn size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 1679d879cb83SAl Viro struct iov_iter *i) 1680d879cb83SAl Viro { 168152cbd23aSWillem de Bruijn struct csum_state *csstate = _csstate; 1682d879cb83SAl Viro __wsum sum, next; 168378e1f386SAl Viro 168478e1f386SAl Viro if (unlikely(iov_iter_is_pipe(i))) 168552cbd23aSWillem de Bruijn return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); 168678e1f386SAl Viro 1687594e450bSAl Viro sum = csum_shift(csstate->csum, csstate->off); 168878e1f386SAl Viro if (unlikely(iov_iter_is_discard(i))) { 1689241699cdSAl Viro WARN_ON(1); /* for now */ 1690241699cdSAl Viro return 0; 1691241699cdSAl Viro } 1692*7baa5099SAl Viro iterate_and_advance(i, bytes, base, len, off, ({ 1693*7baa5099SAl Viro next = csum_and_copy_to_user(addr + off, base, len); 1694622838f3SAl Viro if (next) 1695d879cb83SAl Viro sum = csum_block_add(sum, next, off); 1696*7baa5099SAl Viro next ? 0 : len; 1697d879cb83SAl Viro }), ({ 1698*7baa5099SAl Viro sum = csum_and_memcpy(base, addr + off, len, sum, off); 1699d879cb83SAl Viro }) 1700d879cb83SAl Viro ) 1701594e450bSAl Viro csstate->csum = csum_shift(sum, csstate->off); 1702594e450bSAl Viro csstate->off += bytes; 1703d879cb83SAl Viro return bytes; 1704d879cb83SAl Viro } 1705d879cb83SAl Viro EXPORT_SYMBOL(csum_and_copy_to_iter); 1706d879cb83SAl Viro 1707d05f4435SSagi Grimberg size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, 1708d05f4435SSagi Grimberg struct iov_iter *i) 1709d05f4435SSagi Grimberg { 17107999096fSHerbert Xu #ifdef CONFIG_CRYPTO_HASH 1711d05f4435SSagi Grimberg struct ahash_request *hash = hashp; 1712d05f4435SSagi Grimberg struct scatterlist sg; 1713d05f4435SSagi Grimberg size_t copied; 1714d05f4435SSagi Grimberg 1715d05f4435SSagi Grimberg copied = copy_to_iter(addr, bytes, i); 1716d05f4435SSagi Grimberg sg_init_one(&sg, addr, copied); 1717d05f4435SSagi Grimberg ahash_request_set_crypt(hash, &sg, NULL, copied); 1718d05f4435SSagi Grimberg crypto_ahash_update(hash); 1719d05f4435SSagi Grimberg return copied; 172027fad74aSYueHaibing #else 172127fad74aSYueHaibing return 0; 172227fad74aSYueHaibing #endif 1723d05f4435SSagi Grimberg } 1724d05f4435SSagi Grimberg EXPORT_SYMBOL(hash_and_copy_to_iter); 1725d05f4435SSagi Grimberg 172666531c65SAl Viro static int iov_npages(const struct iov_iter *i, int maxpages) 1727d879cb83SAl Viro { 172866531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 172966531c65SAl Viro const struct iovec *p; 1730d879cb83SAl Viro int npages = 0; 1731d879cb83SAl Viro 173266531c65SAl Viro for (p = i->iov; size; skip = 0, p++) { 173366531c65SAl Viro unsigned offs = offset_in_page(p->iov_base + skip); 173466531c65SAl Viro size_t len = min(p->iov_len - skip, size); 1735d879cb83SAl Viro 173666531c65SAl Viro if (len) { 173766531c65SAl Viro size -= len; 173866531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 173966531c65SAl Viro if (unlikely(npages > maxpages)) 174066531c65SAl Viro return maxpages; 174166531c65SAl Viro } 174266531c65SAl Viro } 174366531c65SAl Viro return npages; 174466531c65SAl Viro } 174566531c65SAl Viro 174666531c65SAl Viro static int bvec_npages(const struct iov_iter *i, int maxpages) 174766531c65SAl Viro { 174866531c65SAl Viro size_t skip = i->iov_offset, size = i->count; 174966531c65SAl Viro const struct bio_vec *p; 175066531c65SAl Viro int npages = 0; 175166531c65SAl Viro 175266531c65SAl Viro for (p = i->bvec; size; skip = 0, p++) { 175366531c65SAl Viro unsigned offs = (p->bv_offset + skip) % PAGE_SIZE; 175466531c65SAl Viro size_t len = min(p->bv_len - skip, size); 175566531c65SAl Viro 175666531c65SAl Viro size -= len; 175766531c65SAl Viro npages += DIV_ROUND_UP(offs + len, PAGE_SIZE); 175866531c65SAl Viro if (unlikely(npages > maxpages)) 175966531c65SAl Viro return maxpages; 176066531c65SAl Viro } 176166531c65SAl Viro return npages; 176266531c65SAl Viro } 176366531c65SAl Viro 176466531c65SAl Viro int iov_iter_npages(const struct iov_iter *i, int maxpages) 176566531c65SAl Viro { 176666531c65SAl Viro if (unlikely(!i->count)) 176766531c65SAl Viro return 0; 176866531c65SAl Viro /* iovec and kvec have identical layouts */ 176966531c65SAl Viro if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) 177066531c65SAl Viro return iov_npages(i, maxpages); 177166531c65SAl Viro if (iov_iter_is_bvec(i)) 177266531c65SAl Viro return bvec_npages(i, maxpages); 177366531c65SAl Viro if (iov_iter_is_pipe(i)) { 17748cefc107SDavid Howells unsigned int iter_head; 177566531c65SAl Viro int npages; 1776241699cdSAl Viro size_t off; 1777241699cdSAl Viro 1778241699cdSAl Viro if (!sanity(i)) 1779241699cdSAl Viro return 0; 1780241699cdSAl Viro 17818cefc107SDavid Howells data_start(i, &iter_head, &off); 1782241699cdSAl Viro /* some of this one + all after this one */ 178366531c65SAl Viro npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); 178466531c65SAl Viro return min(npages, maxpages); 178566531c65SAl Viro } 178666531c65SAl Viro if (iov_iter_is_xarray(i)) { 1787e4f8df86SAl Viro unsigned offset = (i->xarray_start + i->iov_offset) % PAGE_SIZE; 1788e4f8df86SAl Viro int npages = DIV_ROUND_UP(offset + i->count, PAGE_SIZE); 178966531c65SAl Viro return min(npages, maxpages); 179066531c65SAl Viro } 179166531c65SAl Viro return 0; 1792d879cb83SAl Viro } 1793d879cb83SAl Viro EXPORT_SYMBOL(iov_iter_npages); 1794d879cb83SAl Viro 1795d879cb83SAl Viro const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) 1796d879cb83SAl Viro { 1797d879cb83SAl Viro *new = *old; 179800e23707SDavid Howells if (unlikely(iov_iter_is_pipe(new))) { 1799241699cdSAl Viro WARN_ON(1); 1800241699cdSAl Viro return NULL; 1801241699cdSAl Viro } 18027ff50620SDavid Howells if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) 18039ea9ce04SDavid Howells return NULL; 180400e23707SDavid Howells if (iov_iter_is_bvec(new)) 1805d879cb83SAl Viro return new->bvec = kmemdup(new->bvec, 1806d879cb83SAl Viro new->nr_segs * sizeof(struct bio_vec), 1807d879cb83SAl Viro flags); 1808d879cb83SAl Viro else 1809d879cb83SAl Viro /* iovec and kvec have identical layout */ 1810d879cb83SAl Viro return new->iov = kmemdup(new->iov, 1811d879cb83SAl Viro new->nr_segs * sizeof(struct iovec), 1812d879cb83SAl Viro flags); 1813d879cb83SAl Viro } 1814d879cb83SAl Viro EXPORT_SYMBOL(dup_iter); 1815bc917be8SAl Viro 1816bfdc5970SChristoph Hellwig static int copy_compat_iovec_from_user(struct iovec *iov, 1817bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1818bfdc5970SChristoph Hellwig { 1819bfdc5970SChristoph Hellwig const struct compat_iovec __user *uiov = 1820bfdc5970SChristoph Hellwig (const struct compat_iovec __user *)uvec; 1821bfdc5970SChristoph Hellwig int ret = -EFAULT, i; 1822bfdc5970SChristoph Hellwig 1823a959a978SChristoph Hellwig if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) 1824bfdc5970SChristoph Hellwig return -EFAULT; 1825bfdc5970SChristoph Hellwig 1826bfdc5970SChristoph Hellwig for (i = 0; i < nr_segs; i++) { 1827bfdc5970SChristoph Hellwig compat_uptr_t buf; 1828bfdc5970SChristoph Hellwig compat_ssize_t len; 1829bfdc5970SChristoph Hellwig 1830bfdc5970SChristoph Hellwig unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); 1831bfdc5970SChristoph Hellwig unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); 1832bfdc5970SChristoph Hellwig 1833bfdc5970SChristoph Hellwig /* check for compat_size_t not fitting in compat_ssize_t .. */ 1834bfdc5970SChristoph Hellwig if (len < 0) { 1835bfdc5970SChristoph Hellwig ret = -EINVAL; 1836bfdc5970SChristoph Hellwig goto uaccess_end; 1837bfdc5970SChristoph Hellwig } 1838bfdc5970SChristoph Hellwig iov[i].iov_base = compat_ptr(buf); 1839bfdc5970SChristoph Hellwig iov[i].iov_len = len; 1840bfdc5970SChristoph Hellwig } 1841bfdc5970SChristoph Hellwig 1842bfdc5970SChristoph Hellwig ret = 0; 1843bfdc5970SChristoph Hellwig uaccess_end: 1844bfdc5970SChristoph Hellwig user_access_end(); 1845bfdc5970SChristoph Hellwig return ret; 1846bfdc5970SChristoph Hellwig } 1847bfdc5970SChristoph Hellwig 1848bfdc5970SChristoph Hellwig static int copy_iovec_from_user(struct iovec *iov, 1849bfdc5970SChristoph Hellwig const struct iovec __user *uvec, unsigned long nr_segs) 1850fb041b59SDavid Laight { 1851fb041b59SDavid Laight unsigned long seg; 1852bfdc5970SChristoph Hellwig 1853bfdc5970SChristoph Hellwig if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) 1854bfdc5970SChristoph Hellwig return -EFAULT; 1855bfdc5970SChristoph Hellwig for (seg = 0; seg < nr_segs; seg++) { 1856bfdc5970SChristoph Hellwig if ((ssize_t)iov[seg].iov_len < 0) 1857bfdc5970SChristoph Hellwig return -EINVAL; 1858bfdc5970SChristoph Hellwig } 1859bfdc5970SChristoph Hellwig 1860bfdc5970SChristoph Hellwig return 0; 1861bfdc5970SChristoph Hellwig } 1862bfdc5970SChristoph Hellwig 1863bfdc5970SChristoph Hellwig struct iovec *iovec_from_user(const struct iovec __user *uvec, 1864bfdc5970SChristoph Hellwig unsigned long nr_segs, unsigned long fast_segs, 1865bfdc5970SChristoph Hellwig struct iovec *fast_iov, bool compat) 1866bfdc5970SChristoph Hellwig { 1867bfdc5970SChristoph Hellwig struct iovec *iov = fast_iov; 1868bfdc5970SChristoph Hellwig int ret; 1869fb041b59SDavid Laight 1870fb041b59SDavid Laight /* 1871bfdc5970SChristoph Hellwig * SuS says "The readv() function *may* fail if the iovcnt argument was 1872bfdc5970SChristoph Hellwig * less than or equal to 0, or greater than {IOV_MAX}. Linux has 1873fb041b59SDavid Laight * traditionally returned zero for zero segments, so... 1874fb041b59SDavid Laight */ 1875bfdc5970SChristoph Hellwig if (nr_segs == 0) 1876bfdc5970SChristoph Hellwig return iov; 1877bfdc5970SChristoph Hellwig if (nr_segs > UIO_MAXIOV) 1878bfdc5970SChristoph Hellwig return ERR_PTR(-EINVAL); 1879fb041b59SDavid Laight if (nr_segs > fast_segs) { 1880fb041b59SDavid Laight iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); 1881bfdc5970SChristoph Hellwig if (!iov) 1882bfdc5970SChristoph Hellwig return ERR_PTR(-ENOMEM); 1883fb041b59SDavid Laight } 1884bfdc5970SChristoph Hellwig 1885bfdc5970SChristoph Hellwig if (compat) 1886bfdc5970SChristoph Hellwig ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); 1887bfdc5970SChristoph Hellwig else 1888bfdc5970SChristoph Hellwig ret = copy_iovec_from_user(iov, uvec, nr_segs); 1889bfdc5970SChristoph Hellwig if (ret) { 1890bfdc5970SChristoph Hellwig if (iov != fast_iov) 1891bfdc5970SChristoph Hellwig kfree(iov); 1892bfdc5970SChristoph Hellwig return ERR_PTR(ret); 1893fb041b59SDavid Laight } 1894bfdc5970SChristoph Hellwig 1895bfdc5970SChristoph Hellwig return iov; 1896bfdc5970SChristoph Hellwig } 1897bfdc5970SChristoph Hellwig 1898bfdc5970SChristoph Hellwig ssize_t __import_iovec(int type, const struct iovec __user *uvec, 1899bfdc5970SChristoph Hellwig unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, 1900bfdc5970SChristoph Hellwig struct iov_iter *i, bool compat) 1901bfdc5970SChristoph Hellwig { 1902bfdc5970SChristoph Hellwig ssize_t total_len = 0; 1903bfdc5970SChristoph Hellwig unsigned long seg; 1904bfdc5970SChristoph Hellwig struct iovec *iov; 1905bfdc5970SChristoph Hellwig 1906bfdc5970SChristoph Hellwig iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); 1907bfdc5970SChristoph Hellwig if (IS_ERR(iov)) { 1908bfdc5970SChristoph Hellwig *iovp = NULL; 1909bfdc5970SChristoph Hellwig return PTR_ERR(iov); 1910fb041b59SDavid Laight } 1911fb041b59SDavid Laight 1912fb041b59SDavid Laight /* 1913bfdc5970SChristoph Hellwig * According to the Single Unix Specification we should return EINVAL if 1914bfdc5970SChristoph Hellwig * an element length is < 0 when cast to ssize_t or if the total length 1915bfdc5970SChristoph Hellwig * would overflow the ssize_t return value of the system call. 1916fb041b59SDavid Laight * 1917fb041b59SDavid Laight * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the 1918fb041b59SDavid Laight * overflow case. 1919fb041b59SDavid Laight */ 1920fb041b59SDavid Laight for (seg = 0; seg < nr_segs; seg++) { 1921fb041b59SDavid Laight ssize_t len = (ssize_t)iov[seg].iov_len; 1922fb041b59SDavid Laight 1923bfdc5970SChristoph Hellwig if (!access_ok(iov[seg].iov_base, len)) { 1924bfdc5970SChristoph Hellwig if (iov != *iovp) 1925bfdc5970SChristoph Hellwig kfree(iov); 1926bfdc5970SChristoph Hellwig *iovp = NULL; 1927bfdc5970SChristoph Hellwig return -EFAULT; 1928fb041b59SDavid Laight } 1929bfdc5970SChristoph Hellwig 1930bfdc5970SChristoph Hellwig if (len > MAX_RW_COUNT - total_len) { 1931bfdc5970SChristoph Hellwig len = MAX_RW_COUNT - total_len; 1932fb041b59SDavid Laight iov[seg].iov_len = len; 1933fb041b59SDavid Laight } 1934bfdc5970SChristoph Hellwig total_len += len; 1935fb041b59SDavid Laight } 1936bfdc5970SChristoph Hellwig 1937bfdc5970SChristoph Hellwig iov_iter_init(i, type, iov, nr_segs, total_len); 1938bfdc5970SChristoph Hellwig if (iov == *iovp) 1939bfdc5970SChristoph Hellwig *iovp = NULL; 1940bfdc5970SChristoph Hellwig else 1941bfdc5970SChristoph Hellwig *iovp = iov; 1942bfdc5970SChristoph Hellwig return total_len; 1943fb041b59SDavid Laight } 1944fb041b59SDavid Laight 1945ffecee4fSVegard Nossum /** 1946ffecee4fSVegard Nossum * import_iovec() - Copy an array of &struct iovec from userspace 1947ffecee4fSVegard Nossum * into the kernel, check that it is valid, and initialize a new 1948ffecee4fSVegard Nossum * &struct iov_iter iterator to access it. 1949ffecee4fSVegard Nossum * 1950ffecee4fSVegard Nossum * @type: One of %READ or %WRITE. 1951bfdc5970SChristoph Hellwig * @uvec: Pointer to the userspace array. 1952ffecee4fSVegard Nossum * @nr_segs: Number of elements in userspace array. 1953ffecee4fSVegard Nossum * @fast_segs: Number of elements in @iov. 1954bfdc5970SChristoph Hellwig * @iovp: (input and output parameter) Pointer to pointer to (usually small 1955ffecee4fSVegard Nossum * on-stack) kernel array. 1956ffecee4fSVegard Nossum * @i: Pointer to iterator that will be initialized on success. 1957ffecee4fSVegard Nossum * 1958ffecee4fSVegard Nossum * If the array pointed to by *@iov is large enough to hold all @nr_segs, 1959ffecee4fSVegard Nossum * then this function places %NULL in *@iov on return. Otherwise, a new 1960ffecee4fSVegard Nossum * array will be allocated and the result placed in *@iov. This means that 1961ffecee4fSVegard Nossum * the caller may call kfree() on *@iov regardless of whether the small 1962ffecee4fSVegard Nossum * on-stack array was used or not (and regardless of whether this function 1963ffecee4fSVegard Nossum * returns an error or not). 1964ffecee4fSVegard Nossum * 196587e5e6daSJens Axboe * Return: Negative error code on error, bytes imported on success 1966ffecee4fSVegard Nossum */ 1967bfdc5970SChristoph Hellwig ssize_t import_iovec(int type, const struct iovec __user *uvec, 1968bc917be8SAl Viro unsigned nr_segs, unsigned fast_segs, 1969bfdc5970SChristoph Hellwig struct iovec **iovp, struct iov_iter *i) 1970bc917be8SAl Viro { 197189cd35c5SChristoph Hellwig return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, 197289cd35c5SChristoph Hellwig in_compat_syscall()); 1973bc917be8SAl Viro } 1974bc917be8SAl Viro EXPORT_SYMBOL(import_iovec); 1975bc917be8SAl Viro 1976bc917be8SAl Viro int import_single_range(int rw, void __user *buf, size_t len, 1977bc917be8SAl Viro struct iovec *iov, struct iov_iter *i) 1978bc917be8SAl Viro { 1979bc917be8SAl Viro if (len > MAX_RW_COUNT) 1980bc917be8SAl Viro len = MAX_RW_COUNT; 198196d4f267SLinus Torvalds if (unlikely(!access_ok(buf, len))) 1982bc917be8SAl Viro return -EFAULT; 1983bc917be8SAl Viro 1984bc917be8SAl Viro iov->iov_base = buf; 1985bc917be8SAl Viro iov->iov_len = len; 1986bc917be8SAl Viro iov_iter_init(i, rw, iov, 1, len); 1987bc917be8SAl Viro return 0; 1988bc917be8SAl Viro } 1989e1267585SAl Viro EXPORT_SYMBOL(import_single_range); 1990