diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/iov_iter.c | 826 |
1 files changed, 371 insertions, 455 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 0e0be334dbee..4b7fce72e3e5 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -16,6 +16,16 @@ #define PIPE_PARANOIA /* for now */ +/* covers ubuf and kbuf alike */ +#define iterate_buf(i, n, base, len, off, __p, STEP) { \ + size_t __maybe_unused off = 0; \ + len = n; \ + base = __p + i->iov_offset; \ + len -= (STEP); \ + i->iov_offset += len; \ + n = len; \ +} + /* covers iovec and kvec alike */ #define iterate_iovec(i, n, base, len, off, __p, STEP) { \ size_t off = 0; \ @@ -110,7 +120,12 @@ __out: \ if (unlikely(i->count < n)) \ n = i->count; \ if (likely(n)) { \ - if (likely(iter_is_iovec(i))) { \ + if (likely(iter_is_ubuf(i))) { \ + void __user *base; \ + size_t len; \ + iterate_buf(i, n, base, len, off, \ + i->ubuf, (I)) \ + } else if (likely(iter_is_iovec(i))) { \ const struct iovec *iov = i->iov; \ void __user *base; \ size_t len; \ @@ -168,26 +183,31 @@ static int copyin(void *to, const void __user *from, size_t n) return n; } +static inline struct pipe_buffer *pipe_buf(const struct pipe_inode_info *pipe, + unsigned int slot) +{ + return &pipe->bufs[slot & (pipe->ring_size - 1)]; +} + #ifdef PIPE_PARANOIA static bool sanity(const struct iov_iter *i) { struct pipe_inode_info *pipe = i->pipe; unsigned int p_head = pipe->head; unsigned int p_tail = pipe->tail; - unsigned int p_mask = pipe->ring_size - 1; unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); unsigned int i_head = i->head; unsigned int idx; - if (i->iov_offset) { + if (i->last_offset) { struct pipe_buffer *p; if (unlikely(p_occupancy == 0)) goto Bad; // pipe must be non-empty if (unlikely(i_head != p_head - 1)) goto Bad; // must be at the last buffer... - p = &pipe->bufs[i_head & p_mask]; - if (unlikely(p->offset + p->len != i->iov_offset)) + p = pipe_buf(pipe, i_head); + if (unlikely(p->offset + p->len != abs(i->last_offset))) goto Bad; // ... at the end of segment } else { if (i_head != p_head) @@ -195,7 +215,7 @@ static bool sanity(const struct iov_iter *i) } return true; Bad: - printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); + printk(KERN_ERR "idx = %d, offset = %d\n", i_head, i->last_offset); printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", p_head, p_tail, pipe->ring_size); for (idx = 0; idx < pipe->ring_size; idx++) @@ -211,15 +231,79 @@ Bad: #define sanity(i) true #endif +static struct page *push_anon(struct pipe_inode_info *pipe, unsigned size) +{ + struct page *page = alloc_page(GFP_USER); + if (page) { + struct pipe_buffer *buf = pipe_buf(pipe, pipe->head++); + *buf = (struct pipe_buffer) { + .ops = &default_pipe_buf_ops, + .page = page, + .offset = 0, + .len = size + }; + } + return page; +} + +static void push_page(struct pipe_inode_info *pipe, struct page *page, + unsigned int offset, unsigned int size) +{ + struct pipe_buffer *buf = pipe_buf(pipe, pipe->head++); + *buf = (struct pipe_buffer) { + .ops = &page_cache_pipe_buf_ops, + .page = page, + .offset = offset, + .len = size + }; + get_page(page); +} + +static inline int last_offset(const struct pipe_buffer *buf) +{ + if (buf->ops == &default_pipe_buf_ops) + return buf->len; // buf->offset is 0 for those + else + return -(buf->offset + buf->len); +} + +static struct page *append_pipe(struct iov_iter *i, size_t size, + unsigned int *off) +{ + struct pipe_inode_info *pipe = i->pipe; + int offset = i->last_offset; + struct pipe_buffer *buf; + struct page *page; + + if (offset > 0 && offset < PAGE_SIZE) { + // some space in the last buffer; add to it + buf = pipe_buf(pipe, pipe->head - 1); + size = min_t(size_t, size, PAGE_SIZE - offset); + buf->len += size; + i->last_offset += size; + i->count -= size; + *off = offset; + return buf->page; + } + // OK, we need a new buffer + *off = 0; + size = min_t(size_t, size, PAGE_SIZE); + if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) + return NULL; + page = push_anon(pipe, size); + if (!page) + return NULL; + i->head = pipe->head - 1; + i->last_offset = size; + i->count -= size; + return page; +} + static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, struct iov_iter *i) { struct pipe_inode_info *pipe = i->pipe; - struct pipe_buffer *buf; - unsigned int p_tail = pipe->tail; - unsigned int p_mask = pipe->ring_size - 1; - unsigned int i_head = i->head; - size_t off; + unsigned int head = pipe->head; if (unlikely(bytes > i->count)) bytes = i->count; @@ -230,32 +314,21 @@ static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t by if (!sanity(i)) return 0; - off = i->iov_offset; - buf = &pipe->bufs[i_head & p_mask]; - if (off) { - if (offset == off && buf->page == page) { - /* merge with the last one */ + if (offset && i->last_offset == -offset) { // could we merge it? + struct pipe_buffer *buf = pipe_buf(pipe, head - 1); + if (buf->page == page) { buf->len += bytes; - i->iov_offset += bytes; - goto out; + i->last_offset -= bytes; + i->count -= bytes; + return bytes; } - i_head++; - buf = &pipe->bufs[i_head & p_mask]; } - if (pipe_full(i_head, p_tail, pipe->max_usage)) + if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) return 0; - buf->ops = &page_cache_pipe_buf_ops; - buf->flags = 0; - get_page(page); - buf->page = page; - buf->offset = offset; - buf->len = bytes; - - pipe->head = i_head + 1; - i->iov_offset = offset + bytes; - i->head = i_head; -out: + push_page(pipe, page, offset, bytes); + i->last_offset = -(offset + bytes); + i->head = head; i->count -= bytes; return bytes; } @@ -275,7 +348,11 @@ out: */ size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t size) { - if (iter_is_iovec(i)) { + if (iter_is_ubuf(i)) { + size_t n = min(size, iov_iter_count(i)); + n -= fault_in_readable(i->ubuf + i->iov_offset, n); + return size - n; + } else if (iter_is_iovec(i)) { size_t count = min(size, iov_iter_count(i)); const struct iovec *p; size_t skip; @@ -314,7 +391,11 @@ EXPORT_SYMBOL(fault_in_iov_iter_readable); */ size_t fault_in_iov_iter_writeable(const struct iov_iter *i, size_t size) { - if (iter_is_iovec(i)) { + if (iter_is_ubuf(i)) { + size_t n = min(size, iov_iter_count(i)); + n -= fault_in_safe_writeable(i->ubuf + i->iov_offset, n); + return size - n; + } else if (iter_is_iovec(i)) { size_t count = min(size, iov_iter_count(i)); const struct iovec *p; size_t skip; @@ -345,6 +426,7 @@ void iov_iter_init(struct iov_iter *i, unsigned int direction, *i = (struct iov_iter) { .iter_type = ITER_IOVEC, .nofault = false, + .user_backed = true, .data_source = direction, .iov = iov, .nr_segs = nr_segs, @@ -354,101 +436,43 @@ void iov_iter_init(struct iov_iter *i, unsigned int direction, } EXPORT_SYMBOL(iov_iter_init); -static inline bool allocated(struct pipe_buffer *buf) -{ - return buf->ops == &default_pipe_buf_ops; -} - -static inline void data_start(const struct iov_iter *i, - unsigned int *iter_headp, size_t *offp) -{ - unsigned int p_mask = i->pipe->ring_size - 1; - unsigned int iter_head = i->head; - size_t off = i->iov_offset; - - if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || - off == PAGE_SIZE)) { - iter_head++; - off = 0; - } - *iter_headp = iter_head; - *offp = off; -} - -static size_t push_pipe(struct iov_iter *i, size_t size, - int *iter_headp, size_t *offp) +// returns the offset in partial buffer (if any) +static inline unsigned int pipe_npages(const struct iov_iter *i, int *npages) { struct pipe_inode_info *pipe = i->pipe; - unsigned int p_tail = pipe->tail; - unsigned int p_mask = pipe->ring_size - 1; - unsigned int iter_head; - size_t off; - ssize_t left; + int used = pipe->head - pipe->tail; + int off = i->last_offset; - if (unlikely(size > i->count)) - size = i->count; - if (unlikely(!size)) - return 0; + *npages = max((int)pipe->max_usage - used, 0); - left = size; - data_start(i, &iter_head, &off); - *iter_headp = iter_head; - *offp = off; - if (off) { - left -= PAGE_SIZE - off; - if (left <= 0) { - pipe->bufs[iter_head & p_mask].len += size; - return size; - } - pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; - iter_head++; + if (off > 0 && off < PAGE_SIZE) { // anon and not full + (*npages)++; + return off; } - while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { - struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; - struct page *page = alloc_page(GFP_USER); - if (!page) - break; - - buf->ops = &default_pipe_buf_ops; - buf->flags = 0; - buf->page = page; - buf->offset = 0; - buf->len = min_t(ssize_t, left, PAGE_SIZE); - left -= buf->len; - iter_head++; - pipe->head = iter_head; - - if (left == 0) - return size; - } - return size - left; + return 0; } static size_t copy_pipe_to_iter(const void *addr, size_t bytes, struct iov_iter *i) { - struct pipe_inode_info *pipe = i->pipe; - unsigned int p_mask = pipe->ring_size - 1; - unsigned int i_head; - size_t n, off; + unsigned int off, chunk; - if (!sanity(i)) + if (unlikely(bytes > i->count)) + bytes = i->count; + if (unlikely(!bytes)) return 0; - bytes = n = push_pipe(i, bytes, &i_head, &off); - if (unlikely(!n)) + if (!sanity(i)) return 0; - do { - size_t chunk = min_t(size_t, n, PAGE_SIZE - off); - memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); - i->head = i_head; - i->iov_offset = off + chunk; - n -= chunk; + + for (size_t n = bytes; n; n -= chunk) { + struct page *page = append_pipe(i, n, &off); + chunk = min_t(size_t, n, PAGE_SIZE - off); + if (!page) + return bytes - n; + memcpy_to_page(page, off, addr, chunk); addr += chunk; - off = 0; - i_head++; - } while (n); - i->count -= bytes; + } return bytes; } @@ -462,31 +486,32 @@ static __wsum csum_and_memcpy(void *to, const void *from, size_t len, static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, struct iov_iter *i, __wsum *sump) { - struct pipe_inode_info *pipe = i->pipe; - unsigned int p_mask = pipe->ring_size - 1; __wsum sum = *sump; size_t off = 0; - unsigned int i_head; - size_t r; + unsigned int chunk, r; + + if (unlikely(bytes > i->count)) + bytes = i->count; + if (unlikely(!bytes)) + return 0; if (!sanity(i)) return 0; - bytes = push_pipe(i, bytes, &i_head, &r); while (bytes) { - size_t chunk = min_t(size_t, bytes, PAGE_SIZE - r); - char *p = kmap_local_page(pipe->bufs[i_head & p_mask].page); + struct page *page = append_pipe(i, bytes, &r); + char *p; + + if (!page) + break; + chunk = min_t(size_t, bytes, PAGE_SIZE - r); + p = kmap_local_page(page); sum = csum_and_memcpy(p + r, addr + off, chunk, sum, off); kunmap_local(p); - i->head = i_head; - i->iov_offset = r + chunk; - bytes -= chunk; off += chunk; - r = 0; - i_head++; + bytes -= chunk; } *sump = sum; - i->count -= off; return off; } @@ -494,7 +519,7 @@ size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) { if (unlikely(iov_iter_is_pipe(i))) return copy_pipe_to_iter(addr, bytes, i); - if (iter_is_iovec(i)) + if (user_backed_iter(i)) might_fault(); iterate_and_advance(i, bytes, base, len, off, copyout(base, addr + off, len), @@ -518,39 +543,36 @@ static int copyout_mc(void __user *to, const void *from, size_t n) static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, struct iov_iter *i) { - struct pipe_inode_info *pipe = i->pipe; - unsigned int p_mask = pipe->ring_size - 1; - unsigned int i_head; - unsigned int valid = pipe->head; - size_t n, off, xfer = 0; + size_t xfer = 0; + unsigned int off, chunk; + + if (unlikely(bytes > i->count)) + bytes = i->count; + if (unlikely(!bytes)) + return 0; if (!sanity(i)) return 0; - n = push_pipe(i, bytes, &i_head, &off); - while (n) { - size_t chunk = min_t(size_t, n, PAGE_SIZE - off); - char *p = kmap_local_page(pipe->bufs[i_head & p_mask].page); + while (bytes) { + struct page *page = append_pipe(i, bytes, &off); unsigned long rem; + char *p; + + if (!page) + break; + chunk = min_t(size_t, bytes, PAGE_SIZE - off); + p = kmap_local_page(page); rem = copy_mc_to_kernel(p + off, addr + xfer, chunk); chunk -= rem; kunmap_local(p); - if (chunk) { - i->head = i_head; - i->iov_offset = off + chunk; - xfer += chunk; - valid = i_head + 1; - } + xfer += chunk; + bytes -= chunk; if (rem) { - pipe->bufs[i_head & p_mask].len -= rem; - pipe_discard_from(pipe, valid); + iov_iter_revert(i, rem); break; } - n -= chunk; - off = 0; - i_head++; } - i->count -= xfer; return xfer; } @@ -583,7 +605,7 @@ size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) { if (unlikely(iov_iter_is_pipe(i))) return copy_mc_pipe_to_iter(addr, bytes, i); - if (iter_is_iovec(i)) + if (user_backed_iter(i)) might_fault(); __iterate_and_advance(i, bytes, base, len, off, copyout_mc(base, addr + off, len), @@ -601,7 +623,7 @@ size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) WARN_ON(1); return 0; } - if (iter_is_iovec(i)) + if (user_backed_iter(i)) might_fault(); iterate_and_advance(i, bytes, base, len, off, copyin(addr + off, base, len), @@ -684,30 +706,21 @@ static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) return false; } -static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes, - struct iov_iter *i) -{ - if (unlikely(iov_iter_is_pipe(i))) { - return copy_page_to_iter_pipe(page, offset, bytes, i); - } else { - void *kaddr = kmap_local_page(page); - size_t wanted = _copy_to_iter(kaddr + offset, bytes, i); - kunmap_local(kaddr); - return wanted; - } -} - size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, struct iov_iter *i) { size_t res = 0; if (unlikely(!page_copy_sane(page, offset, bytes))) return 0; + if (unlikely(iov_iter_is_pipe(i))) + return copy_page_to_iter_pipe(page, offset, bytes, i); page += offset / PAGE_SIZE; // first subpage offset %= PAGE_SIZE; while (1) { - size_t n = __copy_page_to_iter(page, offset, - min(bytes, (size_t)PAGE_SIZE - offset), i); + void *kaddr = kmap_local_page(page); + size_t n = min(bytes, (size_t)PAGE_SIZE - offset); + n = _copy_to_iter(kaddr + offset, n, i); + kunmap_local(kaddr); res += n; bytes -= n; if (!bytes || !n) @@ -725,42 +738,53 @@ EXPORT_SYMBOL(copy_page_to_iter); size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, struct iov_iter *i) { - if (page_copy_sane(page, offset, bytes)) { + size_t res = 0; + if (!page_copy_sane(page, offset, bytes)) + return 0; + page += offset / PAGE_SIZE; // first subpage + offset %= PAGE_SIZE; + while (1) { void *kaddr = kmap_local_page(page); - size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); + size_t n = min(bytes, (size_t)PAGE_SIZE - offset); + n = _copy_from_iter(kaddr + offset, n, i); kunmap_local(kaddr); - return wanted; + res += n; + bytes -= n; + if (!bytes || !n) + break; + offset += n; + if (offset == PAGE_SIZE) { + page++; + offset = 0; + } } - return 0; + return res; } EXPORT_SYMBOL(copy_page_from_iter); static size_t pipe_zero(size_t bytes, struct iov_iter *i) { - struct pipe_inode_info *pipe = i->pipe; - unsigned int p_mask = pipe->ring_size - 1; - unsigned int i_head; - size_t n, off; + unsigned int chunk, off; - if (!sanity(i)) + if (unlikely(bytes > i->count)) + bytes = i->count; + if (unlikely(!bytes)) return 0; - bytes = n = push_pipe(i, bytes, &i_head, &off); - if (unlikely(!n)) + if (!sanity(i)) return 0; - do { - size_t chunk = min_t(size_t, n, PAGE_SIZE - off); - char *p = kmap_local_page(pipe->bufs[i_head & p_mask].page); + for (size_t n = bytes; n; n -= chunk) { + struct page *page = append_pipe(i, n, &off); + char *p; + + if (!page) + return bytes - n; + chunk = min_t(size_t, n, PAGE_SIZE - off); + p = kmap_local_page(page); memset(p + off, 0, chunk); kunmap_local(p); - i->head = i_head; - i->iov_offset = off + chunk; - n -= chunk; - off = 0; - i_head++; - } while (n); - i->count -= bytes; + } return bytes; } @@ -799,56 +823,30 @@ size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t byt } EXPORT_SYMBOL(copy_page_from_iter_atomic); -static inline void pipe_truncate(struct iov_iter *i) -{ - struct pipe_inode_info *pipe = i->pipe; - unsigned int p_tail = pipe->tail; - unsigned int p_head = pipe->head; - unsigned int p_mask = pipe->ring_size - 1; - - if (!pipe_empty(p_head, p_tail)) { - struct pipe_buffer *buf; - unsigned int i_head = i->head; - size_t off = i->iov_offset; - - if (off) { - buf = &pipe->bufs[i_head & p_mask]; - buf->len = off - buf->offset; - i_head++; - } - while (p_head != i_head) { - p_head--; - pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); - } - - pipe->head = p_head; - } -} - static void pipe_advance(struct iov_iter *i, size_t size) { struct pipe_inode_info *pipe = i->pipe; - if (size) { - struct pipe_buffer *buf; - unsigned int p_mask = pipe->ring_size - 1; - unsigned int i_head = i->head; - size_t off = i->iov_offset, left = size; + int off = i->last_offset; + if (!off && !size) { + pipe_discard_from(pipe, i->start_head); // discard everything + return; + } + i->count -= size; + while (1) { + struct pipe_buffer *buf = pipe_buf(pipe, i->head); if (off) /* make it relative to the beginning of buffer */ - left += off - pipe->bufs[i_head & p_mask].offset; - while (1) { - buf = &pipe->bufs[i_head & p_mask]; - if (left <= buf->len) - break; - left -= buf->len; - i_head++; + size += abs(off) - buf->offset; + if (size <= buf->len) { + buf->len = size; + i->last_offset = last_offset(buf); + break; } - i->head = i_head; - i->iov_offset = buf->offset + left; + size -= buf->len; + i->head++; + off = 0; } - i->count -= size; - /* ... and discard everything past that point */ - pipe_truncate(i); + pipe_discard_from(pipe, i->head + 1); // discard everything past this one } static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) @@ -894,16 +892,16 @@ void iov_iter_advance(struct iov_iter *i, size_t size) { if (unlikely(i->count < size)) size = i->count; - if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { + if (likely(iter_is_ubuf(i)) || unlikely(iov_iter_is_xarray(i))) { + i->iov_offset += size; + i->count -= size; + } else if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) { /* iovec and kvec have identical layouts */ iov_iter_iovec_advance(i, size); } else if (iov_iter_is_bvec(i)) { iov_iter_bvec_advance(i, size); } else if (iov_iter_is_pipe(i)) { pipe_advance(i, size); - } else if (unlikely(iov_iter_is_xarray(i))) { - i->iov_offset += size; - i->count -= size; } else if (iov_iter_is_discard(i)) { i->count -= size; } @@ -919,28 +917,22 @@ void iov_iter_revert(struct iov_iter *i, size_t unroll) i->count += unroll; if (unlikely(iov_iter_is_pipe(i))) { struct pipe_inode_info *pipe = i->pipe; - unsigned int p_mask = pipe->ring_size - 1; - unsigned int i_head = i->head; - size_t off = i->iov_offset; - while (1) { - struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; - size_t n = off - b->offset; - if (unroll < n) { - off -= unroll; - break; - } - unroll -= n; - if (!unroll && i_head == i->start_head) { - off = 0; - break; + unsigned int head = pipe->head; + + while (head > i->start_head) { + struct pipe_buffer *b = pipe_buf(pipe, --head); + if (unroll < b->len) { + b->len -= unroll; + i->last_offset = last_offset(b); + i->head = head; + return; } - i_head--; - b = &pipe->bufs[i_head & p_mask]; - off = b->offset + b->len; + unroll -= b->len; + pipe_buf_release(pipe, b); + pipe->head--; } - i->iov_offset = off; - i->head = i_head; - pipe_truncate(i); + i->last_offset = 0; + i->head = head; return; } if (unlikely(iov_iter_is_discard(i))) @@ -950,7 +942,7 @@ void iov_iter_revert(struct iov_iter *i, size_t unroll) return; } unroll -= i->iov_offset; - if (iov_iter_is_xarray(i)) { + if (iov_iter_is_xarray(i) || iter_is_ubuf(i)) { BUG(); /* We should never go beyond the start of the specified * range since we might then be straying into pages that * aren't pinned. @@ -1042,7 +1034,7 @@ void iov_iter_pipe(struct iov_iter *i, unsigned int direction, .pipe = pipe, .head = pipe->head, .start_head = pipe->head, - .iov_offset = 0, + .last_offset = 0, .count = count }; } @@ -1158,6 +1150,14 @@ static bool iov_iter_aligned_bvec(const struct iov_iter *i, unsigned addr_mask, bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask, unsigned len_mask) { + if (likely(iter_is_ubuf(i))) { + if (i->count & len_mask) + return false; + if ((unsigned long)(i->ubuf + i->iov_offset) & addr_mask) + return false; + return true; + } + if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) return iov_iter_aligned_iovec(i, addr_mask, len_mask); @@ -1165,13 +1165,12 @@ bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask, return iov_iter_aligned_bvec(i, addr_mask, len_mask); if (iov_iter_is_pipe(i)) { - unsigned int p_mask = i->pipe->ring_size - 1; size_t size = i->count; if (size & len_mask) return false; - if (size && allocated(&i->pipe->bufs[i->head & p_mask])) { - if (i->iov_offset & addr_mask) + if (size && i->last_offset > 0) { + if (i->last_offset & addr_mask) return false; } @@ -1233,6 +1232,13 @@ static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) unsigned long iov_iter_alignment(const struct iov_iter *i) { + if (likely(iter_is_ubuf(i))) { + size_t size = i->count; + if (size) + return ((unsigned long)i->ubuf + i->iov_offset) | size; + return 0; + } + /* iovec and kvec have identical layouts */ if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) return iov_iter_alignment_iovec(i); @@ -1241,11 +1247,10 @@ unsigned long iov_iter_alignment(const struct iov_iter *i) return iov_iter_alignment_bvec(i); if (iov_iter_is_pipe(i)) { - unsigned int p_mask = i->pipe->ring_size - 1; size_t size = i->count; - if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) - return size | i->iov_offset; + if (size && i->last_offset > 0) + return size | i->last_offset; return size; } @@ -1263,6 +1268,9 @@ unsigned long iov_iter_gap_alignment(const struct iov_iter *i) size_t size = i->count; unsigned k; + if (iter_is_ubuf(i)) + return 0; + if (WARN_ON(!iter_is_iovec(i))) return ~0U; @@ -1281,45 +1289,50 @@ unsigned long iov_iter_gap_alignment(const struct iov_iter *i) } EXPORT_SYMBOL(iov_iter_gap_alignment); -static inline ssize_t __pipe_get_pages(struct iov_iter *i, - size_t maxsize, - struct page **pages, - int iter_head, - size_t *start) +static int want_pages_array(struct page ***res, size_t size, + size_t start, unsigned int maxpages) { - struct pipe_inode_info *pipe = i->pipe; - unsigned int p_mask = pipe->ring_size - 1; - ssize_t n = push_pipe(i, maxsize, &iter_head, start); - if (!n) - return -EFAULT; + unsigned int count = DIV_ROUND_UP(size + start, PAGE_SIZE); - maxsize = n; - n += *start; - while (n > 0) { - get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); - iter_head++; - n -= PAGE_SIZE; + if (count > maxpages) + count = maxpages; + WARN_ON(!count); // caller should've prevented that + if (!*res) { + *res = kvmalloc_array(count, sizeof(struct page *), GFP_KERNEL); + if (!*res) + return 0; } - - return maxsize; + return count; } static ssize_t pipe_get_pages(struct iov_iter *i, - struct page **pages, size_t maxsize, unsigned maxpages, + struct page ***pages, size_t maxsize, unsigned maxpages, size_t *start) { - unsigned int iter_head, npages; - size_t capacity; + unsigned int npages, count, off, chunk; + struct page **p; + size_t left; if (!sanity(i)) return -EFAULT; - data_start(i, &iter_head, start); - /* Amount of free space: some of this one + all after this one */ - npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); - capacity = min(npages, maxpages) * PAGE_SIZE - *start; - - return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); + *start = off = pipe_npages(i, &npages); + if (!npages) + return -EFAULT; + count = want_pages_array(pages, maxsize, off, min(npages, maxpages)); + if (!count) + return -ENOMEM; + p = *pages; + for (npages = 0, left = maxsize ; npages < count; npages++, left -= chunk) { + struct page *page = append_pipe(i, left, &off); + if (!page) + break; + chunk = min_t(size_t, left, PAGE_SIZE - off); + get_page(*p++ = page); + } + if (!npages) + return -EFAULT; + return maxsize - left; } static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, @@ -1350,47 +1363,40 @@ static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa } static ssize_t iter_xarray_get_pages(struct iov_iter *i, - struct page **pages, size_t maxsize, + struct page ***pages, size_t maxsize, unsigned maxpages, size_t *_start_offset) { - unsigned nr, offset; - pgoff_t index, count; - size_t size = maxsize; + unsigned nr, offset, count; + pgoff_t index; loff_t pos; - if (!size || !maxpages) - return 0; - pos = i->xarray_start + i->iov_offset; index = pos >> PAGE_SHIFT; offset = pos & ~PAGE_MASK; *_start_offset = offset; - count = 1; - if (size > PAGE_SIZE - offset) { - size -= PAGE_SIZE - offset; - count += size >> PAGE_SHIFT; - size &= ~PAGE_MASK; - if (size) - count++; - } - - if (count > maxpages) - count = maxpages; - - nr = iter_xarray_populate_pages(pages, i->xarray, index, count); + count = want_pages_array(pages, maxsize, offset, maxpages); + if (!count) + return -ENOMEM; + nr = iter_xarray_populate_pages(*pages, i->xarray, index, count); if (nr == 0) return 0; - return min_t(size_t, nr * PAGE_SIZE - offset, maxsize); + maxsize = min_t(size_t, nr * PAGE_SIZE - offset, maxsize); + i->iov_offset += maxsize; + i->count -= maxsize; + return maxsize; } -/* must be done on non-empty ITER_IOVEC one */ +/* must be done on non-empty ITER_UBUF or ITER_IOVEC one */ static unsigned long first_iovec_segment(const struct iov_iter *i, size_t *size) { size_t skip; long k; + if (iter_is_ubuf(i)) + return (unsigned long)i->ubuf + i->iov_offset; + for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) { size_t len = i->iov[k].iov_len - skip; @@ -1419,11 +1425,11 @@ static struct page *first_bvec_segment(const struct iov_iter *i, return page; } -ssize_t iov_iter_get_pages(struct iov_iter *i, - struct page **pages, size_t maxsize, unsigned maxpages, - size_t *start) +static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, + struct page ***pages, size_t maxsize, + unsigned int maxpages, size_t *start) { - int n, res; + unsigned int n; if (maxsize > i->count) maxsize = i->count; @@ -1432,9 +1438,10 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, if (maxsize > MAX_RW_COUNT) maxsize = MAX_RW_COUNT; - if (likely(iter_is_iovec(i))) { + if (likely(user_backed_iter(i))) { unsigned int gup_flags = 0; unsigned long addr; + int res; if (iov_iter_rw(i) != WRITE) gup_flags |= FOLL_WRITE; @@ -1444,24 +1451,36 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, addr = first_iovec_segment(i, &maxsize); *start = addr % PAGE_SIZE; addr &= PAGE_MASK; - n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); - if (n > maxpages) - n = maxpages; - res = get_user_pages_fast(addr, n, gup_flags, pages); + n = want_pages_array(pages, maxsize, *start, maxpages); + if (!n) + return -ENOMEM; + res = get_user_pages_fast(addr, n, gup_flags, *pages); if (unlikely(res <= 0)) return res; - return min_t(size_t, maxsize, res * PAGE_SIZE - *start); + maxsize = min_t(size_t, maxsize, res * PAGE_SIZE - *start); + iov_iter_advance(i, maxsize); + return maxsize; } if (iov_iter_is_bvec(i)) { + struct page **p; struct page *page; page = first_bvec_segment(i, &maxsize, start); - n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); - if (n > maxpages) - n = maxpages; + n = want_pages_array(pages, maxsize, *start, maxpages); + if (!n) + return -ENOMEM; + p = *pages; for (int k = 0; k < n; k++) - get_page(*pages++ = page++); - return min_t(size_t, maxsize, n * PAGE_SIZE - *start); + get_page(p[k] = page + k); + maxsize = min_t(size_t, maxsize, n * PAGE_SIZE - *start); + i->count -= maxsize; + i->iov_offset += maxsize; + if (i->iov_offset == i->bvec->bv_len) { + i->iov_offset = 0; + i->bvec++; + i->nr_segs--; + } + return maxsize; } if (iov_iter_is_pipe(i)) return pipe_get_pages(i, pages, maxsize, maxpages, start); @@ -1469,140 +1488,35 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, return iter_xarray_get_pages(i, pages, maxsize, maxpages, start); return -EFAULT; } -EXPORT_SYMBOL(iov_iter_get_pages); -static struct page **get_pages_array(size_t n) -{ - return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); -} - -static ssize_t pipe_get_pages_alloc(struct iov_iter *i, - struct page ***pages, size_t maxsize, +ssize_t iov_iter_get_pages2(struct iov_iter *i, + struct page **pages, size_t maxsize, unsigned maxpages, size_t *start) { - struct page **p; - unsigned int iter_head, npages; - ssize_t n; - - if (!sanity(i)) - return -EFAULT; - - data_start(i, &iter_head, start); - /* Amount of free space: some of this one + all after this one */ - npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); - n = npages * PAGE_SIZE - *start; - if (maxsize > n) - maxsize = n; - else - npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); - p = get_pages_array(npages); - if (!p) - return -ENOMEM; - n = __pipe_get_pages(i, maxsize, p, iter_head, start); - if (n > 0) - *pages = p; - else - kvfree(p); - return n; -} - -static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i, - struct page ***pages, size_t maxsize, - size_t *_start_offset) -{ - struct page **p; - unsigned nr, offset; - pgoff_t index, count; - size_t size = maxsize; - loff_t pos; - - if (!size) + if (!maxpages) return 0; + BUG_ON(!pages); - pos = i->xarray_start + i->iov_offset; - index = pos >> PAGE_SHIFT; - offset = pos & ~PAGE_MASK; - *_start_offset = offset; - - count = 1; - if (size > PAGE_SIZE - offset) { - size -= PAGE_SIZE - offset; - count += size >> PAGE_SHIFT; - size &= ~PAGE_MASK; - if (size) - count++; - } - - p = get_pages_array(count); - if (!p) - return -ENOMEM; - *pages = p; - - nr = iter_xarray_populate_pages(p, i->xarray, index, count); - if (nr == 0) - return 0; - - return min_t(size_t, nr * PAGE_SIZE - offset, maxsize); + return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start); } +EXPORT_SYMBOL(iov_iter_get_pages2); -ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, +ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages, size_t maxsize, size_t *start) { - struct page **p; - int n, res; + ssize_t len; - if (maxsize > i->count) - maxsize = i->count; - if (!maxsize) - return 0; - if (maxsize > MAX_RW_COUNT) - maxsize = MAX_RW_COUNT; - - if (likely(iter_is_iovec(i))) { - unsigned int gup_flags = 0; - unsigned long addr; - - if (iov_iter_rw(i) != WRITE) - gup_flags |= FOLL_WRITE; - if (i->nofault) - gup_flags |= FOLL_NOFAULT; - - addr = first_iovec_segment(i, &maxsize); - *start = addr % PAGE_SIZE; - addr &= PAGE_MASK; - n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); - p = get_pages_array(n); - if (!p) - return -ENOMEM; - res = get_user_pages_fast(addr, n, gup_flags, p); - if (unlikely(res <= 0)) { - kvfree(p); - *pages = NULL; - return res; - } - *pages = p; - return min_t(size_t, maxsize, res * PAGE_SIZE - *start); - } - if (iov_iter_is_bvec(i)) { - struct page *page; + *pages = NULL; - page = first_bvec_segment(i, &maxsize, start); - n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); - *pages = p = get_pages_array(n); - if (!p) - return -ENOMEM; - for (int k = 0; k < n; k++) - get_page(*p++ = page++); - return min_t(size_t, maxsize, n * PAGE_SIZE - *start); + len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start); + if (len <= 0) { + kvfree(*pages); + *pages = NULL; } - if (iov_iter_is_pipe(i)) - return pipe_get_pages_alloc(i, pages, maxsize, start); - if (iov_iter_is_xarray(i)) - return iter_xarray_get_pages_alloc(i, pages, maxsize, start); - return -EFAULT; + return len; } -EXPORT_SYMBOL(iov_iter_get_pages_alloc); +EXPORT_SYMBOL(iov_iter_get_pages_alloc2); size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i) @@ -1715,22 +1629,23 @@ int iov_iter_npages(const struct iov_iter *i, int maxpages) { if (unlikely(!i->count)) return 0; + if (likely(iter_is_ubuf(i))) { + unsigned offs = offset_in_page(i->ubuf + i->iov_offset); + int npages = DIV_ROUND_UP(offs + i->count, PAGE_SIZE); + return min(npages, maxpages); + } /* iovec and kvec have identical layouts */ if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) return iov_npages(i, maxpages); if (iov_iter_is_bvec(i)) return bvec_npages(i, maxpages); if (iov_iter_is_pipe(i)) { - unsigned int iter_head; int npages; - size_t off; if (!sanity(i)) return 0; - data_start(i, &iter_head, &off); - /* some of this one + all after this one */ - npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); + pipe_npages(i, &npages); return min(npages, maxpages); } if (iov_iter_is_xarray(i)) { @@ -1749,17 +1664,16 @@ const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) WARN_ON(1); return NULL; } - if (unlikely(iov_iter_is_discard(new) || iov_iter_is_xarray(new))) - return NULL; if (iov_iter_is_bvec(new)) return new->bvec = kmemdup(new->bvec, new->nr_segs * sizeof(struct bio_vec), flags); - else + else if (iov_iter_is_kvec(new) || iter_is_iovec(new)) /* iovec and kvec have identical layout */ return new->iov = kmemdup(new->iov, new->nr_segs * sizeof(struct iovec), flags); + return NULL; } EXPORT_SYMBOL(dup_iter); @@ -1953,10 +1867,12 @@ EXPORT_SYMBOL(import_single_range); void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state) { if (WARN_ON_ONCE(!iov_iter_is_bvec(i) && !iter_is_iovec(i)) && - !iov_iter_is_kvec(i)) + !iov_iter_is_kvec(i) && !iter_is_ubuf(i)) return; i->iov_offset = state->iov_offset; i->count = state->count; + if (iter_is_ubuf(i)) + return; /* * For the *vec iters, nr_segs + iov is constant - if we increment * the vec, then we also decrement the nr_segs count. Hence we don't |