diff options
Diffstat (limited to 'lib/iov_iter.c')
| -rw-r--r-- | lib/iov_iter.c | 44 |
1 files changed, 19 insertions, 25 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 8834f3f61220..12dda1013bea 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -436,18 +436,20 @@ void iov_iter_init(struct iov_iter *i, unsigned int direction, } EXPORT_SYMBOL(iov_iter_init); -static inline void data_start(const struct iov_iter *i, - unsigned 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; + int used = pipe->head - pipe->tail; int off = i->last_offset; + *npages = max((int)pipe->max_usage - used, 0); + if (off > 0 && off < PAGE_SIZE) { // anon and not full - *iter_headp = i->pipe->head - 1; - *offp = off; - } else { - *iter_headp = i->pipe->head; - *offp = 0; + (*npages)++; + return off; } + return 0; } static size_t copy_pipe_to_iter(const void *addr, size_t bytes, @@ -1318,18 +1320,16 @@ static ssize_t pipe_get_pages(struct iov_iter *i, struct page **pages, size_t maxsize, unsigned maxpages, size_t *start) { - unsigned int iter_head, npages; + unsigned int npages, off; size_t capacity; 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; + *start = off = pipe_npages(i, &npages); + capacity = min(npages, maxpages) * PAGE_SIZE - off; - return __pipe_get_pages(i, min(maxsize, capacity), pages, *start); + return __pipe_get_pages(i, min(maxsize, capacity), pages, off); } static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, @@ -1494,24 +1494,22 @@ static ssize_t pipe_get_pages_alloc(struct iov_iter *i, size_t *start) { struct page **p; - unsigned int iter_head, npages; + unsigned int npages, off; 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; + *start = off = pipe_npages(i, &npages); + n = npages * PAGE_SIZE - off; if (maxsize > n) maxsize = n; else - npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); + npages = DIV_ROUND_UP(maxsize + off, PAGE_SIZE); p = get_pages_array(npages); if (!p) return -ENOMEM; - n = __pipe_get_pages(i, maxsize, p, *start); + n = __pipe_get_pages(i, maxsize, p, off); if (n > 0) *pages = p; else @@ -1739,16 +1737,12 @@ int iov_iter_npages(const struct iov_iter *i, int 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)) { |