diff options
| -rw-r--r-- | lib/iov_iter.c | 77 |
1 files changed, 32 insertions, 45 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c index a9446efac70d..f003a20d8683 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1284,9 +1284,20 @@ unsigned long iov_iter_gap_alignment(const struct iov_iter *i) } EXPORT_SYMBOL(iov_iter_gap_alignment); -static struct page **get_pages_array(size_t n) +static int want_pages_array(struct page ***res, size_t size, + size_t start, unsigned int maxpages) { - return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); + unsigned int count = DIV_ROUND_UP(size + start, 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 count; } static ssize_t pipe_get_pages(struct iov_iter *i, @@ -1294,27 +1305,20 @@ static ssize_t pipe_get_pages(struct iov_iter *i, size_t *start) { struct pipe_inode_info *pipe = i->pipe; - unsigned int npages, off; + unsigned int npages, off, count; struct page **p; ssize_t left; - int count; if (!sanity(i)) return -EFAULT; *start = off = pipe_npages(i, &npages); - count = DIV_ROUND_UP(maxsize + off, PAGE_SIZE); - if (count > npages) - count = npages; - if (count > maxpages) - count = maxpages; + if (!npages) + return -EFAULT; + count = want_pages_array(pages, maxsize, off, min(npages, maxpages)); + if (!count) + return -ENOMEM; p = *pages; - if (!p) { - *pages = p = get_pages_array(count); - if (!p) - return -ENOMEM; - } - left = maxsize; npages = 0; if (off) { @@ -1377,9 +1381,8 @@ static ssize_t iter_xarray_get_pages(struct iov_iter *i, 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; pos = i->xarray_start + i->iov_offset; @@ -1387,16 +1390,9 @@ static ssize_t iter_xarray_get_pages(struct iov_iter *i, offset = pos & ~PAGE_MASK; *_start_offset = offset; - count = DIV_ROUND_UP(size + offset, PAGE_SIZE); - if (count > maxpages) - count = maxpages; - - if (!*pages) { - *pages = get_pages_array(count); - if (!*pages) - return -ENOMEM; - } - + 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; @@ -1445,7 +1441,7 @@ 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; @@ -1457,6 +1453,7 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *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; @@ -1466,14 +1463,9 @@ static ssize_t __iov_iter_get_pages_alloc(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; - if (!*pages) { - *pages = get_pages_array(n); - if (!*pages) - return -ENOMEM; - } + 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; @@ -1484,15 +1476,10 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, 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; - if (!p) { - *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); |