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authorAl Viro <viro@zeniv.linux.org.uk>2022-06-17 19:35:35 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2022-08-09 04:37:20 +0200
commitacbdeb8320b0a470bef1b6c0105d8c2bbc4c4ba0 (patch)
tree71d93eebaecb1fa4e5fb453b821dec3d1f83f90c /lib
parentiov_iter_get_pages(): sanity-check arguments (diff)
downloadlinux-acbdeb8320b0a470bef1b6c0105d8c2bbc4c4ba0.tar.xz
linux-acbdeb8320b0a470bef1b6c0105d8c2bbc4c4ba0.zip
unify pipe_get_pages() and pipe_get_pages_alloc()
The differences between those two are * pipe_get_pages() gets a non-NULL struct page ** value pointing to preallocated array + array size. * pipe_get_pages_alloc() gets an address of struct page ** variable that contains NULL, allocates the array and (on success) stores its address in that variable. Not hard to combine - always pass struct page ***, have the previous pipe_get_pages_alloc() caller pass ~0U as cap for array size. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'lib')
-rw-r--r--lib/iov_iter.c49
1 files changed, 17 insertions, 32 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 7d3158d1f8ea..916c628f80a0 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1284,6 +1284,11 @@ 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)
+{
+ return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL);
+}
+
static inline ssize_t __pipe_get_pages(struct iov_iter *i,
size_t maxsize,
struct page **pages,
@@ -1317,10 +1322,11 @@ static inline ssize_t __pipe_get_pages(struct iov_iter *i,
}
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 npages, off;
+ struct page **p;
size_t capacity;
if (!sanity(i))
@@ -1328,8 +1334,15 @@ static ssize_t pipe_get_pages(struct iov_iter *i,
*start = off = pipe_npages(i, &npages);
capacity = min(npages, maxpages) * PAGE_SIZE - off;
+ maxsize = min(maxsize, capacity);
+ p = *pages;
+ if (!p) {
+ *pages = p = get_pages_array(DIV_ROUND_UP(maxsize + off, PAGE_SIZE));
+ if (!p)
+ return -ENOMEM;
+ }
- return __pipe_get_pages(i, min(maxsize, capacity), pages, off);
+ return __pipe_get_pages(i, maxsize, p, off);
}
static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa,
@@ -1475,41 +1488,13 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
return min_t(size_t, maxsize, n * PAGE_SIZE - *start);
}
if (iov_iter_is_pipe(i))
- return pipe_get_pages(i, pages, maxsize, maxpages, start);
+ return pipe_get_pages(i, &pages, maxsize, maxpages, start);
if (iov_iter_is_xarray(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,
- size_t *start)
-{
- struct page **p;
- unsigned int npages, off;
- ssize_t n;
-
- if (!sanity(i))
- return -EFAULT;
-
- *start = off = pipe_npages(i, &npages);
- n = npages * PAGE_SIZE - off;
- if (maxsize > n)
- maxsize = n;
- else
- npages = DIV_ROUND_UP(maxsize + off, PAGE_SIZE);
- *pages = p = get_pages_array(npages);
- if (!p)
- return -ENOMEM;
- return __pipe_get_pages(i, maxsize, p, off);
-}
-
static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i,
struct page ***pages, size_t maxsize,
size_t *_start_offset)
@@ -1593,7 +1578,7 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
return min_t(size_t, maxsize, n * PAGE_SIZE - *start);
}
if (iov_iter_is_pipe(i))
- return pipe_get_pages_alloc(i, pages, maxsize, start);
+ return pipe_get_pages(i, pages, maxsize, ~0U, start);
if (iov_iter_is_xarray(i))
return iter_xarray_get_pages_alloc(i, pages, maxsize, start);
return -EFAULT;