Fix shmem_splice_read() to splice only part of the partial page at the end
of a splice and not all of it.
This can be seen by splicing from a tmpfs file that's not a multiple of
PAGE_SIZE in size. Without this fix, it splices extra data to round up to
PAGE_SIZE.
Fixes: bd194b187115 ("shmem: Implement splice-read")
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Hugh Dickins <hughd@xxxxxxxxxx>
cc: Christoph Hellwig <hch@xxxxxx>
cc: Jens Axboe <axboe@xxxxxxxxx>
cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
cc: John Hubbard <jhubbard@xxxxxxxxxx>
cc: David Hildenbrand <david@xxxxxxxxxx>
cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
cc: Chuck Lever <chuck.lever@xxxxxxxxxx>
cc: linux-block@xxxxxxxxxxxxxxx
cc: linux-fsdevel@xxxxxxxxxxxxxxx
cc: linux-mm@xxxxxxxxx
---
mm/shmem.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index 2f2e0e618072..0164cccdcd71 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2841,7 +2841,7 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
folio_put(folio);
folio = NULL;
} else {
- n = splice_zeropage_into_pipe(pipe, *ppos, len);
+ n = splice_zeropage_into_pipe(pipe, *ppos, part);
}
if (!n)
