[PATCH v21 06/30] splice: Check for zero count in vfs_splice_read()

David Howells
2023-05-20T00:01:19Z

Make vfs_splice_read() return immediately if the length is 0.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Christoph Hellwig <hch@lst.de>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
---
fs/splice.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/splice.c b/fs/splice.c
index d815a69f6589..fe3309ffeb26 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -891,6 +891,8 @@ long vfs_splice_read(struct file *in, loff_t *ppos,

if (unlikely(!(in->f_mode & FMODE_READ)))
return -EBADF;
+ if (!len)
+ return 0;

/* Don't try to read more the pipe has space for. */
p_space = pipe->max_usage - pipe_occupancy(pipe->head, pipe->tail);