linux-kernel - [PATCH] fs : initialize return for iter_file_splice

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Date:   Wed, 17 Jun 2020 06:07:11 -0700
From:   trix@...hat.com
To:     viro@...iv.linux.org.uk
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Tom Rix <trix@...hat.com>
Subject: [PATCH] fs : initialize return for iter_file_splice_write

From: Tom Rix <trix@...hat.com>

clang static analysis flags this garbarge return
fs/splice.c:786:2: warning: Undefined or garbage value returned to caller [core.uninitialized.UndefReturn]
        return ret;
        ^~~~~~~~~~

ssize_t
iter_file_splice_write( ... size_t len, ..
	sd.total_len = len

	ssize_t ret;

	while (sd.total_len) {
	      ...
	      ret =
	}

If the input len is 0, the while loop will never run and ret will
not be set.

So handle similar to splice_direct_to_actor and initialize ret to 0

Signed-off-by: Tom Rix <trix@...hat.com>
---
 fs/splice.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/splice.c b/fs/splice.c
index d7c8a7c4db07..f65e072bcc2c 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -691,7 +691,7 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 	int nbufs = pipe->max_usage;
 	struct bio_vec *array = kcalloc(nbufs, sizeof(struct bio_vec),
 					GFP_KERNEL);
-	ssize_t ret;
+	ssize_t ret = 0;
 
 	if (unlikely(!array))
 		return -ENOMEM;
-- 
2.18.1