path: root/samples/kfifo/record-example.c
diff options
authorDan Carpenter <dan.carpenter@oracle.com>2021-04-29 22:54:15 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-04-30 11:20:35 -0700
commit926ee00ea24320052b46745ef4b00d91c05bd03d (patch)
treee307a013836cf34e6ed669eaab2b839bbe288d05 /samples/kfifo/record-example.c
parentocfs2/dlm: remove unused function (diff)
kfifo: fix ternary sign extension bugs
The intent with this code was to return negative error codes but instead it returns positives. The problem is how type promotion works with ternary operations. These functions return long, "ret" is an int and "copied" is a u32. The negative error code is first cast to u32 so it becomes a high positive and then cast to long where it's still a positive. We could fix this by declaring "ret" as a ssize_t but let's just get rid of the ternaries instead. Link: https://lkml.kernel.org/r/YIE+/cK1tBzSuQPU@mwanda Fixes: 5bf2b19320ec ("kfifo: add example files to the kernel sample directory") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Stefani Seibold <stefani@seibold.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'samples/kfifo/record-example.c')
1 files changed, 6 insertions, 2 deletions
diff --git a/samples/kfifo/record-example.c b/samples/kfifo/record-example.c
index c507998a2617..f64f3d62d6c2 100644
--- a/samples/kfifo/record-example.c
+++ b/samples/kfifo/record-example.c
@@ -129,8 +129,10 @@ static ssize_t fifo_write(struct file *file, const char __user *buf,
ret = kfifo_from_user(&test, buf, count, &copied);
+ if (ret)
+ return ret;
- return ret ? ret : copied;
+ return copied;
static ssize_t fifo_read(struct file *file, char __user *buf,
@@ -145,8 +147,10 @@ static ssize_t fifo_read(struct file *file, char __user *buf,
ret = kfifo_to_user(&test, buf, count, &copied);
+ if (ret)
+ return ret;
- return ret ? ret : copied;
+ return copied;
static const struct proc_ops fifo_proc_ops = {