From 5ffa828534036348fa90fb3079ccc0972d202c4a Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Fri, 23 Apr 2021 09:39:19 +0930
Subject: [PATCH] soc: aspeed: fix a ternary sign expansion bug
The intent here was to return negative error codes but it actually
returns positive values. The problem is that type promotion with
ternary operations is quite complicated.
"ret" is an int. "copied" is a u32. And the snoop_file_read() function
returns long. What happens is that "ret" is cast to u32 and becomes
positive then it's cast to long and it's still positive.
Fix this by removing the ternary so that "ret" is type promoted directly
to long.
Fixes: 3772e5da4454 ("drivers/misc: Aspeed LPC snoop output using misc chardev")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Patrick Venture <venture@google.com>
Link: https://lore.kernel.org/r/YIE90PSXsMTa2Y8n@mwanda
Link: https://lore.kernel.org/r/20210423000919.1249474-1-joel@jms.id.au'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/soc/aspeed/aspeed-lpc-snoop.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/soc/aspeed/aspeed-lpc-snoop.c b/drivers/soc/aspeed/aspeed-lpc-snoop.c
index 210455efb321e8..eceeaf8dfbebaf 100644
--- a/drivers/soc/aspeed/aspeed-lpc-snoop.c
+++ b/drivers/soc/aspeed/aspeed-lpc-snoop.c
@@ -94,8 +94,10 @@ static ssize_t snoop_file_read(struct file *file, char __user *buffer,
return -EINTR;
}
ret = kfifo_to_user(&chan->fifo, buffer, count, &copied);
+ if (ret)
+ return ret;
- return ret ? ret : copied;
+ return copied;
}
static __poll_t snoop_file_poll(struct file *file,
--
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