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soc: aspeed: fix a ternary sign expansion bug 

[ Upstream commit 5ffa828534 ]

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: 3772e5da44 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
pull/339/head^2
Dan Carpenter 2021-04-23 09:39:19 +09:30 committed by Greg Kroah-Hartman
parent bbe9de67ac
commit 8e81ff6d51
1 changed files with 3 additions and 1 deletions
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4
drivers/soc/aspeed/aspeed-lpc-snoop.c
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@ -95,8 +95,10 @@ 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,