[cocci] [PATCH] Input: usbtouchscreen - Return directly after a failed kmalloc() in nexio_init()

[cocci] [PATCH] Input: usbtouchscreen - Return directly after a failed kmalloc() in nexio_init()

[Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Tue, 26 Dec 2023 21:00:25 +0100

The kfree() function was called in one case by
the nexio_init() function during error handling
even if the passed variable contained a null pointer.
This issue was detected by using the Coccinelle software.

Thus return directly after a call of the function “kmalloc” failed
at the beginning.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 drivers/input/touchscreen/usbtouchscreen.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/input/touchscreen/usbtouchscreen.c b/drivers/input/touchscreen/usbtouchscreen.c
index 60354ebc7242..1873c7918a78 100644
--- a/drivers/input/touchscreen/usbtouchscreen.c
+++ b/drivers/input/touchscreen/usbtouchscreen.c
@@ -977,7 +977,7 @@ static int nexio_init(struct usbtouch_usb *usbtouch)

 	buf = kmalloc(NEXIO_BUFSIZE, GFP_NOIO);
 	if (!buf)
-		goto out_buf;
+		return ret;

 	/* two empty reads */
 	for (i = 0; i < 2; i++) {
--
2.43.0

Re: [cocci] Input: usbtouchscreen - Return directly after a failed kmalloc() in nexio_init()

[Markus Elfring]

>> The kfree() function was called in one case by
>> the nexio_init() function during error handling
>> even if the passed variable contained a null pointer.
>
> Which is perfectly valid thing to do, like free(), kfree() accepts NULL argument.

I find such a function call with this special parameter not so useful.


>> Thus return directly after a call of the function “kmalloc” failed
>> at the beginning.
>
> This is simply a matter of preference, the original author preferred
> that style, I see no objective reason to change it.

Would you ever like to avoid redundant data processing a bit more?

Regards,
Markus