[PATCH] connector: Delete an error message for a failed memory allocation in cn_queue_alloc_callback_entry()

From: Markus Elfring <redacted>
Date: Sun, 27 Aug 2017 21:18:37 +0200

Omit an extra message for a memory allocation failure in this function.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <redacted>
---
 drivers/connector/cn_queue.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/connector/cn_queue.c b/drivers/connector/cn_queue.c
index 1f8bf054d11c..e4f31d679f02 100644
--- a/drivers/connector/cn_queue.c
+++ b/drivers/connector/cn_queue.c

@@ -40,10 +40,8 @@ cn_queue_alloc_callback_entry(struct cn_queue_dev *dev, const char *name,
 	struct cn_callback_entry *cbq;
 
 	cbq = kzalloc(sizeof(*cbq), GFP_KERNEL);
-	if (!cbq) {
-		pr_err("Failed to create new callback queue.\n");
+	if (!cbq)
 		return NULL;
-	}
 
 	atomic_set(&cbq->refcnt, 1);
 

-- 
2.14.1

On 8/27/17 3:26 PM, SF Markus Elfring wrote:

From: Markus Elfring <redacted>
Date: Sun, 27 Aug 2017 21:18:37 +0200

Omit an extra message for a memory allocation failure in this function.

This issue was detected by using the Coccinelle software.

Did coccinelle trip on the message or the fact you weren't returning NULL?

Wny not:

	if (!cbq) {
		pr_err("Failed to create new callback queue.\n");
+		return NULL;
	}

  
  	atomic_set(&cbq->refcnt, 1);
  

On Sun, Aug 27, 2017 at 11:16:06PM +0000, Waskiewicz Jr, Peter wrote:

On 8/27/17 3:26 PM, SF Markus Elfring wrote:

quoted

From: Markus Elfring <redacted>
Date: Sun, 27 Aug 2017 21:18:37 +0200

Omit an extra message for a memory allocation failure in this function.

This issue was detected by using the Coccinelle software.

Did coccinelle trip on the message or the fact you weren't returning NULL?

You've misread the patch somehow.  The existing code has a NULL return
and it's preserved in Markus's patch.  This sort of patch is to fix a
checkpatch.pl warning.  The error message from this kzalloc() isn't going
to get printed because it's a small allocation and small allocations
always succeed in current kernels.  But probably the main reason
checkpatch complains is that kmalloc() already prints a stack trace and
a bunch of other information so the printk doesn't add anyting.
Removing it saves a little memory.

I'm mostly a fan of running checkpatch on new patches or staging and not
on old code...

regards,
dan carpenter

Did coccinelle trip on the message

I suggest to reconsider this implementation detail with the combination
of a function call like “kzalloc”.
A script for the semantic patch language can point various update candidates
out according to a source code search pattern which is similar to “OOM_MESSAGE”
in the script “checkpatch.pl”.

or the fact you weren't returning NULL?

How does this concern fit to my update suggestion?

Regards,
Markus

On 8/28/17 2:06 AM, Dan Carpenter wrote:

On Sun, Aug 27, 2017 at 11:16:06PM +0000, Waskiewicz Jr, Peter wrote:

quoted

On 8/27/17 3:26 PM, SF Markus Elfring wrote:

quoted

From: Markus Elfring <redacted>
Date: Sun, 27 Aug 2017 21:18:37 +0200

Omit an extra message for a memory allocation failure in this function.

This issue was detected by using the Coccinelle software.

Did coccinelle trip on the message or the fact you weren't returning NULL?

You've misread the patch somehow.  The existing code has a NULL return
and it's preserved in Markus's patch.  This sort of patch is to fix a
checkpatch.pl warning.  The error message from this kzalloc() isn't going
to get printed because it's a small allocation and small allocations
always succeed in current kernels.  But probably the main reason
checkpatch complains is that kmalloc() already prints a stack trace and
a bunch of other information so the printk doesn't add anyting.
Removing it saves a little memory.

I'm mostly a fan of running checkpatch on new patches or staging and not
on old code...

And this is what I get for reading the patch with a crappy 
mailer...thanks Doubtlook.

Sorry for the noise.

Hi everyone

27.08.2017, 22:25, "SF Markus Elfring" [off-list ref]:

From: Markus Elfring <redacted>
Date: Sun, 27 Aug 2017 21:18:37 +0200

Omit an extra message for a memory allocation failure in this function.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <redacted>

Looks good to me, thanks Markus.
There is virtually zero useful information in this print if we are in the situation, when kernel can not allocate
a few bytes to run connector queue.

Acked-by: Evgeniy Polyakov <redacted>

kernel-janitors@ please queue this patch up