[PATCH v3] ax25: use GFP_KERNEL in ax25_dev_device_up()

[PATCH v3] ax25: use GFP_KERNEL in ax25_dev_device_up()

[Peter Lafreniere]

ax25_dev_device_up() is only called during device setup, which is
done in user context. In addition, ax25_dev_device_up()
unconditionally calls ax25_register_dev_sysctl(), which already
allocates with GFP_KERNEL.

Since it is allowed to sleep in this function, here we change
ax25_dev_device_up() to use GFP_KERNEL to reduce unnecessary
out-of-memory errors.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Peter Lafreniere <pjlafren@mtu.edu>
---
v2 -> v3:
 - Rebased for clean application to net-next

v1 -> v2:
 - Renamed patch from "ax25: use GFP_KERNEL over GFP_ATOMIC where possible"
   (Is that okay?)
 - Removed invalid changes to ax25_rt_add()

 net/ax25/ax25_dev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
index ab88b6ac5401..2093f94f6852 100644
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -52,7 +52,7 @@ void ax25_dev_device_up(struct net_device *dev)
 {
 	ax25_dev *ax25_dev;
 
-	if ((ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_ATOMIC)) == NULL) {
+	if ((ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_KERNEL)) == NULL) {
 		printk(KERN_ERR "AX.25: ax25_dev_device_up - out of memory\n");
 		return;
 	}
@@ -60,7 +60,7 @@ void ax25_dev_device_up(struct net_device *dev)
 	refcount_set(&ax25_dev->refcount, 1);
 	dev->ax25_ptr     = ax25_dev;
 	ax25_dev->dev     = dev;
-	netdev_hold(dev, &ax25_dev->dev_tracker, GFP_ATOMIC);
+	netdev_hold(dev, &ax25_dev->dev_tracker, GFP_KERNEL);
 	ax25_dev->forward = NULL;
 	ax25_dev->device_up = true;
 

base-commit: fbb89d02e33a8c8f522d75882f5f19c65b722b46
-- 
2.36.1

Re: [PATCH v3] ax25: use GFP_KERNEL in ax25_dev_device_up()

[Paolo Abeni]

Hello,

On Wed, 2022-06-15 at 18:09 -0400, Peter Lafreniere wrote:
> ax25_dev_device_up() is only called during device setup, which is
> done in user context. In addition, ax25_dev_device_up()
> unconditionally calls ax25_register_dev_sysctl(), which already
> allocates with GFP_KERNEL.
> 
> Since it is allowed to sleep in this function, here we change
> ax25_dev_device_up() to use GFP_KERNEL to reduce unnecessary
> out-of-memory errors.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Peter Lafreniere <pjlafren@mtu.edu>
> ---
> v2 -> v3:
>  - Rebased for clean application to net-next
> 
> v1 -> v2:
>  - Renamed patch from "ax25: use GFP_KERNEL over GFP_ATOMIC where possible"
>    (Is that okay?)
>  - Removed invalid changes to ax25_rt_add()
> 
>  net/ax25/ax25_dev.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
> index ab88b6ac5401..2093f94f6852 100644
> --- a/net/ax25/ax25_dev.c
> +++ b/net/ax25/ax25_dev.c
> @@ -52,7 +52,7 @@ void ax25_dev_device_up(struct net_device *dev)
>  {
>  	ax25_dev *ax25_dev;
>  
> -	if ((ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_ATOMIC)) == NULL) {
> +	if ((ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_KERNEL)) == NULL) {
>  		printk(KERN_ERR "AX.25: ax25_dev_device_up - out of memory\n");
>  		return;
>  	}

Since you are touching this line, please move the assignment in a
separate statement:

	ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_KERNEL);
	if (!ax25_dev) {

so that we get rid of this obsolete codying style.

Thanks!

Paolo