[PATCH] net/mlx5: Use kasprintf instead of hand-writing it

[PATCH] net/mlx5: Use kasprintf instead of hand-writing it

[Christophe JAILLET]

'kasprintf()' can replace a kmalloc/strcpy/strcat sequence.
It is less verbose and avoid the use of a magic number (64).

Anyway, the underlying 'alloc_workqueue()' would only keep the 24 first
chars (i.e. sizeof(struct workqueue_struct->name) = WQ_NAME_LEN).

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
 drivers/net/ethernet/mellanox/mlx5/core/health.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/health.c b/drivers/net/ethernet/mellanox/mlx5/core/health.c
index 9ff163c5bcde..a5383e701b4b 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/health.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/health.c
@@ -802,12 +802,10 @@ int mlx5_health_init(struct mlx5_core_dev *dev)
 	mlx5_fw_reporters_create(dev);
 
 	health = &dev->priv.health;
-	name = kmalloc(64, GFP_KERNEL);
+	name = kasprintf(GFP_KERNEL, "mlx5_health%s", dev_name(dev->device));
 	if (!name)
 		goto out_err;
 
-	strcpy(name, "mlx5_health");
-	strcat(name, dev_name(dev->device));
 	health->wq = create_singlethread_workqueue(name);
 	kfree(name);
 	if (!health->wq)
-- 
2.27.0

Re: [PATCH] net/mlx5: Use kasprintf instead of hand-writing it

[Bart Van Assche]

On 4/17/21 12:16 AM, Christophe JAILLET wrote:
> 'kasprintf()' can replace a kmalloc/strcpy/strcat sequence.
> It is less verbose and avoid the use of a magic number (64).
> 
> Anyway, the underlying 'alloc_workqueue()' would only keep the 24 first
> chars (i.e. sizeof(struct workqueue_struct->name) = WQ_NAME_LEN).
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
>  drivers/net/ethernet/mellanox/mlx5/core/health.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/health.c b/drivers/net/ethernet/mellanox/mlx5/core/health.c
> index 9ff163c5bcde..a5383e701b4b 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/health.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/health.c
> @@ -802,12 +802,10 @@ int mlx5_health_init(struct mlx5_core_dev *dev)
>  	mlx5_fw_reporters_create(dev);
>  
>  	health = &dev->priv.health;
> -	name = kmalloc(64, GFP_KERNEL);
> +	name = kasprintf(GFP_KERNEL, "mlx5_health%s", dev_name(dev->device));
>  	if (!name)
>  		goto out_err;
>  
> -	strcpy(name, "mlx5_health");
> -	strcat(name, dev_name(dev->device));
>  	health->wq = create_singlethread_workqueue(name);
>  	kfree(name);
>  	if (!health->wq)

Instead of modifying the mlx5 driver, please change the definition of
the create_singlethread_workqueue() such that it accept a format
specifier and a variable number of arguments.

Thanks,

Bart.

Re: [PATCH] net/mlx5: Use kasprintf instead of hand-writing it

[Christophe JAILLET]

Le 18/04/2021 à 22:03, Bart Van Assche a écrit :
> On 4/17/21 12:16 AM, Christophe JAILLET wrote:
>> 'kasprintf()' can replace a kmalloc/strcpy/strcat sequence.
>> It is less verbose and avoid the use of a magic number (64).
>>
>> Anyway, the underlying 'alloc_workqueue()' would only keep the 24 first
>> chars (i.e. sizeof(struct workqueue_struct->name) = WQ_NAME_LEN).
>>
>> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
>> ---
>>   drivers/net/ethernet/mellanox/mlx5/core/health.c | 4 +---
>>   1 file changed, 1 insertion(+), 3 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/health.c b/drivers/net/ethernet/mellanox/mlx5/core/health.c
>> index 9ff163c5bcde..a5383e701b4b 100644
>> --- a/drivers/net/ethernet/mellanox/mlx5/core/health.c
>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/health.c
>> @@ -802,12 +802,10 @@ int mlx5_health_init(struct mlx5_core_dev *dev)
>>   	mlx5_fw_reporters_create(dev);
>>   
>>   	health = &dev->priv.health;
>> -	name = kmalloc(64, GFP_KERNEL);
>> +	name = kasprintf(GFP_KERNEL, "mlx5_health%s", dev_name(dev->device));
>>   	if (!name)
>>   		goto out_err;
>>   
>> -	strcpy(name, "mlx5_health");
>> -	strcat(name, dev_name(dev->device));
>>   	health->wq = create_singlethread_workqueue(name);
>>   	kfree(name);
>>   	if (!health->wq)
> 
> Instead of modifying the mlx5 driver, please change the definition of
> the create_singlethread_workqueue() such that it accept a format
> specifier and a variable number of arguments.
> 

Agreed. I've sent another patch serie which is more elegant.
Thanks for the feedback.

CJ

> Thanks,
> 
> Bart.
> 
> 
>