[PATCH] xen-netback: corretly check failed allocation

[PATCH] xen-netback: corretly check failed allocation

[Insu Yun]

Since vzalloc can be failed in memory pressure,
return value should be checked and return ENOMEM.

Signed-off-by: Insu Yun <wuninsu@gmail.com>
---
 drivers/net/xen-netback/xenbus.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 929a6e7..e288246 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -788,6 +788,11 @@ static void connect(struct backend_info *be)
 	/* Use the number of queues requested by the frontend */
 	be->vif->queues = vzalloc(requested_num_queues *
 				  sizeof(struct xenvif_queue));
+  if (!be->vif->queues)  {
+    xenbus_dev_fatal(dev, -ENOMEM, "allocating queues");
+    return;
+  }
+
 	be->vif->num_queues = requested_num_queues;
 	be->vif->stalled_queues = requested_num_queues;
 
-- 
1.9.1

Re: [PATCH] xen-netback: corretly check failed allocation

[Ian Campbell]

On Thu, 2015-10-15 at 12:26 -0400, Insu Yun wrote:
> Since vzalloc can be failed in memory pressure,
> return value should be checked and return ENOMEM.
> 
> Signed-off-by: Insu Yun <wuninsu@gmail.com>
> ---
>  drivers/net/xen-netback/xenbus.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen
> -netback/xenbus.c
> index 929a6e7..e288246 100644
> --- a/drivers/net/xen-netback/xenbus.c
> +++ b/drivers/net/xen-netback/xenbus.c
> @@ -788,6 +788,11 @@ static void connect(struct backend_info *be)
>  	/* Use the number of queues requested by the frontend */
>  	be->vif->queues = vzalloc(requested_num_queues *
>  				  sizeof(struct xenvif_queue));
> +  if (!be->vif->queues)  {
> +    xenbus_dev_fatal(dev, -ENOMEM, "allocating queues");
> +    return;
> +  }

Please fix the coding style, perhaps using checkpatch.pl or by observing
the surrounding code.

Ian.

> +
>  	be->vif->num_queues = requested_num_queues;
>  	be->vif->stalled_queues = requested_num_queues;
>  

Re: [PATCH] xen-netback: corretly check failed allocation

[Wei Liu]

On Thu, Oct 15, 2015 at 12:26:16PM -0400, Insu Yun wrote:
> Since vzalloc can be failed in memory pressure,
> return value should be checked and return ENOMEM.

This function doesn't return ENOMEM, instead it writes to xenstore to
indicate error. The commit log needs to be updated.

> 
> Signed-off-by: Insu Yun <wuninsu@gmail.com>
> ---
>  drivers/net/xen-netback/xenbus.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
> index 929a6e7..e288246 100644
> --- a/drivers/net/xen-netback/xenbus.c
> +++ b/drivers/net/xen-netback/xenbus.c
> @@ -788,6 +788,11 @@ static void connect(struct backend_info *be)
>  	/* Use the number of queues requested by the frontend */
>  	be->vif->queues = vzalloc(requested_num_queues *
>  				  sizeof(struct xenvif_queue));
> +  if (!be->vif->queues)  {
> +    xenbus_dev_fatal(dev, -ENOMEM, "allocating queues");
> +    return;
> +  }
> +

The indentation is wrong. Please configure your email client properly.

And please use "goto err" for error handling -- yes, I understand there
is existing code that returns directly but IMHO that should be fixed
too.

We.

>  	be->vif->num_queues = requested_num_queues;
>  	be->vif->stalled_queues = requested_num_queues;
>  
> -- 
> 1.9.1

Re: [PATCH] xen-netback: corretly check failed allocation

[David Miller]

From: Insu Yun <wuninsu@gmail.com>
Date: Thu, 15 Oct 2015 12:26:16 -0400

> Since vzalloc can be failed in memory pressure,
> return value should be checked and return ENOMEM.
> 
> Signed-off-by: Insu Yun <wuninsu@gmail.com>
> ---
>  drivers/net/xen-netback/xenbus.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
> index 929a6e7..e288246 100644
> --- a/drivers/net/xen-netback/xenbus.c
> +++ b/drivers/net/xen-netback/xenbus.c
> @@ -788,6 +788,11 @@ static void connect(struct backend_info *be)
>  	/* Use the number of queues requested by the frontend */
>  	be->vif->queues = vzalloc(requested_num_queues *
>  				  sizeof(struct xenvif_queue));
> +  if (!be->vif->queues)  {
> +    xenbus_dev_fatal(dev, -ENOMEM, "allocating queues");
> +    return;
> +  }

This is definitely not indented correctly.