linux-kernel - Re: Drivers: hv: vmbus: One function call less in create_gpadl

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Date: Wed, 10 Jan 2024 18:08:17 +0100
From: Markus Elfring <Markus.Elfring@....de>
To: Michael Kelley <mhklinux@...look.com>, linux-hyperv@...r.kernel.org,
 kernel-janitors@...r.kernel.org, Dexuan Cui <decui@...rosoft.com>,
 Haiyang Zhang <haiyangz@...rosoft.com>, "K. Y. Srinivasan"
 <kys@...rosoft.com>, Wei Liu <wei.liu@...nel.org>
Cc: LKML <linux-kernel@...r.kernel.org>, "cocci@...ia.fr" <cocci@...ia.fr>
Subject: Re: Drivers: hv: vmbus: One function call less in
 create_gpadl_header() after error detection

> It occurred to me overnight that the existing error handling
> in create_gpadl_header() is unnecessarily complicated.  Here's
> an approach that I think would fix what you have flagged, and
> would reduce complexity instead of increasing it.  Thoughts?

I find this development view interesting.


> diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
> index 56f7e06c673e..44b1d5c8dfed 100644
> --- a/drivers/hv/channel.c
> +++ b/drivers/hv/channel.c
> @@ -336,7 +336,7 @@ static int create_gpadl_header(enum hv_gpadl_type type, void *kbuffer,
>  			  sizeof(struct gpa_range) + pfncount * sizeof(u64);
>  		msgheader =  kzalloc(msgsize, GFP_KERNEL);
>  		if (!msgheader)
> -			goto nomem;
> +			return -ENOMEM;
>
>  		INIT_LIST_HEAD(&msgheader->submsglist);
>  		msgheader->msgsize = msgsize;
> @@ -386,8 +386,8 @@ static int create_gpadl_header(enum hv_gpadl_type type, void *kbuffer,
>  					list_del(&pos->msglistentry);
>  					kfree(pos);
>  				}
> -
> -				goto nomem;
> +				kfree(msgheader);
> +				return -ENOMEM;
>  			}
>
>  			msgbody->msgsize = msgsize;
> @@ -416,8 +416,8 @@ static int create_gpadl_header(enum hv_gpadl_type type, void *kbuffer,
>  			  sizeof(struct vmbus_channel_gpadl_header) +
>  			  sizeof(struct gpa_range) + pagecount * sizeof(u64);
>  		msgheader = kzalloc(msgsize, GFP_KERNEL);
> -		if (msgheader == NULL)
> -			goto nomem;
> +		if (!msgheader)
> +			return -ENOMEM;
>
>  		INIT_LIST_HEAD(&msgheader->submsglist);
>  		msgheader->msgsize = msgsize;
> @@ -437,10 +437,6 @@ static int create_gpadl_header(enum hv_gpadl_type type, void *kbuffer,
>  	}
>
>  	return 0;
> -nomem:
> -	kfree(msgheader);
> -	kfree(msgbody);
> -	return -ENOMEM;
>  }
>
>  /*
>

Should up to two memory areas still be released after a data processing failure?

Regards,
Markus