netdev - Re: [PATCH net-next v5 1/2] netconsole: Create a allocation helper

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Date: Thu, 10 Aug 2023 22:17:18 +0200
From: Simon Horman <horms@...nel.org>
To: Breno Leitao <leitao@...ian.org>
Cc: rdunlap@...radead.org, benjamin.poirier@...il.com, davem@...emloft.net,
	kuba@...nel.org, edumazet@...gle.com,
	Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org,
	open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH net-next v5 1/2] netconsole: Create a allocation helper

On Thu, Aug 10, 2023 at 02:54:50AM -0700, Breno Leitao wrote:
> De-duplicate the initialization and allocation code for struct
> netconsole_target.
> 
> The same allocation and initialization code is duplicated in two
> different places in the netconsole subsystem, when the netconsole target
> is initialized by command line parameters (alloc_param_target()), and
> dynamically by sysfs (make_netconsole_target()).
> 
> Create a helper function, and call it from the two different functions.
> 
> Suggested-by: Eric Dumazet <edumazet@...gle.com>
> Signed-off-by: Breno Leitao <leitao@...ian.org>
> ---
>  drivers/net/netconsole.c | 42 +++++++++++++++++++++-------------------
>  1 file changed, 22 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> index 87f18aedd3bd..f93b98d64a3c 100644
> --- a/drivers/net/netconsole.c
> +++ b/drivers/net/netconsole.c
> @@ -167,19 +167,16 @@ static void netconsole_target_put(struct netconsole_target *nt)
>  
>  #endif	/* CONFIG_NETCONSOLE_DYNAMIC */
>  
> -/* Allocate new target (from boot/module param) and setup netpoll for it */
> -static struct netconsole_target *alloc_param_target(char *target_config)
> +/* Allocate and initialize with defaults.
> + * Note that these targets get their config_item fields zeroed-out.
> + */
> +static struct netconsole_target *alloc_and_init(void)
>  {
> -	int err = -ENOMEM;
>  	struct netconsole_target *nt;
>  
> -	/*
> -	 * Allocate and initialize with defaults.
> -	 * Note that these targets get their config_item fields zeroed-out.
> -	 */
>  	nt = kzalloc(sizeof(*nt), GFP_KERNEL);
>  	if (!nt)
> -		goto fail;
> +		return nt;
>  
>  	nt->np.name = "netconsole";
>  	strscpy(nt->np.dev_name, "eth0", IFNAMSIZ);
> @@ -187,6 +184,21 @@ static struct netconsole_target *alloc_param_target(char *target_config)
>  	nt->np.remote_port = 6666;
>  	eth_broadcast_addr(nt->np.remote_mac);
>  
> +	return nt;
> +}
> +
> +/* Allocate new target (from boot/module param) and setup netpoll for it */
> +static struct netconsole_target *alloc_param_target(char *target_config)
> +{
> +	struct netconsole_target *nt;
> +	int err;

Hi Breno,

This function returns err.
However, clang-16 W=1 and Smatch warn that there is a case
where this may occur without err having being initialised.

> +
> +	nt = alloc_and_init();
> +	if (!nt) {
> +		err = -ENOMEM;
> +		goto fail;
> +	}
> +
>  	if (*target_config == '+') {
>  		nt->extended = true;
>  		target_config++;

...

-- 
pw-bot: changes-requested