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Date:   Sat, 14 Oct 2023 17:53:32 -0700
From:   Joel Becker <jlbec@evilplan.org>
To:     Breno Leitao <leitao@debian.org>
Cc:     kuba@kernel.org, davem@davemloft.net, pabeni@redhat.com,
        Eric Dumazet <edumazet@google.com>, hch@lst.de,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        horms@kernel.org
Subject: Re: [PATCH net-next v4 2/4] netconsole: Initialize configfs_item for
 default targets
Message-ID: <ZSs4DF1o9pDlRP7w@google.com>
Mail-Followup-To: Breno Leitao <leitao@debian.org>, kuba@kernel.org,
        davem@davemloft.net, pabeni@redhat.com,
        Eric Dumazet <edumazet@google.com>, hch@lst.de,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        horms@kernel.org
References: <20231012111401.333798-1-leitao@debian.org>
 <20231012111401.333798-3-leitao@debian.org>
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Sender: Joel Becker <jlbec@ftp.linux.org.uk>
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On Thu, Oct 12, 2023 at 04:13:59AM -0700, Breno Leitao wrote:
> For netconsole targets allocated during the boot time (passing
> netconsole=... argument), netconsole_target->item is not initialized.
> That is not a problem because it is not used inside configfs.
> 
> An upcoming patch will be using it, thus, initialize the targets with
> the name 'cmdline' plus a counter starting from 0.  This name will match
> entries in the configfs later.
> 
> Suggested-by: Joel Becker <jlbec@evilplan.org>
> Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Joel Becker <jlbec@evilplan.org>

> ---
>  drivers/net/netconsole.c | 25 +++++++++++++++++++++++--
>  1 file changed, 23 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> index d609fb59cf99..e153bce4dee4 100644
> --- a/drivers/net/netconsole.c
> +++ b/drivers/net/netconsole.c
> @@ -53,6 +53,8 @@ static bool oops_only = false;
>  module_param(oops_only, bool, 0600);
>  MODULE_PARM_DESC(oops_only, "Only log oops messages");
>  
> +#define NETCONSOLE_PARAM_TARGET_PREFIX "cmdline"
> +
>  #ifndef	MODULE
>  static int __init option_setup(char *opt)
>  {
> @@ -165,6 +167,10 @@ static void netconsole_target_put(struct netconsole_target *nt)
>  {
>  }
>  
> +static void populate_configfs_item(struct netconsole_target *nt,
> +				   int cmdline_count)
> +{
> +}
>  #endif	/* CONFIG_NETCONSOLE_DYNAMIC */
>  
>  /* Allocate and initialize with defaults.
> @@ -688,6 +694,17 @@ static struct configfs_subsystem netconsole_subsys = {
>  	},
>  };
>  
> +static void populate_configfs_item(struct netconsole_target *nt,
> +				   int cmdline_count)
> +{
> +	char target_name[16];
> +
> +	snprintf(target_name, sizeof(target_name), "%s%d",
> +		 NETCONSOLE_PARAM_TARGET_PREFIX, cmdline_count);
> +	config_item_init_type_name(&nt->item, target_name,
> +				   &netconsole_target_type);
> +}
> +
>  #endif	/* CONFIG_NETCONSOLE_DYNAMIC */
>  
>  /* Handle network interface device notifications */
> @@ -887,7 +904,8 @@ static void write_msg(struct console *con, const char *msg, unsigned int len)
>  }
>  
>  /* Allocate new target (from boot/module param) and setup netpoll for it */
> -static struct netconsole_target *alloc_param_target(char *target_config)
> +static struct netconsole_target *alloc_param_target(char *target_config,
> +						    int cmdline_count)
>  {
>  	struct netconsole_target *nt;
>  	int err;
> @@ -922,6 +940,7 @@ static struct netconsole_target *alloc_param_target(char *target_config)
>  	if (err)
>  		goto fail;
>  
> +	populate_configfs_item(nt, cmdline_count);
>  	nt->enabled = true;
>  
>  	return nt;
> @@ -954,6 +973,7 @@ static int __init init_netconsole(void)
>  {
>  	int err;
>  	struct netconsole_target *nt, *tmp;
> +	unsigned int count = 0;
>  	bool extended = false;
>  	unsigned long flags;
>  	char *target_config;
> @@ -961,7 +981,7 @@ static int __init init_netconsole(void)
>  
>  	if (strnlen(input, MAX_PARAM_LENGTH)) {
>  		while ((target_config = strsep(&input, ";"))) {
> -			nt = alloc_param_target(target_config);
> +			nt = alloc_param_target(target_config, count);
>  			if (IS_ERR(nt)) {
>  				err = PTR_ERR(nt);
>  				goto fail;
> @@ -977,6 +997,7 @@ static int __init init_netconsole(void)
>  			spin_lock_irqsave(&target_list_lock, flags);
>  			list_add(&nt->list, &target_list);
>  			spin_unlock_irqrestore(&target_list_lock, flags);
> +			count++;
>  		}
>  	}
>  
> -- 
> 2.34.1
> 

-- 

"I don't want to achieve immortality through my work; I want to
 achieve immortality through not dying."
        - Woody Allen

			http://www.jlbec.org/
			jlbec@evilplan.org