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Reply-To: mchristi@redhat.com
Subject: Re: [PATCH] scsi: tcmu: Simplify 'tcmu_update_uio_info()'
To:     Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        martin.petersen@oracle.com
Cc:     linux-scsi@vger.kernel.org, target-devel@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
References: <20190616070220.24189-1-christophe.jaillet@wanadoo.fr>
From:   Michael Christie <mchristi@redhat.com>
Organization: Red Hat
Message-ID: <2ffa1964-30b1-d8bd-a2e2-608fe4f06f45@redhat.com>
Date:   Tue, 18 Jun 2019 17:43:57 -0500
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On 06/16/2019 02:02 AM, Christophe JAILLET wrote:
> Use 'kasprintf()' instead of:
>    - snprintf(NULL, 0...
>    - kmalloc(...
>    - snprintf(...
> 
> This is less verbose and saves 7 bytes (i.e. the space for '/(null)') if
> 'udev->dev_config' is NULL.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
>  drivers/target/target_core_user.c | 16 +++++++---------
>  1 file changed, 7 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
> index b43d6385a1a0..04eda111920e 100644
> --- a/drivers/target/target_core_user.c
> +++ b/drivers/target/target_core_user.c
> @@ -1824,20 +1824,18 @@ static int tcmu_update_uio_info(struct tcmu_dev *udev)
>  {
>  	struct tcmu_hba *hba = udev->hba->hba_ptr;
>  	struct uio_info *info;
> -	size_t size, used;
>  	char *str;
>  
>  	info = &udev->uio_info;
> -	size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name,
> -			udev->dev_config);
> -	size += 1; /* for \0 */
> -	str = kmalloc(size, GFP_KERNEL);
> -	if (!str)
> -		return -ENOMEM;
>  
> -	used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name);
>  	if (udev->dev_config[0])
> -		snprintf(str + used, size - used, "/%s", udev->dev_config);
> +		str = kasprintf(GFP_KERNEL, "tcm-user/%u/%s/%s", hba->host_id,
> +				udev->name, udev->dev_config);
> +	else
> +		str = kasprintf(GFP_KERNEL, "tcm-user/%u/%s", hba->host_id,
> +				udev->name);
> +	if (!str)
> +		return -ENOMEM;
>  
>  	/* If the old string exists, free it */
>  	kfree(info->name);
> 

Thanks.

Acked-by: Mike Christie <mchristi@redhat.com>