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Subject: Re: [PATCH] mtd: nand: nandsim: fix error check
To: Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
        Boris Brezillon <boris.brezillon@free-electrons.com>,
        Richard Weinberger <richard@nod.at>,
        David Woodhouse <dwmw2@infradead.org>,
        Brian Norris <computersforpeace@gmail.com>,
        Cyrille Pitchen <cyrille.pitchen@atmel.com>
References: <1479251395-3100-1-git-send-email-sudipm.mukherjee@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org
From: Marek Vasut <marek.vasut@gmail.com>
Message-ID: <0ad0b3d4-bde6-57ab-6856-de771ade3c32@gmail.com>
Date: Wed, 16 Nov 2016 00:42:37 +0100
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On 11/16/2016 12:09 AM, Sudip Mukherjee wrote:
> debugfs_create_dir() and debugfs_create_file() returns NULL on error or
> a pointer on success. They do not return the error value with ERR_PTR.
> So we should not check the return with IS_ERR_OR_NULL, instead we
> should just check for NULL.
> 
> Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
> ---
>  drivers/mtd/nand/nandsim.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mtd/nand/nandsim.c b/drivers/mtd/nand/nandsim.c
> index c76287a..9b0d79a 100644
> --- a/drivers/mtd/nand/nandsim.c
> +++ b/drivers/mtd/nand/nandsim.c
> @@ -525,15 +525,13 @@ static int nandsim_debugfs_create(struct nandsim *dev)
>  {
>  	struct nandsim_debug_info *dbg = &dev->dbg;
>  	struct dentry *dent;
> -	int err;
> +	int err = -ENODEV;

Why don't you just nuke the err altogether and just return -ENODEV ?

>  	if (!IS_ENABLED(CONFIG_DEBUG_FS))
>  		return 0;
>  
>  	dent = debugfs_create_dir("nandsim", NULL);
> -	if (IS_ERR_OR_NULL(dent)) {
> -		int err = dent ? -ENODEV : PTR_ERR(dent);
> -
> +	if (!dent) {
>  		NS_ERR("cannot create \"nandsim\" debugfs directory, err %d\n",
>  			err);
>  		return err;
> @@ -542,7 +540,7 @@ static int nandsim_debugfs_create(struct nandsim *dev)
>  
>  	dent = debugfs_create_file("wear_report", S_IRUSR,
>  				   dbg->dfs_root, dev, &dfs_fops);
> -	if (IS_ERR_OR_NULL(dent))
> +	if (!dent)
>  		goto out_remove;
>  	dbg->dfs_wear_report = dent;
>  
> @@ -550,7 +548,6 @@ static int nandsim_debugfs_create(struct nandsim *dev)
>  
>  out_remove:
>  	debugfs_remove_recursive(dbg->dfs_root);
> -	err = dent ? PTR_ERR(dent) : -ENODEV;
>  	return err;
>  }
>  
> 


-- 
Best regards,
Marek Vasut