linux-kernel - Re: [PATCH 5/5] cris: nand: Split a condition check in crisv32_nand_flash

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Date:   Wed, 4 Oct 2017 22:26:45 +0200
From:   Alexander Sverdlin <alexander.sverdlin@...il.com>
To:     SF Markus Elfring <elfring@...rs.sourceforge.net>,
        linux-cris-kernel@...s.com,
        Jesper Nilsson <jesper.nilsson@...s.com>,
        Mikael Starvik <starvik@...s.com>
Cc:     LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 5/5] cris: nand: Split a condition check in
 crisv32_nand_flash_probe()

Hello Markus,

On 04/10/17 20:50, SF Markus Elfring wrote:
> * Split a condition check for failed calls of the function "ioremap"
>   so that the return value in the variable "write_cs" will also be
>   immediately checked.
> 
> * Adjust jump targets according to the Linux coding style convention.
> 
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
>  arch/cris/arch-v32/drivers/mach-fs/nandflash.c | 17 +++++++++++------
>  1 file changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/cris/arch-v32/drivers/mach-fs/nandflash.c b/arch/cris/arch-v32/drivers/mach-fs/nandflash.c
> index 2b53f0c615ea..564218a12213 100644
> --- a/arch/cris/arch-v32/drivers/mach-fs/nandflash.c
> +++ b/arch/cris/arch-v32/drivers/mach-fs/nandflash.c
> @@ -113,13 +113,17 @@ struct mtd_info *__init crisv32_nand_flash_probe(void)
>  		return NULL;
>  
>  	read_cs = ioremap(MEM_CSP0_START | MEM_NON_CACHEABLE, 8192);
> -	write_cs = ioremap(MEM_CSP1_START | MEM_NON_CACHEABLE, 8192);
> -
> -	if (!read_cs || !write_cs) {
> +	if (!read_cs) {
>  		printk(KERN_ERR "CRISv32 NAND ioremap failed\n");
>  		goto out_mtd;
>  	}
>  
> +	write_cs = ioremap(MEM_CSP1_START | MEM_NON_CACHEABLE, 8192);
> +	if (!write_cs) {
> +		printk(KERN_ERR "CRISv32 NAND ioremap failed\n");
> +		goto unmap_read;
> +	}
> +

Instead of duplicating the error message I'd rather put an "if" in the
iounmap() path.

>  	/* Get pointer to private data */
>  	this = &wrapper->chip;
>  	crisv32_mtd = nand_to_mtd(this);
> @@ -149,13 +153,14 @@ struct mtd_info *__init crisv32_nand_flash_probe(void)
>  
>  	/* Scan to find existence of the device */
>  	if (nand_scan(crisv32_mtd, 1))
> -		goto out_ior;
> +		goto unmap_io;
>  
>  	return crisv32_mtd;
>  
> -out_ior:
> -	iounmap((void *)read_cs);
> +unmap_io:
>  	iounmap((void *)write_cs);
> +unmap_read:
> +	iounmap((void *)read_cs);

I believe, (void *) casting is wrong, it does nothing than
removing __iomem qualifier.

I'd rather write
if (read_cs)
	iounmap(read_cs);
if (write_cs)
	iounmap(write_cs);

>  out_mtd:
>  	kfree(wrapper);