linux-kernel - Re: [PATCH 6/6] staging: sm750fb: Spinlock and unlock in the same block

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Message-ID: <20150311090911.GW10964@mwanda>
Date:	Wed, 11 Mar 2015 12:09:11 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	Lorenzo Stoakes <lstoakes@...il.com>
Cc:	sudipm.mukherjee@...il.com, teddy.wang@...iconmotion.com,
	gregkh@...uxfoundation.org, devel@...verdev.osuosl.org,
	linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6/6] staging: sm750fb: Spinlock and unlock in the same
 block

On Wed, Mar 11, 2015 at 01:28:45AM +0000, Lorenzo Stoakes wrote:
> -static inline void myspin_lock(spinlock_t * sl){
> -	struct lynx_share * share;
> -	share = container_of(sl,struct lynx_share,slock);
> -	if(share->dual){
> -		spin_lock(sl);
> -	}
> -}

Yes, good.  We all hate locking wrappers but these are worse than
normal.

> +	/* if not use spin_lock,system will die if user load driver
> +	 * and immediatly unload driver frequently (dual)*/
> +	if (share->dual) {
> +		spin_lock(&share->slock);
> +		share->accel.de_fillrect(&share->accel,
> +					base,pitch,Bpp,
> +					region->dx,region->dy,
> +					region->width,region->height,
> +					color,rop);
> +		spin_unlock(&share->slock);
> +	} else
> +		share->accel.de_fillrect(&share->accel,
> +					base,pitch,Bpp,
> +					region->dx,region->dy,
> +					region->width,region->height,
> +					color,rop);
>  }

No.  You've made the code uglier to work around Sparse stupidness.  Also
the braces are not according to kernel style.

	if (share->dual)
		spin_lock(&share->slock);

	share->accel.de_fillrect(&share->accel,
				 base,pitch,Bpp,
				 region->dx,region->dy,
				 region->width,region->height,
				 color,rop);

	if (share->dual)
		spin_unlock(&share->slock);

Sparse will still complain but no one cares.

regards,
--
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