linux-kernel - Re: [PATCH v4] video: fbdev: vesafb: add missed release

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Date:   Fri, 17 Apr 2020 16:08:23 +0200
From:   Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
To:     Chuhong Yuan <hslester96@...il.com>
Cc:     dri-devel@...ts.freedesktop.org, linux-fbdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] video: fbdev: vesafb: add missed release_region


On 3/29/20 4:58 PM, Chuhong Yuan wrote:
> The driver forgets to free the I/O region in remove and probe
> failure.
> Add the missed calls to fix it.
> 
> Since the success of request_region() is optional, add the "region" field
> in vesafb_par to represent whether request_region() succeeds.
> Then only call release_region() when "region" is not null.
> 
> Signed-off-by: Chuhong Yuan <hslester96@...il.com>

Patch queued for v5.8, thanks.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

> ---
> Changes in v4:
>   - Add a field in vesafb_par to represent whether request_region() succeeds.
>   - Only call release_region() when request_region() succeeds.
>   - Adjust the order in the error handler of probe.
>   - Modify commit message.
> 
>  drivers/video/fbdev/vesafb.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/video/fbdev/vesafb.c b/drivers/video/fbdev/vesafb.c
> index a1fe24ea869b..df6de5a9dd4c 100644
> --- a/drivers/video/fbdev/vesafb.c
> +++ b/drivers/video/fbdev/vesafb.c
> @@ -32,6 +32,7 @@
>  struct vesafb_par {
>  	u32 pseudo_palette[256];
>  	int wc_cookie;
> +	struct resource *region;
>  };
>  
>  static struct fb_var_screeninfo vesafb_defined = {
> @@ -411,7 +412,7 @@ static int vesafb_probe(struct platform_device *dev)
>  
>  	/* request failure does not faze us, as vgacon probably has this
>  	 * region already (FIXME) */
> -	request_region(0x3c0, 32, "vesafb");
> +	par->region = request_region(0x3c0, 32, "vesafb");
>  
>  	if (mtrr == 3) {
>  		unsigned int temp_size = size_total;
> @@ -439,7 +440,7 @@ static int vesafb_probe(struct platform_device *dev)
>  		       "vesafb: abort, cannot ioremap video memory 0x%x @ 0x%lx\n",
>  			vesafb_fix.smem_len, vesafb_fix.smem_start);
>  		err = -EIO;
> -		goto err;
> +		goto err_release_region;
>  	}
>  
>  	printk(KERN_INFO "vesafb: framebuffer at 0x%lx, mapped to 0x%p, "
> @@ -458,19 +459,22 @@ static int vesafb_probe(struct platform_device *dev)
>  
>  	if (fb_alloc_cmap(&info->cmap, 256, 0) < 0) {
>  		err = -ENOMEM;
> -		goto err;
> +		goto err_release_region;
>  	}
>  	if (register_framebuffer(info)<0) {
>  		err = -EINVAL;
>  		fb_dealloc_cmap(&info->cmap);
> -		goto err;
> +		goto err_release_region;
>  	}
>  	fb_info(info, "%s frame buffer device\n", info->fix.id);
>  	return 0;
> -err:
> +err_release_region:
>  	arch_phys_wc_del(par->wc_cookie);
>  	if (info->screen_base)
>  		iounmap(info->screen_base);
> +	if (par->region)
> +		release_region(0x3c0, 32);
> +err:
>  	framebuffer_release(info);
>  	release_mem_region(vesafb_fix.smem_start, size_total);
>  	return err;
> @@ -481,6 +485,8 @@ static int vesafb_remove(struct platform_device *pdev)
>  	struct fb_info *info = platform_get_drvdata(pdev);
>  
>  	unregister_framebuffer(info);
> +	if (((struct vesafb_par *)(info->par))->region)
> +		release_region(0x3c0, 32);
>  	framebuffer_release(info);
>  
>  	return 0;
>