Re: [PATCH V2 7/7] watchdog: ts72xx_wdt: use devm_*() functions

[Jingoo Han]

On Wednesday, May 01, 2013 12:06 AM, Guenter Roeck wrote:
> On Tue, Apr 30, 2013 at 02:02:25PM +0900, Jingoo Han wrote:
> > Use devm_*() functions to make cleanup paths simpler.
> >
> > Signed-off-by: Jingoo Han <jg1.han@xxxxxxxxxxx>
> > ---
> > No changes since v1:
> >
> Side note: If you make no changes, there is no need to send V2, especially not
> one marked as another version. Usually, when I do that kind of thing, I just
> resend.
> 
> This also applies if you get a Reviewed-by:, Acked-by:, or similar response.
> You can leave it up to the maintainer to add those to the patch.
> 
> >  drivers/watchdog/ts72xx_wdt.c |   64 +++++++----------------------------------
> >  1 files changed, 11 insertions(+), 53 deletions(-)
> >
> > diff --git a/drivers/watchdog/ts72xx_wdt.c b/drivers/watchdog/ts72xx_wdt.c
> > index b8a9245..b19ca75 100644
> > --- a/drivers/watchdog/ts72xx_wdt.c
> > +++ b/drivers/watchdog/ts72xx_wdt.c
> > @@ -396,7 +396,7 @@ static int ts72xx_wdt_probe(struct platform_device *pdev)
> >  	struct resource *r1, *r2;
> >  	int error = 0;
> >
> > -	wdt = kzalloc(sizeof(struct ts72xx_wdt), GFP_KERNEL);
> > +	wdt = devm_kzalloc(&pdev->dev, sizeof(struct ts72xx_wdt), GFP_KERNEL);
> >  	if (!wdt) {
> >  		dev_err(&pdev->dev, "failed to allocate memory\n");
> 
> My understanding from other conversations is that this error message is no
> longer needed.

The error message for devm_ioremap_resource() is not necessary,
however, the error message for devm_kzalloc() is necessary.
In devm_kzalloc(), there is no error message.
It just return NULL, when it fails as below:

./drivers/base/devres.c

773 void * devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
774 {
775         struct devres *dr;
776
777         /* use raw alloc_dr for kmalloc caller tracing */
778         dr = alloc_dr(devm_kzalloc_release, size, gfp);
779         if (unlikely(!dr))
780                 return NULL;
781
782         set_node_dbginfo(&dr->node, "devm_kzalloc_release", size);
783         devres_add(dev, dr->data);
784         return dr->data;
785 }
786 EXPORT_SYMBOL_GPL(devm_kzalloc);


> 
> >  		return -ENOMEM;
> > @@ -405,44 +405,22 @@ static int ts72xx_wdt_probe(struct platform_device *pdev)
> >  	r1 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >  	if (!r1) {
> >  		dev_err(&pdev->dev, "failed to get memory resource\n");
> > -		error = -ENODEV;
> > -		goto fail;
> > -	}
> > -
> > -	r1 = request_mem_region(r1->start, resource_size(r1), pdev->name);
> > -	if (!r1) {
> > -		dev_err(&pdev->dev, "cannot request memory region\n");
> > -		error = -EBUSY;
> > -		goto fail;
> > +		return -ENODEV;
> >  	}
> >
> > -	wdt->control_reg = ioremap(r1->start, resource_size(r1));
> > -	if (!wdt->control_reg) {
> > -		dev_err(&pdev->dev, "failed to map memory\n");
> > -		error = -ENODEV;
> > -		goto fail_free_control;
> > -	}
> > +	wdt->control_reg = devm_ioremap_resource(&pdev->dev, r1);
> > +	if (IS_ERR(wdt->control_reg))
> > +		return PTR_ERR(wdt->control_reg);
> >
> >  	r2 = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> >  	if (!r2) {
> >  		dev_err(&pdev->dev, "failed to get memory resource\n");
> > -		error = -ENODEV;
> > -		goto fail_unmap_control;
> > +		return -ENODEV;
> >  	}
> >
> > -	r2 = request_mem_region(r2->start, resource_size(r2), pdev->name);
> > -	if (!r2) {
> > -		dev_err(&pdev->dev, "cannot request memory region\n");
> > -		error = -EBUSY;
> > -		goto fail_unmap_control;
> > -	}
> > -
> > -	wdt->feed_reg = ioremap(r2->start, resource_size(r2));
> > -	if (!wdt->feed_reg) {
> > -		dev_err(&pdev->dev, "failed to map memory\n");
> > -		error = -ENODEV;
> > -		goto fail_free_feed;
> > -	}
> > +	wdt->feed_reg = devm_ioremap_resource(&pdev->dev, r2);
> > +	if (IS_ERR(wdt->feed_reg))
> > +		return PTR_ERR(wdt->feed_reg);
> >
> >  	platform_set_drvdata(pdev, wdt);
> >  	ts72xx_wdt_pdev = pdev;
> > @@ -455,45 +433,25 @@ static int ts72xx_wdt_probe(struct platform_device *pdev)
> >  	error = misc_register(&ts72xx_wdt_miscdev);
> >  	if (error) {
> >  		dev_err(&pdev->dev, "failed to register miscdev\n");
> > -		goto fail_unmap_feed;
> > +		goto fail;
> >  	}
> >
> >  	dev_info(&pdev->dev, "TS-72xx Watchdog driver\n");
> >
> >  	return 0;
> >
> > -fail_unmap_feed:
> > -	platform_set_drvdata(pdev, NULL);
> > -	iounmap(wdt->feed_reg);
> > -fail_free_feed:
> > -	release_mem_region(r2->start, resource_size(r2));
> > -fail_unmap_control:
> > -	iounmap(wdt->control_reg);
> > -fail_free_control:
> > -	release_mem_region(r1->start, resource_size(r1));
> >  fail:
> > -	kfree(wdt);
> > +	platform_set_drvdata(pdev, NULL);
> 
> 	platform_set_drvdata(pdev, NULL);
> 
> is not needed. By eliminating it you could get rid of the entire error path.

OK, I will remove it.
Thank you.

Best regards,
Jingoo Han

> 
> >  	return error;
> >  }
> >
> >  static int ts72xx_wdt_remove(struct platform_device *pdev)
> >  {
> > -	struct ts72xx_wdt *wdt = platform_get_drvdata(pdev);
> > -	struct resource *res;
> >  	int error;
> >
> >  	error = misc_deregister(&ts72xx_wdt_miscdev);
> >  	platform_set_drvdata(pdev, NULL);
> >
> > -	iounmap(wdt->feed_reg);
> > -	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> > -	release_mem_region(res->start, resource_size(res));
> > -
> > -	iounmap(wdt->control_reg);
> > -	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > -	release_mem_region(res->start, resource_size(res));
> > -
> > -	kfree(wdt);
> >  	return error;
> >  }
> >
> > --
> > 1.7.2.5
> >
> >
> > --
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> >

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