diff mbox series

[v1,1/2] devres: Switch to use dev_err_probe() for unification

Message ID 20240227175910.3031342-2-andriy.shevchenko@linux.intel.com
State New
Headers
Series devres: A couple of cleanups |

Commit Message

Andy Shevchenko Feb. 27, 2024, 5:58 p.m. UTC 
  The devm_*() APIs are supposed to be called during the ->probe() stage.
Many drivers (especially new ones) has switched to use dev_err_probe()
for error messaging for the sake of unification. Let's do the same in
the devres APIs.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 lib/devres.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

Comments

Philipp Stanner Feb. 29, 2024, 8:52 a.m. UTC | #1 
On Tue, 2024-02-27 at 19:58 +0200, Andy Shevchenko wrote:
> The devm_*() APIs are supposed to be called during the ->probe()
> stage.
> Many drivers (especially new ones) has switched to use

has -> have

> dev_err_probe()
> for error messaging for the sake of unification. Let's do the same in
> the devres APIs.

No objections on principle. Just one thing about the implementation:

> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  lib/devres.c | 17 +++++++++--------
>  1 file changed, 9 insertions(+), 8 deletions(-)
> 
> diff --git a/lib/devres.c b/lib/devres.c
> index fe0c63caeb68..27f280a39dca 100644
> --- a/lib/devres.c
> +++ b/lib/devres.c
> @@ -125,12 +125,13 @@ __devm_ioremap_resource(struct device *dev,
> const struct resource *res,
>         resource_size_t size;
>         void __iomem *dest_ptr;
>         char *pretty_name;
> +       int ret;
>  
>         BUG_ON(!dev);
>  
>         if (!res || resource_type(res) != IORESOURCE_MEM) {
> -               dev_err(dev, "invalid resource %pR\n", res);
> -               return IOMEM_ERR_PTR(-EINVAL);
> +               ret = dev_err_probe(dev, -EINVAL, "invalid resource
> %pR\n", res);
> +               return IOMEM_ERR_PTR(ret);

So as I see it -EINVAL is just piped through dev_err_probe() and is
never changed.
Don't you think it would be better to drop variable 'ret' and just do
return IOMEM_ERR_PTR(-EINVAL);
as before?

That way it would be obvious that the error code is never changed and
it will always return -EINVAL. Otherwise you have to look up the
function definition of dev_err_probe().

The same would apply below.

Regards,
P.

>         }
>  
>         if (type == DEVM_IOREMAP && res->flags &
> IORESOURCE_MEM_NONPOSTED)
> @@ -144,20 +145,20 @@ __devm_ioremap_resource(struct device *dev,
> const struct resource *res,
>         else
>                 pretty_name = devm_kstrdup(dev, dev_name(dev),
> GFP_KERNEL);
>         if (!pretty_name) {
> -               dev_err(dev, "can't generate pretty name for resource
> %pR\n", res);
> -               return IOMEM_ERR_PTR(-ENOMEM);
> +               ret = dev_err_probe(dev, -ENOMEM, "can't generate
> pretty name for resource %pR\n", res);
> +               return IOMEM_ERR_PTR(ret);
>         }
>  
>         if (!devm_request_mem_region(dev, res->start, size,
> pretty_name)) {
> -               dev_err(dev, "can't request region for resource
> %pR\n", res);
> -               return IOMEM_ERR_PTR(-EBUSY);
> +               ret = dev_err_probe(dev, -EBUSY, "can't request
> region for resource %pR\n", res);
> +               return IOMEM_ERR_PTR(ret);
>         }
>  
>         dest_ptr = __devm_ioremap(dev, res->start, size, type);
>         if (!dest_ptr) {
> -               dev_err(dev, "ioremap failed for resource %pR\n",
> res);
>                 devm_release_mem_region(dev, res->start, size);
> -               dest_ptr = IOMEM_ERR_PTR(-ENOMEM);
> +               ret = dev_err_probe(dev, -ENOMEM, "ioremap failed for
> resource %pR\n", res);
> +               return IOMEM_ERR_PTR(ret);
>         }
>  
>         return dest_ptr;
Andy Shevchenko Feb. 29, 2024, 10:39 a.m. UTC | #2 
On Thu, Feb 29, 2024 at 09:52:34AM +0100, Philipp Stanner wrote:
> On Tue, 2024-02-27 at 19:58 +0200, Andy Shevchenko wrote:
> > The devm_*() APIs are supposed to be called during the ->probe()
> > stage.
> > Many drivers (especially new ones) has switched to use
> 
> has -> have

Thanks, will fix.

> > dev_err_probe()
> > for error messaging for the sake of unification. Let's do the same in
> > the devres APIs.
> 
> No objections on principle. Just one thing about the implementation:

..

> > +               ret = dev_err_probe(dev, -EINVAL, "invalid resource
> > %pR\n", res);
> > +               return IOMEM_ERR_PTR(ret);
> 
> So as I see it -EINVAL is just piped through dev_err_probe() and is
> never changed.
> Don't you think it would be better to drop variable 'ret' and just do
> return IOMEM_ERR_PTR(-EINVAL);
> as before?

dev_err_probe() requires error code as a parameter. Are you suggesting to have
a duplication?

	dev_err_probe(-EINVAL);
	return -EINVAL;

I don't think it's a good suggestion, so the answer is "No, I don't think it
would be better."

> That way it would be obvious that the error code is never changed and
> it will always return -EINVAL. Otherwise you have to look up the
> function definition of dev_err_probe().

..

> The same would apply below.

Same answer.
Andy Shevchenko Feb. 29, 2024, 10:41 a.m. UTC | #3 
On Thu, Feb 29, 2024 at 12:39:55PM +0200, Andy Shevchenko wrote:
> On Thu, Feb 29, 2024 at 09:52:34AM +0100, Philipp Stanner wrote:
> > On Tue, 2024-02-27 at 19:58 +0200, Andy Shevchenko wrote:

..

> > That way it would be obvious that the error code is never changed and
> > it will always return -EINVAL. Otherwise you have to look up the
> > function definition of dev_err_probe().

And to this, it's a common pattern in some cases, esp. when you have a chain of
the similar calls and you want to simplify the code (see CCI accessors in
Video4Linux2 as an example). So, I also don't think it's something unusual.
diff mbox series

Patch

diff --git a/lib/devres.c b/lib/devres.c
index fe0c63caeb68..27f280a39dca 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -125,12 +125,13 @@  __devm_ioremap_resource(struct device *dev, const struct resource *res,
 	resource_size_t size;
 	void __iomem *dest_ptr;
 	char *pretty_name;
+	int ret;
 
 	BUG_ON(!dev);
 
 	if (!res || resource_type(res) != IORESOURCE_MEM) {
-		dev_err(dev, "invalid resource %pR\n", res);
-		return IOMEM_ERR_PTR(-EINVAL);
+		ret = dev_err_probe(dev, -EINVAL, "invalid resource %pR\n", res);
+		return IOMEM_ERR_PTR(ret);
 	}
 
 	if (type == DEVM_IOREMAP && res->flags & IORESOURCE_MEM_NONPOSTED)
@@ -144,20 +145,20 @@  __devm_ioremap_resource(struct device *dev, const struct resource *res,
 	else
 		pretty_name = devm_kstrdup(dev, dev_name(dev), GFP_KERNEL);
 	if (!pretty_name) {
-		dev_err(dev, "can't generate pretty name for resource %pR\n", res);
-		return IOMEM_ERR_PTR(-ENOMEM);
+		ret = dev_err_probe(dev, -ENOMEM, "can't generate pretty name for resource %pR\n", res);
+		return IOMEM_ERR_PTR(ret);
 	}
 
 	if (!devm_request_mem_region(dev, res->start, size, pretty_name)) {
-		dev_err(dev, "can't request region for resource %pR\n", res);
-		return IOMEM_ERR_PTR(-EBUSY);
+		ret = dev_err_probe(dev, -EBUSY, "can't request region for resource %pR\n", res);
+		return IOMEM_ERR_PTR(ret);
 	}
 
 	dest_ptr = __devm_ioremap(dev, res->start, size, type);
 	if (!dest_ptr) {
-		dev_err(dev, "ioremap failed for resource %pR\n", res);
 		devm_release_mem_region(dev, res->start, size);
-		dest_ptr = IOMEM_ERR_PTR(-ENOMEM);
+		ret = dev_err_probe(dev, -ENOMEM, "ioremap failed for resource %pR\n", res);
+		return IOMEM_ERR_PTR(ret);
 	}
 
 	return dest_ptr;