[PATCH] lightnvm: propagate device_add() error code

[PATCH] lightnvm: propagate device_add() error code

[Arnd Bergmann]

device_add() may fail, and all callers are supposed to check the
return value, but one new user in lightnvm doesn't:

drivers/lightnvm/sysfs.c: In function 'nvm_sysfs_register_dev':
drivers/lightnvm/sysfs.c:184:2: error: ignoring return value of 'device_add', declared with attribute warn_unused_result [-Werror=unused-result]

This changes the caller to propagate any error codes, which avoids
the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 38c9e260b9f9 ("lightnvm: expose device geometry through sysfs")
---
 drivers/lightnvm/lightnvm.h | 2 +-
 drivers/lightnvm/sysfs.c    | 9 ++++++---
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/lightnvm/lightnvm.h b/drivers/lightnvm/lightnvm.h
index 93f1aacc9f02..305c181509a6 100644
--- a/drivers/lightnvm/lightnvm.h
+++ b/drivers/lightnvm/lightnvm.h
@@ -24,7 +24,7 @@
 #include <linux/lightnvm.h>
 
 /* core -> sysfs.c */
-int nvm_sysfs_register_dev(struct nvm_dev *);
+int __must_check nvm_sysfs_register_dev(struct nvm_dev *);
 void nvm_sysfs_unregister_dev(struct nvm_dev *);
 int nvm_sysfs_register(void);
 void nvm_sysfs_unregister(void);
diff --git a/drivers/lightnvm/sysfs.c b/drivers/lightnvm/sysfs.c
index 72ad089c0269..0338c27ab95a 100644
--- a/drivers/lightnvm/sysfs.c
+++ b/drivers/lightnvm/sysfs.c
@@ -174,6 +174,8 @@ static struct device_type nvm_type = {
 
 int nvm_sysfs_register_dev(struct nvm_dev *dev)
 {
+	int ret;
+
 	if (!dev->parent_dev)
 		return 0;
 
@@ -181,11 +183,12 @@ int nvm_sysfs_register_dev(struct nvm_dev *dev)
 	dev_set_name(&dev->dev, "%s", dev->name);
 	dev->dev.type = &nvm_type;
 	device_initialize(&dev->dev);
-	device_add(&dev->dev);
+	ret = device_add(&dev->dev);
 
-	blk_mq_register_dev(&dev->dev, dev->q);
+	if (!ret)
+		blk_mq_register_dev(&dev->dev, dev->q);
 
-	return 0;
+	return ret;
 }
 
 void nvm_sysfs_unregister_dev(struct nvm_dev *dev)
-- 
2.9.0

Re: [PATCH] lightnvm: propagate device_add() error code

[Matias Bjørling]

On 09/15/2016 05:53 PM, Arnd Bergmann wrote:
> device_add() may fail, and all callers are supposed to check the
> return value, but one new user in lightnvm doesn't:
>
> drivers/lightnvm/sysfs.c: In function 'nvm_sysfs_register_dev':
> drivers/lightnvm/sysfs.c:184:2: error: ignoring return value of 'device_add', declared with attribute warn_unused_result [-Werror=unused-result]
>
> This changes the caller to propagate any error codes, which avoids
> the warning.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Fixes: 38c9e260b9f9 ("lightnvm: expose device geometry through sysfs")
> ---
>   drivers/lightnvm/lightnvm.h | 2 +-
>   drivers/lightnvm/sysfs.c    | 9 ++++++---
>   2 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/lightnvm/lightnvm.h b/drivers/lightnvm/lightnvm.h
> index 93f1aacc9f02..305c181509a6 100644
> --- a/drivers/lightnvm/lightnvm.h
> +++ b/drivers/lightnvm/lightnvm.h
> @@ -24,7 +24,7 @@
>   #include <linux/lightnvm.h>
>
>   /* core -> sysfs.c */
> -int nvm_sysfs_register_dev(struct nvm_dev *);
> +int __must_check nvm_sysfs_register_dev(struct nvm_dev *);
>   void nvm_sysfs_unregister_dev(struct nvm_dev *);
>   int nvm_sysfs_register(void);
>   void nvm_sysfs_unregister(void);
> diff --git a/drivers/lightnvm/sysfs.c b/drivers/lightnvm/sysfs.c
> index 72ad089c0269..0338c27ab95a 100644
> --- a/drivers/lightnvm/sysfs.c
> +++ b/drivers/lightnvm/sysfs.c
> @@ -174,6 +174,8 @@ static struct device_type nvm_type = {
>
>   int nvm_sysfs_register_dev(struct nvm_dev *dev)
>   {
> +	int ret;
> +
>   	if (!dev->parent_dev)
>   		return 0;
>
> @@ -181,11 +183,12 @@ int nvm_sysfs_register_dev(struct nvm_dev *dev)
>   	dev_set_name(&dev->dev, "%s", dev->name);
>   	dev->dev.type = &nvm_type;
>   	device_initialize(&dev->dev);
> -	device_add(&dev->dev);
> +	ret = device_add(&dev->dev);
>
> -	blk_mq_register_dev(&dev->dev, dev->q);
> +	if (!ret)
> +		blk_mq_register_dev(&dev->dev, dev->q);
>
> -	return 0;
> +	return ret;
>   }
>
>   void nvm_sysfs_unregister_dev(struct nvm_dev *dev)
>

Thans Arnd. Applied for 4.9.