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

From: Matias BjÃrling
Date: Fri Sep 16 2016 - 06:20:05 EST


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@xxxxxxxx>
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.