[PATCH v3] drivers:block:Use IS_ERR() to check debugfs_create_dir() return value

[PATCH v3] drivers:block:Use IS_ERR() to check debugfs_create_dir() return value

[Yang Ruibin]

The debugfs_create_dir() function returns error pointers.It
never returns NULL. So use IS_ERR() to check its return value.

Fixes: f40eb99897af ("pktcdvd: remove driver.")
Signed-off-by: Yang Ruibin <11162571@vivo.com>
---
Changes v3:
- Add corresponding fixes.The revert original fixes information 
- is used compared to the v2 version
---
 drivers/block/pktcdvd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 7cece5884b9c..030b7a063a0b 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -498,7 +498,7 @@ static void pkt_debugfs_dev_new(struct pktcdvd_device *pd)
 	if (!pkt_debugfs_root)
 		return;
 	pd->dfs_d_root = debugfs_create_dir(pd->disk->disk_name, pkt_debugfs_root);
-	if (!pd->dfs_d_root)
+	if (IS_ERR(pd->dfs_d_root))
 		return;
 
 	pd->dfs_f_info = debugfs_create_file("info", 0444, pd->dfs_d_root,
-- 
2.34.1

Re: [PATCH v3] drivers:block:Use IS_ERR() to check debugfs_create_dir() return value

[Greg Kroah-Hartman]

On Fri, Aug 23, 2024 at 06:10:46PM +0800, Yang Ruibin wrote:
> The debugfs_create_dir() function returns error pointers.It
> never returns NULL. So use IS_ERR() to check its return value.

Close, but no.  Please just never check debugfs functions, you shouldn't
need to do that at all.

> 
> Fixes: f40eb99897af ("pktcdvd: remove driver.")
> Signed-off-by: Yang Ruibin <11162571@vivo.com>
> ---
> Changes v3:
> - Add corresponding fixes.The revert original fixes information 
> - is used compared to the v2 version
> ---
>  drivers/block/pktcdvd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
> index 7cece5884b9c..030b7a063a0b 100644
> --- a/drivers/block/pktcdvd.c
> +++ b/drivers/block/pktcdvd.c
> @@ -498,7 +498,7 @@ static void pkt_debugfs_dev_new(struct pktcdvd_device *pd)
>  	if (!pkt_debugfs_root)
>  		return;
>  	pd->dfs_d_root = debugfs_create_dir(pd->disk->disk_name, pkt_debugfs_root);
> -	if (!pd->dfs_d_root)
> +	if (IS_ERR(pd->dfs_d_root))
>  		return;

No need to check at all, no logic should care if debugfs works or not.
And any return value from debugfs can be passed into other debugfs
calls, so it's safe to pass in errors that it gives you.

So just remove these 2 lines please.

thanks,

greg k-h