From: Lv Ruyi <lv.ruyi@zte.com.cn>

If major equal 0, register_chrdev() returns error code when it fails.
This function dynamically allocate a major and return its number on
success, so we should use "< 0" to check it instead of "!".

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
---
 drivers/net/wan/cosa.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wan/cosa.c b/drivers/net/wan/cosa.c
index 23d2954d9747..1e5672019922 100644
--- a/drivers/net/wan/cosa.c
+++ b/drivers/net/wan/cosa.c
@@ -349,7 +349,7 @@ static int __init cosa_init(void)
 		}
 	} else {
 		cosa_major = register_chrdev(0, "cosa", &cosa_fops);
-		if (!cosa_major) {
+		if (cosa_major < 0) {
 			pr_warn("unable to register chardev\n");
 			err = -EIO;
 			goto out;
-- 
2.25.1

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:

On Mon, 18 Apr 2022 10:58:34 +0000 you wrote:
> From: Lv Ruyi <lv.ruyi@zte.com.cn>
> 
> If major equal 0, register_chrdev() returns error code when it fails.
> This function dynamically allocate a major and return its number on
> success, so we should use "< 0" to check it instead of "!".
> 
> Reported-by: Zeal Robot <zealci@zte.com.cn>
> Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
> 
> [...]

Here is the summary with links:
  - net: cosa: fix error check return value of register_chrdev()
    https://git.kernel.org/netdev/net/c/d48fea8401cf

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
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Acked-By: Jan "Yenya" Kasprzak <kas@fi.muni.cz>

Thanks!

-Yenya

cgel.zte@gmail.com wrote:
: From: Lv Ruyi <lv.ruyi@zte.com.cn>
: 
: If major equal 0, register_chrdev() returns error code when it fails.
: This function dynamically allocate a major and return its number on
: success, so we should use "< 0" to check it instead of "!".
: 
: Reported-by: Zeal Robot <zealci@zte.com.cn>
: Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
: ---
:  drivers/net/wan/cosa.c | 2 +-
:  1 file changed, 1 insertion(+), 1 deletion(-)
: 
: diff --git a/drivers/net/wan/cosa.c b/drivers/net/wan/cosa.c
: index 23d2954d9747..1e5672019922 100644
: --- a/drivers/net/wan/cosa.c
: +++ b/drivers/net/wan/cosa.c
: @@ -349,7 +349,7 @@ static int __init cosa_init(void)
:  		}
:  	} else {
:  		cosa_major = register_chrdev(0, "cosa", &cosa_fops);
: -		if (!cosa_major) {
: +		if (cosa_major < 0) {
:  			pr_warn("unable to register chardev\n");
:  			err = -EIO;
:  			goto out;
: -- 
: 2.25.1
: 

-- 
| Jan "Yenya" Kasprzak <kas at {fi.muni.cz - work | yenya.net - private}> |
| http://www.fi.muni.cz/~kas/                         GPG: 4096R/A45477D5 |
    We all agree on the necessity of compromise. We just can't agree on
    when it's necessary to compromise.                     --Larry Wall