diff mbox series

[2/2] drivers/base/memory: Use array to show memory block state

Message ID 20230120055727.355483-3-gshan@redhat.com
State New
Headers
Series drivers/base/memory: Two small cleanups |

Commit Message

Gavin Shan Jan. 20, 2023, 5:57 a.m. UTC 
  Use an array to show memory block state from '/sys/devices/system/
memory/memoryX/state', to simplify the code.

No functional change intended.

Signed-off-by: Gavin Shan <gshan@redhat.com>
---
 drivers/base/memory.c | 25 ++++++-------------------
 1 file changed, 6 insertions(+), 19 deletions(-)

Comments

Greg KH Jan. 20, 2023, 1:14 p.m. UTC | #1 
On Fri, Jan 20, 2023 at 01:57:27PM +0800, Gavin Shan wrote:
> Use an array to show memory block state from '/sys/devices/system/
> memory/memoryX/state', to simplify the code.
> 
> No functional change intended.
> 
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
>  drivers/base/memory.c | 25 ++++++-------------------
>  1 file changed, 6 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index b456ac213610..9474f25c452c 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -141,28 +141,15 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr,
>  			  char *buf)
>  {
>  	struct memory_block *mem = to_memory_block(dev);
> -	const char *output;
> +	static const char *const mem_state_str[] = {
> +		NULL, "online", "going-offline", NULL, "offline",
> +	};
>  
> -	/*
> -	 * We can probably put these states in a nice little array
> -	 * so that they're not open-coded
> -	 */
> -	switch (mem->state) {
> -	case MEM_ONLINE:
> -		output = "online";
> -		break;
> -	case MEM_OFFLINE:
> -		output = "offline";
> -		break;
> -	case MEM_GOING_OFFLINE:
> -		output = "going-offline";
> -		break;
> -	default:
> -		WARN_ON(1);
> +	if (WARN_ON(mem->state >= ARRAY_SIZE(mem_state_str) ||
> +		    !mem_state_str[mem->state]))

Ick, the whole WARN_ON() should just be removed please.  We don't want
to reboot any systems if this changed incorrectly.

Please fix this up to properly handle this and keep going on, don't mess
with WARN_ON() anymore in code that can recover properly.

thanks,

greg k-h
Gavin Shan Jan. 20, 2023, 10:59 p.m. UTC | #2 
On 1/21/23 12:14 AM, Greg KH wrote:
> On Fri, Jan 20, 2023 at 01:57:27PM +0800, Gavin Shan wrote:
>> Use an array to show memory block state from '/sys/devices/system/
>> memory/memoryX/state', to simplify the code.
>>
>> No functional change intended.
>>
>> Signed-off-by: Gavin Shan <gshan@redhat.com>
>> ---
>>   drivers/base/memory.c | 25 ++++++-------------------
>>   1 file changed, 6 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
>> index b456ac213610..9474f25c452c 100644
>> --- a/drivers/base/memory.c
>> +++ b/drivers/base/memory.c
>> @@ -141,28 +141,15 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr,
>>   			  char *buf)
>>   {
>>   	struct memory_block *mem = to_memory_block(dev);
>> -	const char *output;
>> +	static const char *const mem_state_str[] = {
>> +		NULL, "online", "going-offline", NULL, "offline",
>> +	};
>>   
>> -	/*
>> -	 * We can probably put these states in a nice little array
>> -	 * so that they're not open-coded
>> -	 */
>> -	switch (mem->state) {
>> -	case MEM_ONLINE:
>> -		output = "online";
>> -		break;
>> -	case MEM_OFFLINE:
>> -		output = "offline";
>> -		break;
>> -	case MEM_GOING_OFFLINE:
>> -		output = "going-offline";
>> -		break;
>> -	default:
>> -		WARN_ON(1);
>> +	if (WARN_ON(mem->state >= ARRAY_SIZE(mem_state_str) ||
>> +		    !mem_state_str[mem->state]))
> 
> Ick, the whole WARN_ON() should just be removed please.  We don't want
> to reboot any systems if this changed incorrectly.
> 
> Please fix this up to properly handle this and keep going on, don't mess
> with WARN_ON() anymore in code that can recover properly.
> 

Thanks for your review, Greg. Indeed, the WARN_ON() here is no sense because
the warning can be caught from the return value. "ERROR-UNKNOWN-%ld\n" is
returned for unknown or invalid state.

I will drop WARN_ON() in v2. PATCH[1/2] won't be reposted since it has been
merged to driver.core git tree.

Thanks,
Gavin
diff mbox series

Patch

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index b456ac213610..9474f25c452c 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -141,28 +141,15 @@  static ssize_t state_show(struct device *dev, struct device_attribute *attr,
 			  char *buf)
 {
 	struct memory_block *mem = to_memory_block(dev);
-	const char *output;
+	static const char *const mem_state_str[] = {
+		NULL, "online", "going-offline", NULL, "offline",
+	};
 
-	/*
-	 * We can probably put these states in a nice little array
-	 * so that they're not open-coded
-	 */
-	switch (mem->state) {
-	case MEM_ONLINE:
-		output = "online";
-		break;
-	case MEM_OFFLINE:
-		output = "offline";
-		break;
-	case MEM_GOING_OFFLINE:
-		output = "going-offline";
-		break;
-	default:
-		WARN_ON(1);
+	if (WARN_ON(mem->state >= ARRAY_SIZE(mem_state_str) ||
+		    !mem_state_str[mem->state]))
 		return sysfs_emit(buf, "ERROR-UNKNOWN-%ld\n", mem->state);
-	}
 
-	return sysfs_emit(buf, "%s\n", output);
+	return sysfs_emit(buf, "%s\n", mem_state_str[mem->state]);
 }
 
 int memory_notify(unsigned long val, void *v)