slub: correct return errno on slab_sysfs_init failure

From: Jie Liu <[email protected]>

Return ENOMEM instead of ENOSYS if slab_sysfs_init() failed

Signed-off-by Jie Liu <[email protected]>

---
 mm/slub.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

mm/slub.c +0 -0

index 2b1ce69..75ca109 100644

Quoted 9 lines · Jeff Liu

From: Jie Liu <[email protected]>

Return ENOMEM instead of ENOSYS if slab_sysfs_init() failed

Signed-off-by Jie Liu <[email protected]>

---
 mm/slub.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

mm/slub.c static int __init slab_sysfs_init(void) · line 5307

Quoted 10 lines

mm/slub.c +1 -1

index 2b1ce69..75ca109 100644
@@ -5304,7 +5304,7 @@ static int __init slab_sysfs_init(void)
        if (!slab_kset) {
                mutex_unlock(&slab_mutex);
                printk(KERN_ERR "Cannot register slab subsystem.\n");
-               return -ENOSYS;
+               return -ENOMEM;

What is the motivation for this change? AFAICT, kset_create_and_add() can fail for other reasons than ENOMEM, no?

From: Jie Liu <[email protected]>

Return ENOMEM instead of ENOSYS if slab_sysfs_init() failed

Quoted 3 lines · Jeff Liu

From: Jie Liu <[email protected]>

Return ENOMEM instead of ENOSYS if slab_sysfs_init() failed

The reason that I used ENOSYS there is that the whole sysfs portion of the slab allocator will be disabled. Could be due to a number of issues since kset_create_and_add() returns NULL for any error.

Thanks for your clarification and sorry for the noise.

Quoted 1 line · Jeff Liu

Thanks for your clarification and sorry for the noise.

Dont be worried. I am not sure anymore that this was such a wise move. Maybe get kset_create_and_add to return an error code instead and return that instead of -ENOSYS?

Quoted 4 lines

Dont be worried. I am not sure anymore that this was such a wise move. Maybe get kset_create_and_add to return an error code instead and return that instead of -ENOSYS?

Personally, I prefer to get kset_create_and_add() to return an error which can reflect the actual cause of the failure given that kset_register() can failed due to different reasons. If so, however, looks we have to make a certain amount of change for the existing modules which are support sysfs since they all return -ENOMEM if kset_create_and_add() return NULL, maybe this is inherited from samples/kobject/kset-example.c...

Quoted 11 lines · Jeff Liu

Quoted 4 lines

Dont be worried. I am not sure anymore that this was such a wise move. Maybe get kset_create_and_add to return an error code instead and return that instead of -ENOSYS?

Personally, I prefer to get kset_create_and_add() to return an error which can reflect the actual cause of the failure given that kset_register() can failed due to different reasons. If so, however, looks we have to make a certain amount of change for the existing modules which are support sysfs since they all return -ENOMEM if kset_create_and_add() return NULL, maybe this is inherited from samples/kobject/kset-example.c...

Probably. Could you come up with patchset to clean this up? ERR_PTR() can be used to return an error code in a pointer value.