Re: [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache

[Chen Wandun <chenwandun@huawei.com>]

On 2022/6/5 19:49, Matthew Wilcox wrote:
> On Sun, Jun 05, 2022 at 11:55:55AM +0800, Chen Wandun wrote:
>> It will result in null pointer access if shmem_init_inodecache fail,
>> so check return value of shmem_init_inodecache
> You ignored my suggestion from v1.  Here, let me write it out for you.
Hi Matthew,
I didn't ignore your suggestion,  some explanation is needed, sorry for 
that.

In V1, Kefeng point:
"kmem_cache_create return a pointer to the cache on success, NULL on 
failure,
so error = -ENOMEM; is right :)"

so, I look some similar code such as init_inodecache in kinds of file 
system,  they all
return -ENOMEM on failure, so is it OK to return -ENOMEM on failure :)

Besides,  kmem_cache_create return NULL on failure, maybe returning 
error code
on failure is more proper, but it is another job.
>
> +static int shmem_init_inodecache(void)
>   {
>    	shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
>    				sizeof(struct shmem_inode_info),
>    				0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode);
> +	if (!shmem_inode_cachep)
> +		return -ENOMEM;
> +	return 0;
>   }
>
> ...
>
> +	error = shmem_init_inodecache();
> +	if (error)
> +		goto out2;
>
>
> .