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

[Chen Wandun]

在 2022/6/6 10:08, Matthew Wilcox 写道:
> On Mon, Jun 06, 2022 at 09:34:13AM +0800, Chen Wandun wrote:
> > 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.
> I literally wrote out what I think you should do instead.  Stop arguing.
>
> > > +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;
Oh, I misunderstood what you said, feel so sorry.
I will send a new version.

Thanks.
> > > .
> .