Re: [RESEND PATCH 1/2] iommu/iova: Add check for cpu_rcache in free_iova_rcaches

[zhangzekun (A)]

在 2023/8/11 21:32, Robin Murphy 写道:
> On 2023-08-11 14:02, Zhang Zekun wrote:
> > free_iova_rcaches() needs to check if cpu_rcache->loaded and
> > cpu_rcache->prev is NULL before freeing them.
>
> Why? iova_magazine_free() is just kfree(), and kfree(NULL) is 
> perfectly valid, specifically to avoid having to make cleanup paths 
> all fiddly and overcomplicated like this.
>
> Thanks,
> Robin.
Hi, Robin
Thanks for your review, I have missed that kfree() can handle NULL and 
it is safe
to iterate through all cpus, because __alloc_percpu() will alloc a 
zero-filled area,
and pointers passed to kfree() will be either NULL or a vaild one. There 
is no need
to add check before these pointers.

Thanks,
Zekun