RE: [PATCH v8 6/7] apei/ghes: Use unrcu_pointer for cmpxchg

[Justin He]

Hi Borislav

> -----Original Message-----
> From: Borislav Petkov <bp@xxxxxxxxx>
> Sent: Tuesday, October 11, 2022 6:34 PM
> To: Justin He <Justin.He@xxxxxxx>
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> Subject: Re: [PATCH v8 6/7] apei/ghes: Use unrcu_pointer for cmpxchg
> 
> On Mon, Oct 10, 2022 at 02:35:58AM +0000, Jia He wrote:
> > ghes_estatus_caches should be add rcu annotation to avoid sparse warnings.
> >    drivers/acpi/apei/ghes.c:733:25: sparse: sparse: incompatible types in
> comparison expression (different address spaces):
> >    drivers/acpi/apei/ghes.c:733:25: sparse:    struct ghes_estatus_cache
> [noderef] __rcu *
> >    drivers/acpi/apei/ghes.c:733:25: sparse:    struct ghes_estatus_cache *
> >    drivers/acpi/apei/ghes.c:813:25: sparse: sparse: incompatible types in
> comparison expression (different address spaces):
> >    drivers/acpi/apei/ghes.c:813:25: sparse:    struct ghes_estatus_cache
> [noderef] __rcu *
> >    drivers/acpi/apei/ghes.c:813:25: sparse:    struct ghes_estatus_cache *
> >
> > unrcu_pointer is to strip the __rcu in cmpxchg.
> 
> Is this only to shut up sparse or actually fixing anything?

My original purpose is to make it pass the sparse checking. 

--
Cheers,
Justin (Jia He)