Re: [PATCH 3/3] blk-cgroup: move async bio punt state to blkcg

[Nilay Shroff <nilay@linux.ibm.com>]

On 8/23/26 7:00 PM, Yu Kuai wrote:
> @@ -111,10 +104,15 @@ struct blkcg {
>   	/*
>   	 * List of updated percpu blkg_iostat_set's since the last flush.
>   	 */
>   	struct llist_head __percpu	*lhead;
>   
> +#ifdef CONFIG_BLK_CGROUP_PUNT_BIO
> +	spinlock_t			async_bio_lock; /* protects async_bios */
> +	struct bio_list			async_bios;
> +	struct work_struct		async_bio_work;
> +#endif
>   #ifdef CONFIG_BLK_CGROUP_FC_APPID
>   	char                            fc_app_id[FC_APPID_LEN];
>   #endif
>   #ifdef CONFIG_CGROUP_WRITEBACK
>   	struct list_head		cgwb_list;

As I mentioned, Clang context annotations are now officially supported
in the block layer. Since you're touching this code, I suggest annotating
async_bios with __guarded_by(&async_bio_lock) as well.

This would allow the Clang thread-safety analyzer to verify that every
access to async_bios is properly protected by async_bio_lock.

Thanks,
--Nilay