Re: [PATCH 1/3] s390/vfio_ccw: Add __must_hold() attribute to vfio_ccw_sch_quiesce()

[Christian Borntraeger <borntraeger@linux.ibm.com>]

Am 06.08.26 um 17:38 schrieb Heiko Carstens:
> Add __must_hold() attribute to vfio_ccw_sch_quiesce() in order to let
> clang's context analysis know that sch->lock must be held on function
> entry. This can also be easily verified when inspecting the function.
> 
> Without this annotation this leads to a valid warning when context
> analysis is enabled:
> 
> drivers/s390/cio/vfio_ccw_drv.c:55:9: warning:
>    expecting spinlock 'sch->lock' to be held at start of each loop [-Wthread-safety-analysis]
>     55 |                 ret = cio_cancel_halt_clear(sch, &iretry);
>        |                       ^
> 
> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
> ---
>   drivers/s390/cio/vfio_ccw_drv.c     | 1 +
>   drivers/s390/cio/vfio_ccw_private.h | 3 ++-
>   2 files changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
> index 1a095085bc72..ed9ca77c5b23 100644
> --- a/drivers/s390/cio/vfio_ccw_drv.c
> +++ b/drivers/s390/cio/vfio_ccw_drv.c
> @@ -35,6 +35,7 @@ debug_info_t *vfio_ccw_debug_trace_id;
>    * Helpers
>    */
>   int vfio_ccw_sch_quiesce(struct subchannel *sch)
> +	__must_hold(&sch->lock);
Looks like this ; is wrong     ^

will fixup when applying.

>   {
>   	struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
>   	struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
> diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
> index 0501d4bbcdbd..8db29519dbfd 100644
> --- a/drivers/s390/cio/vfio_ccw_private.h
> +++ b/drivers/s390/cio/vfio_ccw_private.h
> @@ -127,7 +127,8 @@ struct vfio_ccw_private {
>   	struct work_struct	crw_work;
>   } __aligned(8);
>   
> -int vfio_ccw_sch_quiesce(struct subchannel *sch);
> +int vfio_ccw_sch_quiesce(struct subchannel *sch)
> +	__must_hold(&sch->lock);
>   void vfio_ccw_sch_io_todo(struct work_struct *work);
>   void vfio_ccw_crw_todo(struct work_struct *work);
>