Re: [PATCH 1/2] s390/con3215: Add __must_hold() attribute to raw3215_make_room()

[Sven Schnelle <svens@linux.ibm.com>]

Heiko Carstens <hca@linux.ibm.com> writes:

> Add __must_hold() attribute to raw3215_make_room() in order to let
> clang's context analysis know that "get_ccwdev_lock(raw->cdev)" 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/char/con3215.c:485:9: warning:
>   expecting spinlock 'raw->cdev->ccwlock' to be held at start of each loop [-Wthread-safety-analysis]
>   485 |         while (RAW3215_BUFFER_SIZE - raw->count < length) {
>
> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
> ---
>  drivers/s390/char/con3215.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c
> index 46265f4fbfd8..57fefa8986d6 100644
> --- a/drivers/s390/char/con3215.c
> +++ b/drivers/s390/char/con3215.c
> @@ -481,6 +481,7 @@ static unsigned int raw3215_drop(struct raw3215_info *raw)
>   */
>  static unsigned int raw3215_make_room(struct raw3215_info *raw,
>  				      unsigned int length, bool drop)
> +	__must_hold(get_ccwdev_lock(raw->cdev))
>  {
>  	while (RAW3215_BUFFER_SIZE - raw->count < length) {
>  		if (drop)

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>