Re: [PATCH 12/14] staging: lustre: llog: change lgh_hdr_lock to mutex

[Greg Kroah-Hartman]

On Sat, Feb 18, 2017 at 04:47:13PM -0500, James Simmons wrote:
> From: wang di <di.wang@xxxxxxxxx>
> 
> Change lgh_hdr_lock from spinlock to mutex because if
> the llog object is a remote object it can be stalled
> while being fetched.

but this lock is never even used!  Why have it at all?

> 
> Signed-off-by: wang di <di.wang@xxxxxxxxx>
> Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6602
> Reviewed-on: http://review.whamcloud.com/15274
> Reviewed-by: James Simmons <uja.ornl@xxxxxxxxx>
> Reviewed-by: Lai Siyao <lai.siyao@xxxxxxxxx>
> Reviewed-by: Oleg Drokin <oleg.drokin@xxxxxxxxx>
> Signed-off-by: James Simmons <jsimmons@xxxxxxxxxxxxx>
> ---
>  drivers/staging/lustre/lustre/include/lustre_log.h | 2 +-
>  drivers/staging/lustre/lustre/obdclass/llog.c      | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/lustre/lustre/include/lustre_log.h b/drivers/staging/lustre/lustre/include/lustre_log.h
> index 35e37eb..33f56ff 100644
> --- a/drivers/staging/lustre/lustre/include/lustre_log.h
> +++ b/drivers/staging/lustre/lustre/include/lustre_log.h
> @@ -211,7 +211,7 @@ struct llog_operations {
>  /* In-memory descriptor for a log object or log catalog */
>  struct llog_handle {
>  	struct rw_semaphore	 lgh_lock;
> -	spinlock_t		 lgh_hdr_lock; /* protect lgh_hdr data */
> +	struct mutex		 lgh_hdr_mutex; /* protect lgh_hdr data */
>  	struct llog_logid	 lgh_id; /* id of this log */
>  	struct llog_log_hdr	*lgh_hdr;
>  	size_t			 lgh_hdr_size;
> diff --git a/drivers/staging/lustre/lustre/obdclass/llog.c b/drivers/staging/lustre/lustre/obdclass/llog.c
> index 736ea10..83c5b62 100644
> --- a/drivers/staging/lustre/lustre/obdclass/llog.c
> +++ b/drivers/staging/lustre/lustre/obdclass/llog.c
> @@ -61,7 +61,7 @@ static struct llog_handle *llog_alloc_handle(void)
>  		return NULL;
>  
>  	init_rwsem(&loghandle->lgh_lock);
> -	spin_lock_init(&loghandle->lgh_hdr_lock);
> +	mutex_init(&loghandle->lgh_hdr_mutex);

Can't we delete it?

thanks,

greg k-h