[lustre-devel] [PATCH 3/9] lustre: ptlrpc: use smp unsafe at_init only for initialization

[James Simmons]

> From: Vladimir Saveliev <vladimir.saveliev at seagate.com>
> 
> at_init() is not smp safe, so it is not supposed to be used anywhere
> but in at initialization.
> Add at_reinit() - safe version of at_init().

Reviewed-by: James Simmons <jsimmons at infradead.org>
 
> Signed-off-by: Vladimir Saveliev <vladimir.saveliev at seagate.com>
> WC-bug-id: https://jira.whamcloud.com/browse/LU-6805
> Reviewed-on: http://review.whamcloud.com/15522
> Reviewed-by: Andreas Dilger <andreas.dilger at intel.com>
> Reviewed-by: Chris Horn <hornc at cray.com>
> Signed-off-by: NeilBrown <neilb at suse.com>
> ---
>  .../staging/lustre/lustre/include/lustre_import.h  |   19 +++++++++++++++++--
>  drivers/staging/lustre/lustre/ptlrpc/import.c      |    2 +-
>  2 files changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/staging/lustre/lustre/include/lustre_import.h b/drivers/staging/lustre/lustre/include/lustre_import.h
> index a629f6bba814..8a8a125bd130 100644
> --- a/drivers/staging/lustre/lustre/include/lustre_import.h
> +++ b/drivers/staging/lustre/lustre/include/lustre_import.h
> @@ -331,12 +331,17 @@ static inline unsigned int at_timeout2est(unsigned int val)
>  	return (max((val << 2) / 5, 5U) - 4);
>  }
>  
> -static inline void at_reset(struct adaptive_timeout *at, int val)
> +static inline void at_reset_nolock(struct adaptive_timeout *at, int val)
>  {
> -	spin_lock(&at->at_lock);
>  	at->at_current = val;
>  	at->at_worst_ever = val;
>  	at->at_worst_time = ktime_get_real_seconds();
> +}
> +
> +static inline void at_reset(struct adaptive_timeout *at, int val)
> +{
> +	spin_lock(&at->at_lock);
> +	at_reset_nolock(at, val);
>  	spin_unlock(&at->at_lock);
>  }
>  
> @@ -348,6 +353,16 @@ static inline void at_init(struct adaptive_timeout *at, int val, int flags)
>  	at_reset(at, val);
>  }
>  
> +static inline void at_reinit(struct adaptive_timeout *at, int val, int flags)
> +{
> +	spin_lock(&at->at_lock);
> +	at->at_binstart = 0;
> +	memset(at->at_hist, 0, sizeof(at->at_hist));
> +	at->at_flags = flags;
> +	at_reset_nolock(at, val);
> +	spin_unlock(&at->at_lock);
> +}
> +
>  extern unsigned int at_min;
>  static inline int at_get(struct adaptive_timeout *at)
>  {
> diff --git a/drivers/staging/lustre/lustre/ptlrpc/import.c b/drivers/staging/lustre/lustre/ptlrpc/import.c
> index 07dc87d9513e..480c860d066e 100644
> --- a/drivers/staging/lustre/lustre/ptlrpc/import.c
> +++ b/drivers/staging/lustre/lustre/ptlrpc/import.c
> @@ -1036,7 +1036,7 @@ static int ptlrpc_connect_interpret(const struct lu_env *env,
>  	 * The net statistics after (re-)connect is not valid anymore,
>  	 * because may reflect other routing, etc.
>  	 */
> -	at_init(&imp->imp_at.iat_net_latency, 0, 0);
> +	at_reinit(&imp->imp_at.iat_net_latency, 0, 0);
>  	ptlrpc_at_adj_net_latency(request,
>  				  lustre_msg_get_service_time(request->rq_repmsg));
>  
> 
> 
>