Re: [PATCH 2/2] staging: lustre: lnet: Replace semaphore ln_rc_signal with completion

From: James Simmons <jsimmons@infradead.org>
To: Binoy Jayan <binoy.jayan@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Oleg Drokin <oleg.drokin@intel.com>,
	Andreas Dilger <andreas.dilger@intel.com>,
	lustre-devel@lists.lustre.org,
	driverdev-devel@linuxdriverproject.org,
	linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH 2/2] staging: lustre: lnet: Replace semaphore ln_rc_signal with completion
Date: Wed, 8 Jun 2016 23:52:00 +0100 (BST)	[thread overview]
Message-ID: <alpine.LFD.2.20.1606082351370.30765@casper.infradead.org> (raw)
In-Reply-To: <1465372242-7116-3-git-send-email-binoy.jayan@linaro.org>

> The semaphore ln_rc_signal is used as completion, so convert it to
> struct completion.  Semaphores are going away in the future.
> 
> Signed-off-by: Binoy Jayan <binoy.jayan@linaro.org>

No problems in testing.

Acked-by: James Simmons <jsimmons@infradead.org>

> ---
>  drivers/staging/lustre/include/linux/lnet/lib-types.h | 3 ++-
>  drivers/staging/lustre/lnet/lnet/router.c             | 9 +++++----
>  2 files changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/staging/lustre/include/linux/lnet/lib-types.h b/drivers/staging/lustre/include/linux/lnet/lib-types.h
> index 24c4a08..7967b01 100644
> --- a/drivers/staging/lustre/include/linux/lnet/lib-types.h
> +++ b/drivers/staging/lustre/include/linux/lnet/lib-types.h
> @@ -38,6 +38,7 @@
>  #include <linux/kthread.h>
>  #include <linux/uio.h>
>  #include <linux/types.h>
> +#include <linux/completion.h>
>  
>  #include "types.h"
>  #include "lnetctl.h"
> @@ -610,7 +611,7 @@ typedef struct {
>  	/* rcd ready for free */
>  	struct list_head		  ln_rcd_zombie;
>  	/* serialise startup/shutdown */
> -	struct semaphore		  ln_rc_signal;
> +	struct completion		  ln_rc_signal;
>  
>  	struct mutex			  ln_api_mutex;
>  	struct mutex			  ln_lnd_mutex;
> diff --git a/drivers/staging/lustre/lnet/lnet/router.c b/drivers/staging/lustre/lnet/lnet/router.c
> index b01dc42..0635432 100644
> --- a/drivers/staging/lustre/lnet/lnet/router.c
> +++ b/drivers/staging/lustre/lnet/lnet/router.c
> @@ -18,6 +18,7 @@
>   */
>  
>  #define DEBUG_SUBSYSTEM S_LNET
> +#include <linux/completion.h>
>  #include "../../include/linux/lnet/lib-lnet.h"
>  
>  #define LNET_NRB_TINY_MIN	512	/* min value for each CPT */
> @@ -1065,7 +1066,7 @@ lnet_router_checker_start(void)
>  		return -EINVAL;
>  	}
>  
> -	sema_init(&the_lnet.ln_rc_signal, 0);
> +	init_completion(&the_lnet.ln_rc_signal);
>  
>  	rc = LNetEQAlloc(0, lnet_router_checker_event, &the_lnet.ln_rc_eqh);
>  	if (rc) {
> @@ -1079,7 +1080,7 @@ lnet_router_checker_start(void)
>  		rc = PTR_ERR(task);
>  		CERROR("Can't start router checker thread: %d\n", rc);
>  		/* block until event callback signals exit */
> -		down(&the_lnet.ln_rc_signal);
> +		wait_for_completion(&the_lnet.ln_rc_signal);
>  		rc = LNetEQFree(the_lnet.ln_rc_eqh);
>  		LASSERT(!rc);
>  		the_lnet.ln_rc_state = LNET_RC_STATE_SHUTDOWN;
> @@ -1112,7 +1113,7 @@ lnet_router_checker_stop(void)
>  	wake_up(&the_lnet.ln_rc_waitq);
>  
>  	/* block until event callback signals exit */
> -	down(&the_lnet.ln_rc_signal);
> +	wait_for_completion(&the_lnet.ln_rc_signal);
>  	LASSERT(the_lnet.ln_rc_state == LNET_RC_STATE_SHUTDOWN);
>  
>  	rc = LNetEQFree(the_lnet.ln_rc_eqh);
> @@ -1295,7 +1296,7 @@ rescan:
>  	lnet_prune_rc_data(1); /* wait for UNLINK */
>  
>  	the_lnet.ln_rc_state = LNET_RC_STATE_SHUTDOWN;
> -	up(&the_lnet.ln_rc_signal);
> +	complete(&the_lnet.ln_rc_signal);
>  	/* The unlink event callback will signal final completion */
>  	return 0;
>  }
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 
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