linux-kernel - [PATCH 14/15] dm kcopyd: change mutex to spinlock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.LRH.2.02.1512101216180.25927@file01.intranet.prod.int.rdu2.redhat.com>
Date:	Thu, 10 Dec 2015 12:31:15 -0500 (EST)
From:	Mikulas Patocka <mpatocka@...hat.com>
To:	"James E.J. Bottomley" <JBottomley@...n.com>,
	"Martin K. Petersen" <martin.petersen@...cle.com>,
	Jens Axboe <axboe@...nel.dk>,
	Mike Snitzer <msnitzer@...hat.com>,
	Jonathan Brassow <jbrassow@...hat.com>
cc:	dm-devel@...hat.com, linux-scsi@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-block@...r.kernel.org
Subject: [PATCH 14/15] dm kcopyd: change mutex to spinlock

job->lock is only taken for a finite amount of time and the process
doesn't block while holding it, so change it from mutex to spinlock.

This change is needed for the next patch that makes it possible to call
segment_complete from an interrupt. Taking mutexes inside an interrupt is
not allowed.

Signed-off-by: Mikulas Patocka <mpatocka@...hat.com>

---
 drivers/md/dm-kcopyd.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

Index: linux-3.16-rc5/drivers/md/dm-kcopyd.c
===================================================================
--- linux-3.16-rc5.orig/drivers/md/dm-kcopyd.c	2014-07-15 19:20:34.000000000 +0200
+++ linux-3.16-rc5/drivers/md/dm-kcopyd.c	2014-07-15 19:24:20.000000000 +0200
@@ -21,7 +21,7 @@
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/workqueue.h>
-#include <linux/mutex.h>
+#include <linux/spinlock.h>
 #include <linux/delay.h>
 #include <linux/device-mapper.h>
 #include <linux/dm-kcopyd.h>
@@ -356,7 +356,7 @@ struct kcopyd_job {
 	 * These fields are only used if the job has been split
 	 * into more manageable parts.
 	 */
-	struct mutex lock;
+	spinlock_t lock;
 	atomic_t sub_jobs;
 	sector_t progress;
 
@@ -629,7 +629,7 @@ static void segment_complete(int read_er
 	struct kcopyd_job *job = sub_job->master_job;
 	struct dm_kcopyd_client *kc = job->kc;
 
-	mutex_lock(&job->lock);
+	spin_lock(&job->lock);
 
 	/* update the error */
 	if (read_err)
@@ -653,7 +653,7 @@ static void segment_complete(int read_er
 			job->progress += count;
 		}
 	}
-	mutex_unlock(&job->lock);
+	spin_unlock(&job->lock);
 
 	if (count) {
 		int i;
@@ -708,7 +708,7 @@ static void submit_job(struct kcopyd_job
 	if (job->source.count <= SUB_JOB_SIZE)
 		dispatch_job(job);
 	else {
-		mutex_init(&job->lock);
+		spin_lock_init(&job->lock);
 		job->progress = 0;
 		split_job(job);
 	}

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/