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authorThomas Gleixner <tglx@linutronix.de>2010-04-06 16:51:31 +0200
committerClark Williams <williams@redhat.com>2011-12-28 16:25:43 -0600
commit133993c72b8b765134b4fb81aa7036a6b7f223c0 (patch)
tree22d238609c502107d00a54cb7984200e62108336
parenta55fe21283d39b3ae46e4a904c7ff5d094a6d86f (diff)
md: raid5: Make raid5_percpu handling RT aware
__raid_run_ops() disables preemption with get_cpu() around the access to the raid5_percpu variables. That causes scheduling while atomic spews on RT. Serialize the access to the percpu data with a lock and keep the code preemptible. Reported-by: Udo van den Heuvel <udovdh@xs4all.nl> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Udo van den Heuvel <udovdh@xs4all.nl>
-rw-r--r--drivers/md/raid5.c7
-rw-r--r--drivers/md/raid5.h1
2 files changed, 6 insertions, 2 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 31670f8d6b65..2b0b96c192c9 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1245,8 +1245,9 @@ static void __raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
struct raid5_percpu *percpu;
unsigned long cpu;
- cpu = get_cpu();
+ cpu = get_cpu_light();
percpu = per_cpu_ptr(conf->percpu, cpu);
+ spin_lock(&percpu->lock);
if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
ops_run_biofill(sh);
overlap_clear++;
@@ -1298,7 +1299,8 @@ static void __raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
if (test_and_clear_bit(R5_Overlap, &dev->flags))
wake_up(&sh->raid_conf->wait_for_overlap);
}
- put_cpu();
+ spin_unlock(&percpu->lock);
+ put_cpu_light();
}
#ifdef CONFIG_MULTICORE_RAID456
@@ -4533,6 +4535,7 @@ static int raid5_alloc_percpu(struct r5conf *conf)
break;
}
per_cpu_ptr(conf->percpu, cpu)->scribble = scribble;
+ spin_lock_init(&per_cpu_ptr(conf->percpu, cpu)->lock);
}
#ifdef CONFIG_HOTPLUG_CPU
conf->cpu_notify.notifier_call = raid456_cpu_notify;
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index e10c5531f9c5..010a96916bc2 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -405,6 +405,7 @@ struct r5conf {
int recovery_disabled;
/* per cpu variables */
struct raid5_percpu {
+ spinlock_t lock; /* Protection for -RT */
struct page *spare_page; /* Used when checking P/Q in raid6 */
void *scribble; /* space for constructing buffer
* lists and performing address