diff options
Diffstat (limited to 'features/rt/md-raid5-Make-raid5_percpu-handling-RT-aware.patch')
-rw-r--r-- | features/rt/md-raid5-Make-raid5_percpu-handling-RT-aware.patch | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/features/rt/md-raid5-Make-raid5_percpu-handling-RT-aware.patch b/features/rt/md-raid5-Make-raid5_percpu-handling-RT-aware.patch new file mode 100644 index 00000000..43380924 --- /dev/null +++ b/features/rt/md-raid5-Make-raid5_percpu-handling-RT-aware.patch @@ -0,0 +1,68 @@ +From 28893cffb6465718d2196b201ec4dc9e41aca776 Mon Sep 17 00:00:00 2001 +From: Thomas Gleixner <tglx@linutronix.de> +Date: Tue, 6 Apr 2010 16:51:31 +0200 +Subject: [PATCH 135/191] 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> +--- + drivers/md/raid5.c | 7 +++++-- + drivers/md/raid5.h | 1 + + 2 files changed, 6 insertions(+), 2 deletions(-) + +diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c +index 5d57a5bd171f..86d6a676a509 100644 +--- a/drivers/md/raid5.c ++++ b/drivers/md/raid5.c +@@ -2216,8 +2216,9 @@ 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++; +@@ -2276,7 +2277,8 @@ 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(); + } + + static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh) +@@ -7079,6 +7081,7 @@ static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node) + __func__, cpu); + return -ENOMEM; + } ++ spin_lock_init(&per_cpu_ptr(conf->percpu, cpu)->lock); + return 0; + } + +diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h +index 5c05acf20e1f..665fe138ab4f 100644 +--- a/drivers/md/raid5.h ++++ b/drivers/md/raid5.h +@@ -635,6 +635,7 @@ 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 +-- +2.19.1 + |