blk-mq: revert raw locks, post pone notifier to POST_DEAD

The blk_mq_cpu_notify_lock should be raw because some CPU down levels
are called with interrupts off. The notifier itself calls currently one
function that is blk_mq_hctx_notify().
That function acquires the ctx->lock lock which is sleeping and I would
prefer to keep it that way. That function only moves IO-requests from
the CPU that is going offline to another CPU and it is currently the
only one. Therefore I revert the list lock back to sleeping spinlocks
and let the notifier run at POST_DEAD time.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

diff --git a/block/blk-mq-cpu.c b/block/blk-mq-cpu.c
index bb3ed488f7b5b26053e91dd3a5f02a0f2c472a70..628c6c13c48237ecab4238f2bead5f05fa9c3dbf 100644 (file)
--- a/block/blk-mq-cpu.c
+++ b/block/blk-mq-cpu.c
@@ -16,7 +16,7 @@
 #include "blk-mq.h"
 
 static LIST_HEAD(blk_mq_cpu_notify_list);
-static DEFINE_RAW_SPINLOCK(blk_mq_cpu_notify_lock);
+static DEFINE_SPINLOCK(blk_mq_cpu_notify_lock);
 
 static int blk_mq_main_cpu_notify(struct notifier_block *self,
                                  unsigned long action, void *hcpu)
@@ -25,7 +25,10 @@ static int blk_mq_main_cpu_notify(struct notifier_block *self,
        struct blk_mq_cpu_notifier *notify;
        int ret = NOTIFY_OK;
 
-       raw_spin_lock(&blk_mq_cpu_notify_lock);
+       if (action != CPU_POST_DEAD)
+               return NOTIFY_OK;
+
+       spin_lock(&blk_mq_cpu_notify_lock);
 
        list_for_each_entry(notify, &blk_mq_cpu_notify_list, list) {
                ret = notify->notify(notify->data, action, cpu);
@@ -33,7 +36,7 @@ static int blk_mq_main_cpu_notify(struct notifier_block *self,
                        break;
        }
 
-       raw_spin_unlock(&blk_mq_cpu_notify_lock);
+       spin_unlock(&blk_mq_cpu_notify_lock);
        return ret;
 }
 
@@ -41,16 +44,16 @@ void blk_mq_register_cpu_notifier(struct blk_mq_cpu_notifier *notifier)
 {
        BUG_ON(!notifier->notify);
 
-       raw_spin_lock(&blk_mq_cpu_notify_lock);
+       spin_lock(&blk_mq_cpu_notify_lock);
        list_add_tail(&notifier->list, &blk_mq_cpu_notify_list);
-       raw_spin_unlock(&blk_mq_cpu_notify_lock);
+       spin_unlock(&blk_mq_cpu_notify_lock);
 }
 
 void blk_mq_unregister_cpu_notifier(struct blk_mq_cpu_notifier *notifier)
 {
-       raw_spin_lock(&blk_mq_cpu_notify_lock);
+       spin_lock(&blk_mq_cpu_notify_lock);
        list_del(&notifier->list);
-       raw_spin_unlock(&blk_mq_cpu_notify_lock);
+       spin_unlock(&blk_mq_cpu_notify_lock);
 }
 
 void blk_mq_init_cpu_notifier(struct blk_mq_cpu_notifier *notifier,

diff --git a/block/blk-mq.c b/block/blk-mq.c
index d80a91cd8db3a800a9eb0efcf26821e1e9b05fae..b7f0ed2d35494e7ce85ea7475d5b96eb6c204575 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1601,7 +1601,7 @@ static int blk_mq_hctx_notify(void *data, unsigned long action,
 {
        struct blk_mq_hw_ctx *hctx = data;
 
-       if (action == CPU_DEAD || action == CPU_DEAD_FROZEN)
+       if (action == CPU_POST_DEAD)
                return blk_mq_hctx_cpu_offline(hctx, cpu);
 
        /*