Linux 3.10.49

[firefly-linux-kernel-4.4.55.git] / block / elevator.c

diff --git a/block/elevator.c b/block/elevator.c
index a0ffdd943c98aa5e0f39f102b98f1bc4cf9777f5..6d765f7e2b2bd905984ee54fc4dde56d1f5d1744 100644 (file)
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -34,6 +34,7 @@
 #include <linux/blktrace_api.h>
 #include <linux/hash.h>
 #include <linux/uaccess.h>
+#include <linux/pm_runtime.h>
 
 #include <trace/events/block.h>
 
@@ -149,7 +150,7 @@ void __init load_default_elevator_module(void)
 
 static struct kobj_type elv_ktype;
 
-static struct elevator_queue *elevator_alloc(struct request_queue *q,
+struct elevator_queue *elevator_alloc(struct request_queue *q,
                                  struct elevator_type *e)
 {
        struct elevator_queue *eq;
@@ -169,6 +170,7 @@ err:
        elevator_put(e);
        return NULL;
 }
+EXPORT_SYMBOL(elevator_alloc);
 
 static void elevator_release(struct kobject *kobj)
 {
@@ -184,6 +186,12 @@ int elevator_init(struct request_queue *q, char *name)
        struct elevator_type *e = NULL;
        int err;
 
+       /*
+        * q->sysfs_lock must be held to provide mutual exclusion between
+        * elevator_switch() and here.
+        */
+       lockdep_assert_held(&q->sysfs_lock);
+
        if (unlikely(q->elevator))
                return 0;
 
@@ -220,16 +228,7 @@ int elevator_init(struct request_queue *q, char *name)
                }
        }
 
-       q->elevator = elevator_alloc(q, e);
-       if (!q->elevator)
-               return -ENOMEM;
-
-       err = e->ops.elevator_init_fn(q);
-       if (err) {
-               kobject_put(&q->elevator->kobj);
-               return err;
-       }
-
+       err = e->ops.elevator_init_fn(q, e);
        return 0;
 }
 EXPORT_SYMBOL(elevator_init);
@@ -536,6 +535,27 @@ void elv_bio_merged(struct request_queue *q, struct request *rq,
                e->type->ops.elevator_bio_merged_fn(q, rq, bio);
 }
 
+#ifdef CONFIG_PM_RUNTIME
+static void blk_pm_requeue_request(struct request *rq)
+{
+       if (rq->q->dev && !(rq->cmd_flags & REQ_PM))
+               rq->q->nr_pending--;
+}
+
+static void blk_pm_add_request(struct request_queue *q, struct request *rq)
+{
+       if (q->dev && !(rq->cmd_flags & REQ_PM) && q->nr_pending++ == 0 &&
+           (q->rpm_status == RPM_SUSPENDED || q->rpm_status == RPM_SUSPENDING))
+               pm_request_resume(q->dev);
+}
+#else
+static inline void blk_pm_requeue_request(struct request *rq) {}
+static inline void blk_pm_add_request(struct request_queue *q,
+                                     struct request *rq)
+{
+}
+#endif
+
 void elv_requeue_request(struct request_queue *q, struct request *rq)
 {
        /*
@@ -550,6 +570,8 @@ void elv_requeue_request(struct request_queue *q, struct request *rq)
 
        rq->cmd_flags &= ~REQ_STARTED;
 
+       blk_pm_requeue_request(rq);
+
        __elv_add_request(q, rq, ELEVATOR_INSERT_REQUEUE);
 }
 
@@ -572,6 +594,8 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where)
 {
        trace_block_rq_insert(q, rq);
 
+       blk_pm_add_request(q, rq);
+
        rq->q = q;
 
        if (rq->cmd_flags & REQ_SOFTBARRIER) {
@@ -909,16 +933,9 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e)
        spin_unlock_irq(q->queue_lock);
 
        /* allocate, init and register new elevator */
-       err = -ENOMEM;
-       q->elevator = elevator_alloc(q, new_e);
-       if (!q->elevator)
-               goto fail_init;
-
-       err = new_e->ops.elevator_init_fn(q);
-       if (err) {
-               kobject_put(&q->elevator->kobj);
+       err = new_e->ops.elevator_init_fn(q, new_e);
+       if (err)
                goto fail_init;
-       }
 
        if (registered) {
                err = elv_register_queue(q);
@@ -948,7 +965,7 @@ fail_init:
 /*
  * Switch this queue to the given IO scheduler.
  */
-int elevator_change(struct request_queue *q, const char *name)
+static int __elevator_change(struct request_queue *q, const char *name)
 {
        char elevator_name[ELV_NAME_MAX];
        struct elevator_type *e;
@@ -970,6 +987,18 @@ int elevator_change(struct request_queue *q, const char *name)
 
        return elevator_switch(q, e);
 }
+
+int elevator_change(struct request_queue *q, const char *name)
+{
+       int ret;
+
+       /* Protect q->elevator from elevator_init() */
+       mutex_lock(&q->sysfs_lock);
+       ret = __elevator_change(q, name);
+       mutex_unlock(&q->sysfs_lock);
+
+       return ret;
+}
 EXPORT_SYMBOL(elevator_change);
 
 ssize_t elv_iosched_store(struct request_queue *q, const char *name,
@@ -980,7 +1009,7 @@ ssize_t elv_iosched_store(struct request_queue *q, const char *name,
        if (!q->elevator)
                return count;
 
-       ret = elevator_change(q, name);
+       ret = __elevator_change(q, name);
        if (!ret)
                return count;