1 files changed, 39 insertions, 21 deletions

diff --git a/drivers/s390/cio/chp.c b/drivers/s390/cio/chp.c
index e96aced58627..46be25c7461e 100644
--- a/drivers/s390/cio/chp.c
+++ b/drivers/s390/cio/chp.c
@@ -37,8 +37,7 @@ enum cfg_task_t {
 
 /* Map for pending configure tasks. */
 static enum cfg_task_t chp_cfg_task[__MAX_CSSID + 1][__MAX_CHPID + 1];
-static DEFINE_MUTEX(cfg_lock);
-static int cfg_busy;
+static DEFINE_SPINLOCK(cfg_lock);
 
 /* Map for channel-path status. */
 static struct sclp_chp_info chp_info;
@@ -666,6 +665,20 @@ static void cfg_set_task(struct chp_id chpid, enum cfg_task_t cfg)
 	chp_cfg_task[chpid.cssid][chpid.id] = cfg;
 }
 
+/* Fetch the first configure task. Set chpid accordingly. */
+static enum cfg_task_t chp_cfg_fetch_task(struct chp_id *chpid)
+{
+	enum cfg_task_t t = cfg_none;
+
+	chp_id_for_each(chpid) {
+		t = cfg_get_task(*chpid);
+		if (t != cfg_none)
+			break;
+	}
+
+	return t;
+}
+
 /* Perform one configure/deconfigure request. Reschedule work function until
  * last request. */
 static void cfg_func(struct work_struct *work)
@@ -674,16 +687,9 @@ static void cfg_func(struct work_struct *work)
 	enum cfg_task_t t;
 	int rc;
 
-	mutex_lock(&cfg_lock);
-	t = cfg_none;
-	chp_id_for_each(&chpid) {
-		t = cfg_get_task(chpid);
-		if (t != cfg_none) {
-			cfg_set_task(chpid, cfg_none);
-			break;
-		}
-	}
-	mutex_unlock(&cfg_lock);
+	spin_lock(&cfg_lock);
+	t = chp_cfg_fetch_task(&chpid);
+	spin_unlock(&cfg_lock);
 
 	switch (t) {
 	case cfg_configure:
@@ -709,12 +715,13 @@ static void cfg_func(struct work_struct *work)
 	case cfg_none:
 		/* Get updated information after last change. */
 		info_update();
-		mutex_lock(&cfg_lock);
-		cfg_busy = 0;
-		mutex_unlock(&cfg_lock);
 		wake_up_interruptible(&cfg_wait_queue);
 		return;
 	}
+	spin_lock(&cfg_lock);
+	if (t == cfg_get_task(chpid))
+		cfg_set_task(chpid, cfg_none);
+	spin_unlock(&cfg_lock);
 	schedule_work(&cfg_work);
 }
 
@@ -729,10 +736,9 @@ void chp_cfg_schedule(struct chp_id chpid, int configure)
 {
 	CIO_MSG_EVENT(2, "chp_cfg_sched%x.%02x=%d\n", chpid.cssid, chpid.id,
 		      configure);
-	mutex_lock(&cfg_lock);
+	spin_lock(&cfg_lock);
 	cfg_set_task(chpid, configure ? cfg_configure : cfg_deconfigure);
-	cfg_busy = 1;
-	mutex_unlock(&cfg_lock);
+	spin_unlock(&cfg_lock);
 	schedule_work(&cfg_work);
 }
 
@@ -746,15 +752,27 @@ void chp_cfg_schedule(struct chp_id chpid, int configure)
 void chp_cfg_cancel_deconfigure(struct chp_id chpid)
 {
 	CIO_MSG_EVENT(2, "chp_cfg_cancel:%x.%02x\n", chpid.cssid, chpid.id);
-	mutex_lock(&cfg_lock);
+	spin_lock(&cfg_lock);
 	if (cfg_get_task(chpid) == cfg_deconfigure)
 		cfg_set_task(chpid, cfg_none);
-	mutex_unlock(&cfg_lock);
+	spin_unlock(&cfg_lock);
+}
+
+static bool cfg_idle(void)
+{
+	struct chp_id chpid;
+	enum cfg_task_t t;
+
+	spin_lock(&cfg_lock);
+	t = chp_cfg_fetch_task(&chpid);
+	spin_unlock(&cfg_lock);
+
+	return t == cfg_none;
 }
 
 static int cfg_wait_idle(void)
 {
-	if (wait_event_interruptible(cfg_wait_queue, !cfg_busy))
+	if (wait_event_interruptible(cfg_wait_queue, cfg_idle()))
 		return -ERESTARTSYS;
 	return 0;
 }