Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[cascardo/linux.git] / drivers / s390 / cio / chp.c

diff --git a/drivers/s390/cio/chp.c b/drivers/s390/cio/chp.c
index e96aced..46be25c 100644 (file)
--- 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;
 }