s390/cio: convert cfg_lock mutex to spinlock

cfg_lock is never held long and we don't want to sleep while the
lock is being held. Thus it can be converted to a simple spinlock.
In addition we can now use the lock during the evaluation of a
wake_up condition.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/drivers/s390/cio/chp.c b/drivers/s390/cio/chp.c
index e96aced5862714bb2c41558ced331f9603d65dab..c602211ab94ee69d25b3954472dad82e98088db4 100644 (file)
--- a/drivers/s390/cio/chp.c
+++ b/drivers/s390/cio/chp.c
@@ -37,7 +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 DEFINE_SPINLOCK(cfg_lock);
 static int cfg_busy;
 
 /* Map for channel-path status. */
@@ -674,7 +674,7 @@ static void cfg_func(struct work_struct *work)
        enum cfg_task_t t;
        int rc;
 
-       mutex_lock(&cfg_lock);
+       spin_lock(&cfg_lock);
        t = cfg_none;
        chp_id_for_each(&chpid) {
                t = cfg_get_task(chpid);
@@ -683,7 +683,7 @@ static void cfg_func(struct work_struct *work)
                        break;
                }
        }
-       mutex_unlock(&cfg_lock);
+       spin_unlock(&cfg_lock);
 
        switch (t) {
        case cfg_configure:
@@ -709,9 +709,9 @@ static void cfg_func(struct work_struct *work)
        case cfg_none:
                /* Get updated information after last change. */
                info_update();
-               mutex_lock(&cfg_lock);
+               spin_lock(&cfg_lock);
                cfg_busy = 0;
-               mutex_unlock(&cfg_lock);
+               spin_unlock(&cfg_lock);
                wake_up_interruptible(&cfg_wait_queue);
                return;
        }
@@ -729,10 +729,10 @@ 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);
 }
 
@@ -746,10 +746,10 @@ 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 int cfg_wait_idle(void)