[S390] dasd: fix race between tasklet and dasd_sleep_on

[sfrench/cifs-2.6.git] / drivers / s390 / block / dasd.c

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index acf222f91f5a97ac0564c25a5bea9386466d045b..fa2339cb1681f43fb19e337ad037f75d908b8d89 100644 (file)
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -37,6 +37,9 @@
  */
 #define DASD_CHANQ_MAX_SIZE 4
 
+#define DASD_SLEEPON_START_TAG (void *) 1
+#define DASD_SLEEPON_END_TAG   (void *) 2
+
 /*
  * SECTION: exported variables of dasd.c
  */
@@ -1472,7 +1475,10 @@ void dasd_add_request_tail(struct dasd_ccw_req *cqr)
  */
 static void dasd_wakeup_cb(struct dasd_ccw_req *cqr, void *data)
 {
-       wake_up((wait_queue_head_t *) data);
+       spin_lock_irq(get_ccwdev_lock(cqr->startdev->cdev));
+       cqr->callback_data = DASD_SLEEPON_END_TAG;
+       spin_unlock_irq(get_ccwdev_lock(cqr->startdev->cdev));
+       wake_up(&generic_waitq);
 }
 
 static inline int _wait_for_wakeup(struct dasd_ccw_req *cqr)
@@ -1482,10 +1488,7 @@ static inline int _wait_for_wakeup(struct dasd_ccw_req *cqr)
 
        device = cqr->startdev;
        spin_lock_irq(get_ccwdev_lock(device->cdev));
-       rc = ((cqr->status == DASD_CQR_DONE ||
-              cqr->status == DASD_CQR_NEED_ERP ||
-              cqr->status == DASD_CQR_TERMINATED) &&
-             list_empty(&cqr->devlist));
+       rc = (cqr->callback_data == DASD_SLEEPON_END_TAG);
        spin_unlock_irq(get_ccwdev_lock(device->cdev));
        return rc;
 }
@@ -1573,7 +1576,7 @@ static int _dasd_sleep_on(struct dasd_ccw_req *maincqr, int interruptible)
                        wait_event(generic_waitq, !(device->stopped));
 
                cqr->callback = dasd_wakeup_cb;
-               cqr->callback_data = (void *) &generic_waitq;
+               cqr->callback_data = DASD_SLEEPON_START_TAG;
                dasd_add_request_tail(cqr);
                if (interruptible) {
                        rc = wait_event_interruptible(
@@ -1652,7 +1655,7 @@ int dasd_sleep_on_immediatly(struct dasd_ccw_req *cqr)
        }
 
        cqr->callback = dasd_wakeup_cb;
-       cqr->callback_data = (void *) &generic_waitq;
+       cqr->callback_data = DASD_SLEEPON_START_TAG;
        cqr->status = DASD_CQR_QUEUED;
        list_add(&cqr->devlist, &device->ccw_queue);