[S390] dasd: fix device shutdown process.

Fix clear_IO handling (need to wait for interrupt) and
introduced error-handling in shutdown processing.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 137 insertions, 65 deletions

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index d8e9b95f0a1a..25c1ef6dfd44 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -52,7 +52,7 @@ static void dasd_setup_queue(struct dasd_device * device);
 static void dasd_free_queue(struct dasd_device * device);
 static void dasd_flush_request_queue(struct dasd_device *);
 static void dasd_int_handler(struct ccw_device *, unsigned long, struct irb *);
-static void dasd_flush_ccw_queue(struct dasd_device *, int);
+static int dasd_flush_ccw_queue(struct dasd_device *, int);
 static void dasd_tasklet(struct dasd_device *);
 static void do_kick_device(void *data);
 
@@ -60,6 +60,7 @@ static void do_kick_device(void *data);
  * SECTION: Operations on the device structure.
  */
 static wait_queue_head_t dasd_init_waitq;
+static wait_queue_head_t dasd_flush_wq;
 
 /*
  * Allocate memory for a new device structure.
@@ -121,7 +122,7 @@ dasd_free_device(struct dasd_device *device)
 /*
  * Make a new device known to the system.
  */
-static inline int
+static int
 dasd_state_new_to_known(struct dasd_device *device)
 {
         int rc;
@@ -145,7 +146,7 @@ dasd_state_new_to_known(struct dasd_device *device)
 /*
  * Let the system forget about a device.
  */
-static inline void
+static int
 dasd_state_known_to_new(struct dasd_device * device)
 {
         /* Disable extended error reporting for this device. */
@@ -163,12 +164,13 @@ dasd_state_known_to_new(struct dasd_device * device)
 
         /* Give up reference we took in dasd_state_new_to_known. */
         dasd_put_device(device);
+        return 0;
 }
 
 /*
  * Request the irq line for the device.
  */
-static inline int
+static int
 dasd_state_known_to_basic(struct dasd_device * device)
 {
         int rc;
@@ -192,17 +194,23 @@ dasd_state_known_to_basic(struct dasd_device * device)
 /*
  * Release the irq line for the device. Terminate any running i/o.
  */
-static inline void
+static int
 dasd_state_basic_to_known(struct dasd_device * device)
 {
+        int rc;
+
         dasd_gendisk_free(device);
-        dasd_flush_ccw_queue(device, 1);
+        rc = dasd_flush_ccw_queue(device, 1);
+        if (rc)
+                return rc;
+
         DBF_DEV_EVENT(DBF_EMERG, device, "%p debug area deleted", device);
         if (device->debug_area != NULL) {
                 debug_unregister(device->debug_area);
                 device->debug_area = NULL;
         }
         device->state = DASD_STATE_KNOWN;
+        return 0;
 }
 
 /*
@@ -219,7 +227,7 @@ dasd_state_basic_to_known(struct dasd_device * device)
  * In case the analysis returns an error, the device setup is stopped
  * (a fake disk was already added to allow formatting).
  */
-static inline int
+static int
 dasd_state_basic_to_ready(struct dasd_device * device)
 {
         int rc;
@@ -247,25 +255,31 @@ dasd_state_basic_to_ready(struct dasd_device * device)
  * Forget format information. Check if the target level is basic
  * and if it is create fake disk for formatting.
  */
-static inline void
+static int
 dasd_state_ready_to_basic(struct dasd_device * device)
 {
-        dasd_flush_ccw_queue(device, 0);
+        int rc;
+
+        rc = dasd_flush_ccw_queue(device, 0);
+        if (rc)
+                return rc;
         dasd_destroy_partitions(device);
         dasd_flush_request_queue(device);
         device->blocks = 0;
         device->bp_block = 0;
         device->s2b_shift = 0;
         device->state = DASD_STATE_BASIC;
+        return 0;
 }
 
 /*
  * Back to basic.
  */
-static inline void
+static int
 dasd_state_unfmt_to_basic(struct dasd_device * device)
 {
         device->state = DASD_STATE_BASIC;
+        return 0;
 }
 
 /*
@@ -273,7 +287,7 @@ dasd_state_unfmt_to_basic(struct dasd_device * device)
  * the requeueing of requests from the linux request queue to the
  * ccw queue.
  */
-static inline int
+static int
 dasd_state_ready_to_online(struct dasd_device * device)
 {
         device->state = DASD_STATE_ONLINE;
@@ -284,16 +298,17 @@ dasd_state_ready_to_online(struct dasd_device * device)
 /*
  * Stop the requeueing of requests again.
  */
-static inline void
+static int
 dasd_state_online_to_ready(struct dasd_device * device)
 {
         device->state = DASD_STATE_READY;
+        return 0;
 }
 
 /*
  * Device startup state changes.
  */
-static inline int
+static int
 dasd_increase_state(struct dasd_device *device)
 {
         int rc;
@@ -329,30 +344,37 @@ dasd_increase_state(struct dasd_device *device)
 /*
  * Device shutdown state changes.
  */
-static inline int
+static int
 dasd_decrease_state(struct dasd_device *device)
 {
+        int rc;
+
+        rc = 0;
         if (device->state == DASD_STATE_ONLINE &&
             device->target <= DASD_STATE_READY)
-                dasd_state_online_to_ready(device);
+                rc = dasd_state_online_to_ready(device);
 
-        if (device->state == DASD_STATE_READY &&
+        if (!rc &&
+            device->state == DASD_STATE_READY &&
             device->target <= DASD_STATE_BASIC)
-                dasd_state_ready_to_basic(device);
+                rc = dasd_state_ready_to_basic(device);
 
-        if (device->state == DASD_STATE_UNFMT &&
+        if (!rc &&
+            device->state == DASD_STATE_UNFMT &&
             device->target <= DASD_STATE_BASIC)
-                dasd_state_unfmt_to_basic(device);
+                rc = dasd_state_unfmt_to_basic(device);
 
-        if (device->state == DASD_STATE_BASIC &&
+        if (!rc &&
+            device->state == DASD_STATE_BASIC &&
             device->target <= DASD_STATE_KNOWN)
-                dasd_state_basic_to_known(device);
+                rc = dasd_state_basic_to_known(device);
 
-        if (device->state == DASD_STATE_KNOWN &&
+        if (!rc &&
+            device->state == DASD_STATE_KNOWN &&
             device->target <= DASD_STATE_NEW)
-                dasd_state_known_to_new(device);
+                rc = dasd_state_known_to_new(device);
 
-        return 0;
+        return rc;
 }
 
 /*
@@ -701,6 +723,7 @@ dasd_term_IO(struct dasd_ccw_req * cqr)
                         cqr->retries--;
                         cqr->status = DASD_CQR_CLEAR;
                         cqr->stopclk = get_clock();
+                        cqr->starttime = 0;
                         DBF_DEV_EVENT(DBF_DEBUG, device,
                                       "terminate cqr %p successful",
                                       cqr);
@@ -978,6 +1001,7 @@ dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
             irb->scsw.fctl & SCSW_FCTL_CLEAR_FUNC) {
                 cqr->status = DASD_CQR_QUEUED;
                 dasd_clear_timer(device);
+                wake_up(&dasd_flush_wq);
                 dasd_schedule_bh(device);
                 return;
         }
@@ -1241,6 +1265,10 @@ __dasd_check_expire(struct dasd_device * device)
         cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, list);
         if (cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) {
                 if (time_after_eq(jiffies, cqr->expires + cqr->starttime)) {
+                        DEV_MESSAGE(KERN_ERR, device,
+                                    "internal error - timeout (%is) expired "
+                                    "for cqr %p (%i retries left)",
+                                    (cqr->expires/HZ), cqr, cqr->retries);
                         if (device->discipline->term_IO(cqr) != 0)
                                 /* Hmpf, try again in 1/10 sec */
                                 dasd_set_timer(device, 10);
@@ -1285,46 +1313,100 @@ __dasd_start_head(struct dasd_device * device)
                 dasd_set_timer(device, 50);
 }
 
+static inline int
+_wait_for_clear(struct dasd_ccw_req *cqr)
+{
+        return (cqr->status == DASD_CQR_QUEUED);
+}
+
 /*
- * Remove requests from the ccw queue.
+ * Remove all requests from the ccw queue (all = '1') or only block device
+ * requests in case all = '0'.
+ * Take care of the erp-chain (chained via cqr->refers) and remove either
+ * the whole erp-chain or none of the erp-requests.
+ * If a request is currently running, term_IO is called and the request
+ * is re-queued. Prior to removing the terminated request we need to wait
+ * for the clear-interrupt.
+ * In case termination is not possible we stop processing and just finishing
+ * the already moved requests.
  */
-static void
+static int
 dasd_flush_ccw_queue(struct dasd_device * device, int all)
 {
+        struct dasd_ccw_req *cqr, *orig, *n;
+        int rc, i;
+
         struct list_head flush_queue;
-        struct list_head *l, *n;
-        struct dasd_ccw_req *cqr;
 
         INIT_LIST_HEAD(&flush_queue);
         spin_lock_irq(get_ccwdev_lock(device->cdev));
-        list_for_each_safe(l, n, &device->ccw_queue) {
-                cqr = list_entry(l, struct dasd_ccw_req, list);
+        rc = 0;
+restart:
+        list_for_each_entry_safe(cqr, n, &device->ccw_queue, list) {
+                /* get original request of erp request-chain */
+                for (orig = cqr; orig->refers != NULL; orig = orig->refers);
+
                 /* Flush all request or only block device requests? */
-                if (all == 0 && cqr->callback == dasd_end_request_cb)
+                if (all == 0 && cqr->callback != dasd_end_request_cb &&
+                    orig->callback != dasd_end_request_cb) {
                         continue;
-                if (cqr->status == DASD_CQR_IN_IO)
-                        device->discipline->term_IO(cqr);
-                if (cqr->status != DASD_CQR_DONE ||
-                    cqr->status != DASD_CQR_FAILED) {
-                        cqr->status = DASD_CQR_FAILED;
+                }
+                /* Check status and move request to flush_queue */
+                switch (cqr->status) {
+                case DASD_CQR_IN_IO:
+                        rc = device->discipline->term_IO(cqr);
+                        if (rc) {
+                                /* unable to terminate requeust */
+                                DEV_MESSAGE(KERN_ERR, device,
+                                            "dasd flush ccw_queue is unable "
+                                            " to terminate request %p",
+                                            cqr);
+                                /* stop flush processing */
+                                goto finished;
+                        }
+                        break;
+                case DASD_CQR_QUEUED:
+                case DASD_CQR_ERROR:
+                        /* set request to FAILED */
                         cqr->stopclk = get_clock();
+                        cqr->status = DASD_CQR_FAILED;
+                        break;
+                default: /* do not touch the others */
+                        break;
+                }
+                /* Rechain request (including erp chain) */
+                for (i = 0; cqr != NULL; cqr = cqr->refers, i++) {
+                        cqr->endclk = get_clock();
+                        list_move_tail(&cqr->list, &flush_queue);
+                }
+                if (i > 1)
+                        /* moved more than one request - need to restart */
+                        goto restart;
+        }
+
+finished:
+        spin_unlock_irq(get_ccwdev_lock(device->cdev));
+        /* Now call the callback function of flushed requests */
+restart_cb:
+        list_for_each_entry_safe(cqr, n, &flush_queue, list) {
+                if (cqr->status == DASD_CQR_CLEAR) {
+                        /* wait for clear interrupt! */
+                        wait_event(dasd_flush_wq, _wait_for_clear(cqr));
+                        cqr->status = DASD_CQR_FAILED;
                 }
                 /* Process finished ERP request. */
                 if (cqr->refers) {
                         __dasd_process_erp(device, cqr);
-                        continue;
+                        /* restart list_for_xx loop since dasd_process_erp
+                         * might remove multiple elements */
+                        goto restart_cb;
                 }
-                /* Rechain request on device request queue */
+                /* call the callback function */
                 cqr->endclk = get_clock();
-                list_move_tail(&cqr->list, &flush_queue);
-        }
-        spin_unlock_irq(get_ccwdev_lock(device->cdev));
-        /* Now call the callback function of flushed requests */
-        list_for_each_safe(l, n, &flush_queue) {
-                cqr = list_entry(l, struct dasd_ccw_req, list);
                 if (cqr->callback != NULL)
                         (cqr->callback)(cqr, cqr->callback_data);
         }
+        return rc;
 }
 
 /*
@@ -1510,10 +1592,8 @@ dasd_sleep_on_interruptible(struct dasd_ccw_req * cqr)
                         if (device->discipline->term_IO) {
                                 cqr->retries = -1;
                                 device->discipline->term_IO(cqr);
-                                /*nished =
-                                 * wait (non-interruptible) for final status
-                                 * because signal ist still pending
-                                 */
+                                /* wait (non-interruptible) for final status
+                                 * because signal ist still pending */
                                 spin_unlock_irq(get_ccwdev_lock(device->cdev));
                                 wait_event(wait_q, _wait_for_wakeup(cqr));
                                 spin_lock_irq(get_ccwdev_lock(device->cdev));
@@ -1546,19 +1626,11 @@ static inline int
 _dasd_term_running_cqr(struct dasd_device *device)
 {
         struct dasd_ccw_req *cqr;
-        int rc;
 
         if (list_empty(&device->ccw_queue))
                 return 0;
         cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, list);
-        rc = device->discipline->term_IO(cqr);
-        if (rc == 0) {
-                /* termination successful */
-                cqr->status = DASD_CQR_QUEUED;
-                cqr->startclk = cqr->stopclk = 0;
-                cqr->starttime = 0;
-        }
-        return rc;
+        return device->discipline->term_IO(cqr);
 }
 
 int
@@ -1726,10 +1798,7 @@ dasd_flush_request_queue(struct dasd_device * device)
                 return;
 
         spin_lock_irq(&device->request_queue_lock);
-        while (!list_empty(&device->request_queue->queue_head)) {
-                req = elv_next_request(device->request_queue);
-                if (req == NULL)
-                        break;
+        while ((req = elv_next_request(device->request_queue))) {
                 blkdev_dequeue_request(req);
                 dasd_end_request(req, 0);
         }
@@ -2091,6 +2160,7 @@ dasd_init(void)
         int rc;
 
         init_waitqueue_head(&dasd_init_waitq);
+        init_waitqueue_head(&dasd_flush_wq);
 
         /* register 'common' DASD debug area, used for all DBF_XXX calls */
         dasd_debug_area = debug_register("dasd", 1, 2, 8 * sizeof (long));
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index 4c272b70f41a..d163632101d2 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -83,10 +83,12 @@ dasd_gendisk_alloc(struct dasd_device *device)
 void
 dasd_gendisk_free(struct dasd_device *device)
 {
-        del_gendisk(device->gdp);
-        device->gdp->queue = NULL;
-        put_disk(device->gdp);
-        device->gdp = NULL;
+        if (device->gdp) {
+                del_gendisk(device->gdp);
+                device->gdp->queue = NULL;
+                put_disk(device->gdp);
+                device->gdp = NULL;
+        }
 }
 
 /*