s390/dasd: fix hanging device after resume with internal error 13

If too many ccw requests are pre-build before a suspend/resume cycle
the device might not get enough memory to do path verification
during resume.
Requeue requests to the block device request queue on suspend and free
pre-build ccw requests.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 4195cc05efeb3b7bd8354bccb1d2d81c39f5154c..82758cbb220be6a6bc2f27396c4063c6272ffeff 100644 (file)
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2751,6 +2751,26 @@ static void _dasd_wake_block_flush_cb(struct dasd_ccw_req *cqr, void *data)
        wake_up(&dasd_flush_wq);
 }
 
+/*
+ * Requeue a request back to the block request queue
+ * only works for block requests
+ */
+static int _dasd_requeue_request(struct dasd_ccw_req *cqr)
+{
+       struct dasd_block *block = cqr->block;
+       struct request *req;
+       unsigned long flags;
+
+       if (!block)
+               return -EINVAL;
+       spin_lock_irqsave(&block->queue_lock, flags);
+       req = (struct request *) cqr->callback_data;
+       blk_requeue_request(block->request_queue, req);
+       spin_unlock_irqrestore(&block->queue_lock, flags);
+
+       return 0;
+}
+
 /*
  * Go through all request on the dasd_block request queue, cancel them
  * on the respective dasd_device, and return them to the generic
@@ -3469,10 +3489,11 @@ EXPORT_SYMBOL_GPL(dasd_generic_verify_path);
 
 int dasd_generic_pm_freeze(struct ccw_device *cdev)
 {
+       struct dasd_device *device = dasd_device_from_cdev(cdev);
+       struct list_head freeze_queue;
        struct dasd_ccw_req *cqr, *n;
+       struct dasd_ccw_req *refers;
        int rc;
-       struct list_head freeze_queue;
-       struct dasd_device *device = dasd_device_from_cdev(cdev);
 
        if (IS_ERR(device))
                return PTR_ERR(device);
@@ -3485,7 +3506,8 @@ int dasd_generic_pm_freeze(struct ccw_device *cdev)
 
        /* disallow new I/O  */
        dasd_device_set_stop_bits(device, DASD_STOPPED_PM);
-       /* clear active requests */
+
+       /* clear active requests and requeue them to block layer if possible */
        INIT_LIST_HEAD(&freeze_queue);
        spin_lock_irq(get_ccwdev_lock(cdev));
        rc = 0;
@@ -3505,7 +3527,6 @@ int dasd_generic_pm_freeze(struct ccw_device *cdev)
                }
                list_move_tail(&cqr->devlist, &freeze_queue);
        }
-
        spin_unlock_irq(get_ccwdev_lock(cdev));
 
        list_for_each_entry_safe(cqr, n, &freeze_queue, devlist) {
@@ -3513,12 +3534,38 @@ int dasd_generic_pm_freeze(struct ccw_device *cdev)
                           (cqr->status != DASD_CQR_CLEAR_PENDING));
                if (cqr->status == DASD_CQR_CLEARED)
                        cqr->status = DASD_CQR_QUEUED;
+
+               /* requeue requests to blocklayer will only work for
+                  block device requests */
+               if (_dasd_requeue_request(cqr))
+                       continue;
+
+               /* remove requests from device and block queue */
+               list_del_init(&cqr->devlist);
+               while (cqr->refers != NULL) {
+                       refers = cqr->refers;
+                       /* remove the request from the block queue */
+                       list_del(&cqr->blocklist);
+                       /* free the finished erp request */
+                       dasd_free_erp_request(cqr, cqr->memdev);
+                       cqr = refers;
+               }
+               if (cqr->block)
+                       list_del_init(&cqr->blocklist);
+               cqr->block->base->discipline->free_cp(
+                       cqr, (struct request *) cqr->callback_data);
        }
-       /* move freeze_queue to start of the ccw_queue */
-       spin_lock_irq(get_ccwdev_lock(cdev));
-       list_splice_tail(&freeze_queue, &device->ccw_queue);
-       spin_unlock_irq(get_ccwdev_lock(cdev));
 
+       /*
+        * if requests remain then they are internal request
+        * and go back to the device queue
+        */
+       if (!list_empty(&freeze_queue)) {
+               /* move freeze_queue to start of the ccw_queue */
+               spin_lock_irq(get_ccwdev_lock(cdev));
+               list_splice_tail(&freeze_queue, &device->ccw_queue);
+               spin_unlock_irq(get_ccwdev_lock(cdev));
+       }
        dasd_put_device(device);
        return rc;
 }