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>

1 files changed, 55 insertions, 8 deletions

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 4195cc05efeb..82758cbb220b 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2752,6 +2752,26 @@ static void _dasd_wake_block_flush_cb(struct dasd_ccw_req *cqr, void *data)
 }
 
 /*
+ * 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
  * block layer.
@@ -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;
 }