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 4195cc0..82758cb 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2752,6 +2752,26 @@
}
/*
+ * 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 @@
int dasd_generic_pm_freeze(struct ccw_device *cdev)
{
- struct dasd_ccw_req *cqr, *n;
- int rc;
- struct list_head freeze_queue;
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;
if (IS_ERR(device))
return PTR_ERR(device);
@@ -3485,7 +3506,8 @@
/* 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 @@
}
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 @@
(cqr->status != DASD_CQR_CLEAR_PENDING));
if (cqr->status == DASD_CQR_CLEARED)
cqr->status = DASD_CQR_QUEUED;
- }
- /* 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));
+ /* 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);
+ }
+
+ /*
+ * 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;
}