Revert "Move xen patchset to new version's subdir."

[people/pmueller/ipfire-2.x.git] / src / patches / suse-2.6.27.25 / patches.arch / s390-02-09-tape-lock.patch

From: Gerald Schaefer <geraldsc@de.ibm.com>
Subject: tape device driver: improve locking
References: bnc#434333

Symptom:     1. message "Badness at include/linux/blkdev.h"
             2. lockdep message "INFO: inconsistent lock state"
Problem:     1. Tape block device driver does not hold request queue lock
                when completing request via __blk_end_request.
             2. During open() processing tape device driver receives
                interrupt while holding the tape device lock.
Solution:    1. Use blk_end_request rather than __blk_end_request
             2. Use spin_lock_irq to disable interrupts rather than spin_lock.

Acked-by: John Jolly <jjolly@suse.de>
---
 drivers/s390/char/tape_block.c |    6 ++++--
 drivers/s390/char/tape_core.c  |    8 ++++----
 2 files changed, 8 insertions(+), 6 deletions(-)

Index: temp_orig/drivers/s390/char/tape_block.c
===================================================================
--- temp_orig.orig/drivers/s390/char/tape_block.c
+++ temp_orig/drivers/s390/char/tape_block.c
@@ -76,7 +76,7 @@ tapeblock_trigger_requeue(struct tape_de
 static void
 tapeblock_end_request(struct request *req, int error)
 {
-	if (__blk_end_request(req, error, blk_rq_bytes(req)))
+	if (blk_end_request(req, error, blk_rq_bytes(req)))
 		BUG();
 }
 
@@ -166,7 +166,7 @@ tapeblock_requeue(struct work_struct *wo
 		nr_queued++;
 	spin_unlock(get_ccwdev_lock(device->cdev));
 
-	spin_lock(&device->blk_data.request_queue_lock);
+	spin_lock_irq(&device->blk_data.request_queue_lock);
 	while (
 		!blk_queue_plugged(queue) &&
 		elv_next_request(queue)   &&
@@ -176,7 +176,9 @@ tapeblock_requeue(struct work_struct *wo
 		if (rq_data_dir(req) == WRITE) {
 			DBF_EVENT(1, "TBLOCK: Rejecting write request\n");
 			blkdev_dequeue_request(req);
+			spin_unlock_irq(&device->blk_data.request_queue_lock);
 			tapeblock_end_request(req, -EIO);
+			spin_lock_irq(&device->blk_data.request_queue_lock);
 			continue;
 		}
 		blkdev_dequeue_request(req);
Index: temp_orig/drivers/s390/char/tape_core.c
===================================================================
--- temp_orig.orig/drivers/s390/char/tape_core.c
+++ temp_orig/drivers/s390/char/tape_core.c
@@ -1199,7 +1199,7 @@ tape_open(struct tape_device *device)
 {
 	int rc;
 
-	spin_lock(get_ccwdev_lock(device->cdev));
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
 	if (device->tape_state == TS_NOT_OPER) {
 		DBF_EVENT(6, "TAPE:nodev\n");
 		rc = -ENODEV;
@@ -1217,7 +1217,7 @@ tape_open(struct tape_device *device)
 		tape_state_set(device, TS_IN_USE);
 		rc = 0;
 	}
-	spin_unlock(get_ccwdev_lock(device->cdev));
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
 	return rc;
 }
 
@@ -1227,11 +1227,11 @@ tape_open(struct tape_device *device)
 int
 tape_release(struct tape_device *device)
 {
-	spin_lock(get_ccwdev_lock(device->cdev));
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
 	if (device->tape_state == TS_IN_USE)
 		tape_state_set(device, TS_UNUSED);
 	module_put(device->discipline->owner);
-	spin_unlock(get_ccwdev_lock(device->cdev));
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
 	return 0;
 }