Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Martin Schwidefsky:
 "The bulk of the s390 patches for 4.13. Some new things but mostly bug
  fixes and cleanups. Noteworthy changes:

   - The SCM block driver is converted to blk-mq

   - Switch s390 to 5 level page tables. The virtual address space for a
     user space process can now have up to 16EB-4KB.

   - Introduce a ELF phdr flag for qemu to avoid the global
     vm.alloc_pgste which forces all processes to large page tables

   - A couple of PCI improvements to improve error recovery

   - Included is the merge of the base support for proper machine checks
     for KVM"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (52 commits)
  s390/dasd: Fix faulty ENODEV for RO sysfs attribute
  s390/pci: recognize name clashes with uids
  s390/pci: provide more debug information
  s390/pci: fix handling of PEC 306
  s390/pci: improve pci hotplug
  s390/pci: introduce clp_get_state
  s390/pci: improve error handling during fmb (de)registration
  s390/pci: improve unreg_ioat error handling
  s390/pci: improve error handling during interrupt deregistration
  s390/pci: don't cleanup in arch_setup_msi_irqs
  KVM: s390: Backup the guest's machine check info
  s390/nmi: s390: New low level handling for machine check happening in guest
  s390/fpu: export save_fpu_regs for all configs
  s390/kvm: avoid global config of vm.alloc_pgste=1
  s390: rename struct psw_bits members
  s390: rename psw_bits enums
  s390/mm: use correct address space when enabling DAT
  s390/cio: introduce io_subchannel_type
  s390/ipl: revert Load Normal semantics for LPAR CCW-type re-IPL
  s390/dumpstack: remove raw stack dump
  ...

1 files changed, 44 insertions, 32 deletions

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index b7cbd5d2cdea..0f1fe4ff7f51 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -1965,8 +1965,12 @@ static int __dasd_device_is_unusable(struct dasd_device *device,
 {
 	int mask = ~(DASD_STOPPED_DC_WAIT | DASD_UNRESUMED_PM);
 
-	if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) {
-		/* dasd is being set offline. */
+	if (test_bit(DASD_FLAG_OFFLINE, &device->flags) &&
+	    !test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
+		/*
+		 * dasd is being set offline
+		 * but it is no safe offline where we have to allow I/O
+		 */
 		return 1;
 	}
 	if (device->stopped) {
@@ -3570,57 +3574,69 @@ int dasd_generic_set_offline(struct ccw_device *cdev)
 			else
 				pr_warn("%s: The DASD cannot be set offline while it is in use\n",
 					dev_name(&cdev->dev));
-			clear_bit(DASD_FLAG_OFFLINE, &device->flags);
-			goto out_busy;
+			rc = -EBUSY;
+			goto out_err;
 		}
 	}
 
-	if (test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
-		/*
-		 * safe offline already running
-		 * could only be called by normal offline so safe_offline flag
-		 * needs to be removed to run normal offline and kill all I/O
-		 */
-		if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags))
-			/* Already doing normal offline processing */
-			goto out_busy;
-		else
-			clear_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags);
-	} else {
-		if (test_bit(DASD_FLAG_OFFLINE, &device->flags))
-			/* Already doing offline processing */
-			goto out_busy;
+	/*
+	 * Test if the offline processing is already running and exit if so.
+	 * If a safe offline is being processed this could only be a normal
+	 * offline that should be able to overtake the safe offline and
+	 * cancel any I/O we do not want to wait for any longer
+	 */
+	if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) {
+		if (test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
+			clear_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING,
+				  &device->flags);
+		} else {
+			rc = -EBUSY;
+			goto out_err;
+		}
 	}
-
 	set_bit(DASD_FLAG_OFFLINE, &device->flags);
-	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
 
 	/*
-	 * if safe_offline called set safe_offline_running flag and
+	 * if safe_offline is called set safe_offline_running flag and
 	 * clear safe_offline so that a call to normal offline
 	 * can overrun safe_offline processing
 	 */
 	if (test_and_clear_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags) &&
 	    !test_and_set_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
+		/* need to unlock here to wait for outstanding I/O */
+		spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
 		/*
 		 * If we want to set the device safe offline all IO operations
 		 * should be finished before continuing the offline process
 		 * so sync bdev first and then wait for our queues to become
 		 * empty
 		 */
-		/* sync blockdev and partitions */
 		if (device->block) {
 			rc = fsync_bdev(device->block->bdev);
 			if (rc != 0)
 				goto interrupted;
 		}
-		/* schedule device tasklet and wait for completion */
 		dasd_schedule_device_bh(device);
 		rc = wait_event_interruptible(shutdown_waitq,
 					      _wait_for_empty_queues(device));
 		if (rc != 0)
 			goto interrupted;
+
+		/*
+		 * check if a normal offline process overtook the offline
+		 * processing in this case simply do nothing beside returning
+		 * that we got interrupted
+		 * otherwise mark safe offline as not running any longer and
+		 * continue with normal offline
+		 */
+		spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
+		if (!test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
+			rc = -ERESTARTSYS;
+			goto out_err;
+		}
+		clear_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags);
 	}
+	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
 
 	dasd_set_target_state(device, DASD_STATE_NEW);
 	/* dasd_delete_device destroys the device reference. */
@@ -3632,22 +3648,18 @@ int dasd_generic_set_offline(struct ccw_device *cdev)
 	 */
 	if (block)
 		dasd_free_block(block);
+
 	return 0;
 
 interrupted:
 	/* interrupted by signal */
-	clear_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags);
+	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
 	clear_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags);
 	clear_bit(DASD_FLAG_OFFLINE, &device->flags);
-	dasd_put_device(device);
-
-	return rc;
-
-out_busy:
+out_err:
 	dasd_put_device(device);
 	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
-
-	return -EBUSY;
+	return rc;
 }
 EXPORT_SYMBOL_GPL(dasd_generic_set_offline);