Backport fix for scsi device add affecting alua driver

Fixes QubesOS/qubes-issues#2115

patches.fixes/0001-scsi-ignore-errors-from-scsi_dh_add_device.patch

@@ -0,0 +1,44 @@
+From 221255aee67ec1c752001080aafec0c4e9390d95 Mon Sep 17 00:00:00 2001
+From: Hannes Reinecke <hare@suse.de>
+Date: Tue, 1 Dec 2015 10:16:42 +0100
+Subject: [PATCH] scsi: ignore errors from scsi_dh_add_device()
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+device handler initialisation might fail due to a number of
+reasons. But as device_handlers are optional this shouldn't
+cause us to disable the device entirely.
+So just ignore errors from scsi_dh_add_device().
+
+Reviewed-by: Johannes Thumshirn <jthumshirn@suse.com>
+Reviewed-by: Christoph Hellwig <hch@lst.de>
+Signed-off-by: Hannes Reinecke <hare@suse.de>
+Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
+---
+ drivers/scsi/scsi_sysfs.c | 7 ++++---
+ 1 file changed, 4 insertions(+), 3 deletions(-)
+
+diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
+index fc3cd26..d015374 100644
+--- a/drivers/scsi/scsi_sysfs.c
++++ b/drivers/scsi/scsi_sysfs.c
+@@ -1120,11 +1120,12 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
+ 	}
+ 
+ 	error = scsi_dh_add_device(sdev);
+-	if (error) {
++	if (error)
++		/*
++		 * device_handler is optional, so any error can be ignored
++		 */
+ 		sdev_printk(KERN_INFO, sdev,
+ 				"failed to add device handler: %d\n", error);
+-		return error;
+-	}
+ 
+ 	device_enable_async_suspend(&sdev->sdev_dev);
+ 	error = device_add(&sdev->sdev_dev);
+-- 
+2.5.5
+

series.conf

@@ -5,6 +5,7 @@ patches.xen/0001-xen-fix-deadlock-on-proc-xen-xenbus-access.patch
 patches.xen/xen-netfront-detach-crash.patch
 patches.xen/0001-mce-hide-EBUSY-initialization-error-on-Xen.patch
 patches.xen/irq-bind-debug-log.patch
+patches.fixes/0001-scsi-ignore-errors-from-scsi_dh_add_device.patch
 
 # Additional features
 #patches.xen/pvops-0100-usb-xen-pvusb-driver.patch