[PATCH v7 5/9] Disallow changing the device state via sysfs into "deleted"

[Bart Van Assche <bvanassche@acm.org>]

Changing the state of a SCSI device via sysfs into "cancel" or
"deleted" prevents scsi_remove_host() to remove these devices.
Hence do not allow this.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/scsi_sysfs.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 4348f12..b319c20 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -591,13 +591,15 @@ sdev_store_delete(struct device *dev, struct device_attribute *attr,
 };
 static DEVICE_ATTR(delete, S_IWUSR, NULL, sdev_store_delete);
 
+#define INVALID_SDEV_STATE 0
+
 static ssize_t
 store_state_field(struct device *dev, struct device_attribute *attr,
 		  const char *buf, size_t count)
 {
 	int i;
 	struct scsi_device *sdev = to_scsi_device(dev);
-	enum scsi_device_state state = 0;
+	enum scsi_device_state state = INVALID_SDEV_STATE;
 
 	for (i = 0; i < ARRAY_SIZE(sdev_states); i++) {
 		const int len = strlen(sdev_states[i].name);
@@ -607,7 +609,8 @@ store_state_field(struct device *dev, struct device_attribute *attr,
 			break;
 		}
 	}
-	if (!state)
+	if (state == INVALID_SDEV_STATE || state == SDEV_CANCEL ||
+	    state == SDEV_DEL)
 		return -EINVAL;
 
 	if (scsi_device_set_state(sdev, state))
-- 
1.7.10.4