scsi_dh: Verify "dev" is a sdev before accessing it.

Before accessing the device data structure in hardware handlers,
make sure it is a indeed a sdev device.

Yinghai Lu <yhlu.kernel@gmail.com> found the bug on Jul 16, 2008,
and later tested/verified the following fix.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/scsi/device_handler/scsi_dh_emc.c

@@ -416,12 +416,17 @@ static int clariion_bus_notify(struct notifier_block *nb,
 				unsigned long action, void *data)
 {
 	struct device *dev = data;
-	struct scsi_device *sdev = to_scsi_device(dev);
+	struct scsi_device *sdev;
 	struct scsi_dh_data *scsi_dh_data;
 	struct clariion_dh_data *h;
 	int i, found = 0;
 	unsigned long flags;
 
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	sdev = to_scsi_device(dev);
+
 	if (action == BUS_NOTIFY_ADD_DEVICE) {
 		for (i = 0; clariion_dev_list[i].vendor; i++) {
 			if (!strncmp(sdev->vendor, clariion_dev_list[i].vendor,

drivers/scsi/device_handler/scsi_dh_hp_sw.c

@@ -131,11 +131,16 @@ static int hp_sw_bus_notify(struct notifier_block *nb,
 			    unsigned long action, void *data)
 {
 	struct device *dev = data;
-	struct scsi_device *sdev = to_scsi_device(dev);
+	struct scsi_device *sdev;
 	struct scsi_dh_data *scsi_dh_data;
 	int i, found = 0;
 	unsigned long flags;
 
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	sdev = to_scsi_device(dev);
+
 	if (action == BUS_NOTIFY_ADD_DEVICE) {
 		for (i = 0; hp_sw_dh_data_list[i].vendor; i++) {
 			if (!strncmp(sdev->vendor, hp_sw_dh_data_list[i].vendor,

drivers/scsi/device_handler/scsi_dh_rdac.c

@@ -608,12 +608,17 @@ static int rdac_bus_notify(struct notifier_block *nb,
 			    unsigned long action, void *data)
 {
 	struct device *dev = data;
-	struct scsi_device *sdev = to_scsi_device(dev);
+	struct scsi_device *sdev;
 	struct scsi_dh_data *scsi_dh_data;
 	struct rdac_dh_data *h;
 	int i, found = 0;
 	unsigned long flags;
 
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	sdev = to_scsi_device(dev);
+
 	if (action == BUS_NOTIFY_ADD_DEVICE) {
 		for (i = 0; rdac_dev_list[i].vendor; i++) {
 			if (!strncmp(sdev->vendor, rdac_dev_list[i].vendor,