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>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/scsi/device_handler/scsi_dh_hp_sw.c b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
index 12ceab7b3662..ae6be87d6a83 100644
--- a/drivers/scsi/device_handler/scsi_dh_hp_sw.c
+++ b/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,