[PATCH 1/5][resend 2] stex: Fix for potential invalid request

["ed.lin" <ed.lin@promise.com>]

The interrupt routine is good for normal cases. However, if the firmware is 
abnormal and returns an invalid response, the driver may reuse a ccb 
structure that has already been handled. This may cause problem. Fix this by 
setting the req member to NULL. Next time we know the response is invalid and 
handle accordingly if req is NULL.

Signed-off-by: Ed Lin <ed.lin@promise.com>
---

diff --git a/drivers/scsi/stex.c b/drivers/scsi/stex.c
index a3a18ad..6129db4 100644
--- a/drivers/scsi/stex.c
+++ b/drivers/scsi/stex.c
@@ -746,6 +746,7 @@ static void stex_mu_intr(struct st_hba *hba, u32 doorbell)
     stex_copy_data(ccb, resp, size);
   }
 
+  ccb->req = NULL;
   ccb->srb_status = resp->srb_status;
   ccb->scsi_status = resp->scsi_status;