[SCSI] mptspi: fix oops in mptspi_dv_renegotiate_work()

The problem here is that if the ioc faults too early in the bring up
sequence (as it usually does for an irq routing problem), ioc_reset gets
called before the scsi host is even allocated.  This causes an oops when
it later schedules a renegotiation.  Fix this by checking ioc->sh before
trying to renegotiate.

Cc: "Moore, Eric" <Eric.Moore@lsi.com>
Cc: Stable Tree <stable@kernel.org>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

drivers/message/fusion/mptspi.c

@@ -1266,13 +1266,18 @@ mptspi_dv_renegotiate(struct _MPT_SCSI_HOST *hd)
 static int
 mptspi_ioc_reset(MPT_ADAPTER *ioc, int reset_phase)
 {
-	struct _MPT_SCSI_HOST *hd = shost_priv(ioc->sh);
 	int rc;
 
 	rc = mptscsih_ioc_reset(ioc, reset_phase);
 
-	if (reset_phase == MPT_IOC_POST_RESET)
+	/* only try to do a renegotiation if we're properly set up
+	 * if we get an ioc fault on bringup, ioc->sh will be NULL */
+	if (reset_phase == MPT_IOC_POST_RESET &&
+	    ioc->sh) {
+		struct _MPT_SCSI_HOST *hd = shost_priv(ioc->sh);
+
 		mptspi_dv_renegotiate(hd);
+	}
 
 	return rc;
 }