bfa: Fix for crash when bfa_itnim is NULL

Fix a very corner case when the port gets disconnected and the BFA and
FCS layers clean up references to the IT nexus.  During this window if a
task management command is issued by the SCSI-ML and ends up referencing
a NULL itnim, it could lead to a crash.

Signed-off-by: Sudarsana Kalluru <sudarsana.kalluru@qlogic.com>
Signed-off-by: Anil Gurumurthy <anil.gurumurthy@qlogic.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/drivers/scsi/bfa/bfad_im.c b/drivers/scsi/bfa/bfad_im.c
index efcb2470f40a..2c0cf8a46a47 100644
--- a/drivers/scsi/bfa/bfad_im.c
+++ b/drivers/scsi/bfa/bfad_im.c
@@ -272,6 +272,19 @@ bfad_im_target_reset_send(struct bfad_s *bfad, struct scsi_cmnd *cmnd,
         cmnd->host_scribble = NULL;
         cmnd->SCp.Status = 0;
         bfa_itnim = bfa_fcs_itnim_get_halitn(&itnim->fcs_itnim);
+        /*
+         * bfa_itnim can be NULL if the port gets disconnected and the bfa
+         * and fcs layers have cleaned up their nexus with the targets and
+         * the same has not been cleaned up by the shim
+         */
+        if (bfa_itnim == NULL) {
+                bfa_tskim_free(tskim);
+                BFA_LOG(KERN_ERR, bfad, bfa_log_level,
+                        "target reset, bfa_itnim is NULL\n");
+                rc = BFA_STATUS_FAILED;
+                goto out;
+        }
+
         memset(&scsilun, 0, sizeof(scsilun));
         bfa_tskim_start(tskim, bfa_itnim, scsilun,
                             FCP_TM_TARGET_RESET, BFAD_TARGET_RESET_TMO);
@@ -327,6 +340,19 @@ bfad_im_reset_lun_handler(struct scsi_cmnd *cmnd)
         cmnd->SCp.ptr = (char *)&wq;
         cmnd->SCp.Status = 0;
         bfa_itnim = bfa_fcs_itnim_get_halitn(&itnim->fcs_itnim);
+        /*
+         * bfa_itnim can be NULL if the port gets disconnected and the bfa
+         * and fcs layers have cleaned up their nexus with the targets and
+         * the same has not been cleaned up by the shim
+         */
+        if (bfa_itnim == NULL) {
+                bfa_tskim_free(tskim);
+                BFA_LOG(KERN_ERR, bfad, bfa_log_level,
+                        "lun reset, bfa_itnim is NULL\n");
+                spin_unlock_irqrestore(&bfad->bfad_lock, flags);
+                rc = FAILED;
+                goto out;
+        }
         int_to_scsilun(cmnd->device->lun, &scsilun);
         bfa_tskim_start(tskim, bfa_itnim, scsilun,
                             FCP_TM_LUN_RESET, BFAD_LUN_RESET_TMO);