[SCSI] mpt2sas: fix broadcast AEN and task management issue

Properly handling of target reset in multi-initiator environment

Clean up in broadcast change handling:
(1) Need to look at the status of each task management request, and retry
    the TM when there are failures.
(2) Need quiescence IO so the driver doesn't take on more IO request while
    it's in the middle of sending TM  request to firmware
(3)  Add support to keep track of how many pending broadcast AEN events
     are received while the broadcast handling is active, then loop back at
     the end of this routine if there were any events received.

Clean up in mpt2sas_scsih_issue_tm routine:
(1) Make sure proper status is returned when host reset fails
(2) Clean up sanity checks near end of routine, insuring all outstanding
    IOs were completed.
Signed-off-by: Kashyap Desai <kashyap.desai@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/mpt2sas/mpt2sas_base.h

@@ -588,6 +588,16 @@ struct mpt2sas_port_facts {
 	u16			MaxPostedCmdBuffers;
 };
 
+/**
+ * enum mutex_type - task management mutex type
+ * @TM_MUTEX_OFF: mutex is not required becuase calling function is acquiring it
+ * @TM_MUTEX_ON: mutex is required
+ */
+enum mutex_type {
+	TM_MUTEX_OFF = 0,
+	TM_MUTEX_ON = 1,
+};
+
 /**
  * struct MPT2SAS_ADAPTER - per adapter struct
  * @list: ioc_list
@@ -750,6 +760,7 @@ struct MPT2SAS_ADAPTER {
 	 /* misc flags */
 	int		aen_event_read_flag;
 	u8		broadcast_aen_busy;
+	u16		broadcast_aen_pending;
 	u8		shost_recovery;
 
 	struct mutex	reset_in_progress_mutex;
@@ -980,7 +991,7 @@ u8 mpt2sas_scsih_event_callback(struct MPT2SAS_ADAPTER *ioc, u8 msix_index,
     u32 reply);
 int mpt2sas_scsih_issue_tm(struct MPT2SAS_ADAPTER *ioc, u16 handle,
 	uint channel, uint id, uint lun, u8 type, u16 smid_task,
-    ulong timeout, struct scsi_cmnd *scmd);
+	ulong timeout, unsigned long serial_number, enum mutex_type m_type);
 void mpt2sas_scsih_set_tm_flag(struct MPT2SAS_ADAPTER *ioc, u16 handle);
 void mpt2sas_scsih_clear_tm_flag(struct MPT2SAS_ADAPTER *ioc, u16 handle);
 void mpt2sas_expander_remove(struct MPT2SAS_ADAPTER *ioc, u64 sas_address);

drivers/scsi/mpt2sas/mpt2sas_ctl.c

@@ -994,7 +994,7 @@ _ctl_do_mpt_command(struct MPT2SAS_ADAPTER *ioc,
 			mpt2sas_scsih_issue_tm(ioc,
 			    le16_to_cpu(mpi_request->FunctionDependent1), 0, 0,
 			    0, MPI2_SCSITASKMGMT_TASKTYPE_TARGET_RESET, 0, 10,
-			    NULL);
+			    0, TM_MUTEX_ON);
 			ioc->tm_cmds.status = MPT2_CMD_NOT_USED;
 		} else
 			mpt2sas_base_hard_reset_handler(ioc, CAN_SLEEP,