scsi: mpi3mr: Fix I/O failures during controller reset

I/Os can race with controller reset and fail.

Block requests at the mid layer when reset starts using
scsi_host_block(), and resume with scsi_host_unblock() after reset
completes.

Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com>
Link: https://lore.kernel.org/r/20250820084138.228471-4-chandrakanth.patil@broadcom.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: cp890582

drivers/scsi/mpi3mr/mpi3mr_fw.c

@@ -5430,6 +5430,7 @@ int mpi3mr_soft_reset_handler(struct mpi3mr_ioc *mrioc,
 	    mpi3mr_reset_rc_name(reset_reason));
 
 	mrioc->device_refresh_on = 0;
+	scsi_block_requests(mrioc->shost);
 	mrioc->reset_in_progress = 1;
 	mrioc->stop_bsgs = 1;
 	mrioc->prev_reset_result = -1;
@@ -5538,6 +5539,7 @@ int mpi3mr_soft_reset_handler(struct mpi3mr_ioc *mrioc,
 	if (!retval) {
 		mrioc->diagsave_timeout = 0;
 		mrioc->reset_in_progress = 0;
+		scsi_unblock_requests(mrioc->shost);
 		mrioc->pel_abort_requested = 0;
 		if (mrioc->pel_enabled) {
 			mrioc->pel_cmds.retry_count = 0;
@@ -5562,6 +5564,7 @@ int mpi3mr_soft_reset_handler(struct mpi3mr_ioc *mrioc,
 		mrioc->device_refresh_on = 0;
 		mrioc->unrecoverable = 1;
 		mrioc->reset_in_progress = 0;
+		scsi_unblock_requests(mrioc->shost);
 		mrioc->stop_bsgs = 0;
 		retval = -1;
 		mpi3mr_flush_cmds_for_unrecovered_controller(mrioc);

drivers/scsi/mpi3mr/mpi3mr_os.c

@@ -2866,12 +2866,14 @@ static void mpi3mr_preparereset_evt_th(struct mpi3mr_ioc *mrioc,
 		    "prepare for reset event top half with rc=start\n");
 		if (mrioc->prepare_for_reset)
 			return;
+		scsi_block_requests(mrioc->shost);
 		mrioc->prepare_for_reset = 1;
 		mrioc->prepare_for_reset_timeout_counter = 0;
 	} else if (evtdata->reason_code == MPI3_EVENT_PREPARE_RESET_RC_ABORT) {
 		dprint_event_th(mrioc,
 		    "prepare for reset top half with rc=abort\n");
 		mrioc->prepare_for_reset = 0;
+		scsi_unblock_requests(mrioc->shost);
 		mrioc->prepare_for_reset_timeout_counter = 0;
 	}
 	if ((event_reply->msg_flags & MPI3_EVENT_NOTIFY_MSGFLAGS_ACK_MASK)