diff --git a/drivers/scsi/mpt3sas/mpt3sas_ctl.c b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
index 8af944d7d13da258d5ddff2c0f82aa2bb02ff33c..02cd9458d6092d045b80fc921a97bd801af24198 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_ctl.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
@@ -3136,7 +3136,7 @@ _ctl_diag_trigger_mpi_store(struct device *cdev,
 	spin_lock_irqsave(&ioc->diag_trigger_lock, flags);
 	sz = min(sizeof(struct SL_WH_MPI_TRIGGERS_T), count);
 	memset(&ioc->diag_trigger_mpi, 0,
-	    sizeof(struct SL_WH_EVENT_TRIGGERS_T));
+	    sizeof(ioc->diag_trigger_mpi));
 	memcpy(&ioc->diag_trigger_mpi, buf, sz);
 	if (ioc->diag_trigger_mpi.ValidEntries > NUM_VALID_ENTRIES)
 		ioc->diag_trigger_mpi.ValidEntries = NUM_VALID_ENTRIES;