2 files changed, 26 insertions, 0 deletions

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index 9a36ea93cfbd..3c3e4745a7b8 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -1382,6 +1382,16 @@ union reply_descriptor {
 	} u;
 };
 
+static u32 base_mod64(u64 dividend, u32 divisor)
+{
+	u32 remainder;
+
+	if (!divisor)
+		pr_err("mpt3sas: DIVISOR is zero, in div fn\n");
+	remainder = do_div(dividend, divisor);
+	return remainder;
+}
+
 /**
  * _base_process_reply_queue - Process reply descriptors from reply
  *		descriptor post queue.
@@ -2845,6 +2855,11 @@ _base_assign_reply_queues(struct MPT3SAS_ADAPTER *ioc)
 
 	if (!_base_is_controller_msix_enabled(ioc))
 		return;
+	ioc->msix_load_balance = false;
+	if (ioc->reply_queue_count < num_online_cpus()) {
+		ioc->msix_load_balance = true;
+		return;
+	}
 
 	memset(ioc->cpu_msix_table, 0, ioc->cpu_msix_table_sz);
 
@@ -3248,6 +3263,12 @@ mpt3sas_base_get_reply_virt_addr(struct MPT3SAS_ADAPTER *ioc, u32 phys_addr)
 static inline u8
 _base_get_msix_index(struct MPT3SAS_ADAPTER *ioc)
 {
+	/* Enables reply_queue load balancing */
+	if (ioc->msix_load_balance)
+		return ioc->reply_queue_count ?
+		    base_mod64(atomic64_add_return(1,
+		    &ioc->total_io_cnt), ioc->reply_queue_count) : 0;
+
 	return ioc->cpu_msix_table[raw_smp_processor_id()];
 }
 
diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.h b/drivers/scsi/mpt3sas/mpt3sas_base.h
index fb572cdb751e..3895407183ff 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.h
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.h
@@ -1024,6 +1024,9 @@ typedef void (*MPT3SAS_FLUSH_RUNNING_CMDS)(struct MPT3SAS_ADAPTER *ioc);
  * @msix_vector_count: number msix vectors
  * @cpu_msix_table: table for mapping cpus to msix index
  * @cpu_msix_table_sz: table size
+ * @total_io_cnt: Gives total IO count, used to load balance the interrupts
+ * @msix_load_balance: Enables load balancing of interrupts across
+ * the multiple MSIXs
  * @schedule_dead_ioc_flush_running_cmds: callback to flush pending commands
  * @scsi_io_cb_idx: shost generated commands
  * @tm_cb_idx: task management commands
@@ -1200,6 +1203,8 @@ struct MPT3SAS_ADAPTER {
 	u32		ioc_reset_count;
 	MPT3SAS_FLUSH_RUNNING_CMDS schedule_dead_ioc_flush_running_cmds;
 	u32             non_operational_loop;
+	atomic64_t      total_io_cnt;
+	bool            msix_load_balance;
 
 	/* internal commands, callback index */
 	u8		scsi_io_cb_idx;