[PATCH 1/3] megaraid_sas: Add smp_mb__after_atomic_*() for instance->fw_outstanding

["Nicholas A. Bellinger" <nab@linux-iscsi.org>]

From: Nicholas Bellinger <nab@linux-iscsi.org>

This patch adds four missing smp_mb__after_atomic_[inc,dec] barriers
for atomic_inc() and atomic_dec() usage with instance->fw_outstanding
within the main I/O dispatcher megasas_queue_command_lck(), completion
callback megasas_complete_cmd() and struct megasas_instance HW reset
queue drain in megasas_issue_pending_cmds_again().

Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
---
 drivers/scsi/megaraid/megaraid_sas.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas.c b/drivers/scsi/megaraid/megaraid_sas.c
index 7451bc0..c103554 100644
--- a/drivers/scsi/megaraid/megaraid_sas.c
+++ b/drivers/scsi/megaraid/megaraid_sas.c
@@ -1398,6 +1398,7 @@ megasas_queue_command_lck(struct scsi_cmnd *scmd, void (*done) (struct scsi_cmnd
 	 * Issue the command to the FW
 	 */
 	atomic_inc(&instance->fw_outstanding);
+	smp_mb__after_atomic_inc();	
 
 	instance->instancet->fire_cmd(instance, cmd->frame_phys_addr,
 				cmd->frame_count-1, instance->reg_set);
@@ -2068,6 +2069,7 @@ megasas_complete_cmd(struct megasas_instance *instance, struct megasas_cmd *cmd,
 		if (exception) {
 
 			atomic_dec(&instance->fw_outstanding);
+			smp_mb__after_atomic_dec();
 
 			scsi_dma_unmap(cmd->scmd);
 			cmd->scmd->scsi_done(cmd->scmd);
@@ -2116,6 +2118,7 @@ megasas_complete_cmd(struct megasas_instance *instance, struct megasas_cmd *cmd,
 		}
 
 		atomic_dec(&instance->fw_outstanding);
+		smp_mb__after_atomic_dec();
 
 		scsi_dma_unmap(cmd->scmd);
 		cmd->scmd->scsi_done(cmd->scmd);
@@ -2219,6 +2222,7 @@ megasas_issue_pending_cmds_again(struct megasas_instance *instance)
 			cmd, cmd->scmd->cmnd[0], cmd->scmd->serial_number);
 
 			atomic_inc(&instance->fw_outstanding);
+			smp_mb__after_atomic_inc();
 			instance->instancet->fire_cmd(instance,
 					cmd->frame_phys_addr,
 					cmd->frame_count-1, instance->reg_set);
-- 
1.7.2.3