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Commit fb1a24ff authored by Sumit.Saxena@avagotech.com's avatar Sumit.Saxena@avagotech.com Committed by Christoph Hellwig
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megaraid_sas : Host lock less mode to enabled asynchronous IO submission 



Resending the patch. Addressed the review comments from Tomas Henzl.

Megaraid_sas driver can now work in host lock less mode.
Remove host lock less as megaraid_sas driver will have safer access to raid map as described in earlier patch.

We now keep Driver Raid map copy, which will make sure
that driver will always have old or new map
Driver raid map will be replaced safely in MR_PopulateDrvRaidMap(), so there is no issue
even if IO is continue from the scsi mid layer.

There is a plan to remove "host_lock" and "hba_lock" usage from megaraid_sas in future.

Signed-off-by: default avatarSumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: default avatarKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: default avatarTomas Henzl <thenzl@redhat.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 51087a86

drivers/scsi/megaraid/megaraid_sas_base.c

+4 −7
Original line number Diff line number Diff line
@@ -1536,7 +1536,7 @@ megasas_build_and_issue_cmd(struct megasas_instance *instance, 
 * @done:			Callback entry point

 */

static int

megasas_queue_command_lck(struct scsi_cmnd *scmd, void (*done) (struct scsi_cmnd *))

megasas_queue_command(struct Scsi_Host *shost, struct scsi_cmnd *scmd)

{

	struct megasas_instance *instance;

	unsigned long flags;
@@ -1558,7 +1558,7 @@ megasas_queue_command_lck(struct scsi_cmnd *scmd, void (*done) (struct scsi_cmnd 
		} else {

			spin_unlock_irqrestore(&instance->hba_lock, flags);

			scmd->result = DID_NO_CONNECT << 16;

			done(scmd);

			scmd->scsi_done(scmd);

			return 0;

		}

	}
@@ -1566,7 +1566,7 @@ megasas_queue_command_lck(struct scsi_cmnd *scmd, void (*done) (struct scsi_cmnd 
	if (instance->adprecovery == MEGASAS_HW_CRITICAL_ERROR) {

		spin_unlock_irqrestore(&instance->hba_lock, flags);

		scmd->result = DID_NO_CONNECT << 16;

		done(scmd);

		scmd->scsi_done(scmd);

		return 0;

	}
@@ -1577,7 +1577,6 @@ megasas_queue_command_lck(struct scsi_cmnd *scmd, void (*done) (struct scsi_cmnd 


	spin_unlock_irqrestore(&instance->hba_lock, flags);



	scmd->scsi_done = done;

	scmd->result = 0;



	if (MEGASAS_IS_LOGICAL(scmd) &&
@@ -1607,12 +1606,10 @@ megasas_queue_command_lck(struct scsi_cmnd *scmd, void (*done) (struct scsi_cmnd 
	return 0;



 out_done:

	done(scmd);

	scmd->scsi_done(scmd);

	return 0;

}



static DEF_SCSI_QCMD(megasas_queue_command)



static struct megasas_instance *megasas_lookup_instance(u16 host_no)

{

	int i;