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Commit 64bdcbc4 authored by Kashyap.Desai@avagotech.com's avatar Kashyap.Desai@avagotech.com Committed by Christoph Hellwig
Browse files

scsi: add use_cmd_list flag 



Add a use_cmd_list flag in struct Scsi_Host to request keeping track of
all outstanding commands per device.

Default behaviour is not to keep track of cmd_list per sdev, as this may
introduce lock contention. (overhead is more on multi-node NUMA.), and
only enable it on the two drivers that need it.

Signed-off-by: default avatarKashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 2eefd57b

drivers/scsi/aacraid/linit.c

+1 −0
Original line number Diff line number Diff line
@@ -1152,6 +1152,7 @@ static int aac_probe_one(struct pci_dev *pdev, const struct pci_device_id *id) 
	shost->irq = pdev->irq;

	shost->unique_id = unique_id;

	shost->max_cmd_len = 16;

	shost->use_cmd_list = 1;



	aac = (struct aac_dev *)shost->hostdata;

	aac->base_start = pci_resource_start(pdev, 0);

drivers/scsi/dpt_i2o.c

+1 −0
Original line number Diff line number Diff line
@@ -2363,6 +2363,7 @@ static s32 adpt_scsi_host_alloc(adpt_hba* pHba, struct scsi_host_template *sht) 
	host->unique_id = (u32)sys_tbl_pa + pHba->unit;

	host->sg_tablesize = pHba->sg_tablesize;

	host->can_queue = pHba->post_fifo_size;

	host->use_cmd_list = 1;



	return 0;

}

drivers/scsi/scsi_lib.c

+12 −12
Original line number Diff line number Diff line
@@ -645,17 +645,19 @@ static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd) 
static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)

{

	struct scsi_device *sdev = cmd->device;

	struct Scsi_Host *shost = sdev->host;

	unsigned long flags;



	BUG_ON(list_empty(&cmd->list));



	scsi_mq_free_sgtables(cmd);

	scsi_uninit_cmd(cmd);



	if (shost->use_cmd_list) {

		BUG_ON(list_empty(&cmd->list));

		spin_lock_irqsave(&sdev->list_lock, flags);

		list_del_init(&cmd->list);

		spin_unlock_irqrestore(&sdev->list_lock, flags);

	}

}



/*

 * Function:    scsi_release_buffers()
@@ -1815,13 +1817,11 @@ static int scsi_mq_prep_fn(struct request *req) 
	INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);

	cmd->jiffies_at_alloc = jiffies;



	/*

	 * XXX: cmd_list lookups are only used by two drivers, try to get

	 * rid of this list in common code.

	 */

	if (shost->use_cmd_list) {

		spin_lock_irq(&sdev->list_lock);

		list_add_tail(&cmd->list, &sdev->cmd_list);

		spin_unlock_irq(&sdev->list_lock);

	}



	sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;

	cmd->sdb.table.sgl = sg;

include/scsi/scsi_host.h

+1 −0
Original line number Diff line number Diff line
@@ -680,6 +680,7 @@ struct Scsi_Host { 
	unsigned no_write_same:1;



	unsigned use_blk_mq:1;

	unsigned use_cmd_list:1;



	/*

	 * Optional work queue to be utilized by the transport