Commit df8ec249 authored by Stefan Richter's avatar Stefan Richter
Browse files

firewire: fw-sbp2: use an own workqueue (fix system responsiveness) 



Firewire-sbp2 did very uncooperative things in the kernel's shared
workqueue:  Sleeping until reception of management status from the
target for up to 2 seconds, and performing SCSI inquiry and all of the
setup of SCSI command set drivers via scsi_add_device.  If there were
transient or permanent error conditions, this caused long blockage of
the kernel's events process, noticeable e.g. by blocked keyboard input.

We now allocate a workqueue process exclusive to fw-sbp2.  As a side
effect, this also increases parallelism of fw-sbp2's login and reconnect
work versus fw-core's device discovery and device update work which is
performed in the shared workqueue.

Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: default avatarKristian Høgsberg <krh@redhat.com>
parent 2df222b8

drivers/firewire/fw-sbp2.c

+13 −4
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ 
#include <linux/string.h>

#include <linux/stringify.h>

#include <linux/timer.h>

#include <linux/workqueue.h>



#include <scsi/scsi.h>

#include <scsi/scsi_cmnd.h>
@@ -625,6 +626,8 @@ static void sbp2_release_target(struct kref *kref) 
	scsi_host_put(shost);

}



static struct workqueue_struct *sbp2_wq;



static void sbp2_reconnect(struct work_struct *work);



static void sbp2_login(struct work_struct *work)
@@ -647,7 +650,8 @@ static void sbp2_login(struct work_struct *work) 
	if (sbp2_send_management_orb(lu, node_id, generation,

				SBP2_LOGIN_REQUEST, lu->lun, &response) < 0) {

		if (lu->retries++ < 5) {

			schedule_delayed_work(&lu->work, DIV_ROUND_UP(HZ, 5));

			queue_delayed_work(sbp2_wq, &lu->work,

					   DIV_ROUND_UP(HZ, 5));

		} else {

			fw_error("failed to login to %s LUN %04x\n",

				 unit->device.bus_id, lu->lun);
@@ -866,7 +870,7 @@ static int sbp2_probe(struct device *dev) 
	 * work.

	 */

	list_for_each_entry(lu, &tgt->lu_list, link)

		if (schedule_delayed_work(&lu->work, 0))

		if (queue_delayed_work(sbp2_wq, &lu->work, 0))

			kref_get(&tgt->kref);

	return 0;
@@ -910,7 +914,7 @@ static void sbp2_reconnect(struct work_struct *work) 
			lu->retries = 0;

			PREPARE_DELAYED_WORK(&lu->work, sbp2_login);

		}

		schedule_delayed_work(&lu->work, DIV_ROUND_UP(HZ, 5));

		queue_delayed_work(sbp2_wq, &lu->work, DIV_ROUND_UP(HZ, 5));

		return;

	}
@@ -940,7 +944,7 @@ static void sbp2_update(struct fw_unit *unit) 
	 */

	list_for_each_entry(lu, &tgt->lu_list, link) {

		lu->retries = 0;

		if (schedule_delayed_work(&lu->work, 0))

		if (queue_delayed_work(sbp2_wq, &lu->work, 0))

			kref_get(&tgt->kref);

	}

}
@@ -1335,12 +1339,17 @@ MODULE_ALIAS("sbp2"); 


static int __init sbp2_init(void)

{

	sbp2_wq = create_singlethread_workqueue(KBUILD_MODNAME);

	if (!sbp2_wq)

		return -ENOMEM;



	return driver_register(&sbp2_driver.driver);

}



static void __exit sbp2_cleanup(void)

{

	driver_unregister(&sbp2_driver.driver);

	destroy_workqueue(sbp2_wq);

}



module_init(sbp2_init);

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