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Commit 7104e2d5 authored by Pierre Ossman's avatar Pierre Ossman Committed by Linus Torvalds
Browse files

[PATCH] mmc: use own work queue 



The MMC layer uses the standard work queue for doing card detection.  As this
queue is shared with other crucial subsystems, the effects of a long (and
perhaps buggy) detection can cause the system to be unusable.  E.g.  the
keyboard stops working while the detection routine is running.

The solution is to add a specific mmc work queue to run the detection code in.
This is similar to how other subsystems handle detection (a full kernel
thread is the most common theme).

Signed-off-by: default avatarPierre Ossman <drzeus@drzeus.cx>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 8a4da143

drivers/mmc/mmc.c

+3 −3
Original line number Diff line number Diff line
@@ -1166,9 +1166,9 @@ static void mmc_setup(struct mmc_host *host) 
void mmc_detect_change(struct mmc_host *host, unsigned long delay)

{

	if (delay)

		schedule_delayed_work(&host->detect, delay);

		mmc_schedule_delayed_work(&host->detect, delay);

	else

		schedule_work(&host->detect);

		mmc_schedule_work(&host->detect);

}



EXPORT_SYMBOL(mmc_detect_change);
@@ -1311,7 +1311,7 @@ EXPORT_SYMBOL(mmc_remove_host); 
 */

void mmc_free_host(struct mmc_host *host)

{

	flush_scheduled_work();

	mmc_flush_scheduled_work();

	mmc_free_host_sysfs(host);

}

drivers/mmc/mmc.h

+4 −0
Original line number Diff line number Diff line
@@ -18,4 +18,8 @@ struct mmc_host *mmc_alloc_host_sysfs(int extra, struct device *dev); 
int mmc_add_host_sysfs(struct mmc_host *host);

void mmc_remove_host_sysfs(struct mmc_host *host);

void mmc_free_host_sysfs(struct mmc_host *host);



int mmc_schedule_work(struct work_struct *work);

int mmc_schedule_delayed_work(struct work_struct *work, unsigned long delay);

void mmc_flush_scheduled_work(void);

#endif

drivers/mmc/mmc_sysfs.c

+34 −1
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/init.h>

#include <linux/device.h>

#include <linux/idr.h>

#include <linux/workqueue.h>



#include <linux/mmc/card.h>

#include <linux/mmc/host.h>
@@ -317,10 +318,41 @@ void mmc_free_host_sysfs(struct mmc_host *host) 
	class_device_put(&host->class_dev);

}



static struct workqueue_struct *workqueue;



/*

 * Internal function. Schedule work in the MMC work queue.

 */

int mmc_schedule_work(struct work_struct *work)

{

	return queue_work(workqueue, work);

}



/*

 * Internal function. Schedule delayed work in the MMC work queue.

 */

int mmc_schedule_delayed_work(struct work_struct *work, unsigned long delay)

{

	return queue_delayed_work(workqueue, work, delay);

}



/*

 * Internal function. Flush all scheduled work from the MMC work queue.

 */

void mmc_flush_scheduled_work(void)

{

	flush_workqueue(workqueue);

}



static int __init mmc_init(void)

{

	int ret = bus_register(&mmc_bus_type);

	int ret;



	workqueue = create_singlethread_workqueue("kmmcd");

	if (!workqueue)

		return -ENOMEM;



	ret = bus_register(&mmc_bus_type);

	if (ret == 0) {

		ret = class_register(&mmc_host_class);

		if (ret)
@@ -333,6 +365,7 @@ static void __exit mmc_exit(void) 
{

	class_unregister(&mmc_host_class);

	bus_unregister(&mmc_bus_type);

	destroy_workqueue(workqueue);

}



module_init(mmc_init);