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 <>
Cc: Russell King <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 8a4da143
......@@ -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);
......@@ -1311,7 +1311,7 @@ EXPORT_SYMBOL(mmc_remove_host);
void mmc_free_host(struct mmc_host *host)
......@@ -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);
......@@ -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)
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)
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)
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