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: Pierre Ossman <[email protected]>
---
drivers/mmc/mmc.c | 6 +++---
drivers/mmc/mmc.h | 4 ++++
drivers/mmc/mmc_sysfs.c | 35 ++++++++++++++++++++++++++++++++++-
3 files changed, 41 insertions(+), 4 deletions(-)
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 5b9caa7..ee8863c 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -1166,9 +1166,9 @@ static void mmc_setup(struct mmc_host *h
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);
}
diff --git a/drivers/mmc/mmc.h b/drivers/mmc/mmc.h
index 97bae00..cd5e0ab 100644
--- a/drivers/mmc/mmc.h
+++ b/drivers/mmc/mmc.h
@@ -18,4 +18,8 @@ struct mmc_host *mmc_alloc_host_sysfs(in
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
diff --git a/drivers/mmc/mmc_sysfs.c b/drivers/mmc/mmc_sysfs.c
index a2a35fd..10cc973 100644
--- a/drivers/mmc/mmc_sysfs.c
+++ b/drivers/mmc/mmc_sysfs.c
@@ -13,6 +13,7 @@ #include <linux/module.h>
#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
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);
-
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