[PATCH 2/3] serio-pin-driver.patch

Dmitry Torokhov
2004-09-17T05:07:00Z

===================================================================

ChangeSet@1.1903, 2004-09-16 23:06:29-05:00, dtor_core@ameritech.net
Input: add serio_[un]pin_driver() functions so attribute handlers
can safely access driver bound to a serio port.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/serio/serio.c | 20 ++++++++++++--------
include/linux/serio.h | 16 +++++++++++++++-
2 files changed, 27 insertions(+), 9 deletions(-)

===================================================================

diff -Nru a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
--- a/drivers/input/serio/serio.c 2004-09-16 23:31:24 -05:00
+++ b/drivers/input/serio/serio.c 2004-09-16 23:31:24 -05:00
@@ -326,6 +326,7 @@
try_module_get(THIS_MODULE);

spin_lock_init(&serio->lock);
+ init_MUTEX(&serio->drv_sem);
list_add_tail(&serio->node, &serio_list);
snprintf(serio->dev.bus_id, sizeof(serio->dev.bus_id), "serio%d", serio_no++);
serio->dev.bus = &serio_bus;
@@ -595,17 +596,22 @@
up(&serio_sem);
}

-/* called from serio_driver->connect/disconnect methods under serio_sem */
-int serio_open(struct serio *serio, struct serio_driver *drv)
+static void serio_set_drv(struct serio *serio, struct serio_driver *drv)
{
+ down(&serio->drv_sem);
serio_pause_rx(serio);
serio->drv = drv;
serio_continue_rx(serio);
+ up(&serio->drv_sem);
+}
+
+/* called from serio_driver->connect/disconnect methods under serio_sem */
+int serio_open(struct serio *serio, struct serio_driver *drv)
+{
+ serio_set_drv(serio, drv);

if (serio->open && serio->open(serio)) {
- serio_pause_rx(serio);
- serio->drv = NULL;
- serio_continue_rx(serio);
+ serio_set_drv(serio, NULL);
return -1;
}
return 0;
@@ -617,9 +623,7 @@
if (serio->close)
serio->close(serio);

- serio_pause_rx(serio);
- serio->drv = NULL;
- serio_continue_rx(serio);
+ serio_set_drv(serio, NULL);
}

irqreturn_t serio_interrupt(struct serio *serio,
diff -Nru a/include/linux/serio.h b/include/linux/serio.h
--- a/include/linux/serio.h 2004-09-16 23:31:24 -05:00
+++ b/include/linux/serio.h 2004-09-16 23:31:24 -05:00
@@ -45,7 +45,8 @@

struct serio *parent, *child;

- struct serio_driver *drv; /* accessed from interrupt, must be protected by serio->lock */
+ struct serio_driver *drv; /* accessed from interrupt, must be protected by serio->lock and serio->sem */
+ struct semaphore drv_sem; /* protects serio->drv so attributes can pin driver */

struct device dev;

@@ -120,6 +121,19 @@
static __inline__ void serio_continue_rx(struct serio *serio)
{
spin_unlock_irq(&serio->lock);
+}
+
+/*
+ * Use the following fucntions to pin serio's driver in process context
+ */
+static __inline__ int serio_pin_driver(struct serio *serio)
+{
+ return down_interruptible(&serio->drv_sem);
+}
+
+static __inline__ void serio_unpin_driver(struct serio *serio)
+{
+ up(&serio->drv_sem);
}