From: Tim Sell <timothy.s...@unisys.com>
Because visorinput_channel_interrupt() is now called from interrupt
context, we can't use our lock_visor_dev semaphore there. Instead, we
use a new lock_isr spinlock, which is essentially needed to prevent
visorinput_dev from disappearing while we're accessing it in
visorinput_channel_interrupt().
Signed-off-by: David Kershner <david.kersh...@unisys.com>
Signed-off-by: Benjamin Romer <benjamin.ro...@unisys.com>
---
drivers/staging/unisys/visorinput/visorinput.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/drivers/staging/unisys/visorinput/visorinput.c
b/drivers/staging/unisys/visorinput/visorinput.c
index 57193b3..1c2a210 100644
--- a/drivers/staging/unisys/visorinput/visorinput.c
+++ b/drivers/staging/unisys/visorinput/visorinput.c
@@ -102,6 +102,7 @@ struct visorinput_devdata {
struct visor_device *dev;
enum visorinput_device_type devtype;
struct rw_semaphore lock_visor_dev; /* lock for dev */
+ spinlock_t lock_isr; /* for data accessed in isr */
struct input_dev *visorinput_dev;
bool paused;
struct workqueue_struct *wq;
@@ -417,6 +418,7 @@ static void devdata_put(struct visorinput_devdata *devdata)
static void async_change_resolution(struct work_struct *work)
{
+ struct input_dev *visorinput_dev = NULL;
struct change_resolution_work *p_change_resolution_work =
container_of(work, struct change_resolution_work, work);
struct visorinput_devdata *devdata =
@@ -425,13 +427,20 @@ static void async_change_resolution(struct work_struct
*work)
change_resolution_work_data);
down_write(&devdata->lock_visor_dev);
+ spin_lock(&devdata->lock_isr);
- if (devdata->paused) /* don't touch device/channel when paused */
- goto out_locked;
- if (!devdata->visorinput_dev)
- goto out_locked;
+ /* devdata->visorinput_dev can only go NULL when lock_isr is held */
- unregister_client_input(devdata->visorinput_dev);
+ if (devdata->paused || (!devdata->visorinput_dev)) {
+ spin_unlock(&devdata->lock_isr);
+ goto out;
+ }
+ visorinput_dev = devdata->visorinput_dev; /* can't unreg with lock */
+ devdata->visorinput_dev = NULL;
+
+ spin_unlock(&devdata->lock_isr);
+
+ unregister_client_input(visorinput_dev);
/*
* input_set_abs_params is only effective prior to
* input_register_device().
@@ -448,7 +457,7 @@ static void async_change_resolution(struct work_struct
*work)
dev_info(&devdata->dev->device, "created mouse %s\n",
dev_name(&devdata->visorinput_dev->dev));
-out_locked:
+out:
up_write(&devdata->lock_visor_dev);
devdata_put(devdata); /* from schedule_mouse_resolution_change() */
}
@@ -481,6 +490,7 @@ devdata_create(struct visor_device *dev, enum
visorinput_device_type devtype)
INIT_WORK(&devdata->change_resolution_work_data.work,
async_change_resolution);
init_rwsem(&devdata->lock_visor_dev);
+ spin_lock_init(&devdata->lock_isr);
down_write(&devdata->lock_visor_dev);
/*
@@ -665,7 +675,7 @@ visorinput_channel_interrupt(struct visor_device *dev)
if (!devdata)
return;
- down_write(&devdata->lock_visor_dev);
+ spin_lock(&devdata->lock_isr);
if (devdata->paused) /* don't touch device/channel when paused */
goto out_locked;
@@ -771,7 +781,7 @@ visorinput_channel_interrupt(struct visor_device *dev)
}
out_locked:
devdata_put(devdata);
- up_write(&devdata->lock_visor_dev);
+ spin_unlock(&devdata->lock_isr);
}
static int
--
2.5.0
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