mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 19:29:37 +00:00
staging: unisys: visorinput: remove unnecessary locking
Locking in the _interrupt() function is NOT necessary so long as we ensure that interrupts have been stopped whenever we need to pause or resume the device, which we now do. While a device is paused, we ensure that interrupts stay disabled, i.e. that the _interrupt() function will NOT be called, yet remember the desired state in devdata->interrupts_enabled if open() or close() are called are called while the device is paused. Then when the device is resumed, we restore the actual state of interrupts (i.e., whether _interrupt() is going to be called or not) to the desired state in devdata->interrupts_enabled. Signed-off-by: Tim Sell <Timothy.Sell@unisys.com> Signed-off-by: David Kershner <david.kershner@unisys.com> Acked-By: Neil Horman <nhorman@tuxdriver.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
c3d4a97033
commit
83011b6cbe
1 changed files with 47 additions and 10 deletions
|
@ -66,6 +66,7 @@ struct visorinput_devdata {
|
|||
struct rw_semaphore lock_visor_dev; /* lock for dev */
|
||||
struct input_dev *visorinput_dev;
|
||||
bool paused;
|
||||
bool interrupts_enabled;
|
||||
unsigned int keycode_table_bytes; /* size of following array */
|
||||
/* for keyboard devices: visorkbd_keycode[] + visorkbd_ext_keycode[] */
|
||||
unsigned char keycode_table[0];
|
||||
|
@ -228,7 +229,21 @@ static int visorinput_open(struct input_dev *visorinput_dev)
|
|||
return -EINVAL;
|
||||
}
|
||||
dev_dbg(&visorinput_dev->dev, "%s opened\n", __func__);
|
||||
|
||||
/*
|
||||
* If we're not paused, really enable interrupts.
|
||||
* Regardless of whether we are paused, set a flag indicating
|
||||
* interrupts should be enabled so when we resume, interrupts
|
||||
* will really be enabled.
|
||||
*/
|
||||
down_write(&devdata->lock_visor_dev);
|
||||
devdata->interrupts_enabled = true;
|
||||
if (devdata->paused)
|
||||
goto out_unlock;
|
||||
visorbus_enable_channel_interrupts(devdata->dev);
|
||||
|
||||
out_unlock:
|
||||
up_write(&devdata->lock_visor_dev);
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
@ -243,7 +258,22 @@ static void visorinput_close(struct input_dev *visorinput_dev)
|
|||
return;
|
||||
}
|
||||
dev_dbg(&visorinput_dev->dev, "%s closed\n", __func__);
|
||||
|
||||
/*
|
||||
* If we're not paused, really disable interrupts.
|
||||
* Regardless of whether we are paused, set a flag indicating
|
||||
* interrupts should be disabled so when we resume we will
|
||||
* not re-enable them.
|
||||
*/
|
||||
|
||||
down_write(&devdata->lock_visor_dev);
|
||||
devdata->interrupts_enabled = false;
|
||||
if (devdata->paused)
|
||||
goto out_unlock;
|
||||
visorbus_disable_channel_interrupts(devdata->dev);
|
||||
|
||||
out_unlock:
|
||||
up_write(&devdata->lock_visor_dev);
|
||||
}
|
||||
|
||||
/*
|
||||
|
@ -438,10 +468,8 @@ visorinput_remove(struct visor_device *dev)
|
|||
* in visorinput_channel_interrupt()
|
||||
*/
|
||||
|
||||
down_write(&devdata->lock_visor_dev);
|
||||
dev_set_drvdata(&dev->device, NULL);
|
||||
unregister_client_input(devdata->visorinput_dev);
|
||||
up_write(&devdata->lock_visor_dev);
|
||||
kfree(devdata);
|
||||
}
|
||||
|
||||
|
@ -529,13 +557,7 @@ visorinput_channel_interrupt(struct visor_device *dev)
|
|||
if (!devdata)
|
||||
return;
|
||||
|
||||
down_write(&devdata->lock_visor_dev);
|
||||
if (devdata->paused) /* don't touch device/channel when paused */
|
||||
goto out_locked;
|
||||
|
||||
visorinput_dev = devdata->visorinput_dev;
|
||||
if (!visorinput_dev)
|
||||
goto out_locked;
|
||||
|
||||
while (visorchannel_signalremove(dev->visorchannel, 0, &r)) {
|
||||
scancode = r.activity.arg1;
|
||||
|
@ -611,8 +633,6 @@ visorinput_channel_interrupt(struct visor_device *dev)
|
|||
break;
|
||||
}
|
||||
}
|
||||
out_locked:
|
||||
up_write(&devdata->lock_visor_dev);
|
||||
}
|
||||
|
||||
static int
|
||||
|
@ -632,6 +652,14 @@ visorinput_pause(struct visor_device *dev,
|
|||
rc = -EBUSY;
|
||||
goto out_locked;
|
||||
}
|
||||
if (devdata->interrupts_enabled)
|
||||
visorbus_disable_channel_interrupts(dev);
|
||||
|
||||
/*
|
||||
* due to above, at this time no thread of execution will be
|
||||
* in visorinput_channel_interrupt()
|
||||
*/
|
||||
|
||||
devdata->paused = true;
|
||||
complete_func(dev, 0);
|
||||
rc = 0;
|
||||
|
@ -659,6 +687,15 @@ visorinput_resume(struct visor_device *dev,
|
|||
}
|
||||
devdata->paused = false;
|
||||
complete_func(dev, 0);
|
||||
|
||||
/*
|
||||
* Re-establish calls to visorinput_channel_interrupt() if that is
|
||||
* the desired state that we've kept track of in interrupts_enabled
|
||||
* while the device was paused.
|
||||
*/
|
||||
if (devdata->interrupts_enabled)
|
||||
visorbus_enable_channel_interrupts(dev);
|
||||
|
||||
rc = 0;
|
||||
out_locked:
|
||||
up_write(&devdata->lock_visor_dev);
|
||||
|
|
Loading…
Reference in a new issue