From 879aa24d6394aa04b690a600a41ff500441ad384 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Fri, 26 Nov 2010 06:47:28 -0300 Subject: [media] V4L: improve the BKL replacement heuristic The BKL replacement mutex had some serious performance side-effects on V4L drivers. It is replaced by a better heuristic that works around the worst of the side-effects. Read the v4l2-dev.c comments for the whole sorry story. This is a temporary measure only until we can convert all v4l drivers to use unlocked_ioctl. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/v4l2-device.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/media/video/v4l2-device.c') diff --git a/drivers/media/video/v4l2-device.c b/drivers/media/video/v4l2-device.c index 0b08f96b74a..7fe6f92af48 100644 --- a/drivers/media/video/v4l2-device.c +++ b/drivers/media/video/v4l2-device.c @@ -35,6 +35,7 @@ int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev) INIT_LIST_HEAD(&v4l2_dev->subdevs); spin_lock_init(&v4l2_dev->lock); + mutex_init(&v4l2_dev->ioctl_lock); v4l2_dev->dev = dev; if (dev == NULL) { /* If dev == NULL, then name must be filled in by the caller */ -- cgit v1.2.3-70-g09d2