On Thursday 01 April 2010 13:57:13 Stefan Richter wrote: > Hans Verkuil wrote: > > I just read on LWN that the core kernel guys are putting more effort into > > removing the BKL. We are still using it in our own drivers, mostly V4L. > > > > I added a BKL column to my driver list: > > > > http://www.linuxtv.org/wiki/index.php/V4L_framework_progress#Bridge_Drivers > > > > If you 'own' one of these drivers that still use BKL, then it would be nice > > if you can try and remove the use of the BKL from those drivers. > > > > The other part that needs to be done is to move from using the .ioctl file op > > to using .unlocked_ioctl. Very few drivers do that, but I suspect almost no > > driver actually needs to use .ioctl. > > Also note that struct file_operations.llseek() grabs the BKL if .llseek > = default_llseek, or if .llseek == NULL && (struct file.f_mode & > FMODE_LSEEK) != 0. > > I guess V4L/DVB character device file ABIs do not involve lseek() and > friends, do they? If so, are the files flagged as non-seekable? They are. The file op .llseek is always set to no_llseek for v4l. DVB seems to leave it at NULL but I don't believe it is ever implemented. > > On the DVB side there seem to be only two sources that use the BKL: > > > > linux/drivers/media/dvb/bt8xx/dst_ca.c: lock_kernel(); > > linux/drivers/media/dvb/bt8xx/dst_ca.c: unlock_kernel(); > > linux/drivers/media/dvb/dvb-core/dvbdev.c: lock_kernel(); > > linux/drivers/media/dvb/dvb-core/dvbdev.c: unlock_kernel(); > > linux/drivers/media/dvb/dvb-core/dvbdev.c: unlock_kernel(); > > > > At first glance it doesn't seem too difficult to remove them, but I leave > > that to the DVB experts. > > As a dvb/firewire/firedtv user, I started to mess around with dvbdev and > firedtv: https://patchwork.kernel.org/patch/88778/ > Great! Regards, Hans -- Hans Verkuil - video4linux developer - sponsored by TANDBERG -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
