Hi all, This patch series makes improvements to the way the v4l2 core handles locking and how it handles the ioctls. This is driven by some requirements from the work on the gspca driver, but it is also a good starting point to clean up the v4l2-ioctl.c source. The gspca requirement was to have better control over locking. This affects primarily USB drivers as they want to avoid having to take a core lock when (de)queuing buffers and polling for new frames since some of the operations over the USB bus can take a fair amount of time and having to wait for the lock can increase latency. Besides, for those operations it is usually not needed to lock. The same is true for file operations like poll, read and write. So patch 1 makes it possible to skip locking for selected ioctls, while patch 5 inverts the default behavior of the core: it will only take the core lock for the ioctl fop, not for the others unless a flag is set explicitly in the driver. I've set that flag in all drivers that use the core lock, unless it was immediately obvious that they didn't need it. Those drivers need to be audited so that we can eventually remove the flag. While I could have gone for the one-flag-per-fop approach, I thought this made more sense. There are only a few fops as opposed to the zillion ioctls. Since I used a table-driven approach in the first patch I decided to extend it to other parts of v4l2-ioctl as well. So the determination which ioctls are actually implemented in a driver is now done upfront, and whether an ioctl needs to do priority handling is now done by table lookup as well. Eventually I want to replace all the switches by table lookup, which is O(1) and will hopefully be a lot more readable. Some work doing that is available here: http://git.linuxtv.org/hverkuil/media_tree.git/shortlog/refs/heads/ioctl2 This patch series is also available here: git://linuxtv.org/hverkuil/media_tree.git ioctl Comments? Regards, Hans ---------------------------------------------------------------- Hans Verkuil (5): v4l2-dev: make it possible to skip locking for selected ioctls. v4l2-dev/ioctl: determine the valid ioctls upfront. tea575x-tuner: mark VIDIOC_S_HW_FREQ_SEEK as an invalid ioctl. v4l2-ioctl: handle priority handling based on a table lookup. v4l2-dev: add flag to have the core lock all file operations. Documentation/video4linux/v4l2-framework.txt | 27 ++++- drivers/media/common/saa7146_fops.c | 4 + drivers/media/radio/wl128x/fmdrv_v4l2.c | 4 + drivers/media/video/blackfin/bfin_capture.c | 4 + drivers/media/video/cpia2/cpia2_v4l.c | 4 + drivers/media/video/cx231xx/cx231xx-video.c | 4 + drivers/media/video/davinci/vpbe_display.c | 4 + drivers/media/video/davinci/vpif_capture.c | 4 + drivers/media/video/davinci/vpif_display.c | 4 + drivers/media/video/em28xx/em28xx-video.c | 4 + drivers/media/video/fsl-viu.c | 4 + drivers/media/video/ivtv/ivtv-streams.c | 4 + drivers/media/video/mem2mem_testdev.c | 4 + drivers/media/video/mx2_emmaprp.c | 4 + drivers/media/video/s2255drv.c | 4 + drivers/media/video/s5p-fimc/fimc-capture.c | 4 + drivers/media/video/s5p-fimc/fimc-core.c | 4 + drivers/media/video/s5p-g2d/g2d.c | 4 + drivers/media/video/s5p-jpeg/jpeg-core.c | 8 ++ drivers/media/video/s5p-mfc/s5p_mfc.c | 6 + drivers/media/video/s5p-tv/mixer_video.c | 4 + drivers/media/video/sh_vou.c | 4 + drivers/media/video/soc_camera.c | 4 + drivers/media/video/tm6000/tm6000-video.c | 4 + drivers/media/video/usbvision/usbvision-video.c | 4 + drivers/media/video/v4l2-dev.c | 217 ++++++++++++++++++++++++++++++--- drivers/media/video/v4l2-ioctl.c | 539 ++++++++++++++++++++++------------------------------------------------------------ drivers/staging/media/dt3155v4l/dt3155v4l.c | 4 + include/media/v4l2-dev.h | 25 ++++ sound/i2c/other/tea575x-tuner.c | 3 + 30 files changed, 506 insertions(+), 411 deletions(-) -- 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
