[media] v4l2-ioctl: Don't assume file->private_data always points to a v4l2_fh
Commit efbceecd, adds a number of helper functions for ctrl related ioctls to v4l2-ioctl.c, these helpers assume that if file->private_data != NULL, it points to a v4l2_fh, which is only the case for drivers which actually use v4l2_fh. This breaks for example bttv which use the "filedata" pointer for its own uses, and now all the ctrl ioctls try to use whatever its filedata points to as v4l2_fh and think it has a ctrl_handler, leading to: [ 142.499214] BUG: unable to handle kernel NULL pointer dereference at 0000000000000021 [ 142.499270] IP: [<ffffffffa01cb959>] v4l2_queryctrl+0x29/0x230 [videodev] [ 142.514649] [<ffffffffa01c7a77>] v4l_queryctrl+0x47/0x90 [videodev] [ 142.517417] [<ffffffffa01c58b1>] __video_do_ioctl+0x2c1/0x420 [videodev] [ 142.520116] [<ffffffffa01c7ee6>] video_usercopy+0x1a6/0x470 [videodev] ... This patch adds the missing test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) tests to the ctrl ioctl helpers v4l2_fh paths, fixing the issues with for example the bttv driver. Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl> Signed-off-by: NHans de Goede <hdegoede@redhat.com> Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>
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