From: Ian Abbott Date: Mon, 28 Jan 2013 16:14:31 +0000 (+0000) Subject: staging: comedi: disallow COMEDI_DEVCONFIG on non-board minors X-Git-Tag: v3.2.40~136 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6c7050330611973632ce7d73f0e914ed6f63f946;p=pandora-kernel.git staging: comedi: disallow COMEDI_DEVCONFIG on non-board minors commit 754ab5c0e55dd118273ca2c217c4d95e9fbc8259 upstream. Comedi has two sorts of minor devices: (a) normal board minor devices in the range 0 to COMEDI_NUM_BOARD_MINORS-1 inclusive; and (b) special subdevice minor devices in the range COMEDI_NUM_BOARD_MINORS upwards that are used to open the same underlying comedi device as the normal board minor devices, but with non-default read and write subdevices for asynchronous commands. The special subdevice minor devices get created when a board supporting asynchronous commands is attached to a normal board minor device, and destroyed when the board is detached from the normal board minor device. One way to attach or detach a board is by using the COMEDI_DEVCONFIG ioctl. This should only be used on normal board minors as the special subdevice minors are too ephemeral. In particular, the change introduced in commit 7d3135af399e92cf4c9bbc5f86b6c140aab3b88c ("staging: comedi: prevent auto-unconfig of manually configured devices") breaks horribly for special subdevice minor devices. Since there's no legitimate use for the COMEDI_DEVCONFIG ioctl on a special subdevice minor device node, disallow it and return -ENOTTY. Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed