Johannes Stezenbach <js@xxxxxxxxxxx> writes: > I have no idea if we need to do something special to support this, > although I've seen that there's this compat_ioctl in > struct file_operations. Does someone have a clue? Yes, compat_ioctl is for 32bit apps. Had a quick look at the structs and they seem to be identical in 32 and 64 bit. I think simply hooking the ioctl callback into both ioctl and compat_ioctl could do the trick for the frontend device. In case you'll have fields like "long" or "void*" in the ioctl structs which have different sizes for 32/64 bit apps compat_ioctl would have to take care to handle the 32-bit cases correctly. Browse through the kernel source code, there should be quite a few examples ;) Gerd -- -mm seems unusually stable at present. -- akpm about 2.6.12-rc3-mm3
