On Mon, Apr 16, 2001 at 08:42:41PM +0200, Geert Uytterhoeven wrote: > > #define _IOWR(type,nr,size) > > _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size)) > > > > > > and _IOC uses size in this way: > > > > (((size) & _IOC_SLMASK) << _IOC_SIZESHIFT)) // (_IOC_SLMMASK = 0xff) > > > > > > The limited size causes problems on drivers that use size mask to their > > needs, while officialy the allowed limit is 2^13 ( 8kB) by definition . > > This was fixed in the CVS tree some weeks ago. Small addendum to the fix - while it made some ioctls usable it also did result in the affected ioctl number changing which may have broken some software that _appeared_ to be working before. One example is autofs. Just recompile against the updated kernel headers and everything will be ok. The effect gets more visible on the 64-bit kernel which will spit kernel messages for unknown ioctls. Ralf
