Roland Dreier wrote on 11.01.2007 20:54:58: > > > int ehca_mmap(struct ib_ucontext *context, struct vm_area_struct *vma) > > > { > > > > Can you split this monster routine into individual functions for > > each type of mmap please? With two helpers to get and verify the cq/qp > > shared by the individual sub-variants, that would also help to get rid > > of all those magic offsets. > > > > Actually, this routine directly comes from ib_device.mmap - Roland, > > can you shed some light on what's going on here? > > Each userspace-accessible IB device gets a single device node like > /dev/infiniband/uverbsX. Opening that gives userspace a "context". > One of the things userspace can do with that fd is mmap() on it -- > that was originally envisioned as a way to map a page of hardware > registers directly in to the userspace process. > > It seems ehca needs to allocate lots of different things in the kernel > via mmap(). What you're saying I guess is that ideally each of these > would be mmap() on a different fd rather than using different > offsets. It's a little awkward to open multiple device nodes to get > multiple fds, since there's not a good way to attach them all to the > same context. I guess we could create some hack to return more file > handles, but I think that cure is worse than the disease of using > magic offsets... > > Maybe longer term we need to look at a scheme like cell's spufs but > I'm still not confident we have the RDMA interface quite ready to > freeze at the system call level. > > - R.
...as Roland mentions, we're not completely free to change the filehandle usage, it's shared by ~5 drivers now. I'd say lets investigate the direction of an own filesystem unless there's no other clean solution. We can polish the current version a bit, but that won't change the "magic offsets". Roland, could you take this patchset into your tree? We hope it adresses the major security concern and vm_insert_page. We're preparing the next patch for the yield deadlock topic with this patchset as prereq. Gruss / Regards . . . Christoph Raisch - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/