it's always current->mm

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This continues the theme started with vm_brk() and vm_munmap():
vm_mmap() does the same thing as do_mmap(), but additionally does the
required VM locking.

This uninlines (and rewrites it to be clearer) do_mmap(), which sadly
duplicates it in mm/mmap.c and mm/nommu.c.  But that way we don't have
to export our internal do_mmap_pgoff() function.

Some day we hopefully don't have to export do_mmap() either, if all
modular users can become the simpler vm_mmap() instead.  We're actually
very close to that already, with the notable exception of the (broken)
use in i810, and a couple of stragglers in binfmt_elf.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Like the vm_brk() function, this is the same as "do_munmap()", except it
does the VM locking for the caller.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Talking to Al Viro on irc, we can see no possible reason for doing
this, the upper mmap code does it. The code has been there since
first import into drm tree I can find.

Al tracked down this as a requirement pre 2.3.51 hasn't been needed since.

Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>

The current enabling of bus mastering in the drm midlayer allows a large
race condition under kexec. When a kexec'ed kernel re-enables bus mastering
for the GPU, previously setup dma blocks may cause writes to random pieces
of memory. On radeon the writeback mechanism can cause these sorts of issues.

This patch doesn't fix the problem, but it moves the bus master enable under
the individual drivers control so they can move enabling it until later in
their load cycle and close the race.

Fix for radeon kms driver will be in a follow-up patch.

Signed-off-by: Dave Airlie <airlied@redhat.com>

This reverts commit 87499ffdcb1c70f66988cd8febc4ead0ba2f9118.

Where is that paper bag ... ah here.

I've failed to take an odd interaction between my other cleanups and
this reclaim_buffers patch into account and also failed to properly
test it. Looks like there are more dragons and hidden trapdoors in the
drm release path than actual lines of code.

Until I get a clue, let's just revert this.

Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Signed-off-by: Dave Airlie <airlied@redhat.com>

i810 uses a userspace provided mmio map using the drm core map
infrastructure. By the time we reach lastclose, this is all gone
and our mmio_map pointer points at freed memory. Depending upon
luck that still works, most often it just oopses.

Aside: drm maps aren't refcounted, so userspace can essentially oops
the kernel any time it wants to. Who cares.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

My dear old i815 always hits the deadlocked on reclaim_buffers
warning. Switch over to the idlelock duct-tape on hope that
works better. I've fired up my i815 and now closing glxgears doesn't
take 5 seconds anymore. \o/

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

From fdf1fdebaa00f81de18c227f32f8074c8b352d50 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Sun, 30 Oct 2011 19:06:07 -0700
Subject: [PATCH] drm: Make the per-driver file_operations struct const

The DRM layer keeps a copy of struct file_operations inside its
big driver struct... which prevents it from being consistent and static.
For consistency (and the general security objective of having such things
static), it's desirable to get this fixed.

This patch splits out the file_operations field to its own struct,
which is then "static const", and just stick a pointer to this into
the driver struct, making it more consistent with how the rest of the
kernel does this.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

So that we don't get build failures once the implicit module.h
presence is removed.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>