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authorIlija Hadzic <ihadzic@research.bell-labs.com>2012-05-16 00:40:10 +0400
committerDave Airlie <airlied@redhat.com>2012-07-25 08:09:30 +0400
commit949c4a34afacfe800fc442afac117aba15284962 (patch)
treeee7c6ebc5d8b05fbca1113b8c9147fbee7e26321 /drivers/gpu/drm/radeon/radeon_ttm.c
parentb97ce28e9f6d65a800e5c2ee3a2a99c7795bef65 (diff)
downloadlinux-949c4a34afacfe800fc442afac117aba15284962.tar.xz
drm: track dev_mapping in more robust and flexible way
Setting dev_mapping (pointer to the address_space structure used for memory mappings) to the address_space of the first opener's inode and then failing if other openers come in through a different inode has a few restrictions that are eliminated by this patch. If we already have valid dev_mapping and we spot an opener with different i_node, we force its i_mapping pointer to the already established address_space structure (first opener's inode). This will make all mappings from drm device hang off the same address_space object. Some benefits (things that now work and didn't work before) of this patch are: * user space can mknod and use any number of device nodes and they will all work fine as long as the major device number is that of the drm module. * user space can even remove the first opener's device nodes and mknod the new one and the applications and windowing system will still work. * GPU drivers can safely assume that dev->dev_mapping is correct address_space and just blindly copy it into their (private) bdev.dev_mapping For reference, some discussion that lead to this patch can be found here: http://lists.freedesktop.org/archives/dri-devel/2012-April/022283.html Signed-off-by: Ilija Hadzic <ihadzic@research.bell-labs.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers/gpu/drm/radeon/radeon_ttm.c')
-rw-r--r--drivers/gpu/drm/radeon/radeon_ttm.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index 0881131a0388..5b71c716d83f 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -734,9 +734,7 @@ int radeon_ttm_init(struct radeon_device *rdev)
}
DRM_INFO("radeon: %uM of GTT memory ready.\n",
(unsigned)(rdev->mc.gtt_size / (1024 * 1024)));
- if (unlikely(rdev->mman.bdev.dev_mapping == NULL)) {
- rdev->mman.bdev.dev_mapping = rdev->ddev->dev_mapping;
- }
+ rdev->mman.bdev.dev_mapping = rdev->ddev->dev_mapping;
r = radeon_ttm_debugfs_init(rdev);
if (r) {