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authorIlija Hadzic <ihadzic@research.bell-labs.com>2012-05-15 16:40:10 -0400
committerDave Airlie <airlied@redhat.com>2012-07-25 00:09:30 -0400
commit949c4a34afacfe800fc442afac117aba15284962 (patch)
treeee7c6ebc5d8b05fbca1113b8c9147fbee7e26321 /drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
parentb97ce28e9f6d65a800e5c2ee3a2a99c7795bef65 (diff)
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/vmwgfx/vmwgfx_drv.c')
-rw-r--r--drivers/gpu/drm/vmwgfx/vmwgfx_drv.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index 5d5632f5265b..4d9edead01ac 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -769,10 +769,7 @@ static int vmw_driver_open(struct drm_device *dev, struct drm_file *file_priv)
769 goto out_no_tfile; 769 goto out_no_tfile;
770 770
771 file_priv->driver_priv = vmw_fp; 771 file_priv->driver_priv = vmw_fp;
772 772 dev_priv->bdev.dev_mapping = dev->dev_mapping;
773 if (unlikely(dev_priv->bdev.dev_mapping == NULL))
774 dev_priv->bdev.dev_mapping =
775 file_priv->filp->f_path.dentry->d_inode->i_mapping;
776 773
777 return 0; 774 return 0;
778 775