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drm: use anon-inode instead of relying on cdevs

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DRM drivers share a common address_space across all character-devices of a
single DRM device. This allows simple buffer eviction and mapping-control.
However, DRM core currently waits for the first ->open() on any char-dev
to mark the underlying inode as backing inode of the device. This delayed
initialization causes ugly conditions all over the place:
  if (dev->dev_mapping)
    do_sth();

To avoid delayed initialization and to stop reusing the inode of the
char-dev, we allocate an anonymous inode for each DRM device and reset
filp->f_mapping to it on ->open().

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
This commit is contained in:
David Herrmann
2014-01-03 14:24:19 +01:00
parent 31bbe16f6d
commit 6796cb16c0
15 changed files with 44 additions and 54 deletions
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2
drivers/gpu/drm/cirrus/cirrus_ttm.c
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@@ -329,7 +329,7 @@ int cirrus_bo_create(struct drm_device *dev, int size, int align,
}
cirrusbo->bo.bdev = &cirrus->ttm.bdev;
cirrusbo->bo.bdev->dev_mapping = dev->dev_mapping;
cirrusbo->bo.bdev->dev_mapping = dev->anon_inode->i_mapping;
cirrus_ttm_placement(cirrusbo, TTM_PL_FLAG_VRAM | TTM_PL_FLAG_SYSTEM);