From 949c4a34afacfe800fc442afac117aba15284962 Mon Sep 17 00:00:00 2001 From: Ilija Hadzic Date: Tue, 15 May 2012 16:40:10 -0400 Subject: 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 Signed-off-by: Dave Airlie --- drivers/gpu/drm/radeon/radeon_object.c | 4 +--- drivers/gpu/drm/radeon/radeon_ttm.c | 4 +--- 2 files changed, 2 insertions(+), 6 deletions(-) (limited to 'drivers/gpu/drm/radeon') diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c index 6ecb2006e27e..1f77a5afc011 100644 --- a/drivers/gpu/drm/radeon/radeon_object.c +++ b/drivers/gpu/drm/radeon/radeon_object.c @@ -115,9 +115,7 @@ int radeon_bo_create(struct radeon_device *rdev, size = ALIGN(size, PAGE_SIZE); - 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; if (kernel) { type = ttm_bo_type_kernel; } else if (sg) { 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) { -- cgit v1.2.2