linux-stable.git/drivers/gpu/buddy.c, branch linux-rolling-lts Linux kernel stable tree gpu/buddy: bail out of try_harder when alignment cannot be honoured 2026-08-03T09:22:09+00:00 Arunpravin Paneer Selvam Arunpravin.PaneerSelvam@amd.com 2026-07-23T14:19:30+00:00 7185c5262435b93e5eeffa647008992256b9c51a [ Upstream commit 56bc6384314fb9ae98975fb2af8b143097ede3dc ] The try_harder contiguous fallback could return a range whose start offset did not match the caller's min_block_size. When a candidate's start is misaligned, realign it: free the misaligned run and reallocate exactly @size at the next lower min_block_size boundary. This keeps the returned size unchanged with no surplus to trim, and rejects the request only when no aligned candidate fits. v2: align misaligned candidates down to min_block_size instead of bailing out, for both the RHS and LHS paths (Matthew). Fixes: 0a1844bf0b53 ("drm/buddy: Improve contiguous memory allocation") Suggested-by: Christian König <christian.koenig@amd.com> Cc: Matthew Auld <matthew.auld@intel.com> Cc: Christian König <christian.koenig@amd.com> Cc: Timur Kristóf <timur.kristof@gmail.com> Cc: stable@vger.kernel.org Reviewed-by: Matthew Auld <matthew.auld@intel.com> Tested-by: John Olender <john.olender@gmail.com> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com> Link: https://patch.msgid.link/20260709131050.1022759-1-Arunpravin.PaneerSelvam@amd.com Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 56bc6384314fb9ae98975fb2af8b143097ede3dc ]

The try_harder contiguous fallback could return a range whose start
offset did not match the caller's min_block_size. When a candidate's
start is misaligned, realign it: free the misaligned run and reallocate
exactly @size at the next lower min_block_size boundary. This keeps the
returned size unchanged with no surplus to trim, and rejects the request
only when no aligned candidate fits.

v2: align misaligned candidates down to min_block_size instead of
    bailing out, for both the RHS and LHS paths (Matthew).

Fixes: 0a1844bf0b53 ("drm/buddy: Improve contiguous memory allocation")
Suggested-by: Christian König <christian.koenig@amd.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Timur Kristóf <timur.kristof@gmail.com>
Cc: stable@vger.kernel.org
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Tested-by: John Olender <john.olender@gmail.com>
Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Link: https://patch.msgid.link/20260709131050.1022759-1-Arunpravin.PaneerSelvam@amd.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
gpu: Move DRM buddy allocator one level up (part two) 2026-08-03T09:22:09+00:00 Joel Fernandes joelagnelf@nvidia.com 2026-07-23T14:19:29+00:00 65677f7a20c48cf9ed02c56db389cc327d2b61b2 [ Upstream commit ba110db8e1bc206c13fd7d985e79b033f53bfdea ] Move the DRM buddy allocator one level up so that it can be used by GPU drivers (example, nova-core) that have usecases other than DRM (such as VFIO vGPU support). Modify the API, structures and Kconfigs to use "gpu_buddy" terminology. Adapt the drivers and tests to use the new API. The commit cannot be split due to bisectability, however no functional change is intended. Verified by running K-UNIT tests and build tested various configurations. Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com> Reviewed-by: Dave Airlie <airlied@redhat.com> [airlied: I've split this into two so git can find copies easier. I've also just nuked drm_random library, that stuff needs to be done elsewhere and only the buddy tests seem to be using it]. Signed-off-by: Dave Airlie <airlied@redhat.com> Stable-dep-of: 56bc6384314f ("gpu/buddy: bail out of try_harder when alignment cannot be honoured") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit ba110db8e1bc206c13fd7d985e79b033f53bfdea ]

Move the DRM buddy allocator one level up so that it can be used by GPU
drivers (example, nova-core) that have usecases other than DRM (such as
VFIO vGPU support). Modify the API, structures and Kconfigs to use
"gpu_buddy" terminology. Adapt the drivers and tests to use the new API.

The commit cannot be split due to bisectability, however no functional
change is intended. Verified by running K-UNIT tests and build tested
various configurations.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
[airlied: I've split this into two so git can find copies easier.
I've also just nuked drm_random library, that stuff needs to be done
elsewhere and only the buddy tests seem to be using it].
Signed-off-by: Dave Airlie <airlied@redhat.com>
Stable-dep-of: 56bc6384314f ("gpu/buddy: bail out of try_harder when alignment cannot be honoured")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>