Commit Graph

3 Commits

Author SHA1 Message Date
Satyanarayana K V P
16843e6638 drm/sa: Split drm_suballoc_new() into SA alloc and init helpers
drm_suballoc_new() currently both allocates the SA object using kmalloc()
and searches for a suitable hole in the sub-allocator for the requested
size. If SA allocation is done by holding sub-allocator mutex, this design
can lead to reclaim safety issues.

By splitting the kmalloc() step outside of the critical section, we allow
the memory allocation to use GFP_KERNEL (reclaim-safe) while ensuring that
the initialization step that holds reclaim-tainted locks (sub-allocator
mutex) operates in a reclaim-unsafe context with pre-allocated memory.

This separation prevents potential deadlocks where memory reclaim could
attempt to acquire locks that are already held during the sub-allocator
operations.

Signed-off-by: Satyanarayana K V P <satyanarayana.k.v.p@intel.com>
Suggested-by: Matthew Brost <matthew.brost@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: dri-devel@lists.freedesktop.org
Cc: Maarten Lankhorst <dev@lankhorst.se>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Maarten Lankhorst <dev@lankhorst.se>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20260220055519.2485681-6-satyanarayana.k.v.p@intel.com
2026-02-20 10:54:02 -08:00
Jani Nikula
6a91585edc drm/suballoc: fix drm_suballoc.h kernel-doc
Rename dma_fence to fence to match code.

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/36d18b315fd9a6788484667f644b3fea347fb007.1709749576.git.jani.nikula@intel.com
2024-03-07 17:17:25 +02:00
Maarten Lankhorst
849ee8a2f0 drm/suballoc: Extract amdgpu_sa.c as generic suballocation helper
Suballocating a buffer object is something that is not driver-specific
and useful for many drivers.

Use a slightly modified version of amdgpu_sa.c

v2:
- Style cleanups.
- Added / Modified documentation.
- Use u64 for the sizes and offset. The code dates back to 2012 and
  using unsigned int will probably soon come back to bite us.
  We can consider size_t as well for better 32-bit efficiency.
- Add and document gfp, intr and align arguments to drm_suballoc_new().
- Use drm_printer for debug output.

v3:
- Remove stale author info (Christian König)

v4:
- Avoid 64-bit integer divisions (kernel test robot <lkp@intel.com>)
- Use size_t rather than u64 for the managed range. (Thomas)

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Co-developed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: Alex Deucher <alexdeucher@gmail.com>
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230224095152.30134-2-thomas.hellstrom@linux.intel.com
2023-03-01 17:18:19 +01:00