Hi all,
I wanted to take another look at struct_mutex usage in modern (gem) drivers and noticed that for a fair lot we're very to be completely struct_mutex free.
This pile here is the the simple part, which mostly just removes code and mutex_lock/unlock calls. All the patches here are independent and can be merged in any order whatsoever. My plan is to send out a pull request for all those not picked up by driver maintainers in 2-3 weeks or so, assuming no one complains.
Of course review & comments still very much welcome.
The more tricky 2nd part of this (and that one's not yet done) is to rework the gem mmap handler to use the same kref_get_unless_zero trick as ttm. With that there's no core requirement to hold struct_mutex over the final unref, which means we can make that one lockless. I plan to add a gem_object_free_unlocked for all the drivers which don't have any need for this lock.
Also there's a few more drivers which can be made struct_mutex free easily, I'll propably stitch together poc patches for those.
Cheers, Daniel
Daniel Vetter (18): drm/gem: rip out drm vma accounting for gem mmaps drm/cma-helper: Fix locking in drm_fb_cma_debugfs_show drm/gem: Be more friendly with locking checks drm/ast: Don't grab dev->struct_mutex for in mmap offset ioctl drm/bochs: Don't grab dev->struct_mutex for in mmap offset ioctl drm/mga200g: Don't grab dev->struct_mutex for in mmap offset ioctl drm/mga200g: Hold a proper reference for cursor_set drm/cirrus: Don't grab dev->struct_mutex for in mmap offset ioctl drm/cma-helper: Don't grab dev->struct_mutex for in mmap offset ioctl drm/rockchip: Don't grab dev->struct_mutex for in mmap offset ioctl drm/armada: Don't grab dev->struct_mutex for in mmap offset ioctl drm/nouveau: Don't take dev->struct_mutex in fbcon init drm/nouveau: Don't take dev->struct_mutex in ttm_fini drm/qxl: Don't take dev->struct_mutex in bo_force_delete drm/radeon: Don't take dev->struct_mutex in bo_force_delete drm/radeon: Don't take dev->struct_mutex in pm functions drm/amdgpu: Don't take dev->struct_mutex in bo_force_delete drm/amdgpu: don't grab dev->struct_mutex in pm functions
drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 4 +--- drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c | 2 -- drivers/gpu/drm/armada/armada_gem.c | 11 ++++------- drivers/gpu/drm/ast/ast_main.c | 16 +++++----------- drivers/gpu/drm/bochs/bochs_mm.c | 16 ++++------------ drivers/gpu/drm/cirrus/cirrus_main.c | 15 ++++----------- drivers/gpu/drm/drm_fb_cma_helper.c | 16 ++-------------- drivers/gpu/drm/drm_gem.c | 13 ++----------- drivers/gpu/drm/drm_gem_cma_helper.c | 9 +-------- drivers/gpu/drm/mgag200/mgag200_cursor.c | 22 ++++++++++------------ drivers/gpu/drm/mgag200/mgag200_main.c | 16 ++++------------ drivers/gpu/drm/nouveau/nouveau_fbcon.c | 11 +++-------- drivers/gpu/drm/nouveau/nouveau_ttm.c | 2 -- drivers/gpu/drm/qxl/qxl_object.c | 4 +--- drivers/gpu/drm/radeon/radeon_object.c | 4 +--- drivers/gpu/drm/radeon/radeon_pm.c | 5 ----- drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 13 ++++--------- 17 files changed, 46 insertions(+), 133 deletions(-)