Hi,
ignoring my r-b on patch 1, I'd like to rethink the current patches in
general.
I think drm_gem_shmem_pin() should become the locked version of _pin(),
so that drm_gem_shmem_object_pin() can call it directly. The existing
_pin_unlocked() would not be needed any longer. Same for the _unpin()
functions. This change would also fix the consistency with the semantics
of the shmem _vmap() functions, which never take reservation locks.
There are only two external callers of drm_gem_shmem_pin(): the test
case and panthor. These assume that drm_gem_shmem_pin() acquires the
reservation lock. The test case should likely call drm_gem_pin()
instead. That would acquire the reservation lock and the test would
validate that shmem's pin helper integrates well into the overall GEM
framework. The way panthor uses drm_gem_shmem_pin() looks wrong to me.
For now, it could receive a wrapper that takes the lock and that's it.
Best regards
Thomas
Am 01.05.24 um 08:55 schrieb Adrián Larumbe:
This is v3 of https://lore.kernel.org/dri-devel/20240424090429.57de7d1c@xxxxxxxxxxxxx/
The goal of this patch series is fixing a deadlock upon locking the dma reservation
of a DRM gem object when pinning it, at a prime import operation.
Changes from v2:
- Removed comment explaining reason why an already-locked
pin function replaced the locked variant inside Panfrost's
object pin callback.
- Moved already-assigned attachment warning into generic
already-locked gem object pin function
Adrián Larumbe (2):
drm/panfrost: Fix dma_resv deadlock at drm object pin time
drm/gem-shmem: Add import attachment warning to locked pin function
drivers/gpu/drm/drm_gem_shmem_helper.c | 2 ++
drivers/gpu/drm/lima/lima_gem.c | 2 +-
drivers/gpu/drm/panfrost/panfrost_gem.c | 2 +-
3 files changed, 4 insertions(+), 2 deletions(-)
base-commit: 75b68f22e39aafb22f3d8e3071e1aba73560788c
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)
