drm/panfrost: Add the panfrost_gem_mapping concept

With the introduction of per-FD address space, the same BO can be mapped
in different address space if the BO is globally visible (GEM_FLINK)
and opened in different context or if the dmabuf is self-imported. The
current implementation does not take case into account, and attaches the
mapping directly to the panfrost_gem_object.

Let's create a panfrost_gem_mapping struct and allow multiple mappings
per BO.

The mappings are refcounted which helps solve another problem where
mappings were torn down (GEM handle closed by userspace) while GPU
jobs accessing those BOs were still in-flight. Jobs now keep a
reference on the mappings they use.

v2 (robh):
- Minor review comment clean-ups from Steven
- Use list_is_singular helper
- Just WARN if we add a mapping when madvise state is not WILLNEED.
  With that, drop the use of object_name_lock.

v3 (robh):
- Revert returning list iterator in panfrost_gem_mapping_get()

Fixes: a5efb4c9a562 ("drm/panfrost: Restructure the GEM object creation")
Fixes: 7282f7645d06 ("drm/panfrost: Implement per FD address spaces")
Cc: <stable@vger.kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200116021554.15090-1-robh@kernel.org

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.h b/drivers/gpu/drm/panfrost/panfrost_mmu.h
index 7c5b6775ae23..44fc2edf63ce 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.h
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.h
@@ -4,12 +4,12 @@
 #ifndef __PANFROST_MMU_H__
 #define __PANFROST_MMU_H__
 
-struct panfrost_gem_object;
+struct panfrost_gem_mapping;
 struct panfrost_file_priv;
 struct panfrost_mmu;
 
-int panfrost_mmu_map(struct panfrost_gem_object *bo);
-void panfrost_mmu_unmap(struct panfrost_gem_object *bo);
+int panfrost_mmu_map(struct panfrost_gem_mapping *mapping);
+void panfrost_mmu_unmap(struct panfrost_gem_mapping *mapping);
 
 int panfrost_mmu_init(struct panfrost_device *pfdev);
 void panfrost_mmu_fini(struct panfrost_device *pfdev);