This patch completes the removal of struct_mutex from the driver.
Remove the related TODO item, as the transition away from struct_mutex
is now complete.
Also clean up references to struct_mutex in i915.rst to avoid outdated
documentation.
Signed-off-by: Luiz Otavio Mello <luiz.me...@estudante.ufscar.br>
---
Documentation/gpu/i915.rst | 7 -------
Documentation/gpu/todo.rst | 25 -------------------------
2 files changed, 32 deletions(-)
diff --git a/Documentation/gpu/i915.rst b/Documentation/gpu/i915.rst
index 7a469df675d8..ce0bb1a7af1f 100644
--- a/Documentation/gpu/i915.rst
+++ b/Documentation/gpu/i915.rst
@@ -352,8 +352,6 @@ Locking Guidelines
#. All locking rules and interface contracts with cross-driver interfaces
(dma-buf, dma_fence) need to be followed.
-#. No struct_mutex anywhere in the code
-
#. dma_resv will be the outermost lock (when needed) and ww_acquire_ctx
is to be hoisted at highest level and passed down within i915_gem_ctx
in the call chain
@@ -361,11 +359,6 @@ Locking Guidelines
#. While holding lru/memory manager (buddy, drm_mm, whatever) locks
system memory allocations are not allowed
- * Enforce this by priming lockdep (with fs_reclaim). If we
- allocate memory while holding these looks we get a rehash
- of the shrinker vs. struct_mutex saga, and that would be
- real bad.
-
#. Do not nest different lru/memory manager locks within each other.
Take them in turn to update memory allocations, relying on the object’s
dma_resv ww_mutex to serialize against other operations.
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index c57777a24e03..ff8f4ee32bee 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -173,31 +173,6 @@ Contact: Simona Vetter
Level: Intermediate
-Get rid of dev->struct_mutex from GEM drivers
----------------------------------------------
-
-``dev->struct_mutex`` is the Big DRM Lock from legacy days and infested
-everything. Nowadays in modern drivers the only bit where it's mandatory is
-serializing GEM buffer object destruction. Which unfortunately means drivers
-have to keep track of that lock and either call ``unreference`` or
-``unreference_locked`` depending upon context.
-
-Core GEM doesn't have a need for ``struct_mutex`` any more since kernel 4.8,
-and there's a GEM object ``free`` callback for any drivers which are
-entirely ``struct_mutex`` free.
-
-For drivers that need ``struct_mutex`` it should be replaced with a driver-
-private lock. The tricky part is the BO free functions, since those can't
-reliably take that lock any more. Instead state needs to be protected with
-suitable subordinate locks or some cleanup work pushed to a worker thread. For
-performance-critical drivers it might also be better to go with a more
-fine-grained per-buffer object and per-context lockings scheme. Currently only
-the ``msm`` and `i915` drivers use ``struct_mutex``.
-
-Contact: Simona Vetter, respective driver maintainers
-
-Level: Advanced
-
Move Buffer Object Locking to dma_resv_lock()
---------------------------------------------
--
2.50.1
