In theory if clflush_work_create() somehow fails here, and we don't yet
have mm.pages populated then we end up resetting cache_dirty, which is
likely wrong, since that will potentially skip the flush-on-acquire, if
it was needed.
It looks like intel_user_framebuffer_dirty() can arrive here before the
pages are populated.
v2(Thomas):
- Move setting cache_dirty out of the async portion, also add a
comment for why that should still be safe.
Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx>
Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/gem/i915_gem_clflush.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_clflush.c b/drivers/gpu/drm/i915/gem/i915_gem_clflush.c
index f0435c6feb68..47586a8a1b73 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_clflush.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_clflush.c
@@ -109,12 +109,20 @@ bool i915_gem_clflush_object(struct drm_i915_gem_object *obj,
I915_FENCE_GFP);
dma_resv_add_excl_fence(obj->base.resv, &clflush->base.dma);
dma_fence_work_commit(&clflush->base);
+ /*
+ * We must have successfully populated the pages(since we are
+ * holding a pin on the pages as per the flush worker) to reach
+ * this point, which must mean we have already done the required
+ * flush-on-acquire, hence resetting cache_dirty here should be
+ * safe.
+ */
+ obj->cache_dirty = false;
} else if (obj->mm.pages) {
__do_clflush(obj);
+ obj->cache_dirty = false;
} else {
GEM_BUG_ON(obj->write_domain != I915_GEM_DOMAIN_CPU);
}
- obj->cache_dirty = false;
return true;
}
--
2.26.3
