[PATCH 25/32] drm/i915: Prepare for obj->mm.lock removal
Maarten Lankhorst
maarten.lankhorst at linux.intel.com
Mon Sep 14 14:25:05 UTC 2020
From: Thomas Hellström <thomas.hellstrom at intel.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom at intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_object.h | 32 ++++++++++++++++++++++
drivers/gpu/drm/i915/gem/i915_gem_pages.c | 14 ++++++++--
drivers/gpu/drm/i915/gem/i915_gem_stolen.c | 4 +++
3 files changed, 48 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index eecbfec4b152..a8f001e35584 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -115,6 +115,25 @@ i915_gem_object_put(struct drm_i915_gem_object *obj)
#define assert_object_held(obj) dma_resv_assert_held((obj)->base.resv)
+/*
+ * If more than one potential simultaneous locker, assert held.
+ */
+static inline void assert_object_held_shared(struct drm_i915_gem_object *obj)
+{
+ /*
+ * Note mm list lookup is protected by
+ * kref_get_unless_zero().
+ */
+ if (IS_ENABLED(CONFIG_LOCKDEP)) {
+ u32 ref = kref_read(&obj->base.refcount);
+
+ if (ref > 0 && (ref > 1 ||
+ !list_empty_careful(&obj->mm.link) ||
+ !list_empty_careful(&obj->mm.region_link)))
+ lockdep_assert_held(&obj->mm.lock);
+ }
+}
+
static inline int __i915_gem_object_lock(struct drm_i915_gem_object *obj,
struct i915_gem_ww_ctx *ww,
bool intr)
@@ -160,6 +179,19 @@ static inline void i915_gem_object_unlock(struct drm_i915_gem_object *obj)
dma_resv_unlock(obj->base.resv);
}
+/*
+ * Trylock that always succeeds because object isn't published yet.
+ * Helps mimic create locked functionality in TTM
+ */
+static inline void i915_gem_object_lock_isolated(struct drm_i915_gem_object *obj)
+{
+ bool locked;
+
+ assert_object_held_shared(obj);
+ locked = dma_resv_trylock(obj->base.resv);
+ GEM_BUG_ON(!locked);
+}
+
struct dma_fence *
i915_gem_object_lock_fence(struct drm_i915_gem_object *obj);
void i915_gem_object_unlock_fence(struct drm_i915_gem_object *obj,
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index d047ce5369d0..1646906f4b80 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -20,7 +20,7 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
struct list_head *list;
int i;
- lockdep_assert_held(&obj->mm.lock);
+ assert_object_held_shared(obj);
if (i915_gem_object_is_volatile(obj))
obj->mm.madv = I915_MADV_DONTNEED;
@@ -66,6 +66,7 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
if (i915_gem_object_is_shrinkable(obj)) {
unsigned long flags;
+ lockdep_assert_held(&obj->mm.lock);
spin_lock_irqsave(&i915->mm.obj_lock, flags);
i915->mm.shrink_count++;
@@ -97,6 +98,8 @@ int ____i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
struct drm_i915_private *i915 = to_i915(obj->base.dev);
int err;
+ assert_object_held_shared(obj);
+
if (unlikely(obj->mm.madv != I915_MADV_WILLNEED)) {
drm_dbg(&i915->drm,
"Attempting to obtain a purgeable object\n");
@@ -124,6 +127,8 @@ int __i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
if (err)
return err;
+ assert_object_held_shared(obj);
+
if (unlikely(!i915_gem_object_has_pages(obj))) {
GEM_BUG_ON(i915_gem_object_has_pinned_pages(obj));
@@ -151,7 +156,7 @@ void i915_gem_object_truncate(struct drm_i915_gem_object *obj)
/* Try to discard unwanted pages */
void i915_gem_object_writeback(struct drm_i915_gem_object *obj)
{
- lockdep_assert_held(&obj->mm.lock);
+ assert_object_held_shared(obj);
GEM_BUG_ON(i915_gem_object_has_pages(obj));
if (obj->ops->writeback)
@@ -183,6 +188,8 @@ __i915_gem_object_unset_pages(struct drm_i915_gem_object *obj)
struct intel_memory_region *mem = obj->mm.region;
struct sg_table *pages;
+ assert_object_held_shared(obj);
+
pages = fetch_and_zero(&obj->mm.pages);
if (IS_ERR_OR_NULL(pages))
return pages;
@@ -216,6 +223,9 @@ int __i915_gem_object_put_pages_locked(struct drm_i915_gem_object *obj)
if (i915_gem_object_has_pinned_pages(obj))
return -EBUSY;
+ /* May be called by shrinker from within get_pages() (on another bo) */
+ assert_object_held_shared(obj);
+
i915_gem_object_release_mmap_offset(obj);
/*
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
index 9a9242b5a99f..eb17560dc14d 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
@@ -593,15 +593,19 @@ __i915_gem_object_create_stolen(struct intel_memory_region *mem,
cache_level = HAS_LLC(mem->i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
i915_gem_object_set_cache_coherency(obj, cache_level);
+ i915_gem_object_lock_isolated(obj);
+
err = i915_gem_object_pin_pages(obj);
if (err)
goto cleanup;
i915_gem_object_init_memory_region(obj, mem);
+ i915_gem_object_unlock(obj);
return obj;
cleanup:
+ i915_gem_object_unlock(obj);
i915_gem_object_free(obj);
err:
return ERR_PTR(err);
--
2.28.0
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