When we unpin a fence, we do no other operation than mark it available.
This we can do outside of any locking by making the operation atomic.
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/gvt/aperture_gm.c | 2 +-
drivers/gpu/drm/i915/i915_debugfs.c | 2 +-
drivers/gpu/drm/i915/i915_gem_fence_reg.c | 15 ++++++++-------
drivers/gpu/drm/i915/i915_gem_fence_reg.h | 2 +-
drivers/gpu/drm/i915/i915_vma.h | 9 ++++++---
5 files changed, 17 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/drm/i915/gvt/aperture_gm.c
b/drivers/gpu/drm/i915/gvt/aperture_gm.c
index 325618d969fe..c34cd56eb83a 100644
--- a/drivers/gpu/drm/i915/gvt/aperture_gm.c
+++ b/drivers/gpu/drm/i915/gvt/aperture_gm.c
@@ -196,7 +196,7 @@ static int alloc_vgpu_fence(struct intel_vgpu *vgpu)
i = 0;
list_for_each_safe(pos, q, &dev_priv->mm.fence_list) {
reg = list_entry(pos, struct drm_i915_fence_reg, link);
- if (reg->pin_count || reg->vma)
+ if (atomic_read(®->pin_count) || reg->vma)
continue;
list_del(pos);
vgpu->fence.regs[i] = reg;
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c
b/drivers/gpu/drm/i915/i915_debugfs.c
index 9fdafed9a601..cee9d2e8832e 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -965,7 +965,7 @@ static int i915_gem_fence_regs_info(struct seq_file *m,
void *data)
struct i915_vma *vma = dev_priv->fence_regs[i].vma;
seq_printf(m, "Fence %d, pin count = %d, object = ",
- i, dev_priv->fence_regs[i].pin_count);
+ i, atomic_read(&dev_priv->fence_regs[i].pin_count));
if (!vma)
seq_puts(m, "unused");
else
diff --git a/drivers/gpu/drm/i915/i915_gem_fence_reg.c
b/drivers/gpu/drm/i915/i915_gem_fence_reg.c
index d0cd051c19fd..02d487c44a77 100644
--- a/drivers/gpu/drm/i915/i915_gem_fence_reg.c
+++ b/drivers/gpu/drm/i915/i915_gem_fence_reg.c
@@ -340,7 +340,7 @@ int i915_vma_put_fence(struct i915_vma *vma)
GEM_BUG_ON(fence->vma != vma);
- if (fence->pin_count)
+ if (atomic_read(&fence->pin_count))
return -EBUSY;
return fence_update(fence, NULL);
@@ -353,7 +353,7 @@ static struct drm_i915_fence_reg *fence_find(struct
drm_i915_private *dev_priv)
list_for_each_entry(fence, &dev_priv->mm.fence_list, link) {
GEM_BUG_ON(fence->vma && fence->vma->fence != fence);
- if (fence->pin_count)
+ if (atomic_read(&fence->pin_count))
continue;
return fence;
@@ -400,7 +400,7 @@ i915_vma_pin_fence(struct i915_vma *vma)
fence = vma->fence;
if (fence) {
GEM_BUG_ON(fence->vma != vma);
- fence->pin_count++;
+ atomic_inc(&fence->pin_count);
if (!fence->dirty) {
err = i915_gem_active_retire(&fence->pipelined,
&fence->i915->drm.struct_mutex);
@@ -415,7 +415,8 @@ i915_vma_pin_fence(struct i915_vma *vma)
fence = fence_find(vma->vm->i915);
if (IS_ERR(fence))
return PTR_ERR(fence);
- fence->pin_count++;
+
+ atomic_inc(&fence->pin_count);
} else
return 0;
@@ -426,7 +427,7 @@ i915_vma_pin_fence(struct i915_vma *vma)
return 0;
err_unpin:
- fence->pin_count--;
+ atomic_dec(&fence->pin_count);
return err;
}
@@ -459,7 +460,7 @@ int i915_vma_reserve_fence(struct i915_vma *vma)
fence->vma = vma;
fence->dirty = true;
}
- fence->pin_count++;
+ atomic_inc(&fence->pin_count);
list_move_tail(&fence->link, &fence->i915->mm.fence_list);
GEM_BUG_ON(!i915_gem_object_is_tiled(vma->obj));
@@ -478,7 +479,7 @@ int i915_vma_emit_pipelined_fence(struct i915_vma *vma,
int err;
lockdep_assert_held(&vma->vm->i915->drm.struct_mutex);
- GEM_BUG_ON(fence && !fence->pin_count);
+ GEM_BUG_ON(fence && !atomic_read(&fence->pin_count));
if (!fence)
goto out;
diff --git a/drivers/gpu/drm/i915/i915_gem_fence_reg.h
b/drivers/gpu/drm/i915/i915_gem_fence_reg.h
index ce45972fc5c6..f69d894997fb 100644
--- a/drivers/gpu/drm/i915/i915_gem_fence_reg.h
+++ b/drivers/gpu/drm/i915/i915_gem_fence_reg.h
@@ -36,7 +36,7 @@ struct drm_i915_fence_reg {
struct list_head link;
struct drm_i915_private *i915;
struct i915_vma *vma;
- int pin_count;
+ atomic_t pin_count;
int id;
/**
* Whether the tiling parameters for the currently
diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h
index f0dc6eaebeab..9d95fdae017c 100644
--- a/drivers/gpu/drm/i915/i915_vma.h
+++ b/drivers/gpu/drm/i915/i915_vma.h
@@ -347,8 +347,8 @@ int __must_check i915_vma_put_fence(struct i915_vma *vma);
static inline void __i915_vma_unpin_fence(struct i915_vma *vma)
{
- GEM_BUG_ON(vma->fence->pin_count <= 0);
- vma->fence->pin_count--;
+ GEM_BUG_ON(atomic_read(&vma->fence->pin_count) <= 0);
+ atomic_dec(&vma->fence->pin_count);
}
/**
@@ -362,7 +362,10 @@ static inline void __i915_vma_unpin_fence(struct i915_vma
*vma)
static inline void
i915_vma_unpin_fence(struct i915_vma *vma)
{
- lockdep_assert_held(&vma->obj->base.dev->struct_mutex);
+ /* The assumption is if the caller has a fence, the caller owns a pin
+ * on that fence, i.e. that vma->fence cannot become NULL prior to us
+ * releasing our pin.
+ */
if (vma->fence)
__i915_vma_unpin_fence(vma);
}
--
2.13.2
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