[RFC,076/162] drm/i915: Untangle the vma pages_mutex

Commit Message

Matthew Auld Nov. 27, 2020, 12:05 p.m. UTC

From: Thomas Hellström <[e-mail]>

Move the vma pages_mutex out of the way from the object ww locks.

Signed-off-by: Thomas Hellström <[e-mail]>
Cc: Matthew Auld <[e-mail]>
---
 drivers/gpu/drm/i915/i915_vma.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

Patch

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 0c7e4191811a..7243ab593aec 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -792,28 +792,30 @@  static int vma_get_pages(struct i915_vma *vma)
 	if (atomic_add_unless(&vma->pages_count, 1, 0))
 		return 0;
 
+	if (vma->obj) {
+		err = i915_gem_object_pin_pages(vma->obj);
+		if (err)
+			return err;
+	}
+
 	/* Allocations ahoy! */
-	if (mutex_lock_interruptible(&vma->pages_mutex))
-		return -EINTR;
+	if (mutex_lock_interruptible(&vma->pages_mutex)) {
+		err = -EINTR;
+		goto unpin;
+	}
 
 	if (!atomic_read(&vma->pages_count)) {
-		if (vma->obj) {
-			err = i915_gem_object_pin_pages(vma->obj);
-			if (err)
-				goto unlock;
-		}
-
 		err = vma->ops->set_pages(vma);
-		if (err) {
-			if (vma->obj)
-				i915_gem_object_unpin_pages(vma->obj);
+		if (err)
 			goto unlock;
-		}
 	}
 	atomic_inc(&vma->pages_count);
 
 unlock:
 	mutex_unlock(&vma->pages_mutex);
+unpin:
+	if (err && vma->obj)
+		__i915_gem_object_unpin_pages(vma->obj);
 
 	return err;
 }
@@ -826,10 +828,10 @@  static void __vma_put_pages(struct i915_vma *vma, unsigned int count)
 	if (atomic_sub_return(count, &vma->pages_count) == 0) {
 		vma->ops->clear_pages(vma);
 		GEM_BUG_ON(vma->pages);
-		if (vma->obj)
-			i915_gem_object_unpin_pages(vma->obj);
 	}
 	mutex_unlock(&vma->pages_mutex);
+	if (vma->obj)
+		i915_gem_object_unpin_pages(vma->obj);
 }
 
 static void vma_put_pages(struct i915_vma *vma)