drm/i915: Remove pages_mutex and intel_gtt->vma_ops.set/clear_pages members, v3.

Big delta, but boils down to moving set_pages to i915_vma.c, and removing
the special handling, all callers use the defaults anyway. We only remap
in ggtt, so default case will fall through.

Because we still don't require locking in i915_vma_unpin(), handle this by
using xchg in get_pages(), as it's locked with obj->mutex, and cmpxchg in
unpin, which only fails if we race a against a new pin.

Changes since v1:
- aliasing gtt sets ZERO_SIZE_PTR, not -ENODEV, remove special case
  from __i915_vma_get_pages(). (Matt)
Changes since v2:
- Free correct old pages in __i915_vma_get_pages(). (Matt)
  Remove race of clearing vma->pages accidentally from put,
  free it but leave it set, as only get has the lock.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211216142749.1966107-4-maarten.lankhorst@linux.intel.com
Reviewed-by: Matthew Auld <matthew.auld@intel.com>

1 files changed, 9 insertions, 5 deletions

diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
index 48123c3e1ff0..575705c3bce9 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
@@ -1275,7 +1275,7 @@ static void track_vma_bind(struct i915_vma *vma)
 
 	__i915_gem_object_pin_pages(obj);
 
-	GEM_BUG_ON(vma->pages);
+	GEM_BUG_ON(atomic_read(&vma->pages_count));
 	atomic_set(&vma->pages_count, I915_VMA_PAGES_ACTIVE);
 	__i915_gem_object_pin_pages(obj);
 	vma->pages = obj->mm.pages;
@@ -1953,7 +1953,9 @@ static int igt_cs_tlb(void *arg)
 				goto end;
 			}
 
-			err = vma->ops->set_pages(vma);
+			i915_gem_object_lock(bbe, NULL);
+			err = i915_vma_get_pages(vma);
+			i915_gem_object_unlock(bbe);
 			if (err)
 				goto end;
 
@@ -1994,7 +1996,7 @@ end_ww:
 				i915_request_put(rq);
 			}
 
-			vma->ops->clear_pages(vma);
+			i915_vma_put_pages(vma);
 
 			err = context_sync(ce);
 			if (err) {
@@ -2009,7 +2011,9 @@ end_ww:
 				goto end;
 			}
 
-			err = vma->ops->set_pages(vma);
+			i915_gem_object_lock(act, NULL);
+			err = i915_vma_get_pages(vma);
+			i915_gem_object_unlock(act);
 			if (err)
 				goto end;
 
@@ -2047,7 +2051,7 @@ end_ww:
 			}
 			end_spin(batch, count - 1);
 
-			vma->ops->clear_pages(vma);
+			i915_vma_put_pages(vma);
 
 			err = context_sync(ce);
 			if (err) {