drm/i915: Fix partial GGTT faulting

We want to always use the partial VMA as a fallback for a failure to
bind the object into the GGTT. This extends the support partial objects
in the GGTT to cover everything, not just objects too large.

v2: Call the partial view, view not partial.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160818161718.27187-23-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index d29bbc0296fb68201b08ee25c4a43de7b923dbdc..39236b489de8d0d37e8bf44b38a1a88c9d95d9c9 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1702,7 +1702,6 @@ int i915_gem_fault(struct vm_area_struct *area, struct vm_fault *vmf)
        struct drm_device *dev = obj->base.dev;
        struct drm_i915_private *dev_priv = to_i915(dev);
        struct i915_ggtt *ggtt = &dev_priv->ggtt;
-       struct i915_ggtt_view view = i915_ggtt_view_normal;
        bool write = !!(vmf->flags & FAULT_FLAG_WRITE);
        struct i915_vma *vma;
        pgoff_t page_offset;
@@ -1736,11 +1735,14 @@ int i915_gem_fault(struct vm_area_struct *area, struct vm_fault *vmf)
                goto err_unlock;
        }
 
-       /* Use a partial view if the object is bigger than the aperture. */
-       if (obj->base.size >= ggtt->mappable_end &&
-           !i915_gem_object_is_tiled(obj)) {
+       /* Now pin it into the GTT as needed */
+       vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0,
+                                      PIN_MAPPABLE | PIN_NONBLOCK);
+       if (IS_ERR(vma)) {
+               struct i915_ggtt_view view;
                unsigned int chunk_size;
 
+               /* Use a partial view if it is bigger than available space */
                chunk_size = MIN_CHUNK_PAGES;
                if (i915_gem_object_is_tiled(obj))
                        chunk_size = max(chunk_size, tile_row_pages(obj));
@@ -1749,14 +1751,12 @@ int i915_gem_fault(struct vm_area_struct *area, struct vm_fault *vmf)
                view.type = I915_GGTT_VIEW_PARTIAL;
                view.params.partial.offset = rounddown(page_offset, chunk_size);
                view.params.partial.size =
-                       min_t(unsigned int,
-                             chunk_size,
+                       min_t(unsigned int, chunk_size,
                              (area->vm_end - area->vm_start) / PAGE_SIZE -
                              view.params.partial.offset);
-       }
 
-       /* Now pin it into the GTT if needed */
-       vma = i915_gem_object_ggtt_pin(obj, &view, 0, 0, PIN_MAPPABLE);
+               vma = i915_gem_object_ggtt_pin(obj, &view, 0, 0, PIN_MAPPABLE);
+       }
        if (IS_ERR(vma)) {
                ret = PTR_ERR(vma);
                goto err_unlock;
@@ -1774,26 +1774,7 @@ int i915_gem_fault(struct vm_area_struct *area, struct vm_fault *vmf)
        pfn = ggtt->mappable_base + i915_ggtt_offset(vma);
        pfn >>= PAGE_SHIFT;
 
-       if (unlikely(view.type == I915_GGTT_VIEW_PARTIAL)) {
-               /* Overriding existing pages in partial view does not cause
-                * us any trouble as TLBs are still valid because the fault
-                * is due to userspace losing part of the mapping or never
-                * having accessed it before (at this partials' range).
-                */
-               unsigned long base = area->vm_start +
-                                    (view.params.partial.offset << PAGE_SHIFT);
-               unsigned int i;
-
-               for (i = 0; i < view.params.partial.size; i++) {
-                       ret = vm_insert_pfn(area,
-                                           base + i * PAGE_SIZE,
-                                           pfn + i);
-                       if (ret)
-                               break;
-               }
-
-               obj->fault_mappable = true;
-       } else {
+       if (vma->ggtt_view.type == I915_GGTT_VIEW_NORMAL) {
                if (!obj->fault_mappable) {
                        unsigned long size =
                                min_t(unsigned long,
@@ -1809,13 +1790,31 @@ int i915_gem_fault(struct vm_area_struct *area, struct vm_fault *vmf)
                                if (ret)
                                        break;
                        }
-
-                       obj->fault_mappable = true;
                } else
                        ret = vm_insert_pfn(area,
                                            (unsigned long)vmf->virtual_address,
                                            pfn + page_offset);
+       } else {
+               /* Overriding existing pages in partial view does not cause
+                * us any trouble as TLBs are still valid because the fault
+                * is due to userspace losing part of the mapping or never
+                * having accessed it before (at this partials' range).
+                */
+               const struct i915_ggtt_view *view = &vma->ggtt_view;
+               unsigned long base = area->vm_start +
+                       (view->params.partial.offset << PAGE_SHIFT);
+               unsigned int i;
+
+               for (i = 0; i < view->params.partial.size; i++) {
+                       ret = vm_insert_pfn(area,
+                                           base + i * PAGE_SIZE,
+                                           pfn + i);
+                       if (ret)
+                               break;
+               }
        }
+
+       obj->fault_mappable = true;
 err_unpin:
        __i915_vma_unpin(vma);
 err_unlock: