drm/i915: Move ioremap_wc tracking onto VMA

By tracking the iomapping on the VMA itself, we can share that area
between multiple users. Also by only revoking the iomapping upon
unbinding from the mappable portion of the GGTT, we can keep that iomap
across multiple invocations (e.g. execlists context pinning).

Note that by moving the iounnmap tracking to the VMA, we actually end up
fixing a leak of the iomapping in intel_fbdev.

v1.5: Rebase prompted by Tvrtko
v2: Drop dev_priv parameter, we can recover the i915_ggtt from the vma.
v3: Move handling of ioremap space exhaustion to vmap_purge and also
allow vmallocs to recover old iomaps. Add Tvrtko's kerneldoc.
v4: Fix a use-after-free in shrinker and rearrange i915_vma_iomap
v5: Back to i915_vm_to_ggtt
v6: Use i915_vma_pin_iomap and i915_vma_unpin_iomap to mark critical
sections and ensure the VMA cannot be reaped whilst mapped.
v7: Move i915_vma_iounmap so that consumers of the API are not tempted,
and add iomem annotations

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1461833819-3991-5-git-send-email-chris@chris-wilson.co.uk

1 files changed, 22 insertions, 6 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index 425e721aac58..2643d18e41f5 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -386,17 +386,33 @@ i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr
 	struct drm_i915_private *dev_priv =
 		container_of(nb, struct drm_i915_private, mm.vmap_notifier);
 	struct shrinker_lock_uninterruptible slu;
-	unsigned long freed_pages;
+	struct i915_vma *vma, *next;
+	unsigned long freed_pages = 0;
+	int ret;
 
 	if (!i915_gem_shrinker_lock_uninterruptible(dev_priv, &slu, 5000))
 		return NOTIFY_DONE;
 
-	freed_pages = i915_gem_shrink(dev_priv, -1UL,
-				      I915_SHRINK_BOUND |
-				      I915_SHRINK_UNBOUND |
-				      I915_SHRINK_ACTIVE |
-				      I915_SHRINK_VMAPS);
+	/* Force everything onto the inactive lists */
+	ret = i915_gpu_idle(dev_priv->dev);
+	if (ret)
+		goto out;
+
+	freed_pages += i915_gem_shrink(dev_priv, -1UL,
+				       I915_SHRINK_BOUND |
+				       I915_SHRINK_UNBOUND |
+				       I915_SHRINK_ACTIVE |
+				       I915_SHRINK_VMAPS);
+
+	/* We also want to clear any cached iomaps as they wrap vmap */
+	list_for_each_entry_safe(vma, next,
+				 &dev_priv->ggtt.base.inactive_list, vm_link) {
+		unsigned long count = vma->node.size >> PAGE_SHIFT;
+		if (vma->iomap && i915_vma_unbind(vma) == 0)
+			freed_pages += count;
+	}
 
+out:
 	i915_gem_shrinker_unlock_uninterruptible(dev_priv, &slu);
 
 	*(unsigned long *)ptr += freed_pages;