From: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Thu, 8 Aug 2013 07:10:37 +0000 (+0200)
Subject: drm/i915: unpin backing storage in dmabuf_unmap
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=eb91626ac4b9af3d5602a7db888b8bc4cb23eb3b;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

drm/i915: unpin backing storage in dmabuf_unmap

This fixes a WARN in i915_gem_free_object when the
obj->pages_pin_count isn't 0.

v2: Add locking to unmap, noticed by Chris Wilson. Note that even
though we call unmap with our own dev->struct_mutex held that won't
result in an immediate deadlock since we never go through the dma_buf
interfaces for our own, reimported buffers. But it's still easy to
blow up and anger lockdep, but that's already the case with our ->map
implementation. Fixing this for real will involve per dma-buf ww mutex
locking by the callers. And lots of fun. So go with the duct-tape
approach for now.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reported-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Tested-by: Armin K. <krejzi@email.com> (v1)
Tested-by: Dave Airlie <airlied@redhat.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@gmail.com>
---

diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
index dc53a527126b..9e6578330801 100644
--- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
@@ -85,9 +85,17 @@ static void i915_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
 				   struct sg_table *sg,
 				   enum dma_data_direction dir)
 {
+	struct drm_i915_gem_object *obj = attachment->dmabuf->priv;
+
+	mutex_lock(&obj->base.dev->struct_mutex);
+
 	dma_unmap_sg(attachment->dev, sg->sgl, sg->nents, dir);
 	sg_free_table(sg);
 	kfree(sg);
+
+	i915_gem_object_unpin_pages(obj);
+
+	mutex_unlock(&obj->base.dev->struct_mutex);
 }
 
 static void i915_gem_dmabuf_release(struct dma_buf *dma_buf)