From: Christian K?nig <christian.koe...@amd.com>

radeon_crtc_handle_flip can be called concurrently, and if
we set the unpin_work too early, it may try to flip an unpinned BO or
worse.

v2: fix compiler warning, update commit message,
    set crtc->primary->fb only when everything went well

Signed-off-by: Christian K?nig <christian.koenig at amd.com>
Cc: stable at vger.kernel.org
---
 drivers/gpu/drm/radeon/radeon_display.c | 39 ++++++++++++++-------------------
 1 file changed, 17 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_display.c 
b/drivers/gpu/drm/radeon/radeon_display.c
index 356b733..8aaa7ac 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -393,17 +393,6 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc,

        INIT_WORK(&work->work, radeon_unpin_work_func);

-       /* We borrow the event spin lock for protecting unpin_work */
-       spin_lock_irqsave(&dev->event_lock, flags);
-       if (radeon_crtc->unpin_work) {
-               DRM_DEBUG_DRIVER("flip queue: crtc already busy\n");
-               r = -EBUSY;
-               goto unlock_free;
-       }
-       radeon_crtc->unpin_work = work;
-       radeon_crtc->deferred_flip_completion = 0;
-       spin_unlock_irqrestore(&dev->event_lock, flags);
-
        /* pin the new buffer */
        DRM_DEBUG_DRIVER("flip-ioctl() cur_fbo = %p, cur_bbo = %p\n",
                         work->old_rbo, rbo);
@@ -461,13 +450,6 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc,
                base &= ~7;
        }

-       spin_lock_irqsave(&dev->event_lock, flags);
-       work->new_crtc_base = base;
-       spin_unlock_irqrestore(&dev->event_lock, flags);
-
-       /* update crtc fb */
-       crtc->primary->fb = fb;
-
        r = drm_vblank_get(dev, radeon_crtc->crtc_id);
        if (r) {
                DRM_ERROR("failed to get vblank before flip\n");
@@ -477,6 +459,23 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc,
        /* set the proper interrupt */
        radeon_pre_page_flip(rdev, radeon_crtc->crtc_id);

+       /* We borrow the event spin lock for protecting unpin_work */
+       spin_lock_irqsave(&dev->event_lock, flags);
+       if (radeon_crtc->unpin_work) {
+               spin_unlock_irqrestore(&dev->event_lock, flags);
+               radeon_post_page_flip(rdev, radeon_crtc->crtc_id);
+               drm_vblank_put(dev, radeon_crtc->crtc_id);
+
+               DRM_DEBUG_DRIVER("flip queue: crtc already busy\n");
+               r = -EBUSY;
+               goto pflip_cleanup1;
+       }
+       radeon_crtc->unpin_work = work;
+       radeon_crtc->deferred_flip_completion = 0;
+       work->new_crtc_base = base;
+       crtc->primary->fb = fb;
+       spin_unlock_irqrestore(&dev->event_lock, flags);
+
        return 0;

 pflip_cleanup1:
@@ -490,10 +489,6 @@ pflip_cleanup1:
        radeon_bo_unreserve(rbo);

 pflip_cleanup:
-       spin_lock_irqsave(&dev->event_lock, flags);
-       radeon_crtc->unpin_work = NULL;
-unlock_free:
-       spin_unlock_irqrestore(&dev->event_lock, flags);
        drm_gem_object_unreference_unlocked(old_radeon_fb->obj);
        radeon_fence_unref(&work->fence);
        kfree(work);
-- 
1.9.1

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