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authorGerd Hoffmann <kraxel@redhat.com>2018-04-03 11:59:04 +0200
committerSean Paul <seanpaul@chromium.org>2018-04-25 15:03:13 -0400
commitd02d270014f70dcab0117776b81a37b6fca745ae (patch)
tree66df1e84cb2f96ef2a79bde51c615b0cf35d0032 /drivers/gpu
parent7a31805ba28c93f80cf874492e2f21da80851a9f (diff)
drm/virtio: fix vq wait_event condition
Wait until we have enough space in the virt queue to actually queue up our request. Avoids the guest spinning in case we have a non-zero amount of free entries but not enough for the request. Cc: stable@vger.kernel.org Reported-by: Alain Magloire <amagloire@blackberry.com> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> Reviewed-by: Dave Airlie <airlied@redhat.com> Link: http://patchwork.freedesktop.org/patch/msgid/20180403095904.11152-1-kraxel@redhat.com Signed-off-by: Sean Paul <seanpaul@chromium.org>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/virtio/virtgpu_vq.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 48e4f1df6e5d..020070d483d3 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -293,7 +293,7 @@ retry:
ret = virtqueue_add_sgs(vq, sgs, outcnt, incnt, vbuf, GFP_ATOMIC);
if (ret == -ENOSPC) {
spin_unlock(&vgdev->ctrlq.qlock);
- wait_event(vgdev->ctrlq.ack_queue, vq->num_free);
+ wait_event(vgdev->ctrlq.ack_queue, vq->num_free >= outcnt + incnt);
spin_lock(&vgdev->ctrlq.qlock);
goto retry;
} else {
@@ -368,7 +368,7 @@ retry:
ret = virtqueue_add_sgs(vq, sgs, outcnt, 0, vbuf, GFP_ATOMIC);
if (ret == -ENOSPC) {
spin_unlock(&vgdev->cursorq.qlock);
- wait_event(vgdev->cursorq.ack_queue, vq->num_free);
+ wait_event(vgdev->cursorq.ack_queue, vq->num_free >= outcnt);
spin_lock(&vgdev->cursorq.qlock);
goto retry;
} else {