[PATCH xf86-video-ati 2/2] Don't use xorg_list_for_each_entry_safe for signalled flips

[Michel Dänzer]

From: Michel Dänzer <michel.daenzer at amd.com>

drm_wait_pending_flip can get called from drm_handle_event, in which
case xorg_list_for_each_entry_safe can end up processing the same entry
in both. To avoid this, just process the first list entry until the list
is empty.

(Ported from amdgpu commit 26770be44b89b83bf39c28f2fe284c8cb92ed0c0)

Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---
 src/radeon_drm_queue.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/radeon_drm_queue.c b/src/radeon_drm_queue.c
index 61a2f5cef..bf1650ea9 100644
--- a/src/radeon_drm_queue.c
+++ b/src/radeon_drm_queue.c
@@ -257,8 +257,11 @@ radeon_drm_handle_event(int fd, drmEventContext *event_context)
 
     r = drmHandleEvent(fd, event_context);
 
-    xorg_list_for_each_entry_safe(e, tmp, &radeon_drm_flip_signalled, list)
+    while (!xorg_list_is_empty(&radeon_drm_flip_signalled)) {
+	e = xorg_list_first_entry(&radeon_drm_flip_signalled,
+				  struct radeon_drm_queue_entry, list);
 	radeon_drm_queue_handle_one(e);
+    }
 
     xorg_list_for_each_entry_safe(e, tmp, &radeon_drm_vblank_signalled, list) {
 	drmmode_crtc_private_ptr drmmode_crtc = e->crtc->driver_private;
@@ -277,12 +280,15 @@ void radeon_drm_wait_pending_flip(xf86CrtcPtr crtc)
 {
     drmmode_crtc_private_ptr drmmode_crtc = crtc->driver_private;
     RADEONEntPtr pRADEONEnt = RADEONEntPriv(crtc->scrn);
-    struct radeon_drm_queue_entry *e, *tmp;
+    struct radeon_drm_queue_entry *e;
 
     drmmode_crtc->wait_flip_nesting_level++;
 
-    xorg_list_for_each_entry_safe(e, tmp, &radeon_drm_flip_signalled, list)
+    while (!xorg_list_is_empty(&radeon_drm_flip_signalled)) {
+	e = xorg_list_first_entry(&radeon_drm_flip_signalled,
+				  struct radeon_drm_queue_entry, list);
 	radeon_drm_queue_handle_one(e);
+    }
 
     while (drmmode_crtc->flip_pending
 	   && radeon_drm_handle_event(pRADEONEnt->fd,
-- 
2.19.0.rc1