From d25e8fddbba373cb1fbaf504505de81503d56215 Mon Sep 17 00:00:00 2001
From: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Date: Tue, 15 Jan 2013 14:57:10 +0100
Subject: [PATCH] --- yaml --- r: 358161 b: refs/heads/master c:
 f2d476a110bc24fde008698ae9018c99e803e25c h: refs/heads/master i:   358159:
 7aaa318fa3ec2a6ac02afb5f79a1b46982b07911 v: v3

---
 [refs]                                       |  2 +-
 trunk/drivers/gpu/drm/ttm/ttm_execbuf_util.c | 23 ++++++++++++++++++--
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index 0e306de62184..4b7e663a797e 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 5e45d7dfd74100d622f9cdc70bfd1f9fae1671de
+refs/heads/master: f2d476a110bc24fde008698ae9018c99e803e25c
diff --git a/trunk/drivers/gpu/drm/ttm/ttm_execbuf_util.c b/trunk/drivers/gpu/drm/ttm/ttm_execbuf_util.c
index c7d323657798..7b90def15674 100644
--- a/trunk/drivers/gpu/drm/ttm/ttm_execbuf_util.c
+++ b/trunk/drivers/gpu/drm/ttm/ttm_execbuf_util.c
@@ -129,13 +129,17 @@ int ttm_eu_reserve_buffers(struct list_head *list)
 	entry = list_first_entry(list, struct ttm_validate_buffer, head);
 	glob = entry->bo->glob;
 
-retry:
 	spin_lock(&glob->lru_lock);
 	val_seq = entry->bo->bdev->val_seq++;
 
+retry:
 	list_for_each_entry(entry, list, head) {
 		struct ttm_buffer_object *bo = entry->bo;
 
+		/* already slowpath reserved? */
+		if (entry->reserved)
+			continue;
+
 		ret = ttm_bo_reserve_nolru(bo, true, true, true, val_seq);
 		switch (ret) {
 		case 0:
@@ -155,11 +159,26 @@ int ttm_eu_reserve_buffers(struct list_head *list)
 			/* fallthrough */
 		case -EAGAIN:
 			ttm_eu_backoff_reservation_locked(list);
+
+			/*
+			 * temporarily increase sequence number every retry,
+			 * to prevent us from seeing our old reservation
+			 * sequence when someone else reserved the buffer,
+			 * but hasn't updated the seq_valid/seqno members yet.
+			 */
+			val_seq = entry->bo->bdev->val_seq++;
+
 			spin_unlock(&glob->lru_lock);
 			ttm_eu_list_ref_sub(list);
-			ret = ttm_bo_wait_unreserved(bo, true);
+			ret = ttm_bo_reserve_slowpath_nolru(bo, true, val_seq);
 			if (unlikely(ret != 0))
 				return ret;
+			spin_lock(&glob->lru_lock);
+			entry->reserved = true;
+			if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
+				ret = -EBUSY;
+				goto err;
+			}
 			goto retry;
 		default:
 			goto err;