linux-kernel - [PATCH 3/6] drm/gem: use new ww_mutex_(un)lock_for

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Message-Id: <20190614124125.124181-4-christian.koenig@amd.com>
Date:   Fri, 14 Jun 2019 14:41:22 +0200
From:   "Christian König" 
        <ckoenig.leichtzumerken@...il.com>
To:     daniel@...ll.ch, l.stach@...gutronix.de,
        linux+etnaviv@...linux.org.uk, christian.gmeiner@...il.com,
        yuq825@...il.com, eric@...olt.net, peterz@...radead.org,
        thellstrom@...are.com, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, etnaviv@...ts.freedesktop.org,
        lima@...ts.freedesktop.org
Subject: [PATCH 3/6] drm/gem: use new ww_mutex_(un)lock_for_each macros

Use the provided macros instead of implementing deadlock handling on our own.

Signed-off-by: Christian König <christian.koenig@....com>
---
 drivers/gpu/drm/drm_gem.c | 49 ++++++++++-----------------------------
 1 file changed, 12 insertions(+), 37 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 50de138c89e0..6e4623d3bee2 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -1307,51 +1307,26 @@ int
 drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
 			  struct ww_acquire_ctx *acquire_ctx)
 {
-	int contended = -1;
+	struct ww_mutex *contended;
 	int i, ret;
 
 	ww_acquire_init(acquire_ctx, &reservation_ww_class);
 
-retry:
-	if (contended != -1) {
-		struct drm_gem_object *obj = objs[contended];
-
-		ret = ww_mutex_lock_slow_interruptible(&obj->resv->lock,
-						       acquire_ctx);
-		if (ret) {
-			ww_acquire_done(acquire_ctx);
-			return ret;
-		}
-	}
-
-	for (i = 0; i < count; i++) {
-		if (i == contended)
-			continue;
-
-		ret = ww_mutex_lock_interruptible(&objs[i]->resv->lock,
-						  acquire_ctx);
-		if (ret) {
-			int j;
-
-			for (j = 0; j < i; j++)
-				ww_mutex_unlock(&objs[j]->resv->lock);
-
-			if (contended != -1 && contended >= i)
-				ww_mutex_unlock(&objs[contended]->resv->lock);
-
-			if (ret == -EDEADLK) {
-				contended = i;
-				goto retry;
-			}
-
-			ww_acquire_done(acquire_ctx);
-			return ret;
-		}
-	}
+	ww_mutex_lock_for_each(for (i = 0; i < count; i++),
+			       &objs[i]->resv->lock, contended, ret, true,
+			       acquire_ctx)
+		if (ret)
+			goto error;
 
 	ww_acquire_done(acquire_ctx);
 
 	return 0;
+
+error:
+	ww_mutex_unlock_for_each(for (i = 0; i < count; i++),
+				 &objs[i]->resv->lock, contended);
+	ww_acquire_done(acquire_ctx);
+	return ret;
 }
 EXPORT_SYMBOL(drm_gem_lock_reservations);
 
-- 
2.17.1