linux-kernel - [PATCH 5/6] drm/lima: use new ww_mutex_(un)lock_for

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Date:   Fri, 14 Jun 2019 14:41:24 +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 5/6] drm/lima: 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/lima/lima_gem.c | 41 +++++++++------------------------
 1 file changed, 11 insertions(+), 30 deletions(-)

diff --git a/drivers/gpu/drm/lima/lima_gem.c b/drivers/gpu/drm/lima/lima_gem.c
index 477c0f766663..6a51f100c29e 100644
--- a/drivers/gpu/drm/lima/lima_gem.c
+++ b/drivers/gpu/drm/lima/lima_gem.c
@@ -151,43 +151,24 @@ static int lima_gem_sync_bo(struct lima_sched_task *task, struct lima_bo *bo,
 static int lima_gem_lock_bos(struct lima_bo **bos, u32 nr_bos,
 			     struct ww_acquire_ctx *ctx)
 {
-	int i, ret = 0, contended, slow_locked = -1;
+	struct ww_mutex *contended;
+	int i, ret = 0;
 
 	ww_acquire_init(ctx, &reservation_ww_class);
 
-retry:
-	for (i = 0; i < nr_bos; i++) {
-		if (i == slow_locked) {
-			slow_locked = -1;
-			continue;
-		}
-
-		ret = ww_mutex_lock_interruptible(&bos[i]->gem.resv->lock, ctx);
-		if (ret < 0) {
-			contended = i;
-			goto err;
-		}
-	}
+	ww_mutex_lock_for_each(for (i = 0; i < nr_bos; i++),
+			       &bos[i]->gem.resv->lock, contended, ret, true,
+			       ctx)
+		if (ret)
+			goto error;
 
 	ww_acquire_done(ctx);
-	return 0;
 
-err:
-	for (i--; i >= 0; i--)
-		ww_mutex_unlock(&bos[i]->gem.resv->lock);
-
-	if (slow_locked >= 0)
-		ww_mutex_unlock(&bos[slow_locked]->gem.resv->lock);
+	return 0;
 
-	if (ret == -EDEADLK) {
-		/* we lost out in a seqno race, lock and retry.. */
-		ret = ww_mutex_lock_slow_interruptible(
-			&bos[contended]->gem.resv->lock, ctx);
-		if (!ret) {
-			slow_locked = contended;
-			goto retry;
-		}
-	}
+error:
+	ww_mutex_unlock_for_each(for (i = 0; i < nr_bos; i++),
+				 &bos[i]->gem.resv->lock, contended);
 	ww_acquire_fini(ctx);
 
 	return ret;
-- 
2.17.1