linux-kernel - [PATCH] drm/amdgpu: kref_put() may not require a lock.

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Message-Id: <1608710634-5118-1-git-send-email-yejune.deng@gmail.com>
Date:   Wed, 23 Dec 2020 16:03:54 +0800
From:   Yejune Deng <yejune.deng@...il.com>
To:     alexander.deucher@....com, christian.koenig@....com,
        airlied@...ux.ie, daniel@...ll.ch, nirmoy.das@....com,
        luben.tuikov@....com, Hawking.Zhang@....com, le.ma@....com,
        yejune.deng@...il.com
Cc:     amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] drm/amdgpu: kref_put() may not require a lock.

kref_put() can be outside of mutex_lock(),and use amdgpu_ctx_put()
instead of kref_put().

Signed-off-by: Yejune Deng <yejune.deng@...il.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
index 0350205..af26ec2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
@@ -282,6 +282,15 @@ static void amdgpu_ctx_do_release(struct kref *ref)
 	amdgpu_ctx_fini(ref);
 }
 
+int amdgpu_ctx_put(struct amdgpu_ctx *ctx)
+{
+	if (ctx == NULL)
+		return -EINVAL;
+
+	kref_put(&ctx->refcount, amdgpu_ctx_do_release);
+	return 0;
+}
+
 static int amdgpu_ctx_free(struct amdgpu_fpriv *fpriv, uint32_t id)
 {
 	struct amdgpu_ctx_mgr *mgr = &fpriv->ctx_mgr;
@@ -289,10 +298,9 @@ static int amdgpu_ctx_free(struct amdgpu_fpriv *fpriv, uint32_t id)
 
 	mutex_lock(&mgr->lock);
 	ctx = idr_remove(&mgr->ctx_handles, id);
-	if (ctx)
-		kref_put(&ctx->refcount, amdgpu_ctx_do_release);
 	mutex_unlock(&mgr->lock);
-	return ctx ? 0 : -EINVAL;
+
+	return amdgpu_ctx_put(ctx);
 }
 
 static int amdgpu_ctx_query(struct amdgpu_device *adev,
@@ -439,15 +447,6 @@ struct amdgpu_ctx *amdgpu_ctx_get(struct amdgpu_fpriv *fpriv, uint32_t id)
 	return ctx;
 }
 
-int amdgpu_ctx_put(struct amdgpu_ctx *ctx)
-{
-	if (ctx == NULL)
-		return -EINVAL;
-
-	kref_put(&ctx->refcount, amdgpu_ctx_do_release);
-	return 0;
-}
-
 void amdgpu_ctx_add_fence(struct amdgpu_ctx *ctx,
 			  struct drm_sched_entity *entity,
 			  struct dma_fence *fence, uint64_t *handle)
-- 
1.9.1