linux-kernel - [PATCH] drm/via: reduce no need mutex

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Message-Id: <20200814083021.8962-1-bernard@vivo.com>
Date:   Fri, 14 Aug 2020 01:30:19 -0700
From:   Bernard Zhao <bernard@...o.com>
To:     David Airlie <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        Bernard Zhao <bernard@...o.com>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Cc:     opensource.kernel@...o.com
Subject: [PATCH] drm/via: reduce no need mutex_lock area

In function via_mem_alloc`s error branch, DRM_ERROR is protected
in the mutex_lock(&dev->struct_mutex) area.
>From the code, we see that DRM_ERROR is just an error log print
without any struct element, there is no need to protect this.

Signed-off-by: Bernard Zhao <bernard@...o.com>
---
 drivers/gpu/drm/via/via_mm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/via/via_mm.c b/drivers/gpu/drm/via/via_mm.c
index 45cc9e900260..dae1bacd86c1 100644
--- a/drivers/gpu/drm/via/via_mm.c
+++ b/drivers/gpu/drm/via/via_mm.c
@@ -129,9 +129,9 @@ int via_mem_alloc(struct drm_device *dev, void *data,
 	mutex_lock(&dev->struct_mutex);
 	if (0 == ((mem->type == VIA_MEM_VIDEO) ? dev_priv->vram_initialized :
 		      dev_priv->agp_initialized)) {
+		mutex_unlock(&dev->struct_mutex);
 		DRM_ERROR
 		    ("Attempt to allocate from uninitialized memory manager.\n");
-		mutex_unlock(&dev->struct_mutex);
 		return -EINVAL;
 	}
 
-- 
2.26.2