linux-kernel - [PATCH v2] drm/amd/amdgpu/amdgpu_drv.c: Replace drm_modeset_lock_all with drm_modeset

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Date:   Thu, 22 Apr 2021 20:39:19 +0200
From:   "Fabio M. De Francesco" <fmdefrancesco@...il.com>
To:     outreachy-kernel@...glegroups.com, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org,
        Christian Koenig <christian.koenig@....com>,
        Huang Rui <ray.huang@....com>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Matthew Wilcox <willy@...radead.org>
Cc:     "Fabio M. De Francesco" <fmdefrancesco@...il.com>
Subject: [PATCH v2] drm/amd/amdgpu/amdgpu_drv.c: Replace drm_modeset_lock_all with drm_modeset_lock

drm_modeset_lock_all() is not needed here, so it is replaced with
drm_modeset_lock(). The crtc list around which we are looping never
changes, therefore the only lock we need is to protect access to
crtc->state.

Suggested-by: Daniel Vetter <daniel@...ll.ch>
Suggested-by: Matthew Wilcox <willy@...radead.org>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@...il.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---

Changes from v1: Removed unnecessary braces around single statement
block.

 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 671ec1002230..adfeec2b17c0 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -1439,17 +1439,15 @@ static int amdgpu_pmops_runtime_idle(struct device *dev)
 	if (amdgpu_device_has_dc_support(adev)) {
 		struct drm_crtc *crtc;
 
-		drm_modeset_lock_all(drm_dev);
-
 		drm_for_each_crtc(crtc, drm_dev) {
-			if (crtc->state->active) {
+			drm_modeset_lock(&crtc->mutex, NULL);
+			if (crtc->state->active)
 				ret = -EBUSY;
+			drm_modeset_unlock(&crtc->mutex);
+			if (ret < 0)
 				break;
-			}
 		}
 
-		drm_modeset_unlock_all(drm_dev);
-
 	} else {
 		struct drm_connector *list_connector;
 		struct drm_connector_list_iter iter;
-- 
2.31.1