drm: simplify the locking in the GETCRTC ioctl

No need to grab both plane and crtc locks at the same time, we can do
them one after the other. If userspace races it'll get what it
deserves either way.

This removes another user of drm_modeset_lock_crtc. There's only one
left.

v2: Make sure all access to primary->state is properly protected
(Harry).

Cc: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170328070145.21520-1-daniel.vetter@ffwll.ch

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 660b4c8715de9dcaf70155c54b1f8f9fafea7cf9..55b3da2e2a82a36f6ed54c06018282efaae5a575 100644 (file)
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -406,9 +406,9 @@ int drm_mode_getcrtc(struct drm_device *dev,
        if (!crtc)
                return -ENOENT;
 
-       drm_modeset_lock_crtc(crtc, crtc->primary);
        crtc_resp->gamma_size = crtc->gamma_size;
 
+       drm_modeset_lock(&crtc->primary->mutex, NULL);
        if (crtc->primary->state && crtc->primary->state->fb)
                crtc_resp->fb_id = crtc->primary->state->fb->base.id;
        else if (!crtc->primary->state && crtc->primary->fb)
@@ -416,9 +416,14 @@ int drm_mode_getcrtc(struct drm_device *dev,
        else
                crtc_resp->fb_id = 0;
 
-       if (crtc->state) {
+       if (crtc->primary->state) {
                crtc_resp->x = crtc->primary->state->src_x >> 16;
                crtc_resp->y = crtc->primary->state->src_y >> 16;
+       }
+       drm_modeset_unlock(&crtc->primary->mutex);
+
+       drm_modeset_lock(&crtc->mutex, NULL);
+       if (crtc->state) {
                if (crtc->state->enable) {
                        drm_mode_convert_to_umode(&crtc_resp->mode, &crtc->state->mode);
                        crtc_resp->mode_valid = 1;
@@ -437,7 +442,7 @@ int drm_mode_getcrtc(struct drm_device *dev,
                        crtc_resp->mode_valid = 0;
                }
        }
-       drm_modeset_unlock_crtc(crtc);
+       drm_modeset_unlock(&crtc->mutex);
 
        return 0;
 }

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index e27ea89efd6788b47087467c29b0f991ae8d2ffd..78994fdc00a4ba739c1c66366cc9602257849e53 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12468,6 +12468,11 @@ static int intel_atomic_check(struct drm_device *dev,
        ret = drm_atomic_helper_check_modeset(dev, state);
        if (ret)
                return ret;
+       /* enocder->atomic_check might upgrade some crtc to a full modeset */
+       ret = drm_atomic_helper_check_modeset(dev, state);
+       if (ret)
+               return ret;
+
 
        for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, crtc_state, i) {
                struct intel_crtc_state *pipe_config =