drm/amd/display: Add scoped mutexes for amdgpu_dm_dhcp

[ Upstream commit 6b675ab8efbf2bcee25be29e865455c56e246401 ]

[Why]
Guards automatically release mutex when it goes out of scope making
code easier to follow.

[How]
Replace all use of mutex_lock()/mutex_unlock() with guard(mutex).

Reviewed-by: Alex Hung <[email protected]>
Signed-off-by: Mario Limonciello <[email protected]>
Signed-off-by: Tom Chung <[email protected]>
Tested-by: Daniel Wheeler <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
Stable-dep-of: be593d9d91c5 ("drm/amd/display: Fix slab-use-after-free in hdcp")
Signed-off-by: Sasha Levin <[email protected]>

Author: superm1

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c

@@ -172,7 +172,7 @@ void hdcp_update_display(struct hdcp_workqueue *hdcp_work,
 	struct mod_hdcp_display_adjustment display_adjust;
 	unsigned int conn_index = aconnector->base.index;
 
-	mutex_lock(&hdcp_w->mutex);
+	guard(mutex)(&hdcp_w->mutex);
 	hdcp_w->aconnector[conn_index] = aconnector;
 
 	memset(&link_adjust, 0, sizeof(link_adjust));
@@ -209,7 +209,6 @@ void hdcp_update_display(struct hdcp_workqueue *hdcp_work,
 	mod_hdcp_update_display(&hdcp_w->hdcp, conn_index, &link_adjust, &display_adjust, &hdcp_w->output);
 
 	process_output(hdcp_w);
-	mutex_unlock(&hdcp_w->mutex);
 }
 
 static void hdcp_remove_display(struct hdcp_workqueue *hdcp_work,
@@ -220,7 +219,7 @@ static void hdcp_remove_display(struct hdcp_workqueue *hdcp_work,
 	struct drm_connector_state *conn_state = aconnector->base.state;
 	unsigned int conn_index = aconnector->base.index;
 
-	mutex_lock(&hdcp_w->mutex);
+	guard(mutex)(&hdcp_w->mutex);
 	hdcp_w->aconnector[conn_index] = aconnector;
 
 	/* the removal of display will invoke auth reset -> hdcp destroy and
@@ -239,15 +238,14 @@ static void hdcp_remove_display(struct hdcp_workqueue *hdcp_work,
 	mod_hdcp_remove_display(&hdcp_w->hdcp, aconnector->base.index, &hdcp_w->output);
 
 	process_output(hdcp_w);
-	mutex_unlock(&hdcp_w->mutex);
 }
 
 void hdcp_reset_display(struct hdcp_workqueue *hdcp_work, unsigned int link_index)
 {
 	struct hdcp_workqueue *hdcp_w = &hdcp_work[link_index];
 	unsigned int conn_index;
 
-	mutex_lock(&hdcp_w->mutex);
+	guard(mutex)(&hdcp_w->mutex);
 
 	mod_hdcp_reset_connection(&hdcp_w->hdcp,  &hdcp_w->output);
 
@@ -259,8 +257,6 @@ void hdcp_reset_display(struct hdcp_workqueue *hdcp_work, unsigned int link_inde
 	}
 
 	process_output(hdcp_w);
-
-	mutex_unlock(&hdcp_w->mutex);
 }
 
 void hdcp_handle_cpirq(struct hdcp_workqueue *hdcp_work, unsigned int link_index)
@@ -277,16 +273,14 @@ static void event_callback(struct work_struct *work)
 	hdcp_work = container_of(to_delayed_work(work), struct hdcp_workqueue,
 				 callback_dwork);
 
-	mutex_lock(&hdcp_work->mutex);
+	guard(mutex)(&hdcp_work->mutex);
 
 	cancel_delayed_work(&hdcp_work->callback_dwork);
 
 	mod_hdcp_process_event(&hdcp_work->hdcp, MOD_HDCP_EVENT_CALLBACK,
 			       &hdcp_work->output);
 
 	process_output(hdcp_work);
-
-	mutex_unlock(&hdcp_work->mutex);
 }
 
 static void event_property_update(struct work_struct *work)
@@ -326,7 +320,7 @@ static void event_property_update(struct work_struct *work)
 			continue;
 
 		drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
-		mutex_lock(&hdcp_work->mutex);
+		guard(mutex)(&hdcp_work->mutex);
 
 		if (conn_state->commit) {
 			ret = wait_for_completion_interruptible_timeout(&conn_state->commit->hw_done,
@@ -358,7 +352,6 @@ static void event_property_update(struct work_struct *work)
 			drm_hdcp_update_content_protection(connector,
 							   DRM_MODE_CONTENT_PROTECTION_DESIRED);
 		}
-		mutex_unlock(&hdcp_work->mutex);
 		drm_modeset_unlock(&dev->mode_config.connection_mutex);
 	}
 }
@@ -371,7 +364,7 @@ static void event_property_validate(struct work_struct *work)
 	struct amdgpu_dm_connector *aconnector;
 	unsigned int conn_index;
 
-	mutex_lock(&hdcp_work->mutex);
+	guard(mutex)(&hdcp_work->mutex);
 
 	for (conn_index = 0; conn_index < AMDGPU_DM_MAX_DISPLAY_INDEX;
 	     conn_index++) {
@@ -415,8 +408,6 @@ static void event_property_validate(struct work_struct *work)
 			schedule_work(&hdcp_work->property_update_work);
 		}
 	}
-
-	mutex_unlock(&hdcp_work->mutex);
 }
 
 static void event_watchdog_timer(struct work_struct *work)
@@ -427,7 +418,7 @@ static void event_watchdog_timer(struct work_struct *work)
 				 struct hdcp_workqueue,
 				      watchdog_timer_dwork);
 
-	mutex_lock(&hdcp_work->mutex);
+	guard(mutex)(&hdcp_work->mutex);
 
 	cancel_delayed_work(&hdcp_work->watchdog_timer_dwork);
 
@@ -436,8 +427,6 @@ static void event_watchdog_timer(struct work_struct *work)
 			       &hdcp_work->output);
 
 	process_output(hdcp_work);
-
-	mutex_unlock(&hdcp_work->mutex);
 }
 
 static void event_cpirq(struct work_struct *work)
@@ -446,13 +435,11 @@ static void event_cpirq(struct work_struct *work)
 
 	hdcp_work = container_of(work, struct hdcp_workqueue, cpirq_work);
 
-	mutex_lock(&hdcp_work->mutex);
+	guard(mutex)(&hdcp_work->mutex);
 
 	mod_hdcp_process_event(&hdcp_work->hdcp, MOD_HDCP_EVENT_CPIRQ, &hdcp_work->output);
 
 	process_output(hdcp_work);
-
-	mutex_unlock(&hdcp_work->mutex);
 }
 
 void hdcp_destroy(struct kobject *kobj, struct hdcp_workqueue *hdcp_work)
@@ -486,7 +473,7 @@ static bool enable_assr(void *handle, struct dc_link *link)
 
 	dtm_cmd = (struct ta_dtm_shared_memory *)psp->dtm_context.context.mem_context.shared_buf;
 
-	mutex_lock(&psp->dtm_context.mutex);
+	guard(mutex)(&psp->dtm_context.mutex);
 	memset(dtm_cmd, 0, sizeof(struct ta_dtm_shared_memory));
 
 	dtm_cmd->cmd_id = TA_DTM_COMMAND__TOPOLOGY_ASSR_ENABLE;
@@ -501,8 +488,6 @@ static bool enable_assr(void *handle, struct dc_link *link)
 		res = false;
 	}
 
-	mutex_unlock(&psp->dtm_context.mutex);
-
 	return res;
 }
 
@@ -563,13 +548,11 @@ static void update_config(void *handle, struct cp_psp_stream_config *config)
 			 (!!aconnector->base.state) ?
 			 aconnector->base.state->hdcp_content_type : -1);
 
-	mutex_lock(&hdcp_w->mutex);
+	guard(mutex)(&hdcp_w->mutex);
 
 	mod_hdcp_add_display(&hdcp_w->hdcp, link, display, &hdcp_w->output);
 
 	process_output(hdcp_w);
-	mutex_unlock(&hdcp_w->mutex);
-
 }
 
 /**