[PATCH 07/13] drm/i915: Track all user contexts per client

[Chris Wilson]

From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

We soon want to start answering questions like how much GPU time is the
context belonging to a client which exited still using.

To enable this we start tracking all context belonging to a client on a
separate list.

v2:
 * Keep adding to gem.contexts.list as last. (Lucas)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c     | 17 ++++++++++++++---
 .../gpu/drm/i915/gem/i915_gem_context_types.h   |  3 +++
 drivers/gpu/drm/i915/i915_drm_client.c          |  3 +++
 drivers/gpu/drm/i915/i915_drm_client.h          |  5 +++++
 4 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index ca994ee8ad36..91c077701c37 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -357,13 +357,12 @@ static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx)
 void i915_gem_context_release(struct kref *ref)
 {
 	struct i915_gem_context *ctx = container_of(ref, typeof(*ctx), ref);
-	struct i915_drm_client *client = ctx->client;
 
 	trace_i915_context_free(ctx);
 	GEM_BUG_ON(!i915_gem_context_is_closed(ctx));
 
-	if (client)
-		i915_drm_client_put(client);
+	if (ctx->client)
+		i915_drm_client_put(ctx->client);
 
 	mutex_destroy(&ctx->engines_mutex);
 	mutex_destroy(&ctx->lut_mutex);
@@ -600,6 +599,7 @@ static void set_closed_name(struct i915_gem_context *ctx)
 static void context_close(struct i915_gem_context *ctx)
 {
 	struct i915_address_space *vm;
+	struct i915_drm_client *client;
 
 	/* Flush any concurrent set_engines() */
 	mutex_lock(&ctx->engines_mutex);
@@ -628,6 +628,13 @@ static void context_close(struct i915_gem_context *ctx)
 	list_del(&ctx->link);
 	spin_unlock(&ctx->i915->gem.contexts.lock);
 
+	client = ctx->client;
+	if (client) {
+		spin_lock(&client->ctx_lock);
+		list_del_rcu(&ctx->client_link);
+		spin_unlock(&client->ctx_lock);
+	}
+
 	mutex_unlock(&ctx->mutex);
 
 	/*
@@ -931,6 +938,10 @@ static int gem_context_register(struct i915_gem_context *ctx,
 
 	ctx->client = client;
 
+	spin_lock(&client->ctx_lock);
+	list_add_tail_rcu(&ctx->client_link, &client->ctx_list);
+	spin_unlock(&client->ctx_lock);
+
 	spin_lock(&i915->gem.contexts.lock);
 	list_add_tail(&ctx->link, &i915->gem.contexts.list);
 	spin_unlock(&i915->gem.contexts.lock);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
index c47bb45d2110..085f6a3735e8 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
@@ -102,6 +102,9 @@ struct i915_gem_context {
 	/** client: struct i915_drm_client */
 	struct i915_drm_client *client;
 
+	/** link: &drm_client.context_list */
+	struct list_head client_link;
+
 	/**
 	 * @ref: reference count
 	 *
diff --git a/drivers/gpu/drm/i915/i915_drm_client.c b/drivers/gpu/drm/i915/i915_drm_client.c
index 1606f5af1e84..d3ec8ed9c981 100644
--- a/drivers/gpu/drm/i915/i915_drm_client.c
+++ b/drivers/gpu/drm/i915/i915_drm_client.c
@@ -188,6 +188,9 @@ i915_drm_client_add(struct i915_drm_clients *clients, struct task_struct *task)
 
 	kref_init(&client->kref);
 	mutex_init(&client->update_lock);
+	spin_lock_init(&client->ctx_lock);
+	INIT_LIST_HEAD(&client->ctx_list);
+
 	client->clients = clients;
 
 	ret = xa_alloc_cyclic(&clients->xarray, &client->id, client,
diff --git a/drivers/gpu/drm/i915/i915_drm_client.h b/drivers/gpu/drm/i915/i915_drm_client.h
index b9a64fc5dc51..1de04f79a27f 100644
--- a/drivers/gpu/drm/i915/i915_drm_client.h
+++ b/drivers/gpu/drm/i915/i915_drm_client.h
@@ -9,10 +9,12 @@
 #include <linux/device.h>
 #include <linux/kobject.h>
 #include <linux/kref.h>
+#include <linux/list.h>
 #include <linux/mutex.h>
 #include <linux/pid.h>
 #include <linux/rcupdate.h>
 #include <linux/sched.h>
+#include <linux/spinlock.h>
 #include <linux/xarray.h>
 
 #include "gt/intel_engine_types.h"
@@ -46,6 +48,9 @@ struct i915_drm_client {
 	struct i915_drm_client_name __rcu *name;
 	bool closed;
 
+	spinlock_t ctx_lock; /* For add/remove from ctx_list. */
+	struct list_head ctx_list; /* List of contexts belonging to client. */
+
 	struct i915_drm_clients *clients;
 
 	struct kobject *root;
-- 
2.20.1