[PATCH 5/6] drm/i915: Track all user contexts per client

[Tvrtko Ursulin]

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, plus we make contexts take a reference on their clients
file_priv.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c       | 11 ++++++++++-
 drivers/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, 21 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index cde45c7dbe02..9550cd9e7d73 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -305,8 +305,13 @@ static void i915_gem_context_free(struct i915_gem_context *ctx)
 
 	GEM_BUG_ON(!i915_gem_context_is_closed(ctx));
 
-	if (client)
+	if (client) {
+		spin_lock(&client->ctx_lock);
+		list_del_rcu(&ctx->client_link);
+		spin_unlock(&client->ctx_lock);
+
 		i915_drm_client_put(client);
+	}
 
 	spin_lock(&ctx->i915->gem.contexts.lock);
 	list_del(&ctx->link);
@@ -813,6 +818,10 @@ 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);
+
 	return 0;
 
 err:
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 0c5fb203b754..23421377a43d 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
@@ -97,6 +97,9 @@ struct i915_gem_context {
 	/** client: struct i915_drm_client */
 	struct i915_drm_client *client;
 
+	/** link: &fpriv.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 a517de2281c0..a6de0453890e 100644
--- a/drivers/gpu/drm/i915/i915_drm_client.c
+++ b/drivers/gpu/drm/i915/i915_drm_client.c
@@ -129,6 +129,9 @@ 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 a9d4d7396e43..c526d84a0c7b 100644
--- a/drivers/gpu/drm/i915/i915_drm_client.h
+++ b/drivers/gpu/drm/i915/i915_drm_client.h
@@ -10,10 +10,12 @@
 #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>
 
 struct i915_drm_clients {
@@ -33,6 +35,9 @@ struct i915_drm_client {
 	char __rcu *name;
 	bool closed;
 
+	spinlock_t ctx_lock;
+	struct list_head ctx_list;
+
 	struct i915_drm_clients *clients;
 
 	struct kobject *root;
-- 
2.20.1