drm/i915: Create a unique name for the context

This will be used for communicating issues with this context to
userspace, so we want to identify the parent process and the individual
context. Note that the name isn't quite unique, it makes the presumption
of there only being a single device fd per process.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-31-chris@chris-wilson.co.uk

3 files changed, 21 insertions, 14 deletions

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 4655227eb9d9..f8604a09c101 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -631,17 +631,10 @@ static void print_request(struct seq_file *m,
 			  struct drm_i915_gem_request *rq,
 			  const char *prefix)
 {
-	struct pid *pid = rq->ctx->pid;
-	struct task_struct *task;
-
-	rcu_read_lock();
-	task = pid ? pid_task(pid, PIDTYPE_PID) : NULL;
-	seq_printf(m, "%s%x [%x:%x] @ %d: %s [%d]\n", prefix,
+	seq_printf(m, "%s%x [%x:%x] @ %d: %s\n", prefix,
 		   rq->global_seqno, rq->ctx->hw_id, rq->fence.seqno,
 		   jiffies_to_msecs(jiffies - rq->emitted_jiffies),
-		   task ? task->comm : "<unknown>",
-		   task ? task->pid : -1);
-	rcu_read_unlock();
+		   rq->timeline->common->name);
 }
 
 static int i915_gem_request_info(struct seq_file *m, void *data)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 6bf40276ace6..8b987f772d47 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -937,6 +937,7 @@ struct i915_gem_context {
 	struct drm_i915_file_private *file_priv;
 	struct i915_hw_ppgtt *ppgtt;
 	struct pid *pid;
+	const char *name;
 
 	struct i915_ctx_hang_stats hang_stats;
 
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index a2acb8bb5f34..d3118db244c4 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -158,6 +158,7 @@ void i915_gem_context_free(struct kref *ctx_ref)
 		__i915_gem_object_release_unless_active(ce->state->obj);
 	}
 
+	kfree(ctx->name);
 	put_pid(ctx->pid);
 	list_del(&ctx->link);
 
@@ -303,19 +304,28 @@ __create_hw_context(struct drm_device *dev,
 	}
 
 	/* Default context will never have a file_priv */
-	if (file_priv != NULL) {
+	ret = DEFAULT_CONTEXT_HANDLE;
+	if (file_priv) {
 		ret = idr_alloc(&file_priv->context_idr, ctx,
 				DEFAULT_CONTEXT_HANDLE, 0, GFP_KERNEL);
 		if (ret < 0)
 			goto err_out;
-	} else
-		ret = DEFAULT_CONTEXT_HANDLE;
+	}
+	ctx->user_handle = ret;
 
 	ctx->file_priv = file_priv;
-	if (file_priv)
+	if (file_priv) {
 		ctx->pid = get_task_pid(current, PIDTYPE_PID);
+		ctx->name = kasprintf(GFP_KERNEL, "%s[%d]/%x",
+				      current->comm,
+				      pid_nr(ctx->pid),
+				      ctx->user_handle);
+		if (!ctx->name) {
+			ret = -ENOMEM;
+			goto err_pid;
+		}
+	}
 
-	ctx->user_handle = ret;
 	/* NB: Mark all slices as needing a remap so that when the context first
 	 * loads it will restore whatever remap state already exists. If there
 	 * is no remap info, it will be a NOP. */
@@ -329,6 +339,9 @@ __create_hw_context(struct drm_device *dev,
 
 	return ctx;
 
+err_pid:
+	put_pid(ctx->pid);
+	idr_remove(&file_priv->context_idr, ctx->user_handle);
 err_out:
 	context_close(ctx);
 	return ERR_PTR(ret);