[PATCH 38/43] drm/i915: Create a unique name for the context

[Chris Wilson]

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 at chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c     | 11 ++---------
 drivers/gpu/drm/i915/i915_drv.h         |  1 +
 drivers/gpu/drm/i915/i915_gem_context.c | 23 ++++++++++++++++++-----
 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 1781584217d8..85447e99d428 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -629,17 +629,10 @@ 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 f49d539981ac..f7daf1b2d632 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -932,6 +932,7 @@ 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 449cf45d94eb..3496e589cdba 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);
-- 
2.9.3