Re: [PATCH 1/9] drm/i915: Add i915 perf infrastructure

On Wed, Apr 20, 2016 at 03:23:06PM +0100, Robert Bragg wrote:

+static struct intel_context * +lookup_context(struct drm_i915_private *dev_priv,

•       struct file *user_filp,
  

•       u32 ctx_user_handle)
  

+{

• struct intel_context *ctx;
• mutex_lock(&dev_priv->dev->struct_mutex);
• list_for_each_entry(ctx, &dev_priv->context_list, link) {

• struct drm_file *drm_file;
  

• if (!ctx->file_priv)
  

• 	continue;
  

• drm_file = ctx->file_priv->file;
  

• if (user_filp->private_data == drm_file &&
  

•     ctx->user_handle == ctx_user_handle) {
  

• 	i915_gem_context_reference(ctx);
  

• 	mutex_unlock(&dev_priv->dev->struct_mutex);
  

• 	return ctx;
  

• }
  

• }
• mutex_unlock(&dev_priv->dev->struct_mutex);
• return NULL;

+}

+int i915_perf_open_ioctl_locked(struct drm_device *dev,

• 		struct drm_i915_perf_open_param *param,
  

• 		struct perf_open_properties *props,
  

• 		struct drm_file *file)
  

+{

• struct drm_i915_private *dev_priv = dev->dev_private;
• struct intel_context *specific_ctx = NULL;
• struct i915_perf_stream *stream = NULL;
• unsigned long f_flags = 0;
• int stream_fd;
• int ret = 0;
• if (props->single_context) {

• u32 ctx_handle = props->ctx_handle;
  

• specific_ctx = lookup_context(dev_priv, file->filp, ctx_handle);
  

i915_gem_context_get(file->driver_priv, ctx_handle) ?

Though this doesn't allow ptrace like ability to watch a context elsewhere. For that you need to pass in fd:ctx props. -Chris