drm/i915: Fix error checking/locking in perf/lookup_context()

1acfc104cdf8 missed to convert this one caller to be lockless. The side
effect of that was that the error check in lookup_context() became
incorrect. Convert now this caller too.

Fixes: 1acfc104cdf ("drm/i915: Enable rcu-only context lookups")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170714151242.517-1-imre.deak@intel.com

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index d9f77a4d85db2a35ba7a3d772b307e0769ba5d40..96682fd86f82780c6c28f70ff04840836eb70d20 100644 (file)
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -2483,27 +2483,6 @@ static const struct file_operations fops = {
 };
 
 
-static struct i915_gem_context *
-lookup_context(struct drm_i915_private *dev_priv,
-              struct drm_i915_file_private *file_priv,
-              u32 ctx_user_handle)
-{
-       struct i915_gem_context *ctx;
-       int ret;
-
-       ret = i915_mutex_lock_interruptible(&dev_priv->drm);
-       if (ret)
-               return ERR_PTR(ret);
-
-       ctx = i915_gem_context_lookup(file_priv, ctx_user_handle);
-       if (!IS_ERR(ctx))
-               i915_gem_context_get(ctx);
-
-       mutex_unlock(&dev_priv->drm.struct_mutex);
-
-       return ctx;
-}
-
 /**
  * i915_perf_open_ioctl_locked - DRM ioctl() for userspace to open a stream FD
  * @dev_priv: i915 device instance
@@ -2545,12 +2524,11 @@ i915_perf_open_ioctl_locked(struct drm_i915_private *dev_priv,
                u32 ctx_handle = props->ctx_handle;
                struct drm_i915_file_private *file_priv = file->driver_priv;
 
-               specific_ctx = lookup_context(dev_priv, file_priv, ctx_handle);
-               if (IS_ERR(specific_ctx)) {
-                       ret = PTR_ERR(specific_ctx);
-                       if (ret != -EINTR)
-                               DRM_DEBUG("Failed to look up context with ID %u for opening perf stream\n",
-                                         ctx_handle);
+               specific_ctx = i915_gem_context_lookup(file_priv, ctx_handle);
+               if (!specific_ctx) {
+                       DRM_DEBUG("Failed to look up context with ID %u for opening perf stream\n",
+                                 ctx_handle);
+                       ret = -ENOENT;
                        goto err;
                }
        }