[RFC PATCH 2/2] drm: store encoder name in encoder struct

[Jani Nikula]

This makes drm_get_encoder_name() thread safe.

Reference: http://lkml.kernel.org/r/645ee6e22cad47d38a2b35c21c8d5fe3 at 
DC1-MBX-01\
.ptsecurity.ru
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/drm_crtc.c | 31 +++++++++++++++++--------------
 include/drm/drm_crtc.h     |  2 ++
 2 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 5781130b4126..1c4cb74ede77 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -257,21 +257,11 @@ void drm_connector_ida_destroy(void)

 /**
  * drm_get_encoder_name - return a string for encoder
- * @encoder: encoder to compute name of
- *
- * Note that the buffer used by this function is globally shared and owned by
- * the function itself.
- *
- * FIXME: This isn't really multithreading safe.
+ * @encoder: the encoder to get name for
  */
 const char *drm_get_encoder_name(const struct drm_encoder *encoder)
 {
-       static char buf[32];
-
-       snprintf(buf, 32, "%s-%d",
-                drm_encoder_enum_list[encoder->encoder_type].name,
-                encoder->base.id);
-       return buf;
+       return encoder->name;
 }
 EXPORT_SYMBOL(drm_get_encoder_name);

@@ -986,16 +976,27 @@ int drm_encoder_init(struct drm_device *dev,

        ret = drm_mode_object_get(dev, &encoder->base, DRM_MODE_OBJECT_ENCODER);
        if (ret)
-               goto out;
+               goto out_unlock;

        encoder->dev = dev;
        encoder->encoder_type = encoder_type;
        encoder->funcs = funcs;
+       encoder->name = kasprintf(GFP_KERNEL, "%s-%d",
+                                 drm_encoder_enum_list[encoder_type].name,
+                                 encoder->base.id);
+       if (!encoder->name) {
+               ret = -ENOMEM;
+               goto out_put;
+       }

        list_add_tail(&encoder->head, &dev->mode_config.encoder_list);
        dev->mode_config.num_encoder++;

- out:
+out_put:
+       if (ret)
+               drm_mode_object_put(dev, &encoder->base);
+
+out_unlock:
        drm_modeset_unlock_all(dev);

        return ret;
@@ -1013,6 +1014,8 @@ void drm_encoder_cleanup(struct drm_encoder *encoder)
        struct drm_device *dev = encoder->dev;
        drm_modeset_lock_all(dev);
        drm_mode_object_put(dev, &encoder->base);
+       kfree(encoder->name);
+       encoder->name = NULL;
        list_del(&encoder->head);
        dev->mode_config.num_encoder--;
        drm_modeset_unlock_all(dev);
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index d4cd7e513280..219b533a2c15 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -400,6 +400,7 @@ struct drm_encoder_funcs {
  * @dev: parent DRM device
  * @head: list management
  * @base: base KMS object
+ * @name: encoder name
  * @encoder_type: one of the %DRM_MODE_ENCODER_<foo> types in drm_mode.h
  * @possible_crtcs: bitmask of potential CRTC bindings
  * @possible_clones: bitmask of potential sibling encoders for cloning
@@ -416,6 +417,7 @@ struct drm_encoder {
        struct list_head head;

        struct drm_mode_object base;
+       char *name;
        int encoder_type;
        uint32_t possible_crtcs;
        uint32_t possible_clones;
-- 
1.9.1