On Wed, 2009-01-14 at 10:48 -0800, Jesse Barnes wrote: > >From fc3b2a31f1d2274bcf98929d5f3a5aeaee1baf4d Mon Sep 17 00:00:00 2001 > From: Jesse Barnes <jbar...@virtuousgeek.org> > Date: Wed, 14 Jan 2009 10:38:13 -0800 > Subject: [PATCH] drm: create mode_config idr lock > > Create a separate mode_config IDR lock for simplicity. The core DRM > config structures (connector, mode, etc. lists) are still protected by > the mode_config mutex, but the CRTC IDR (used for the various identifier > IDs) is now protected by the mode_config idr_mutex. Simplifies the > locking a bit and removes a warning.
So, I don't see any refcounting on these objects. What's keeping them
alive over the time that the consumer of these APIs uses an object
returned by drm_mode_object_find()?
> Signed-off-by: Jesse Barnes <jbar...@virtuousgeek.org>
> ---
> drivers/gpu/drm/drm_crtc.c | 15 ++++++++++-----
> include/drm/drm_crtc.h | 3 ++-
> 2 files changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 53c8725..6c9ead8 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -194,7 +194,6 @@ char *drm_get_connector_status_name(enum
> drm_connector_status status)
> * @type: object type
> *
> * LOCKING:
> - * Caller must hold DRM mode_config lock.
> *
> * Create a unique identifier based on @ptr in @dev's identifier space. Used
> * for tracking modes, CRTCs and connectors.
> @@ -209,15 +209,15 @@ static int drm_mode_object_get(struct drm_device *dev,
> int new_id = 0;
> int ret;
>
> - WARN(!mutex_is_locked(&dev->mode_config.mutex),
> - "%s called w/o mode_config lock\n", __FUNCTION__);
> again:
> if (idr_pre_get(&dev->mode_config.crtc_idr, GFP_KERNEL) == 0) {
> DRM_ERROR("Ran out memory getting a mode number\n");
> return -EINVAL;
> }
>
> + mutex_lock(&dev->mode_config.idr_mutex);
> ret = idr_get_new_above(&dev->mode_config.crtc_idr, obj, 1, &new_id);
> + mutex_unlock(&dev->mode_config.idr_mutex);
> if (ret == -EAGAIN)
> goto again;
>
> @@ -239,16 +239,20 @@ again:
> static void drm_mode_object_put(struct drm_device *dev,
> struct drm_mode_object *object)
> {
> + mutex_lock(&dev->mode_config.idr_mutex);
> idr_remove(&dev->mode_config.crtc_idr, object->id);
> + mutex_unlock(&dev->mode_config.idr_mutex);
> }
Fix the doc on this function
> void *drm_mode_object_find(struct drm_device *dev, uint32_t id, uint32_t
> type)
> {
> - struct drm_mode_object *obj;
> + struct drm_mode_object *obj = NULL;
>
> + mutex_lock(&dev->mode_config.idr_mutex);
> obj = idr_find(&dev->mode_config.crtc_idr, id);
> if (!obj || (obj->type != type) || (obj->id != id))
> - return NULL;
> + obj = NULL;
> + mutex_unlock(&dev->mode_config.idr_mutex);
>
> return obj;
> }
> @@ -786,6 +790,7 @@ EXPORT_SYMBOL(drm_mode_create_dithering_property);
> void drm_mode_config_init(struct drm_device *dev)
> {
> mutex_init(&dev->mode_config.mutex);
> + mutex_init(&dev->mode_config.idr_mutex);
> INIT_LIST_HEAD(&dev->mode_config.fb_list);
> INIT_LIST_HEAD(&dev->mode_config.fb_kernel_list);
> INIT_LIST_HEAD(&dev->mode_config.crtc_list);
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 0acb07f..ad113c7 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -528,7 +528,8 @@ struct drm_mode_group {
> *
> */
> struct drm_mode_config {
> - struct mutex mutex; /* protects configuration and IDR */
> + struct mutex mutex; /* protects configuration (mode lists etc.) */
> + struct mutex idr_mutex; /* for IDR management */
> struct idr crtc_idr; /* use this idr for all IDs, fb, crtc, connector,
> modes - just makes life easier */
> /* this is limited to one for now */
> int num_fb;
--
Eric Anholt
e...@anholt.net eric.anh...@intel.com
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