Re: [PATCH 04/10] drm/syncobj: remove drm_syncobj_cb and cleanup

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, Dec 05, 2018 at 11:00:33AM +0100, Christian König wrote:
> Hi Daniel,
> 
> can I get a review for this one? It is essentially just a follow up cleanup
> on one of your patches and shouldn't have any functional effect.

Unfortunately badly backlogged an a handful of massive context switches
away from getting back to this. Also brain's all mushed up :-/

I think better to get Chris/Jason/Dave to take a look and ack.

Apologies :-(
-Daniel

> 
> Thanks,
> Christian.
> 
> Am 04.12.18 um 12:59 schrieb Christian König:
> > This completes "drm/syncobj: Drop add/remove_callback from driver
> > interface" and cleans up the implementation a bit.
> > 
> > Signed-off-by: Christian König <christian.koenig@amd.com>
> > ---
> >   drivers/gpu/drm/drm_syncobj.c | 91 ++++++++++++++-----------------------------
> >   include/drm/drm_syncobj.h     | 21 ----------
> >   2 files changed, 30 insertions(+), 82 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
> > index db30a0e89db8..e19525af0cce 100644
> > --- a/drivers/gpu/drm/drm_syncobj.c
> > +++ b/drivers/gpu/drm/drm_syncobj.c
> > @@ -56,6 +56,16 @@
> >   #include "drm_internal.h"
> >   #include <drm/drm_syncobj.h>
> > +struct syncobj_wait_entry {
> > +	struct list_head node;
> > +	struct task_struct *task;
> > +	struct dma_fence *fence;
> > +	struct dma_fence_cb fence_cb;
> > +};
> > +
> > +static void syncobj_wait_syncobj_func(struct drm_syncobj *syncobj,
> > +				      struct syncobj_wait_entry *wait);
> > +
> >   /**
> >    * drm_syncobj_find - lookup and reference a sync object.
> >    * @file_private: drm file private pointer
> > @@ -82,58 +92,33 @@ struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private,
> >   }
> >   EXPORT_SYMBOL(drm_syncobj_find);
> > -static void drm_syncobj_add_callback_locked(struct drm_syncobj *syncobj,
> > -					    struct drm_syncobj_cb *cb,
> > -					    drm_syncobj_func_t func)
> > +static void drm_syncobj_fence_add_wait(struct drm_syncobj *syncobj,
> > +				       struct syncobj_wait_entry *wait)
> >   {
> > -	cb->func = func;
> > -	list_add_tail(&cb->node, &syncobj->cb_list);
> > -}
> > -
> > -static int drm_syncobj_fence_get_or_add_callback(struct drm_syncobj *syncobj,
> > -						 struct dma_fence **fence,
> > -						 struct drm_syncobj_cb *cb,
> > -						 drm_syncobj_func_t func)
> > -{
> > -	int ret;
> > -
> > -	*fence = drm_syncobj_fence_get(syncobj);
> > -	if (*fence)
> > -		return 1;
> > +	if (wait->fence)
> > +		return;
> >   	spin_lock(&syncobj->lock);
> >   	/* We've already tried once to get a fence and failed.  Now that we
> >   	 * have the lock, try one more time just to be sure we don't add a
> >   	 * callback when a fence has already been set.
> >   	 */
> > -	if (syncobj->fence) {
> > -		*fence = dma_fence_get(rcu_dereference_protected(syncobj->fence,
> > -								 lockdep_is_held(&syncobj->lock)));
> > -		ret = 1;
> > -	} else {
> > -		*fence = NULL;
> > -		drm_syncobj_add_callback_locked(syncobj, cb, func);
> > -		ret = 0;
> > -	}
> > +	if (syncobj->fence)
> > +		wait->fence = dma_fence_get(
> > +			rcu_dereference_protected(syncobj->fence, 1));
> > +	else
> > +		list_add_tail(&wait->node, &syncobj->cb_list);
> >   	spin_unlock(&syncobj->lock);
> > -
> > -	return ret;
> >   }
> > -void drm_syncobj_add_callback(struct drm_syncobj *syncobj,
> > -			      struct drm_syncobj_cb *cb,
> > -			      drm_syncobj_func_t func)
> > +static void drm_syncobj_remove_wait(struct drm_syncobj *syncobj,
> > +				    struct syncobj_wait_entry *wait)
> >   {
> > -	spin_lock(&syncobj->lock);
> > -	drm_syncobj_add_callback_locked(syncobj, cb, func);
> > -	spin_unlock(&syncobj->lock);
> > -}
> > +	if (!wait->node.next)
> > +		return;
> > -void drm_syncobj_remove_callback(struct drm_syncobj *syncobj,
> > -				 struct drm_syncobj_cb *cb)
> > -{
> >   	spin_lock(&syncobj->lock);
> > -	list_del_init(&cb->node);
> > +	list_del_init(&wait->node);
> >   	spin_unlock(&syncobj->lock);
> >   }
> > @@ -148,7 +133,7 @@ void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,
> >   			       struct dma_fence *fence)
> >   {
> >   	struct dma_fence *old_fence;
> > -	struct drm_syncobj_cb *cur, *tmp;
> > +	struct syncobj_wait_entry *cur, *tmp;
> >   	if (fence)
> >   		dma_fence_get(fence);
> > @@ -162,7 +147,7 @@ void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,
> >   	if (fence != old_fence) {
> >   		list_for_each_entry_safe(cur, tmp, &syncobj->cb_list, node) {
> >   			list_del_init(&cur->node);
> > -			cur->func(syncobj, cur);
> > +			syncobj_wait_syncobj_func(syncobj, cur);
> >   		}
> >   	}
> > @@ -608,13 +593,6 @@ drm_syncobj_fd_to_handle_ioctl(struct drm_device *dev, void *data,
> >   					&args->handle);
> >   }
> > -struct syncobj_wait_entry {
> > -	struct task_struct *task;
> > -	struct dma_fence *fence;
> > -	struct dma_fence_cb fence_cb;
> > -	struct drm_syncobj_cb syncobj_cb;
> > -};
> > -
> >   static void syncobj_wait_fence_func(struct dma_fence *fence,
> >   				    struct dma_fence_cb *cb)
> >   {
> > @@ -625,11 +603,8 @@ static void syncobj_wait_fence_func(struct dma_fence *fence,
> >   }
> >   static void syncobj_wait_syncobj_func(struct drm_syncobj *syncobj,
> > -				      struct drm_syncobj_cb *cb)
> > +				      struct syncobj_wait_entry *wait)
> >   {
> > -	struct syncobj_wait_entry *wait =
> > -		container_of(cb, struct syncobj_wait_entry, syncobj_cb);
> > -
> >   	/* This happens inside the syncobj lock */
> >   	wait->fence = dma_fence_get(rcu_dereference_protected(syncobj->fence,
> >   							      lockdep_is_held(&syncobj->lock)));
> > @@ -688,12 +663,8 @@ static signed long drm_syncobj_array_wait_timeout(struct drm_syncobj **syncobjs,
> >   	 */
> >   	if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT) {
> > -		for (i = 0; i < count; ++i) {
> > -			drm_syncobj_fence_get_or_add_callback(syncobjs[i],
> > -							      &entries[i].fence,
> > -							      &entries[i].syncobj_cb,
> > -							      syncobj_wait_syncobj_func);
> > -		}
> > +		for (i = 0; i < count; ++i)
> > +			drm_syncobj_fence_add_wait(syncobjs[i], &entries[i]);
> >   	}
> >   	do {
> > @@ -742,9 +713,7 @@ static signed long drm_syncobj_array_wait_timeout(struct drm_syncobj **syncobjs,
> >   cleanup_entries:
> >   	for (i = 0; i < count; ++i) {
> > -		if (entries[i].syncobj_cb.func)
> > -			drm_syncobj_remove_callback(syncobjs[i],
> > -						    &entries[i].syncobj_cb);
> > +		drm_syncobj_remove_wait(syncobjs[i], &entries[i]);
> >   		if (entries[i].fence_cb.func)
> >   			dma_fence_remove_callback(entries[i].fence,
> >   						  &entries[i].fence_cb);
> > diff --git a/include/drm/drm_syncobj.h b/include/drm/drm_syncobj.h
> > index b1fe921f8e8f..7c6ed845c70d 100644
> > --- a/include/drm/drm_syncobj.h
> > +++ b/include/drm/drm_syncobj.h
> > @@ -28,8 +28,6 @@
> >   #include "linux/dma-fence.h"
> > -struct drm_syncobj_cb;
> > -
> >   /**
> >    * struct drm_syncobj - sync object.
> >    *
> > @@ -62,25 +60,6 @@ struct drm_syncobj {
> >   	struct file *file;
> >   };
> > -typedef void (*drm_syncobj_func_t)(struct drm_syncobj *syncobj,
> > -				   struct drm_syncobj_cb *cb);
> > -
> > -/**
> > - * struct drm_syncobj_cb - callback for drm_syncobj_add_callback
> > - * @node: used by drm_syncob_add_callback to append this struct to
> > - *	  &drm_syncobj.cb_list
> > - * @func: drm_syncobj_func_t to call
> > - *
> > - * This struct will be initialized by drm_syncobj_add_callback, additional
> > - * data can be passed along by embedding drm_syncobj_cb in another struct.
> > - * The callback will get called the next time drm_syncobj_replace_fence is
> > - * called.
> > - */
> > -struct drm_syncobj_cb {
> > -	struct list_head node;
> > -	drm_syncobj_func_t func;
> > -};
> > -
> >   void drm_syncobj_free(struct kref *kref);
> >   /**
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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