It seems that cma_detach_from_dev():
> +static void cma_detach_from_dev(struct rdma_id_private *id_priv)
> +{
> + list_del(&id_priv->list);
> + if (atomic_dec_and_test(&id_priv->cma_dev->refcount))
> + wake_up(&id_priv->cma_dev->wait);
> + id_priv->cma_dev = NULL;
> +}
doesn't need to do atomic_dec_and_test(), because it is never dropping
the last reference to id_priv (and in fact if it was, the last line
would be a use-after-free bug).
Does it make sense to replace it with:
static void cma_detach_from_dev(struct rdma_id_private *id_priv)
{
list_del(&id_priv->list);
/*
* cma_detach_from_dev() will never be dropping the last
* reference to id_priv, so no need to test here.
*/
atomic_dec(&id_priv->cma_dev->refcount);
id_priv->cma_dev = NULL;
}
on my x86_64 build that's worth
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-40 (-40)
function old new delta
cma_detach_from_dev 106 66 -40
- R.
> > +static void cma_detach_from_dev(struct rdma_id_private *id_priv)
> > +{
> > + list_del(&id_priv->list);
> > + if (atomic_dec_and_test(&id_priv->cma_dev->refcount))
> > + wake_up(&id_priv->cma_dev->wait);
> > + id_priv->cma_dev = NULL;
> > +}
>
>doesn't need to do atomic_dec_and_test(), because it is never dropping
>the last reference to id_priv (and in fact if it was, the last line
>would be a use-after-free bug).
It's dropping the reference on cma_dev, as opposed to id_priv.
- Sean
Sean> It's dropping the reference on cma_dev, as opposed to
Sean> id_priv.
Duh, sorry.
- R.