Hi Jean-Philippe,
On Wed, Nov 21, 2018 at 11:16:07AM +0000, Jean-Philippe Brucker wrote:
> On 12/11/2018 14:40, Joerg Roedel wrote:
> > What is the intended use-case for this function?
>
> I'm using it in sva_bind(), to see if there already exists an io_mm
> associated to the mm_struct given as argument
Can we store the pasid in the mm_struct directly? We still need a
reverse mapping for the page-fault path, but storing information in
mm_struct makes at least this path faster.
> diff --git a/drivers/base/ioasid.c b/drivers/base/ioasid.c
> index 5eb3abbf69ac..fa3b48c9c044 100644
> --- a/drivers/base/ioasid.c
> +++ b/drivers/base/ioasid.c
> @@ -13,6 +13,7 @@ struct ioasid_data {
> int id;
> struct ioasid_set *set;
> void *private;
> + struct rcu_head rcu;
> };
>
> static DEFINE_IDR(ioasid_idr);
> @@ -56,7 +57,8 @@ void ioasid_free(ioasid_t ioasid)
> ioasid_data = idr_remove(&ioasid_idr, ioasid);
> idr_unlock(&ioasid_idr);
>
> - kfree(ioasid_data);
> + if (ioasid_data)
> + kfree_rcu(ioasid_data, rcu);
> }
> EXPORT_SYMBOL_GPL(ioasid_free);
>
> @@ -95,9 +97,9 @@ int ioasid_for_each(struct ioasid_set *set,
> ioasid_iter_t func, void *data)
> .data = data,
> };
>
> - idr_lock(&ioasid_idr);
> + rcu_read_lock();
> ret = idr_for_each(&ioasid_idr, ioasid_iter, &iter_data);
> - idr_unlock(&ioasid_idr);
> + rcu_read_unlock();
>
> return ret;
> }
> @@ -111,11 +113,11 @@ void *ioasid_find(struct ioasid_set *set, ioasid_t
> ioasid)
> void *priv = NULL;
> struct ioasid_data *ioasid_data;
>
> - idr_lock(&ioasid_idr);
> + rcu_read_lock();
> ioasid_data = idr_find(&ioasid_idr, ioasid);
> if (ioasid_data && ioasid_data->set == set)
> priv = ioasid_data->private;
> - idr_unlock(&ioasid_idr);
> + rcu_read_unlock();
>
> return priv;
> }
Looks good to me.
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