Re: [PATCH tip/core/rcu 01/12] rcu: Remove rcu_swap_protected()

Paul E. McKenney
2019-12-11T18:37:43Z

On Tue, Dec 10, 2019 at 07:51:22PM -0800, Paul E. McKenney wrote:
> On Tue, Dec 10, 2019 at 10:35:49PM -0500, Martin K. Petersen wrote:
> >
> > Paul,
> >
> > > Now that the calls to rcu_swap_protected() have been replaced by
> > > rcu_replace_pointer(), this commit removes rcu_swap_protected().
> >
> > It appears there are two callers remaining in Linus' master. Otherwise
> > looks good to me.
>
> I did queue a fix for one of them, and thank you for calling my
> attention to the new one. This commit should hit -next soon, so
> hopefully this will discourage further additions. ;-)
>
> > Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
>
> Thank you!

And here is the patch for the new one.

Thanx, Paul

------------------------------------------------------------------------

commit 10699d92c906707d679e28b099cd798a519b4f51
Author: Paul E. McKenney <paulmck@kernel.org>
Date: Wed Dec 11 10:30:21 2019 -0800

wireless/mediatek: Replace rcu_swap_protected() with rcu_replace_pointer()

This commit replaces the use of rcu_swap_protected() with the more
intuitively appealing rcu_replace_pointer() as a step towards removing
rcu_swap_protected().

Link: https://lore.kernel.org/lkml/CAHk-=wiAsJLw1egFEE=Z7-GGtM6wcvtyytXZA1+BHqta4gg6Hw@mail.gmail.com/
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Felix Fietkau <nbd@nbd.name>
Cc: Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Cc: Ryder Lee <ryder.lee@mediatek.com>
Cc: Roy Luo <royluo@google.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: <linux-wireless@vger.kernel.org>
Cc: <netdev@vger.kernel.org>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: <linux-mediatek@lists.infradead.org>

diff --git a/drivers/net/wireless/mediatek/mt76/agg-rx.c b/drivers/net/wireless/mediatek/mt76/agg-rx.c
index 53b5a4b..80986ce 100644
--- a/drivers/net/wireless/mediatek/mt76/agg-rx.c
+++ b/drivers/net/wireless/mediatek/mt76/agg-rx.c
@@ -281,8 +281,8 @@ void mt76_rx_aggr_stop(struct mt76_dev *dev, struct mt76_wcid *wcid, u8 tidno)
{
struct mt76_rx_tid *tid = NULL;

- rcu_swap_protected(wcid->aggr[tidno], tid,
- lockdep_is_held(&dev->mutex));
+ tid = rcu_swap_protected(wcid->aggr[tidno], tid,
+ lockdep_is_held(&dev->mutex));
if (tid) {
mt76_rx_aggr_shutdown(dev, tid);
kfree_rcu(tid, rcu_head);