On 22/05/2023 05.17, Yunsheng Lin wrote:
> page_pool_ring_[un]lock() use in_softirq() to decide which
> spin lock variant to use, and when they are called in the
> context with in_softirq() being false, spin_lock_bh() is
> called in page_pool_ring_lock() while spin_unlock() is
> called in page_pool_ring_unlock(), because spin_lock_bh()
> has disabled the softirq in page_pool_ring_lock(), which
> causes inconsistency for spin lock pair calling.
>
> This patch fixes it by returning in_softirq state from
> page_pool_producer_lock(), and use it to decide which
> spin lock variant to use in page_pool_producer_unlock().
>
> As pool->ring has both producer and consumer lock, so
> rename it to page_pool_producer_[un]lock() to reflect
> the actual usage. Also move them to page_pool.c as they
> are only used there, and remove the 'inline' as the
> compiler may have better idea to do inlining or not.
>
> Fixes: 7886244736a4 ("net: page_pool: Add bulk support for ptr_ring")
> Signed-off-by: Yunsheng Lin<[email protected]>
Thanks for spotting and fixing this! :-)
Acked-by: Jesper Dangaard Brouer <[email protected]>
Thanks Yunsheng
On Mon, 22 May 2023 at 14:08, Jesper Dangaard Brouer <[email protected]> wrote:
>
>
>
> On 22/05/2023 05.17, Yunsheng Lin wrote:
> > page_pool_ring_[un]lock() use in_softirq() to decide which
> > spin lock variant to use, and when they are called in the
> > context with in_softirq() being false, spin_lock_bh() is
> > called in page_pool_ring_lock() while spin_unlock() is
> > called in page_pool_ring_unlock(), because spin_lock_bh()
> > has disabled the softirq in page_pool_ring_lock(), which
> > causes inconsistency for spin lock pair calling.
> >
> > This patch fixes it by returning in_softirq state from
> > page_pool_producer_lock(), and use it to decide which
> > spin lock variant to use in page_pool_producer_unlock().
> >
> > As pool->ring has both producer and consumer lock, so
> > rename it to page_pool_producer_[un]lock() to reflect
> > the actual usage. Also move them to page_pool.c as they
> > are only used there, and remove the 'inline' as the
> > compiler may have better idea to do inlining or not.
> >
> > Fixes: 7886244736a4 ("net: page_pool: Add bulk support for ptr_ring")
> > Signed-off-by: Yunsheng Lin<[email protected]>
>
> Thanks for spotting and fixing this! :-)
>
> Acked-by: Jesper Dangaard Brouer <[email protected]>
>
Acked-by: Ilias Apalodimas <[email protected]>