Re: [PATCH net] page_pool: fix inconsistency for page_pool_ring_[un]lock()

Jesper Dangaard Brouer
2023-05-22T11:14:02Z

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<linyunsheng@huawei.com>

Thanks for spotting and fixing this! :-)

Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>