From: Eric Dumazet <eric.dumazet@gmail.com>
To: Cong Wang <xiyou.wangcong@gmail.com>,
Eric Dumazet <eric.dumazet@gmail.com>
Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>,
Saeed Mahameed <saeedm@mellanox.com>,
Tariq Toukan <tariqt@mellanox.com>
Subject: Re: [Patch net-next v2] mlx5: use RCU lock in mlx5_eq_cq_get()
Date: Wed, 6 Feb 2019 16:28:25 -0800 [thread overview]
Message-ID: <c35f67d1-0190-cb64-74d9-54889eb1aef7@gmail.com> (raw)
In-Reply-To: <CAM_iQpUy0y_NqT82htx_D-3G-wpo4mfguvxk2SPt4d2+KjXetA@mail.gmail.com>
On 02/06/2019 04:04 PM, Cong Wang wrote:
> synchronize_irq() is called before mlx5_cq_put(), so I don't
> see why readers could get 0 refcnt.
Then the more reasons to get rid of the refcount increment/decrement completely ...
Technically, even the rcu_read_lock() and rcu_read_unlock() are not needed,
since synchronize_irq() is enough.
>
> For the rds you mentioned, it doesn't wait for readers, this
> is why it needs to check against 0 and why it is different from
> this one.
>
> Thanks.
>
next prev parent reply other threads:[~2019-02-07 0:28 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-06 23:00 [Patch net-next v2] mlx5: use RCU lock in mlx5_eq_cq_get() Cong Wang
2019-02-06 23:36 ` Eric Dumazet
2019-02-06 23:55 ` Eric Dumazet
2019-02-07 0:04 ` Cong Wang
2019-02-07 0:28 ` Eric Dumazet [this message]
2019-02-07 0:51 ` Saeed Mahameed
2019-02-07 0:53 ` Cong Wang
2019-02-07 0:56 ` Saeed Mahameed
2019-02-11 22:41 ` Saeed Mahameed
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