From: Jason Gunthorpe <jgg@nvidia.com>
To: Mikhail Malygin <m.malygin@yadro.com>
Cc: "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
Sergey Kojushev <S.Kojushev@yadro.com>,
"linux@yadro.com" <linux@yadro.com>
Subject: Re: [PATCH] rdma_rxe: Prevent access to wr->next ptr afrer wr is posted to send queue
Date: Wed, 15 Jul 2020 08:37:43 -0300 [thread overview]
Message-ID: <20200715113743.GC2021234@nvidia.com> (raw)
In-Reply-To: <A9F28BA8-EAB3-48AC-99C0-09E93D7B9DE0@yadro.com>
On Wed, Jul 15, 2020 at 08:57:40AM +0000, Mikhail Malygin wrote:
>
> > Why is this READ_ONCE? The wr list at this point cannot be allowed to
> > change
> >
> > Jason
>
> The idea behind this READ_ONCE was to make sure read of wr->next
> happens before post_send_one(), as there is no data dependency
> between post_send_one and read of wr->next. However I’m not 100%
> sure this is necessary here.
The spinock in post_one_send() guarantees no reordering across
post_one_send()
Jason
next prev parent reply other threads:[~2020-07-15 11:37 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-15 8:57 [PATCH] rdma_rxe: Prevent access to wr->next ptr afrer wr is posted to send queue Mikhail Malygin
2020-07-15 11:37 ` Jason Gunthorpe [this message]
2020-07-15 12:18 ` Mikhail Malygin
2020-07-16 3:17 ` Zhu Yanjun
2020-07-16 11:41 ` Jason Gunthorpe
-- strict thread matches above, loose matches on Subject: below --
2020-06-09 12:54 m.malygin
2020-07-14 19:59 ` Jason Gunthorpe
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