From: Lijun Pan <lijunp213@gmail.com>
To: Jakub Kicinski <kuba@kernel.org>
Cc: Lijun Pan <ljp@linux.ibm.com>, netdev@vger.kernel.org
Subject: Re: [PATCH net 2/3] ibmvnic: remove unnecessary rmb() inside ibmvnic_poll
Date: Sun, 24 Jan 2021 22:38:02 -0600 [thread overview]
Message-ID: <CAOhMmr4r0OvSvbr68B8483mwJKtm=8BjiYUQa3gtin8ajZQ-5w@mail.gmail.com> (raw)
In-Reply-To: <20210123210928.30d79969@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
On Sat, Jan 23, 2021 at 11:11 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Thu, 21 Jan 2021 00:17:09 -0600 Lijun Pan wrote:
> > rmb() was introduced to load rx_scrq->msgs after calling
> > pending_scrq(). Now since pending_scrq() itself already
> > has dma_rmb() at the end of the function, rmb() is
> > duplicated and can be removed.
> >
> > Fixes: ec20f36bb41a ("ibmvnic: Correctly re-enable interrupts in NAPI polling routine")
> > Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
>
> rmb() is a stronger barrier than dma_rmb()
Yes. I think the weaker dma_rmb() here is enough.
And I let it reuse the dma_rmb() in the pending_scrq().
>
> also again, I don't see how this fixes any bugs
I will send to net-next if you are ok with it.
next prev parent reply other threads:[~2021-01-25 4:39 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 6:17 [PATCH net 0/3] fixes the memory barrier for SCRQ/CRQ entry Lijun Pan
2021-01-21 6:17 ` [PATCH net 1/3] ibmvnic: rework to ensure SCRQ entry reads are properly ordered Lijun Pan
2021-01-24 5:08 ` Jakub Kicinski
2021-01-25 4:34 ` Lijun Pan
2021-01-21 6:17 ` [PATCH net 2/3] ibmvnic: remove unnecessary rmb() inside ibmvnic_poll Lijun Pan
2021-01-24 5:09 ` Jakub Kicinski
2021-01-25 4:38 ` Lijun Pan [this message]
2021-01-25 20:35 ` Jakub Kicinski
2021-01-21 6:17 ` [PATCH net 3/3] ibmvnic: Ensure that CRQ entry read/write are correctly ordered Lijun Pan
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