From: Shiraz Saleem <shiraz.saleem-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
To: Jason Gunthorpe
<jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
Cc: "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"Nikolova,
Tatyana E"
<tatyana.e.nikolova-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH rdma-core 06/14] i40iw: Get rid of unique barrier macros
Date: Tue, 7 Mar 2017 17:16:58 -0600 [thread overview]
Message-ID: <20170307231658.GB52428@ssaleem-MOBL4.amr.corp.intel.com> (raw)
In-Reply-To: <20170306190751.GA30663-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
On Mon, Mar 06, 2017 at 12:07:51PM -0700, Jason Gunthorpe wrote:
> On Mon, Mar 06, 2017 at 12:18:09PM -0600, Shiraz Saleem wrote:
> > On Thu, Feb 16, 2017 at 12:23:01PM -0700, Jason Gunthorpe wrote:
> > > Use our standard versions from util instead. There doesn't seem
> > > to be anything tricky here, but the inlined versions were like our
> > > wc_wmb() barriers, not the wmb().
> > >
> > > There appears to be no WC memory in this driver, so despite the comments,
> > > these barriers are also making sure that user DMA data is flushed out. Make
> > > them all wmb()
> > >
> > > Guess at where the missing rmb() should be.
> > >
> > > Signed-off-by: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
> >
> >
> > > @@ -780,6 +780,8 @@ static enum i40iw_status_code i40iw_cq_poll_completion(struct i40iw_cq_uk *cq,
> > > if (polarity != cq->polarity)
> > > return I40IW_ERR_QUEUE_EMPTY;
> > >
> > > + udma_from_device_barrier();
> > > +
> >
> > What is the need for the barrier here?
>
> Every driver doing DMA needs to have a rmb(), I guessed this is
> approximately the right place to put it for i10iw.
>
> Within the PCI producer/consumer model the rmb needs to be placed
> after the CPU observes a DMA write that proves other DMA writes have
> occured.
>
> It serializes the CPU with the write stream from PCI and prevents the
> compiler/CPU from re-ordering dependent loads to be before the proving
> load.
>
OK. This change makes sense. ACK.
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next prev parent reply other threads:[~2017-03-07 23:16 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-16 19:22 [PATCH rdma-core 00/14] Revise the DMA barrier macros in ibverbs Jason Gunthorpe
[not found] ` <1487272989-8215-1-git-send-email-jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-02-16 19:22 ` [PATCH rdma-core 01/14] mlx5: Use stdatomic for the in_use barrier Jason Gunthorpe
2017-02-16 19:22 ` [PATCH rdma-core 02/14] Provide new names for the CPU barriers related to DMA Jason Gunthorpe
[not found] ` <1487272989-8215-3-git-send-email-jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-02-16 22:07 ` Steve Wise
2017-02-17 16:37 ` Jason Gunthorpe
2017-02-16 19:22 ` [PATCH rdma-core 03/14] cxgb3: Update to use new udma write barriers Jason Gunthorpe
[not found] ` <1487272989-8215-4-git-send-email-jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-02-16 21:20 ` Steve Wise
2017-02-16 21:45 ` Jason Gunthorpe
[not found] ` <20170216214527.GA13616-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-02-16 22:01 ` Steve Wise
2017-02-16 19:22 ` [PATCH rdma-core 04/14] cxgb4: " Jason Gunthorpe
[not found] ` <1487272989-8215-5-git-send-email-jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-02-17 20:16 ` Steve Wise
2017-02-16 19:23 ` [PATCH rdma-core 05/14] hns: " Jason Gunthorpe
2017-02-16 19:23 ` [PATCH rdma-core 06/14] i40iw: Get rid of unique barrier macros Jason Gunthorpe
[not found] ` <1487272989-8215-7-git-send-email-jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-01 17:29 ` Shiraz Saleem
[not found] ` <20170301172920.GA11340-GOXS9JX10wfOxmVO0tvppfooFf0ArEBIu+b9c/7xato@public.gmane.org>
2017-03-01 17:55 ` Jason Gunthorpe
[not found] ` <20170301175521.GB14791-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-01 22:14 ` Shiraz Saleem
[not found] ` <20170301221420.GA18548-GOXS9JX10wfOxmVO0tvppfooFf0ArEBIu+b9c/7xato@public.gmane.org>
2017-03-01 23:05 ` Jason Gunthorpe
[not found] ` <20170301230506.GB2820-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-03 21:45 ` Shiraz Saleem
[not found] ` <20170303214514.GA12996-GOXS9JX10wfOxmVO0tvppfooFf0ArEBIu+b9c/7xato@public.gmane.org>
2017-03-03 22:22 ` Jason Gunthorpe
[not found] ` <20170303222244.GA678-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-06 19:16 ` Shiraz Saleem
[not found] ` <20170306191631.GB34252-GOXS9JX10wfOxmVO0tvppfooFf0ArEBIu+b9c/7xato@public.gmane.org>
2017-03-06 19:40 ` Jason Gunthorpe
[not found] ` <20170306194052.GB31672-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-07 22:46 ` Shiraz Saleem
[not found] ` <20170307224622.GA45028-GOXS9JX10wfOxmVO0tvppfooFf0ArEBIu+b9c/7xato@public.gmane.org>
2017-03-07 22:50 ` Jason Gunthorpe
[not found] ` <20170307225027.GA20858-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-07 23:01 ` Shiraz Saleem
[not found] ` <20170307230121.GA52428-GOXS9JX10wfOxmVO0tvppfooFf0ArEBIu+b9c/7xato@public.gmane.org>
2017-03-07 23:11 ` Jason Gunthorpe
[not found] ` <20170307231145.GB20858-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-07 23:23 ` Shiraz Saleem
2017-03-06 18:18 ` Shiraz Saleem
[not found] ` <20170306181808.GA34252-GOXS9JX10wfOxmVO0tvppfooFf0ArEBIu+b9c/7xato@public.gmane.org>
2017-03-06 19:07 ` Jason Gunthorpe
[not found] ` <20170306190751.GA30663-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-07 23:16 ` Shiraz Saleem [this message]
2017-02-16 19:23 ` [PATCH rdma-core 07/14] mlx4: Update to use new udma write barriers Jason Gunthorpe
[not found] ` <1487272989-8215-8-git-send-email-jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-02-20 17:46 ` Yishai Hadas
[not found] ` <206559e5-0488-f6d5-c4ec-bf560e0c3ba6-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2017-02-21 18:14 ` Jason Gunthorpe
[not found] ` <20170221181407.GA13138-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-06 14:57 ` Yishai Hadas
[not found] ` <45d2b7da-9ad6-6b37-d0b2-00f7807966b4-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2017-03-06 17:31 ` Jason Gunthorpe
[not found] ` <20170306173139.GA11805-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-07 16:44 ` Yishai Hadas
[not found] ` <55bcc87e-b059-65df-8079-100120865ffb-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2017-03-07 19:18 ` Jason Gunthorpe
[not found] ` <20170307191824.GD2228-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-08 21:27 ` Yishai Hadas
[not found] ` <6571cf34-63b9-7b83-ddb0-9279e7e20fa9-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2017-03-08 21:56 ` Jason Gunthorpe
[not found] ` <20170308215609.GB4109-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-09 15:42 ` Yishai Hadas
[not found] ` <4dcf0cea-3652-0df2-9d98-74e258e6170a-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2017-03-09 17:03 ` Jason Gunthorpe
[not found] ` <20170309170320.GA12694-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-13 15:17 ` Yishai Hadas
2017-02-16 19:23 ` [PATCH rdma-core 08/14] mlx5: " Jason Gunthorpe
[not found] ` <1487272989-8215-9-git-send-email-jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-02-27 10:56 ` Yishai Hadas
[not found] ` <d5921636-1911-5588-8c59-620066bca01a-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2017-02-27 18:00 ` Jason Gunthorpe
[not found] ` <20170227180009.GL5891-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-02-28 16:02 ` Yishai Hadas
[not found] ` <2969cce4-8b51-8fcf-f099-2b42a6d40a9c-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2017-02-28 17:06 ` Jason Gunthorpe
[not found] ` <20170228170658.GA17995-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-02 9:34 ` Yishai Hadas
[not found] ` <24bf0e37-e032-0862-c5b9-b5a40fcfb343-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2017-03-02 17:12 ` Jason Gunthorpe
[not found] ` <20170302171210.GA8595-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-03-06 14:19 ` Yishai Hadas
2017-02-16 19:23 ` [PATCH rdma-core 09/14] nes: " Jason Gunthorpe
2017-02-16 19:23 ` [PATCH rdma-core 10/14] mthca: Update to use new mmio " Jason Gunthorpe
2017-02-16 19:23 ` [PATCH rdma-core 11/14] ocrdma: Update to use new udma " Jason Gunthorpe
[not found] ` <1487272989-8215-12-git-send-email-jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-02-18 16:21 ` Devesh Sharma
2017-02-16 19:23 ` [PATCH rdma-core 12/14] qedr: " Jason Gunthorpe
[not found] ` <1487272989-8215-13-git-send-email-jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-02-23 13:49 ` Amrani, Ram
[not found] ` <SN1PR07MB2207DE206738E6DD8511CEA1F8530-mikhvbZlbf8TSoR2DauN2+FPX92sqiQdvxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
2017-02-23 17:30 ` Jason Gunthorpe
[not found] ` <20170223173047.GC6688-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-02-24 10:01 ` Amrani, Ram
2017-02-16 19:23 ` [PATCH rdma-core 13/14] vmw_pvrdma: " Jason Gunthorpe
[not found] ` <1487272989-8215-14-git-send-email-jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-02-17 18:05 ` Adit Ranadive
2017-02-16 19:23 ` [PATCH rdma-core 14/14] Remove the old barrier macros Jason Gunthorpe
[not found] ` <1487272989-8215-15-git-send-email-jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-02-23 13:33 ` Amrani, Ram
[not found] ` <SN1PR07MB22070A48ACD50848267A5AD8F8530-mikhvbZlbf8TSoR2DauN2+FPX92sqiQdvxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
2017-02-23 16:59 ` Jason Gunthorpe
2017-02-28 16:00 ` [PATCH rdma-core 00/14] Revise the DMA barrier macros in ibverbs Doug Ledford
[not found] ` <1488297611.86943.215.camel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-02-28 16:38 ` Majd Dibbiny
[not found] ` <C6384D48-FC47-4046-8025-462E1CB02A34-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2017-02-28 17:47 ` Doug Ledford
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