From: Pavel Machek <pavel@ucw.cz>
To: Francois Romieu <romieu@fr.zoreil.com>
Cc: Lino Sanfilippo <LinoSanfilippo@gmx.de>,
bh74.an@samsung.com, ks.giri@samsung.com,
vipul.pandya@samsung.com, peppe.cavallaro@st.com,
alexandre.torgue@st.com, davem@davemloft.net,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH 1/2] net: ethernet: sxgbe: remove private tx queue lock
Date: Mon, 19 Dec 2016 11:02:15 +0100 [thread overview]
Message-ID: <20161219100215.GA6296@amd> (raw)
In-Reply-To: <20161218001507.GA5343@electric-eye.fr.zoreil.com>
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Hi!
> Lino, have you considered via-rhine.c since its "move work from irq to
> workqueue context" changes that started in
> 7ab87ff4c770eed71e3777936299292739fcd0fe [*] ?
>
> It's a shameless plug - originated in r8169.c - but it should be rather
> close to what the sxgbe and friends require. Thought / opinion ?
>
> [*] Including fixes/changes in:
> - 3a5a883a8a663b930908cae4abe5ec913b9b2fd2
> - e1efa87241272104d6a12c8b9fcdc4f62634d447
> - 810f19bcb862f8889b27e0c9d9eceac9593925dd
> - e45af497950a89459a0c4b13ffd91e1729fffef4
> - a926592f5e4e900f3fa903298c4619a131e60963
> - 559bcac35facfed49ab4f408e162971612dcfdf3
Considering the memory barriers... is something like this neccessary
in the via-rhine?
AFAICT... we need a barrier after making sure that descriptor is no
longer owned by DMA (to make sure we don't get stale data in rest of
descriptor)... and we need a barrier before giving the descriptor to
the dma, to make sure DMA engine sees the complete update....?
Thanks,
Pavel
diff --git a/drivers/net/ethernet/via/via-rhine.c b/drivers/net/ethernet/via/via-rhine.c
index ba5c542..3806e72 100644
--- a/drivers/net/ethernet/via/via-rhine.c
+++ b/drivers/net/ethernet/via/via-rhine.c
@@ -1952,6 +1952,7 @@ static void rhine_tx(struct net_device *dev)
entry, txstatus);
if (txstatus & DescOwn)
break;
+ dma_rmb();
skb = rp->tx_skbuff[entry];
if (txstatus & 0x8000) {
netif_dbg(rp, tx_done, dev,
@@ -2061,6 +2062,7 @@ static int rhine_rx(struct net_device *dev, int limit)
if (desc_status & DescOwn)
break;
+ dma_rmb();
netif_dbg(rp, rx_status, dev, "%s() status %08x\n", __func__,
desc_status);
@@ -2146,6 +2148,7 @@ static int rhine_rx(struct net_device *dev, int limit)
u64_stats_update_end(&rp->rx_stats.syncp);
}
give_descriptor_to_nic:
+ dma_wmb();
desc->rx_status = cpu_to_le32(DescOwn);
entry = (++rp->cur_rx) % RX_RING_SIZE;
}
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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next prev parent reply other threads:[~2016-12-19 10:02 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-07 20:05 Remove private locks to avoid possible deadlock Lino Sanfilippo
2016-12-07 20:05 ` [PATCH 1/2] net: ethernet: sxgbe: remove private tx queue lock Lino Sanfilippo
2016-12-07 23:15 ` Francois Romieu
2016-12-08 20:32 ` Lino Sanfilippo
2016-12-08 21:54 ` Pavel Machek
2016-12-08 22:12 ` Lino Sanfilippo
2016-12-08 22:18 ` Pavel Machek
2016-12-08 22:45 ` Lino Sanfilippo
2016-12-08 23:19 ` Francois Romieu
2016-12-09 11:21 ` Pavel Machek
2016-12-10 2:25 ` Lino Sanfilippo
2016-12-11 20:11 ` Pavel Machek
2016-12-15 19:27 ` Lino Sanfilippo
2016-12-15 21:03 ` Pavel Machek
2016-12-15 21:32 ` Lino Sanfilippo
2016-12-15 22:33 ` Lino Sanfilippo
2016-12-17 17:31 ` Pavel Machek
2016-12-18 0:15 ` Francois Romieu
2016-12-18 16:15 ` Lino Sanfilippo
2016-12-18 17:23 ` Pavel Machek
2016-12-18 18:30 ` Pavel Machek
2016-12-19 22:49 ` Lino Sanfilippo
2016-12-18 20:16 ` Pavel Machek
2016-12-19 10:02 ` Pavel Machek [this message]
2016-12-20 0:05 ` Francois Romieu
2016-12-07 20:05 ` [PATCH 2/2] net: ethernet: stmmac: " Lino Sanfilippo
2016-12-07 20:55 ` Pavel Machek
2016-12-07 20:59 ` Pavel Machek
2016-12-07 21:37 ` Pavel Machek
2016-12-07 21:43 ` Lino Sanfilippo
2016-12-07 22:34 ` Lino Sanfilippo
2016-12-07 23:21 ` Pavel Machek
2016-12-07 23:41 ` David Miller
2016-12-08 14:08 ` Pavel Machek
2016-12-08 15:26 ` David Miller
2016-12-08 15:46 ` Pavel Machek
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