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From: John Dykstra <john.dykstra1@gmail.com>
To: netdev <netdev@vger.kernel.org>, Don Fry <pcnet32@verizon.net>
Subject: [PATCH net-next-2.6] pcnet32: Remove pointless memory barriers
Date: Tue, 28 Apr 2009 19:07:39 +0000	[thread overview]
Message-ID: <1240945659.8819.9.camel@Maple> (raw)

These two memory barriers in performance-critical paths are not needed
on x86.  Even if some other architecture does buffer PCI I/O space
writes, the existing memory-mapped I/O barriers are unlikely to be what
is needed.

Signed-off-by: John Dykstra <john.dykstra1@gmail.com>
---
 drivers/net/pcnet32.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/pcnet32.c b/drivers/net/pcnet32.c
index e5e8c59..1c35e1d 100644
--- a/drivers/net/pcnet32.c
+++ b/drivers/net/pcnet32.c
@@ -1405,7 +1405,7 @@ static int pcnet32_poll(struct napi_struct *napi, int budget)
 
 		/* Set interrupt enable. */
 		lp->a.write_csr(ioaddr, CSR0, CSR0_INTEN);
-		mmiowb();
+
 		spin_unlock_irqrestore(&lp->lock, flags);
 	}
 	return work_done;
@@ -2597,7 +2597,7 @@ pcnet32_interrupt(int irq, void *dev_id)
 			val = lp->a.read_csr(ioaddr, CSR3);
 			val |= 0x5f00;
 			lp->a.write_csr(ioaddr, CSR3, val);
-			mmiowb();
+
 			__napi_schedule(&lp->napi);
 			break;
 		}
-- 
1.5.4.3




             reply	other threads:[~2009-04-28 19:32 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-28 19:07 John Dykstra [this message]
2009-04-29  5:16 ` [PATCH net-next-2.6] pcnet32: Remove pointless memory barriers David Miller
2009-04-29 13:48   ` John Dykstra
2009-04-29 17:10     ` Don Fry
2009-04-29 19:07       ` John Dykstra
2009-04-29 22:29       ` Francois Romieu
2009-04-30  0:09 ` Don Fry
2009-04-30  0:16   ` John Dykstra
2009-04-30  0:21     ` David Miller
2009-04-30  0:19   ` David Miller

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