From: David Miller <davem@davemloft.net>
To: krkumar2@in.ibm.com
Cc: netdev@vger.kernel.org, rdreier@cisco.com, general@lists.openfabrics.org
Subject: [ofa-general] Re: [Bug, PATCH and another Bug] Was: Fix refcounting problem with netif_rx_reschedule()
Date: Thu, 20 Sep 2007 11:12:28 -0700 (PDT) [thread overview]
Message-ID: <20070920.111228.76772435.davem@davemloft.net> (raw)
In-Reply-To: <OF8B3BDDEC.3F73CFD4-ON6525735C.001C8A0F-6525735C.001D2340@in.ibm.com>
From: Krishna Kumar2 <krkumar2@in.ibm.com>
Date: Thu, 20 Sep 2007 10:48:15 +0530
> About the "list deletion occurs", isn't the race I mentioned still present?
> If done < budget, the driver does netif_rx_complete (at which time some
> other cpu can add this NAPI to their list). But the first cpu might do some more
> actions on the napi, like ipoib_poll() calls request_notify_cq(priv->cq),
> when other cpu might have started using this napi.
>
> (net_rx_action's 'list_move' however will not execute since work != weight)
It is the driver's responsibility to adhere to the fact that once
netif_rx_complete() is called, the driver is explicitly relinquishing
ownership of the NAPI state.
It therefore must not access that NAPI state until it has successfully
acquired the NAPI_STATE_SCHED bit atomically, via a sched or resched.
prev parent reply other threads:[~2007-09-20 18:12 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-19 11:54 [Bug, PATCH and another Bug] Was: Fix refcounting problem with netif_rx_reschedule() Krishna Kumar
2007-09-19 13:23 ` Jan-Bernd Themann
2007-09-20 5:10 ` Krishna Kumar2
2007-09-20 5:12 ` David Miller
2007-09-20 5:54 ` [ofa-general] " Krishna Kumar2
2007-09-20 18:12 ` David Miller
2007-09-19 16:05 ` David Miller
2007-09-20 5:18 ` Krishna Kumar2
2007-09-20 18:12 ` David Miller [this message]
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