From: "David S. Miller" <davem@redhat.com>
To: jgarzik@pobox.com
Cc: manfred@colorfullife.com, zaitcev@redhat.com,
jbourne@mtroyal.ab.ca, netdev@oss.sgi.com
Subject: Re: NAPI note
Date: Mon, 17 Feb 2003 18:57:19 -0800 (PST) [thread overview]
Message-ID: <20030217.185719.28797590.davem@redhat.com> (raw)
In-Reply-To: <3E4D8295.2050400@pobox.com>
From: Jeff Garzik <jgarzik@pobox.com>
Date: Fri, 14 Feb 2003 18:58:13 -0500
Manfred Spraul wrote:
> It seems to be a generic NAPI restriction:
> The caller of netif_receive_skb() must not own a spinlock that is
> acquired from an interrupt handler.
Thanks much for noticing this, Manfred.
I think this logic is buggy.
In the example I've seen posted, only a NAPI implementation bug
could cause the situation to occur.
If cpu1 is in ->poll() for the driver, then by definition the
device shall not cause interrupts. The device's interrupts
are disabled before we enter the ->poll() handler, and as such
the "cpu2 take device interrupt and takes driver->lock" cannot
occur.
If anything we've found a bug in interrupt disabling in the tg3
driver.
next prev parent reply other threads:[~2003-02-18 2:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <3E4D66DF.3040800@colorfullife.com>
2003-02-14 23:58 ` NAPI note (was Re: lockups with 2.4.20 (tg3? net/core/dev.c|deliver_to_old_ones)) Jeff Garzik
2003-02-18 2:57 ` David S. Miller [this message]
2003-02-18 16:31 ` NAPI note Manfred Spraul
2003-02-19 2:53 ` jamal
2003-02-19 3:14 ` Jeff Garzik
2003-02-19 3:18 ` David S. Miller
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