From: Jeff Garzik <jgarzik@pobox.com>
To: Krzysztof Halasa <khc@pm.waw.pl>
Cc: Maillist netdev <netdev@oss.sgi.com>,
"David S. Miller" <davem@redhat.com>
Subject: Re: double-check me?
Date: Sun, 17 Aug 2003 18:31:02 -0400 [thread overview]
Message-ID: <3F400226.1080006@pobox.com> (raw)
In-Reply-To: <m3n0e8uhl4.fsf@defiant.pm.waw.pl>
Krzysztof Halasa wrote:
> Jeff Garzik <jgarzik@pobox.com> writes:
>
>
>>Maybe you guys can spot something I'm missing here. alloc_netdev is
>>supposed to guarantee that dev->priv is aligned by 32 bytes:
>>
>> struct net_device *dev;
>>
>> if (sizeof_priv)
>> dev->priv = (void *) (((long)(dev + 1) + 31) & ~31);
>>
>>
>>Now... shouldn't that last line of code be "dev + 1 + sizeof(*dev)" ?
>>
>>It seems to work 2.[456] for a long time, so I am doubting
>>myself... surely it would have caused memory corruption or something
>>by now if I have really found a bug.
>
>
> Looks ok... not very readable, though.
>
> dev + 1 = ((u8*)dev) + sizeof(dev) = pointer to end of net_device struct.
C pointer arithmatic. Ok, duh, thanks :)
Jeff, too used to void pointer arith
next prev parent reply other threads:[~2003-08-17 22:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-17 17:45 double-check me? Jeff Garzik
2003-08-17 20:58 ` Krzysztof Halasa
2003-08-17 22:31 ` Jeff Garzik [this message]
2003-08-18 14:38 ` Jason Lunz
2003-08-18 14:41 ` Jeff Garzik
2003-08-17 21:34 ` Jason Lunz
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