From: Ben Dooks <ben.dooks@codethink.co.uk>
To: David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org, David.Laight@aculab.com,
oneukum@suse.com, linux-usb@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-kernel@lists.codethink.co.uk
Subject: usbnet: smsc95xx: simplify tx_fixup code
Date: Sat, 06 Oct 2018 12:27:27 +0100 [thread overview]
Message-ID: <40033993674bb8b5ef33ac33f28f3aff@codethink.co.uk> (raw)
On 2018-10-05 22:24, David Miller wrote:
> From: Ben Dooks <ben.dooks@codethink.co.uk>
> Date: Tue, 2 Oct 2018 17:56:02 +0100
>
>> - memcpy(skb->data, &tx_cmd_a, 4);
>> + ptr = skb_push(skb, 8);
>> + tx_cmd_a = cpu_to_le32(tx_cmd_a);
>> + tx_cmd_b = cpu_to_le32(tx_cmd_b);
>> + memcpy(ptr, &tx_cmd_a, 4);
>> + memcpy(ptr+4, &tx_cmd_b, 4);
>
> Even a memcpy() through a void pointer does not guarantee that gcc will
> not emit word sized loads and stores.
>
> You must use the get_unaligned()/put_unaligned() facilities to do this
> properly.
Thanks, got a new version of the series just being tested with this.
Should it go into the original, or as a separate change?
>
> I also agree that making a proper type and structure instead of using
> a void pointer would be better.
next reply other threads:[~2018-10-06 11:27 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-06 11:27 Ben Dooks [this message]
-- strict thread matches above, loose matches on Subject: below --
2018-10-08 8:41 usbnet: smsc95xx: simplify tx_fixup code David Laight
2018-10-06 17:28 David Miller
2018-10-05 21:24 David Miller
2018-10-03 16:25 Ben Dooks
2018-10-03 13:36 David Laight
2018-10-02 16:56 Ben Dooks
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