netdev - RE: [PATCH net-next V2 5/7] s390/qeth: improve endianness handling

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Message-ID: <063D6719AE5E284EB5DD2968C1650D6DCFFCAAFB@AcuExch.aculab.com>
Date:   Mon, 10 Apr 2017 15:16:27 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Ursula Braun' <ubraun@...ux.vnet.ibm.com>,
        "davem@...emloft.net" <davem@...emloft.net>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-s390@...r.kernel.org" <linux-s390@...r.kernel.org>,
        "jwi@...ux.vnet.ibm.com" <jwi@...ux.vnet.ibm.com>,
        "schwidefsky@...ibm.com" <schwidefsky@...ibm.com>,
        "heiko.carstens@...ibm.com" <heiko.carstens@...ibm.com>,
        "raspl@...ux.vnet.ibm.com" <raspl@...ux.vnet.ibm.com>
Subject: RE: [PATCH net-next V2 5/7] s390/qeth: improve endianness handling

From: Ursula Braun
> Sent: 07 April 2017 08:16
> Avoid endianness warnings reported by sparse by (1) using endianness
> conversions for assigning and using network packet fields, and (2)
> removing unnecessary endianness conversions from qeth_l3_rebuild_skb. No
> functional changes.
...
> -	if (*p == ETH_P_8021Q)
> +	if (be16_to_cpu(*p) == ETH_P_8021Q)
...

This is clearly different on little-endian systems.
Also (probably) better written as:

	if (*p == cpu_to_be16(ETH_P_8021Q))

so that the constant can by byteswapped.

	David