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References: <20190722074133.17777-1-hslester96@gmail.com> <20190722.182235.195933962601112626.davem@davemloft.net>
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From:   Chuhong Yuan <hslester96@gmail.com>
Date:   Tue, 23 Jul 2019 10:16:27 +0800
Message-ID: <CANhBUQ0FMJATcjkb0RYyM8LhA92htq9mddLqcNB94FcxMBGsbg@mail.gmail.com>
Subject: Re: [PATCH] net: usb: Merge cpu_to_le32s + memcpy to put_unaligned_le32
To:     David Miller <davem@davemloft.net>
Cc:     Woojung Huh <woojung.huh@microchip.com>,
        Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>,
        Steve Glendinning <steve.glendinning@shawell.net>,
        linux-usb@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
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David Miller <davem@davemloft.net> =E4=BA=8E2019=E5=B9=B47=E6=9C=8823=E6=97=
=A5=E5=91=A8=E4=BA=8C =E4=B8=8A=E5=8D=889:22=E5=86=99=E9=81=93=EF=BC=9A
>
> From: Chuhong Yuan <hslester96@gmail.com>
> Date: Mon, 22 Jul 2019 15:41:34 +0800
>
> > Merge the combo uses of cpu_to_le32s and memcpy.
> > Use put_unaligned_le32 instead.
> > This simplifies the code.
> >
> > Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
>
> Isn't the skb->data aligned to 4 bytes in these situations?
>
> If so, we should use the aligned variants.
>
> Thank you.

I have checked the five changed files.
I find that they all have used get_unaligned_le32 for skb->data
according to my previous applied patches and existing code.
So I think the skb->data is unaligned in these situations.

Usages of get_unaligned_le32:
asix_common.c: line 104 and 133
ax88179_178a.c: https://lkml.org/lkml/2019/7/19/652
lan78xx.c: https://lkml.org/lkml/2019/7/19/573
smsc75xx.c: https://lkml.org/lkml/2019/7/19/617
sr9800.c: line 73