From: Christoph Hellwig <hch@infradead.org>
To: guoren@kernel.org
Cc: arnd@arndb.de, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-csky@vger.kernel.org,
douzhk@nationalchip.com, Guo Ren <ren_guo@c-sky.com>
Subject: Re: [PATCH 3/3] csky: Support kernel non-aligned access
Date: Tue, 20 Aug 2019 19:17:41 -0700 [thread overview]
Message-ID: <20190821021741.GB32710@infradead.org> (raw)
In-Reply-To: <1566304469-5601-3-git-send-email-guoren@kernel.org>
On Tue, Aug 20, 2019 at 08:34:29PM +0800, guoren@kernel.org wrote:
> From: Guo Ren <ren_guo@c-sky.com>
>
> We prohibit non-aligned access in kernel mode, but some special NIC
> driver needs to support kernel-state unaligned access. For example,
> when the bus does not support unaligned access, IP header parsing
> will cause non-aligned access and driver does not recopy the skb
> buffer to dma for performance reasons.
>
> Added kernel_enable & user_enable to control unaligned access and
> added kernel_count & user_count for statistical unaligned access.
If the NIC drivers requires this it is buggy. Kernel code must
use the get_unaligned* / put_unaligned* helpers for that.
next prev parent reply other threads:[~2019-08-21 2:17 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-20 12:34 [PATCH 1/3] csky: Fixup arch_get_unmapped_area() implementation guoren
2019-08-20 12:34 ` [PATCH 2/3] csky: Fixup defer cache flush for 610 guoren
2019-08-20 12:34 ` [PATCH 3/3] csky: Support kernel non-aligned access guoren
2019-08-21 2:17 ` Christoph Hellwig [this message]
2019-08-21 3:43 ` Guo Ren
2019-08-21 2:16 ` [PATCH 1/3] csky: Fixup arch_get_unmapped_area() implementation Christoph Hellwig
2019-08-21 3:44 ` Guo Ren
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