From: David Miller <davem@davemloft.net>
To: weiyang@linux.vnet.ibm.com
Cc: netdev@vger.kernel.org, gideonn@mellanox.com,
edumazet@google.com, amirv@mellanox.com
Subject: Re: [PATCH net] net/mlx4_en: correct the endianness of doorbell_qpn on big endian platform
Date: Fri, 05 Dec 2014 21:31:12 -0800 (PST) [thread overview]
Message-ID: <20141205.213112.1199355931404701216.davem@davemloft.net> (raw)
In-Reply-To: <1417315431-16761-1-git-send-email-weiyang@linux.vnet.ibm.com>
From: Wei Yang <weiyang@linux.vnet.ibm.com>
Date: Sun, 30 Nov 2014 10:43:51 +0800
> In commit 6a4e812 (net/mlx4_en: Avoid calling bswap in tx fast path), we store
> doorbell_qpn in big endian to avoid bswap(). Then we try to write it directly
> by iowrite32() instead of iowrite32be().
>
> This works fine on little endian platform, while has some problem on big
> endian platform. Here is the definition in general:
>
> #define iowrite32(v, addr) writel((v), (addr))
> #define writel(b,addr) __raw_writel(__cpu_to_le32(b),addr)
>
> On little endian platform, the value is not swapped before write. While on big
> endian platform, the value is swapped. This is not expected to happen.
>
> This patch does the swap on big endian platform before it is written.
>
> Signed-off-by: Wei Yang <weiyang@linux.vnet.ibm.com>
Guys, let's figure out what we are doing with this patch.
next prev parent reply other threads:[~2014-12-06 5:26 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-30 2:43 [PATCH net] net/mlx4_en: correct the endianness of doorbell_qpn on big endian platform Wei Yang
2014-11-30 2:52 ` Wei Yang
2014-11-30 19:27 ` Eric Dumazet
2014-12-01 1:29 ` Wei Yang
2014-12-06 5:31 ` David Miller [this message]
2014-12-06 5:46 ` Eric Dumazet
2014-12-08 3:12 ` Wei Yang
2014-12-08 10:00 ` David Laight
2014-12-08 14:42 ` Wei Yang
2014-12-13 3:13 ` Wei Yang
2014-12-14 4:43 ` David Miller
2014-12-15 1:32 ` Wei Yang
2014-12-15 9:59 ` Amir Vadai
2014-12-15 10:00 ` David Laight
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20141205.213112.1199355931404701216.davem@davemloft.net \
--to=davem@davemloft.net \
--cc=amirv@mellanox.com \
--cc=edumazet@google.com \
--cc=gideonn@mellanox.com \
--cc=netdev@vger.kernel.org \
--cc=weiyang@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).