From: Christoph Hellwig <hch@infradead.org>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: linux-rdma@vger.kernel.org, Max Gurtovoy <maxg@mellanox.com>,
Stephen Rust <srust@blockbridge.com>,
Doug Dumitru <doug@dumitru.com>
Subject: Re: [PATCH] IB/isert: fix unaligned immediate-data handling
Date: Mon, 31 Aug 2020 06:14:53 +0100 [thread overview]
Message-ID: <20200831051453.GA13058@infradead.org> (raw)
In-Reply-To: <20200830103209.378141-1-sagi@grimberg.me>
On Sun, Aug 30, 2020 at 03:32:09AM -0700, Sagi Grimberg wrote:
> Currently we allocate rx buffers in a single contiguous buffers
> for headers (iser and iscsi) and data trailer. This means
> that most likely the data starting offset is aligned to 76
> bytes (size of both headers).
>
> This worked fine for years, but at some point this broke.
> To fix this, we should avoid passing unaligned buffers for
> I/O.
>
> Instead, we allocate our recv buffers with some extra space
> such that we can have the data portion align to 512 byte boundary.
> This also means that we cannot reference headers or data using
> structure but rather accessors (as they may move based on alignment).
> Also, get rid of the wrong __packed annotation from iser_rx_desc
> as this has only harmful effects (not aligned to anything).
>
> This affects the rx descriptors for iscsi login and data plane.
What are the symptoms of the breakage?
next prev parent reply other threads:[~2020-08-31 5:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-30 10:32 [PATCH] IB/isert: fix unaligned immediate-data handling Sagi Grimberg
2020-08-31 5:14 ` Christoph Hellwig [this message]
2020-08-31 5:37 ` Doug Dumitru
2020-08-31 12:18 ` Jason Gunthorpe
2020-08-31 16:29 ` Doug Dumitru
2020-08-31 16:48 ` Sagi Grimberg
[not found] ` <CAAFE1bcXNdMD5AR80tSFVoYouTrEg_swR73ba2FVEB5UH7MXLQ@mail.gmail.com>
2020-08-31 16:59 ` Stephen Rust
2020-08-31 17:02 ` Doug Dumitru
2020-08-31 17:59 ` Jason Gunthorpe
2020-09-01 5:56 ` Christoph Hellwig
2020-09-01 7:42 ` Sagi Grimberg
2020-09-01 1:00 ` Ming Lei
2020-09-01 1:10 ` Sagi Grimberg
2020-09-01 2:01 ` Ming Lei
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=20200831051453.GA13058@infradead.org \
--to=hch@infradead.org \
--cc=doug@dumitru.com \
--cc=linux-rdma@vger.kernel.org \
--cc=maxg@mellanox.com \
--cc=sagi@grimberg.me \
--cc=srust@blockbridge.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