From: Roland Dreier <rdreier@cisco.com>
To: Steve Wise <swise@opengridcomputing.com>
Cc: randy.dunlap@oracle.com, linux-next@vger.kernel.org,
linux-kernel@vger.kernel.org, general@lists.openfabrics.org
Subject: Re: [ofa-general] [PATCH 2.6.30] RDMA/cxgb3: Remove modulo math.
Date: Wed, 11 Feb 2009 10:36:01 -0800 [thread overview]
Message-ID: <adak57w95ym.fsf@cisco.com> (raw)
In-Reply-To: <499319CF.6050204@opengridcomputing.com> (Steve Wise's message of "Wed, 11 Feb 2009 12:32:47 -0600")
> > Is it possible for the page to be bigger than 4GB? If so then yes you
> > might be chopping off high-order bits or something.
> Yes it is possible.
>
> A MR can be created with an iov_base of say 0xffffffff00000000.
>
> Then any sge.addr entries would be the iob_base + any offset.
But the code we're talking about is:
/* to in the WQE == the offset into the page */
wqe->recv.sgl[i].to = cpu_to_be64(((u32) wr->sg_list[i].addr) %
(1UL << (12 + page_size[i])));
so it seems the top address bits don't matter unless page_size[i] is at
least 20 -- in which case using 1UL to shift overflows on 32 bits anyway...
> So you are handling the offset patch that will make it u64 and remove
> the mod usage, correct?
Yeah, I rolled the fix into the "offset needs to be u64" patch, it
should be in linux-next by now (or at least in my for-next branch).
- R.
next prev parent reply other threads:[~2009-02-11 18:36 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-10 18:44 [ofa-general] [PATCH 2.6.30] RDMA/cxgb3: Remove modulo math Steve Wise
2009-02-10 19:04 ` [ofa-general] " Randy Dunlap
2009-02-10 19:10 ` Steve Wise
2009-02-10 19:12 ` Randy Dunlap
2009-02-11 0:38 ` [ofa-general] " Roland Dreier
2009-02-11 1:03 ` Steve Wise
[not found] ` <499223F8.1010204@opengridcomputing.com>
2009-02-11 1:07 ` David Miller
2009-02-11 1:18 ` Roland Dreier
2009-02-11 1:23 ` David Miller
2009-02-11 7:20 ` Roland Dreier
2009-02-11 8:00 ` David Miller
2009-02-11 15:44 ` Steve Wise
2009-02-11 18:12 ` Roland Dreier
2009-02-11 18:32 ` Steve Wise
2009-02-11 18:36 ` Roland Dreier [this message]
2009-02-11 18:44 ` Steve Wise
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