From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-nvdimm@ml01.01.org, Jan Kara <jack@suse.cz>,
Toshi Kani <toshi.kani@hpe.com>,
Matthew Wilcox <mawilcox@microsoft.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Jeff Moyer <jmoyer@redhat.com>, Ingo Molnar <mingo@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ross Zwisler <ross.zwisler@linux.intel.com>
Subject: Re: [PATCH v3] x86, pmem: fix broken __copy_user_nocache cache-bypass assumptions
Date: Tue, 11 Apr 2017 09:49:13 -0600 [thread overview]
Message-ID: <20170411154913.GA20725@linux.intel.com> (raw)
In-Reply-To: <149187075199.40875.9829505688202257056.stgit@dwillia2-desk3.amr.corp.intel.com>
On Mon, Apr 10, 2017 at 05:35:02PM -0700, Dan Williams wrote:
> Before we rework the "pmem api" to stop abusing __copy_user_nocache()
> for memcpy_to_pmem() we need to fix cases where we may strand dirty data
> in the cpu cache. The problem occurs when copy_from_iter_pmem() is used
> for arbitrary data transfers from userspace. There is no guarantee that
> these transfers, performed by dax_iomap_actor(), will have aligned
> destinations or aligned transfer lengths. Backstop the usage
> __copy_user_nocache() with explicit cache management in these unaligned
> cases.
>
> Yes, copy_from_iter_pmem() is now too big for an inline, but addressing
> that is saved for a later patch that moves the entirety of the "pmem
> api" into the pmem driver directly.
>
> Fixes: 5de490daec8b ("pmem: add copy_from_iter_pmem() and clear_pmem()")
> Cc: <stable@vger.kernel.org>
> Cc: <x86@kernel.org>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Jeff Moyer <jmoyer@redhat.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Matthew Wilcox <mawilcox@microsoft.com>
> Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
> Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This looks good to me, thanks for fixing this.
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
prev parent reply other threads:[~2017-04-11 15:49 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-11 0:35 [PATCH v3] x86, pmem: fix broken __copy_user_nocache cache-bypass assumptions Dan Williams
2017-04-11 15:15 ` Kani, Toshimitsu
2017-04-11 15:49 ` Ross Zwisler [this message]
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=20170411154913.GA20725@linux.intel.com \
--to=ross.zwisler@linux.intel.com \
--cc=dan.j.williams@intel.com \
--cc=hch@lst.de \
--cc=hpa@zytor.com \
--cc=jack@suse.cz \
--cc=jmoyer@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nvdimm@ml01.01.org \
--cc=mawilcox@microsoft.com \
--cc=mingo@redhat.com \
--cc=stable@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=toshi.kani@hpe.com \
--cc=viro@zeniv.linux.org.uk \
--cc=x86@kernel.org \
/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).