Linux-NVDIMM Archive on lore.kernel.org
 help / color / Atom feed
From: Dan Williams <dan.j.williams@intel.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	linux-nvdimm <linux-nvdimm@lists.01.org>,
	device-mapper development <dm-devel@redhat.com>
Subject: Re: [PATCH 1/5] dax, pmem: Add a dax operation zero_page_range
Date: Fri, 7 Feb 2020 09:06:32 -0800
Message-ID: <CAPcyv4g8jUhaKXhoh-1cvE4oi2v0JQcLrnFUW9zsRiC4F-7-zQ@mail.gmail.com> (raw)
In-Reply-To: <20200207170150.GC11998@redhat.com>

On Fri, Feb 7, 2020 at 9:02 AM Vivek Goyal <vgoyal@redhat.com> wrote:
>
> On Fri, Feb 07, 2020 at 08:57:39AM -0800, Dan Williams wrote:
> > On Wed, Feb 5, 2020 at 11:41 PM Christoph Hellwig <hch@infradead.org> wrote:
> > >
> > > On Wed, Feb 05, 2020 at 04:40:44PM -0800, Dan Williams wrote:
> > > > > I don't have any reason not to pass phys_addr_t. If that sounds better,
> > > > > will make changes.
> > > >
> > > > The problem is device-mapper. That wants to use offset to route
> > > > through the map to the leaf device. If it weren't for the firmware
> > > > communication requirement you could do:
> > > >
> > > > dax_direct_access(...)
> > > > generic_dax_zero_page_range(...)
> > > >
> > > > ...but as long as the firmware error clearing path is required I think
> > > > we need to do pass the pgoff through the interface and do the pgoff to
> > > > virt / phys translation inside the ops handler.
> > >
> > > Maybe phys_addr_t was the wrong type - but why do we split the offset
> > > into the block device argument into a pgoff and offset into page instead
> > > of a single 64-bit value?
> >
> > Oh, got it yes, that looks odd for sub-page zeroing. Yes, let's just
> > have one device relative byte-offset.
>
> So what's the best type to represent this offset. "u64" or "phys_addr_t"
> or "loff_t" or something else.  I like phys_addr_t followed by u64.

Let's make it u64.

phys_addr_t has already led to confusion in this thread because the
first question I ask when I read it is "why call ->direct_access() to
do the translation when you already have the physical address?".
_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
To unsubscribe send an email to linux-nvdimm-leave@lists.01.org

  reply index

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-03 20:00 [RFC PATCH 0/5][V2] dax,pmem: Provide a dax operation to zero range of memory Vivek Goyal
2020-02-03 20:00 ` [PATCH 1/5] dax, pmem: Add a dax operation zero_page_range Vivek Goyal
2020-02-05 18:30   ` Christoph Hellwig
2020-02-05 20:02     ` Vivek Goyal
2020-02-06  0:40       ` Dan Williams
2020-02-06  7:41         ` Christoph Hellwig
2020-02-07 16:57           ` Dan Williams
2020-02-07 17:01             ` Vivek Goyal
2020-02-07 17:06               ` Dan Williams [this message]
2020-02-06 14:34         ` Vivek Goyal
2020-02-07 16:58           ` Dan Williams
2020-02-03 20:00 ` [PATCH 2/5] s390,dax: Add dax zero_page_range operation to dcssblk driver Vivek Goyal
2020-02-05 18:32   ` Christoph Hellwig
2020-02-05 20:04     ` Vivek Goyal
2020-02-03 20:00 ` [PATCH 3/5] dm,dax: Add dax zero_page_range operation Vivek Goyal
2020-02-05 18:33   ` Christoph Hellwig
2020-02-07 16:34     ` Vivek Goyal
2020-02-03 20:00 ` [PATCH 4/5] dax,iomap: Start using dax native zero_page_range() Vivek Goyal
2020-02-05 18:33   ` Christoph Hellwig
2020-02-05 20:10     ` Vivek Goyal
2020-02-07 15:31     ` Vivek Goyal
2020-02-03 20:00 ` [PATCH 5/5] dax,iomap: Add helper dax_iomap_zero() to zero a range Vivek Goyal
2020-02-04  5:17   ` kbuild test robot
2020-02-05 18:36   ` Christoph Hellwig
2020-02-05 20:15     ` Vivek Goyal

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=CAPcyv4g8jUhaKXhoh-1cvE4oi2v0JQcLrnFUW9zsRiC4F-7-zQ@mail.gmail.com \
    --to=dan.j.williams@intel.com \
    --cc=dm-devel@redhat.com \
    --cc=hch@infradead.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-nvdimm@lists.01.org \
    --cc=vgoyal@redhat.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

Linux-NVDIMM Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-nvdimm/0 linux-nvdimm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-nvdimm linux-nvdimm/ https://lore.kernel.org/linux-nvdimm \
		linux-nvdimm@lists.01.org
	public-inbox-index linux-nvdimm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.01.lists.linux-nvdimm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git