From: Jan Kara <jack@suse.cz>
To: Pankaj Gupta <pagupta@redhat.com>
Cc: linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-acpi@vger.kernel.org,
qemu-devel@nongnu.org, linux-ext4@vger.kernel.org,
linux-xfs@vger.kernel.org, dan.j.williams@intel.com,
zwisler@kernel.org, vishal.l.verma@intel.com,
dave.jiang@intel.com, mst@redhat.com, jasowang@redhat.com,
willy@infradead.org, rjw@rjwysocki.net, hch@infradead.org,
lenb@kernel.org, jack@suse.cz, tytso@mit.edu,
adilger.kernel@dilger.ca, darrick.wong@oracle.com,
lcapitulino@redhat.com, kwolf@redhat.com, imammedo@redhat.com,
jmoyer@redhat.com, nilal@redhat.com, riel@surriel.com,
stefanha@redhat.com, aarcange@redhat.com, david@redhat.com,
david@fromorbit.com, cohuck@redhat.com,
xiaoguangrong.eric@gmail.com, pbonzini@redhat.com,
kilobyte@angband.pl, yuval.shaia@oracle.com
Subject: Re: [PATCH v5 4/6] dax: check synchronous mapping is supported
Date: Wed, 10 Apr 2019 10:25:04 +0200 [thread overview]
Message-ID: <20190410082504.GF1426@quack2.suse.cz> (raw)
In-Reply-To: <20190410040826.24371-5-pagupta@redhat.com>
On Wed 10-04-19 09:38:24, Pankaj Gupta wrote:
> This patch introduces 'daxdev_mapping_supported' helper
> which checks if 'MAP_SYNC' is supported with filesystem
> mapping. It also checks if corresponding dax_device is
> synchronous. Virtio pmem device is asynchronous and
> does not not support VM_SYNC.
>
> Suggested-by: Jan Kara <jack@suse.cz>
> Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
> ---
> include/linux/dax.h | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index b896706a5ee9..4a2a60ffec86 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -38,6 +38,24 @@ void kill_dax(struct dax_device *dax_dev);
> void dax_write_cache(struct dax_device *dax_dev, bool wc);
> bool dax_write_cache_enabled(struct dax_device *dax_dev);
> bool dax_synchronous(struct dax_device *dax_dev);
> +
> +/*
> + * Callers check if synchronous mapping is enabled for DAX file
> + * and attached dax device is also synchronous.
> + *
> + * dax_synchronous function verifies if dax device is synchronous.
> + * Currently, only virtio pmem device supports asynchronous device
> + * flush.
> + */
Thanks for the patch! I'd restructure this comment like:
/*
* Check if given mapping is supported by the file / underlying device.
*/
> +static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
> + struct dax_device *dax_dev)
> +{
/* Everyone supports non-sync mappings */
> + if (!(vma->vm_flags & VM_SYNC))
> + return true;
/* Sync mappings are supported only for files using DAX */
> + if (!IS_DAX(file_inode(vma->vm_file)))
> + return false;
/* Underlying device must support persisting through CPU instructions */
> + return dax_synchronous(dax_dev);
> +}
> #else
> static inline struct dax_device *dax_get_by_host(const char *host)
> {
> @@ -69,6 +87,11 @@ static inline bool dax_synchronous(struct dax_device *dax_dev)
> {
> return true;
> }
> +static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
> + struct dax_device *dax_dev)
> +{
> + return true;
This looks wrong. Shouldn't it rather be:
return !(vma->flags & VM_SYNC);
?
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2019-04-10 8:25 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-10 4:08 [PATCH v5 0/6] virtio pmem driver Pankaj Gupta
2019-04-10 4:08 ` [PATCH v5 1/6] libnvdimm: nd_region flush callback support Pankaj Gupta
2019-04-11 14:51 ` Dan Williams
2019-04-11 15:57 ` [Qemu-devel] " Pankaj Gupta
2019-04-11 16:09 ` Dan Williams
2019-04-11 16:23 ` Pankaj Gupta
2019-04-12 8:32 ` Jan Kara
2019-04-12 13:12 ` Jeff Moyer
2019-04-18 6:27 ` [Qemu-devel] " Pankaj Gupta
2019-04-18 16:05 ` Dan Williams
2019-04-18 16:10 ` Jeff Moyer
2019-04-18 16:18 ` Christoph Hellwig
2019-04-18 18:14 ` Dan Williams
2019-04-22 15:51 ` Jeff Moyer
2019-04-22 19:44 ` Dan Williams
2019-04-22 21:03 ` Jeff Moyer
2019-04-23 4:07 ` Pankaj Gupta
2019-04-10 4:08 ` [PATCH v5 2/5] virtio-pmem: Add virtio pmem driver Pankaj Gupta
2019-04-10 12:24 ` Cornelia Huck
2019-04-10 14:38 ` Yuval Shaia
2019-04-10 15:44 ` Pankaj Gupta
2019-04-10 15:38 ` Pankaj Gupta
2019-04-10 13:12 ` Michael S. Tsirkin
2019-04-10 14:03 ` [Qemu-devel] " Pankaj Gupta
2019-04-10 14:31 ` Cornelia Huck
2019-04-10 16:46 ` Michael S. Tsirkin
2019-04-10 16:52 ` Cornelia Huck
2019-04-10 14:41 ` Yuval Shaia
2019-04-10 4:08 ` [PATCH v5 3/6] libnvdimm: add dax_dev sync flag Pankaj Gupta
2019-04-10 8:28 ` Jan Kara
2019-04-10 8:38 ` Pankaj Gupta
2019-04-11 14:56 ` Dan Williams
2019-04-11 15:39 ` Pankaj Gupta
2019-04-10 4:08 ` [PATCH v5 4/6] dax: check synchronous mapping is supported Pankaj Gupta
2019-04-10 8:25 ` Jan Kara [this message]
2019-04-10 8:31 ` Pankaj Gupta
2019-04-10 4:08 ` [PATCH v5 5/6] ext4: disable map_sync for async flush Pankaj Gupta
2019-04-10 4:08 ` [PATCH v5 6/6] xfs: " Pankaj Gupta
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=20190410082504.GF1426@quack2.suse.cz \
--to=jack@suse.cz \
--cc=aarcange@redhat.com \
--cc=adilger.kernel@dilger.ca \
--cc=cohuck@redhat.com \
--cc=dan.j.williams@intel.com \
--cc=darrick.wong@oracle.com \
--cc=dave.jiang@intel.com \
--cc=david@fromorbit.com \
--cc=david@redhat.com \
--cc=hch@infradead.org \
--cc=imammedo@redhat.com \
--cc=jasowang@redhat.com \
--cc=jmoyer@redhat.com \
--cc=kilobyte@angband.pl \
--cc=kvm@vger.kernel.org \
--cc=kwolf@redhat.com \
--cc=lcapitulino@redhat.com \
--cc=lenb@kernel.org \
--cc=linux-acpi@vger.kernel.org \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nvdimm@lists.01.org \
--cc=linux-xfs@vger.kernel.org \
--cc=mst@redhat.com \
--cc=nilal@redhat.com \
--cc=pagupta@redhat.com \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=riel@surriel.com \
--cc=rjw@rjwysocki.net \
--cc=stefanha@redhat.com \
--cc=tytso@mit.edu \
--cc=virtualization@lists.linux-foundation.org \
--cc=vishal.l.verma@intel.com \
--cc=willy@infradead.org \
--cc=xiaoguangrong.eric@gmail.com \
--cc=yuval.shaia@oracle.com \
--cc=zwisler@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).