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From: Matteo Croce <mcroce@linux.microsoft.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Jens Axboe <axboe@kernel.dk>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Lennart Poettering <lennart@poettering.net>,
	Luca Boccassi <bluca@debian.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Damien Le Moal <damien.lemoal@wdc.com>, Tejun Heo <tj@kernel.org>,
	"Javier Gonz??lez" <javier@javigon.com>,
	Niklas Cassel <niklas.cassel@wdc.com>,
	Johannes Thumshirn <johannes.thumshirn@wdc.com>,
	Hannes Reinecke <hare@suse.de>,
	Matthew Wilcox <willy@infradead.org>,
	JeffleXu <jefflexu@linux.alibaba.com>
Subject: Re: [PATCH v3 1/6] block: add disk sequence number
Date: Wed, 23 Jun 2021 15:10:21 +0200	[thread overview]
Message-ID: <CAFnufp1gdag0rGQ8K4_2oB6_aC+EZgfgwd2eL4-AxpG0mK+_qQ@mail.gmail.com> (raw)
In-Reply-To: <YNMffBWvs/Fz2ptK@infradead.org>

On Wed, Jun 23, 2021 at 1:49 PM Christoph Hellwig <hch@infradead.org> wrote:
>
> On Wed, Jun 23, 2021 at 12:58:53PM +0200, Matteo Croce wrote:
> > +void inc_diskseq(struct gendisk *disk)
> > +{
> > +     static atomic64_t diskseq;
>
> Please don't hide file scope variables in functions.
>

I just didn't want to clobber that file namespace, as that is the only
point where it's used.

> Can you explain a little more why we need a global sequence count vs
> a per-disk one here?

The point of the whole series is to have an unique sequence number for
all the disks.
Events can arrive to the userspace delayed or out-of-order, so this
helps to correlate events to the disk.
It might seem strange, but there isn't a way to do this yet, so I come
up with a global, monotonically incrementing number.

-- 
per aspera ad upstream

  reply	other threads:[~2021-06-23 13:11 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-23 10:58 [PATCH v3 0/6] block: add a sequence number to disks Matteo Croce
2021-06-23 10:58 ` [PATCH v3 1/6] block: add disk sequence number Matteo Croce
2021-06-23 11:48   ` Christoph Hellwig
2021-06-23 13:10     ` Matteo Croce [this message]
2021-06-23 13:51       ` Lennart Poettering
2021-06-23 14:01         ` Hannes Reinecke
2021-06-23 14:07           ` Luca Boccassi
2021-06-23 14:21             ` Hannes Reinecke
2021-06-23 14:34               ` Luca Boccassi
2021-06-23 14:55               ` Lennart Poettering
2021-06-23 14:12           ` Lennart Poettering
2021-06-23 15:02             ` Hannes Reinecke
2021-06-23 15:34               ` Luca Boccassi
2021-06-23 15:48               ` Lennart Poettering
2021-06-23 14:28       ` Christoph Hellwig
2021-06-23 10:58 ` [PATCH v3 2/6] block: add ioctl to read the " Matteo Croce
2021-06-23 10:58 ` [PATCH v3 3/6] block: refactor sysfs code Matteo Croce
2021-06-23 11:52   ` Christoph Hellwig
2021-06-23 19:03     ` Matteo Croce
2021-06-24  6:12       ` Christoph Hellwig
2021-06-23 10:58 ` [PATCH v3 4/6] block: export diskseq in sysfs Matteo Croce
2021-06-23 10:58 ` [PATCH v3 5/6] block: increment sequence number Matteo Croce
2021-06-23 10:58 ` [PATCH v3 6/6] loop: " Matteo Croce
2021-06-23 11:57   ` Christoph Hellwig
2021-06-23 13:13     ` Luca Boccassi
2021-06-23 14:25       ` Christoph Hellwig
2021-06-23 15:29         ` Lennart Poettering
2021-06-24  6:11           ` Christoph Hellwig
2021-06-23 12:03 ` [PATCH v3 0/6] block: add a sequence number to disks Hannes Reinecke
2021-06-23 12:46   ` Luca Boccassi
2021-06-23 14:07   ` Lennart Poettering

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