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Date: Sat, 28 Feb 2015 12:34:15 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Minchan Kim <minchan@kernel.org>,
        Jerome Marchand <jmarchan@redhat.com>, Nitin Gupta <ngupta@vflare.org>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        linux-kernel@vger.kernel.org, Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [PATCH 0/8] introduce dynamic device creation/removal
Message-ID: <20150228033415.GC5768@swordfish>
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 <20150227145109.b5656bdf853c2d283bf9268e@linux-foundation.org>
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On (02/27/15 14:51), Andrew Morton wrote:
> hoo boy.  Creating a /dev node and doing ioctls on it is really old
> school.  So old school that I've forgotten why we don't do it any more.
> 
> Hopefully Alan can recall the thinking?
> 

perhaps, something like

 static struct class_attribute zram_class_attrs[] = {
         __ATTR(zram_control, S_IWUSR | S_IRUGO,
                         zram_control_show, zram_control_store),
         __ATTR_NULL,
 };

 struct class zram_class = {
         .name           = "zram-control",
         .class_attrs    = zram_class_attrs,
 };


 class_register(&zram_class);



or (even better) separate control files

 static struct class_attribute zram_class_attrs[] = {
         __ATTR(zram_add, ....),
         __ATTR(zram_remove, ....),
         __ATTR_NULL,
 };


so we can just echo `device_id' to add/remove devices

echo 1 > /sys/class/zram-control/zram_add
echo 1 > /sys/class/zram-control/zram_remove


handling it in FOO_store() functions:

 static ssize_t zram_add_store(struct class *class,
                         struct class_attribute *attr,
                         char *buf)


how about this?


	-ss