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Subject: Re: [PATCH v2 09/15] leds: trigger: blkdev: Check devices for
 activity and blink LEDs
To:     =?UTF-8?Q?Marek_Beh=c3=ban?= <kabel@kernel.org>
Cc:     axboe@kernel.dk, pavel@ucw.cz, linux-leds@vger.kernel.org,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        gregkh@linuxfoundation.org
References: <20210909222513.2184795-1-arequipeno@gmail.com>
 <20210909222513.2184795-10-arequipeno@gmail.com>
 <20210910041713.4722760a@thinkpad>
From:   Ian Pilcher <arequipeno@gmail.com>
Message-ID: <77111c57-dfb5-44c6-c4e9-e18afb468b6e@gmail.com>
Date:   Fri, 10 Sep 2021 10:09:09 -0500
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On 9/9/21 9:17 PM, Marek Behún wrote:
> So your code allows me to use a partition block device (like sda2) to
> register with the blkdev LED trigger, but when I do this, the code will
> disregard that I just want the LED to blink on activity on that one
> partition. Instead you will blink for whole sda, since you are looking
> at stats of only part0.
> 
> Am I right?

You can't add partitions, only whole devices.

# echo vda2 > link_device
-bash: echo: write error: No such device

static int blkdev_match_name(struct device *const dev, const void *const 
name)
{
	return dev->type == &disk_type
			&& sysfs_streq(dev_to_disk(dev)->disk_name, name);
}

Partitions fail the dev->type == &disk_type check.

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