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From:   Himanshu Madhani <himanshu.madhani@oracle.com>
To:     Daniel Wagner <dwagner@suse.de>
CC:     "linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
        Christoph Hellwig <hch@lst.de>,
        Sagi Grimberg <sagi@grimberg.me>,
        Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>,
        Hannes Reinecke <hare@suse.de>,
        Chao Leng <lengchao@huawei.com>,
        Victor Gladkov <Victor.Gladkov@kioxia.com>
Subject: Re: [PATCH] nvme: Export fast_io_fail_tmo to sysfs
Thread-Topic: [PATCH] nvme: Export fast_io_fail_tmo to sysfs
Thread-Index: AQHXJi+uCqVrwISuNkOtIe+L49QAmqqegt4A
Date:   Wed, 31 Mar 2021 19:54:13 +0000
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References: <20210331131228.131118-1-dwagner@suse.de>
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> On Mar 31, 2021, at 8:12 AM, Daniel Wagner <dwagner@suse.de> wrote:
>=20
> Commit 8c4dfea97f15 ("nvme-fabrics: reject I/O to offline device")
> introduced fast_io_fail_tmo but didn't export the value to sysfs. That
> means the value is hard coded during compile time. Export the timeout
> value to user space via sysfs to allow runtime configuration.
>=20
> Cc: Victor Gladkov <Victor.Gladkov@kioxia.com>
> Signed-off-by: Daniel Wagner <dwagner@suse.de>
> ---
>=20
> This patch is against nvme-5.13
>=20
> BTW, checkpatch complains with
>=20
>  WARNING: Symbolic permissions 'S_IRUGO | S_IWUSR' are not preferred. Con=
sider using octal permissions '0644'.
>=20
> Is this something we want to adapt to?
>=20
> drivers/nvme/host/core.c | 31 +++++++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
>=20
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 40215a0246e4..c8de0e37c7d9 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -3696,6 +3696,36 @@ static ssize_t nvme_ctrl_reconnect_delay_store(str=
uct device *dev,
> static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR,
> 	nvme_ctrl_reconnect_delay_show, nvme_ctrl_reconnect_delay_store);
>=20
> +static ssize_t nvme_ctrl_fast_io_fail_tmo_show(struct device *dev,
> +		struct device_attribute *attr, char *buf)
> +{
> +	struct nvme_ctrl *ctrl =3D dev_get_drvdata(dev);
> +
> +	if (ctrl->opts->fast_io_fail_tmo =3D=3D -1)
> +		return sprintf(buf, "off\n");
> +	return sprintf(buf, "%d\n", ctrl->opts->fast_io_fail_tmo);
> +}
> +
> +static ssize_t nvme_ctrl_fast_io_fail_tmo_store(struct device *dev,
> +		struct device_attribute *attr, const char *buf, size_t count)
> +{
> +	struct nvme_ctrl *ctrl =3D dev_get_drvdata(dev);
> +	struct nvmf_ctrl_options *opts =3D ctrl->opts;
> +	int fast_io_fail_tmo, err;
> +
> +	err =3D kstrtoint(buf, 10, &fast_io_fail_tmo);
> +	if (err)
> +		return -EINVAL;
> +
> +	else if (fast_io_fail_tmo < 0)
> +		opts->fast_io_fail_tmo =3D -1;
> +	else
> +		opts->fast_io_fail_tmo =3D fast_io_fail_tmo;
> +	return count;
> +}
> +static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
> +	nvme_ctrl_fast_io_fail_tmo_show, nvme_ctrl_fast_io_fail_tmo_store);
> +
> static struct attribute *nvme_dev_attrs[] =3D {
> 	&dev_attr_reset_controller.attr,
> 	&dev_attr_rescan_controller.attr,
> @@ -3715,6 +3745,7 @@ static struct attribute *nvme_dev_attrs[] =3D {
> 	&dev_attr_hostid.attr,
> 	&dev_attr_ctrl_loss_tmo.attr,
> 	&dev_attr_reconnect_delay.attr,
> +	&dev_attr_fast_io_fail_tmo.attr,
> 	NULL
> };
>=20
> --=20
> 2.29.2
>=20


Reviewed-by: Himanshu Madhani <himanshu.madhaani@oracle.com>

--
Himanshu Madhani	 Oracle Linux Engineering