RE: [PATCHv3 2/2] nvme: Expose cntrltype and dctype through sysfs

From: "Belanger, Martin" <Martin.Belanger@dell.com>
To: Chaitanya Kulkarni <chaitanyak@nvidia.com>,
	Martin Belanger <nitram_67@hotmail.com>
Cc: "kbusch@kernel.org" <kbusch@kernel.org>,
	"hare@suse.de" <hare@suse.de>, "axboe@fb.com" <axboe@fb.com>,
	"hch@lst.de" <hch@lst.de>, "sagi@grimberg.me" <sagi@grimberg.me>,
	"Hayes, Stuart" <Stuart.Hayes@dell.com>,
	"Rose, Charles" <Charles.Rose@dell.com>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>
Subject: RE: [PATCHv3 2/2] nvme: Expose cntrltype and dctype through sysfs
Date: Tue, 8 Feb 2022 23:53:54 +0000	[thread overview]
Message-ID: <SJ0PR19MB4544A98CC3684F2421BC7220F22D9@SJ0PR19MB4544.namprd19.prod.outlook.com> (raw)
In-Reply-To: <890f6817-7880-79cd-3651-2f91e4454e28@nvidia.com>

> > +static ssize_t cntrltype_show(struct device *dev,
> > +			      struct device_attribute *attr, char *buf) {
> > +	static const char * const type[] = {
> 
> nit:- static cost char *const type[] ...

Hi Chaitanya. I'm afraid I don’t know what you mean by "nit". 
The syntax "static const char * const type[] =" was suggested 
by the checkpatch.pl script.

Regards,
Martin

> 
> > +		[NVME_CTRL_IO] = "io\n",
> > +		[NVME_CTRL_DISC] = "discovery\n",
> > +		[NVME_CTRL_ADMIN] = "admin\n",
> > +	};
> > +	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
> > +
> > +	if (ctrl->cntrltype > NVME_CTRL_ADMIN || !type[ctrl->cntrltype])
> > +		return sysfs_emit(buf, "reserved\n");
> > +
> > +	return sysfs_emit(buf, type[ctrl->cntrltype]); } static
> > +DEVICE_ATTR_RO(cntrltype);
> > +
> > +static ssize_t dctype_show(struct device *dev,
> > +			   struct device_attribute *attr, char *buf) {
> > +	static const char * const type[] = {
> 
> nit:- static cost char *const typep[] ...
> 
> > +		[NVME_DCTYPE_NOT_REPORTED] = "none\n",
> > +		[NVME_DCTYPE_DDC] = "ddc\n",
> > +		[NVME_DCTYPE_CDC] = "cdc\n",
> > +	};
> > +	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
> > +
> > +	if (ctrl->dctype > NVME_DCTYPE_CDC || !type[ctrl->dctype])
> > +		return sysfs_emit(buf, "reserved\n");
> > +
> > +	return sysfs_emit(buf, type[ctrl->dctype]); } static
> > +DEVICE_ATTR_RO(dctype);
> > +
> >   static struct attribute *nvme_dev_attrs[] = {
> >   	&dev_attr_reset_controller.attr,
> >   	&dev_attr_rescan_controller.attr,
> > @@ -3544,6 +3581,8 @@ static struct attribute *nvme_dev_attrs[] = {
> >   	&dev_attr_reconnect_delay.attr,
> >   	&dev_attr_fast_io_fail_tmo.attr,
> >   	&dev_attr_kato.attr,
> > +	&dev_attr_cntrltype.attr,
> > +	&dev_attr_dctype.attr,
> >   	NULL
> >   };
> >
> > diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index
> > a162f6c6da6e..e30626c00791 100644
> > --- a/drivers/nvme/host/nvme.h
> > +++ b/drivers/nvme/host/nvme.h
> > @@ -349,6 +349,9 @@ struct nvme_ctrl {
> >   	unsigned long discard_page_busy;
> >
> >   	struct nvme_fault_inject fault_inject;
> > +
> > +	enum nvme_ctrl_type cntrltype;
> > +	enum nvme_dctype dctype;
> >   };
> >
> >   enum nvme_iopolicy {
> > diff --git a/include/linux/nvme.h b/include/linux/nvme.h index
> > 855dd9b3e84b..21e92e97ca88 100644
> > --- a/include/linux/nvme.h
> > +++ b/include/linux/nvme.h
> > @@ -43,6 +43,12 @@ enum nvme_ctrl_type {
> >   	NVME_CTRL_ADMIN	= 3,		/* Administrative controller
> */
> >   };
> >
> > +enum nvme_dctype {
> > +	NVME_DCTYPE_NOT_REPORTED	= 0,
> > +	NVME_DCTYPE_DDC			= 1, /* Direct Discovery
> Controller */
> > +	NVME_DCTYPE_CDC			= 2, /* Central Discovery
> Controller */
> > +};
> > +
> >   /* Address Family codes for Discovery Log Page entry ADRFAM field */
> >   enum {
> >   	NVMF_ADDR_FAMILY_PCI	= 0,	/* PCIe */
> > @@ -320,7 +326,9 @@ struct nvme_id_ctrl {
> >   	__le16			icdoff;
> >   	__u8			ctrattr;
> >   	__u8			msdbd;
> > -	__u8			rsvd1804[244];
> > +	__u8			rsvd1804[2];
> > +	__u8			dctype;
> > +	__u8			rsvd1807[241];
> >   	struct nvme_id_power_state	psd[32];
> >   	__u8			vs[1024];
> >   };
> >