[PATCH] scsi: Export SCSI Inquiry data to sysfs

[PATCH] scsi: Export SCSI Inquiry data to sysfs

[Johannes Thumshirn]

Export the RAW SCSI Inquiry to sysfs as binfile. This way the data can be
used by userlang without the need to have and ioctl or use the sg_inq tool.

Here is an example of the provided data

linux:~ # hexdump /sys/class/scsi_device/1\:0\:0\:0/device/inquiry
0000000 8005 3205 001f 0000 4551 554d 2020 2020
0000010 4551 554d 4420 4456 522d 4d4f 2020 2020
0000020 2e32 2e33
0000024

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
---
 drivers/scsi/scsi_sysfs.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 9ad4116..5ecb65d 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -773,6 +773,29 @@ static struct bin_attribute dev_attr_vpd_##_page = {		\
 sdev_vpd_pg_attr(pg83);
 sdev_vpd_pg_attr(pg80);
 
+static ssize_t show_inquiry(struct file *filep, struct kobject *kobj,
+			    struct bin_attribute *bin_attr,
+			    char *buf, loff_t off, size_t count)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct scsi_device *sdev = to_scsi_device(dev);
+
+	if (!sdev->inquiry)
+		return -EINVAL;
+
+	return memory_read_from_buffer(buf, count, &off, sdev->inquiry,
+				       sdev->inquiry_len);
+}
+
+static struct bin_attribute dev_attr_inquiry = {
+	.attr = {
+		.name = "inquiry",
+		.mode = S_IRUGO,
+	},
+	.size = 0,
+	.read = show_inquiry,
+};
+
 static ssize_t
 show_iostat_counterbits(struct device *dev, struct device_attribute *attr,
 			char *buf)
@@ -957,6 +980,7 @@ static struct attribute *scsi_sdev_attrs[] = {
 static struct bin_attribute *scsi_sdev_bin_attrs[] = {
 	&dev_attr_vpd_pg83,
 	&dev_attr_vpd_pg80,
+	&dev_attr_inquiry,
 	NULL
 };
 static struct attribute_group scsi_sdev_attr_group = {
-- 
2.5.0

Re: [PATCH] scsi: Export SCSI Inquiry data to sysfs

[Hannes Reinecke]

On 08/13/2015 01:50 PM, Johannes Thumshirn wrote:
> Export the RAW SCSI Inquiry to sysfs as binfile. This way the data can be
> used by userlang without the need to have and ioctl or use the sg_inq tool.
> 
userland!

> Here is an example of the provided data
> 
> linux:~ # hexdump /sys/class/scsi_device/1\:0\:0\:0/device/inquiry
> 0000000 8005 3205 001f 0000 4551 554d 2020 2020
> 0000010 4551 554d 4420 4456 522d 4d4f 2020 2020
> 0000020 2e32 2e33
> 0000024
> 
> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
> ---
>  drivers/scsi/scsi_sysfs.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		               zSeries & Storage
hare@suse.de			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)

Re: [PATCH] scsi: Export SCSI Inquiry data to sysfs

[James Smart]

On 8/14/2015 2:32 AM, Hannes Reinecke wrote:
> On 08/13/2015 01:50 PM, Johannes Thumshirn wrote:
>> Export the RAW SCSI Inquiry to sysfs as binfile. This way the data can be
>> used by userlang without the need to have and ioctl or use the sg_inq tool.
>>
> userland!
>

Just be careful. There are conditions where this could be stale 
data....   LUN reconfig on an array that hasn't been rescanned by the 
mid layer yet is such a case.

Any reason you didn't have the sysfs call initiate a lun scan or send an 
inquiry so it's always valid data ?

-- james s

Re: [PATCH] scsi: Export SCSI Inquiry data to sysfs

[Hannes Reinecke]

On 08/14/2015 02:27 PM, James Smart wrote:
> On 8/14/2015 2:32 AM, Hannes Reinecke wrote:
>> On 08/13/2015 01:50 PM, Johannes Thumshirn wrote:
>>> Export the RAW SCSI Inquiry to sysfs as binfile. This way the
>>> data can be used by userlang without the need to have and ioctl or use the
>>> sg_inq tool.
>>>
>> userland!
>>
> 
> Just be careful. There are conditions where this could be stale
> data....   LUN reconfig on an array that hasn't been rescanned by
> the mid layer yet is such a case.
> 
> Any reason you didn't have the sysfs call initiate a lun scan or
> send an inquiry so it's always valid data ?
> 
Currently the SCSI stack doesn't do LUN rescanning; the only way
to recover from stale data is to remove the device and initiate
a host rescan. That's why we have tools like rescan-scsi-bus.sh etc.

We're working on moving the SCSI stack to do a LUN rescanning, but
that's still future stuff.

So this patch just displays the status quo, without any added
functionality.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		               zSeries & Storage
hare@suse.de			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)