Commit 32ff8ce0 authored by Stefan Haberland's avatar Stefan Haberland Committed by Jens Axboe
Browse files

s390/dasd: add device ping attribute 



Add a function to check if a device is accessible.
This makes mostly sense for copy pair secondary devices but it will work
for all devices.

The sysfs attribute ping is a write only attribute and will issue a NOP
CCW to the device.
In case of success it will return zero. If the device is not accessible
it will return an error code.

Signed-off-by: default avatarStefan Haberland <sth@linux.ibm.com>
Reviewed-by: default avatarJan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20220920192616.808070-8-sth@linux.ibm.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 1fca631a

drivers/s390/block/dasd_devmap.c

+35 −0
Original line number Diff line number Diff line
@@ -2234,6 +2234,40 @@ dasd_copy_role_show(struct device *dev, 
}

static DEVICE_ATTR(copy_role, 0444, dasd_copy_role_show, NULL);



static ssize_t dasd_device_ping(struct device *dev,

				struct device_attribute *attr,

				const char *buf, size_t count)

{

	struct dasd_device *device;

	size_t rc;



	device = dasd_device_from_cdev(to_ccwdev(dev));

	if (IS_ERR(device))

		return -ENODEV;



	/*

	 * do not try during offline processing

	 * early check only

	 * the sleep_on function itself checks for offline

	 * processing again

	 */

	if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) {

		rc = -EBUSY;

		goto out;

	}

	if (!device->discipline || !device->discipline->device_ping) {

		rc = -EOPNOTSUPP;

		goto out;

	}

	rc = device->discipline->device_ping(device);

	if (!rc)

		rc = count;

out:

	dasd_put_device(device);

	return rc;

}

static DEVICE_ATTR(ping, 0200, NULL, dasd_device_ping);



#define DASD_DEFINE_ATTR(_name, _func)					\

static ssize_t dasd_##_name##_show(struct device *dev,			\

				   struct device_attribute *attr,	\
@@ -2292,6 +2326,7 @@ static struct attribute * dasd_attrs[] = { 
	&dev_attr_fc_security.attr,

	&dev_attr_copy_pair.attr,

	&dev_attr_copy_role.attr,

	&dev_attr_ping.attr,

	NULL,

};

drivers/s390/block/dasd_eckd.c

+44 −0
Original line number Diff line number Diff line
@@ -6277,6 +6277,49 @@ static int dasd_eckd_query_pprc_status(struct dasd_device *device, 
	return rc;

}



/*

 * ECKD NOP - no operation

 */

static int dasd_eckd_nop(struct dasd_device *device)

{

	struct dasd_ccw_req *cqr;

	struct ccw1 *ccw;

	int rc;



	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1, 1, device, NULL);

	if (IS_ERR(cqr)) {

		DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "%s",

				"Could not allocate NOP request");

		return PTR_ERR(cqr);

	}

	cqr->startdev = device;

	cqr->memdev = device;

	cqr->block = NULL;

	cqr->retries = 1;

	cqr->expires = 10 * HZ;



	ccw = cqr->cpaddr;

	ccw->cmd_code = DASD_ECKD_CCW_NOP;

	ccw->flags |= CCW_FLAG_SLI;



	cqr->buildclk = get_tod_clock();

	cqr->status = DASD_CQR_FILLED;



	rc = dasd_sleep_on_interruptible(cqr);

	if (rc != 0) {

		DBF_EVENT_DEVID(DBF_WARNING, device->cdev,

				"NOP failed with rc=%d\n", rc);

		rc = -EOPNOTSUPP;

	}

	dasd_sfree_request(cqr, cqr->memdev);

	return rc;

}



static int dasd_eckd_device_ping(struct dasd_device *device)

{

	return dasd_eckd_nop(device);

}



/*

 * Perform Subsystem Function - CUIR response

 */
@@ -6899,6 +6942,7 @@ static struct dasd_discipline dasd_eckd_discipline = { 
	.pprc_status = dasd_eckd_query_pprc_status,

	.pprc_enabled = dasd_eckd_pprc_enabled,

	.copy_pair_swap = dasd_eckd_copy_pair_swap,

	.device_ping = dasd_eckd_device_ping,

};



static int __init

drivers/s390/block/dasd_eckd.h

+1 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
/*****************************************************************************

 * SECTION: CCW Definitions

 ****************************************************************************/

#define DASD_ECKD_CCW_NOP		 0x03

#define DASD_ECKD_CCW_WRITE		 0x05

#define DASD_ECKD_CCW_READ		 0x06

#define DASD_ECKD_CCW_WRITE_HOME_ADDRESS 0x09

drivers/s390/block/dasd_int.h

+1 −0
Original line number Diff line number Diff line
@@ -439,6 +439,7 @@ struct dasd_discipline { 
	int (*pprc_status)(struct dasd_device *, struct	dasd_pprc_data_sc4 *);

	bool (*pprc_enabled)(struct dasd_device *);

	int (*copy_pair_swap)(struct dasd_device *, char *, char *);

	int (*device_ping)(struct dasd_device *);

};



extern struct dasd_discipline *dasd_diag_discipline_pointer;