Commit 43198756 authored by Jan Höppner's avatar Jan Höppner Committed by Jens Axboe
Browse files

s390/dasd: Move device name formatting into separate function 



The device name formatting can be generalized and made more readable
compared to the current state. SCSI already provides a generalized way
to format many devices in the same naming scheme as DASD does, which was
introduced with commit 3e1a7ff8 ("block: allow disk to have extended
device number").

Use this much cleaner code from drivers/scsi/sd.c to handle the legacy
naming scheme in DASD as a replacement for the current implementation.

For easier error handling for the new function, move the gendisk free
portion of dasd_gendisk_free() out into a new function dasd_gd_free().

Signed-off-by: default avatarJan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: default avatarStefan Haberland <sth@linux.ibm.com>
Signed-off-by: default avatarStefan Haberland <sth@linux.ibm.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 764def9e

drivers/s390/block/dasd_genhd.c

+54 −26
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 


static unsigned int queue_depth = 32;

static unsigned int nr_hw_queues = 4;

static void dasd_gd_free(struct gendisk *gdp);



module_param(queue_depth, uint, 0444);

MODULE_PARM_DESC(queue_depth, "Default queue depth for new DASD devices");
@@ -29,6 +30,37 @@ MODULE_PARM_DESC(queue_depth, "Default queue depth for new DASD devices"); 
module_param(nr_hw_queues, uint, 0444);

MODULE_PARM_DESC(nr_hw_queues, "Default number of hardware queues for new DASD devices");



/*

 * Set device name.

 *   dasda - dasdz : 26 devices

 *   dasdaa - dasdzz : 676 devices, added up = 702

 *   dasdaaa - dasdzzz : 17576 devices, added up = 18278

 *   dasdaaaa - dasdzzzz : 456976 devices, added up = 475252

 */

static int dasd_name_format(char *prefix, int index, char *buf, int buflen)

{

	const int base = 'z' - 'a' + 1;

	char *begin = buf + strlen(prefix);

	char *end = buf + buflen;

	char *p;

	int unit;



	p = end - 1;

	*p = '\0';

	unit = base;

	do {

		if (p == begin)

			return -EINVAL;

		*--p = 'a' + (index % unit);

		index = (index / unit) - 1;

	} while (index >= 0);



	memmove(begin, p, end - p);

	memcpy(buf, prefix, strlen(prefix));



	return 0;

}



/*

 * Allocate and register gendisk structure for device.

 */
@@ -45,11 +77,13 @@ int dasd_gendisk_alloc(struct dasd_block *block) 
	};

	struct gendisk *gdp;

	struct dasd_device *base;

	int len, rc;

	unsigned int devindex;

	int rc;



	/* Make sure the minor for this device exists. */

	base = block->base;

	if (base->devindex >= DASD_PER_MAJOR)

	devindex = base->devindex;

	if (devindex >= DASD_PER_MAJOR)

		return -EBUSY;



	block->tag_set.ops = &dasd_mq_ops;
@@ -69,31 +103,17 @@ int dasd_gendisk_alloc(struct dasd_block *block) 


	/* Initialize gendisk structure. */

	gdp->major = DASD_MAJOR;

	gdp->first_minor = base->devindex << DASD_PARTN_BITS;

	gdp->first_minor = devindex << DASD_PARTN_BITS;

	gdp->minors = 1 << DASD_PARTN_BITS;

	gdp->fops = &dasd_device_operations;



	/*

	 * Set device name.

	 *   dasda - dasdz : 26 devices

	 *   dasdaa - dasdzz : 676 devices, added up = 702

	 *   dasdaaa - dasdzzz : 17576 devices, added up = 18278

	 *   dasdaaaa - dasdzzzz : 456976 devices, added up = 475252

	 */

	len = sprintf(gdp->disk_name, "dasd");

	if (base->devindex > 25) {

		if (base->devindex > 701) {

			if (base->devindex > 18277)

			        len += sprintf(gdp->disk_name + len, "%c",

					       'a'+(((base->devindex-18278)

						     /17576)%26));

			len += sprintf(gdp->disk_name + len, "%c",

				       'a'+(((base->devindex-702)/676)%26));

		}

		len += sprintf(gdp->disk_name + len, "%c",

			       'a'+(((base->devindex-26)/26)%26));

	rc = dasd_name_format("dasd", devindex, gdp->disk_name, sizeof(gdp->disk_name));

	if (rc) {

		DBF_DEV_EVENT(DBF_ERR, block->base,

			      "setting disk name failed, rc %d", rc);

		dasd_gd_free(gdp);

		return rc;

	}

	len += sprintf(gdp->disk_name + len, "%c", 'a'+(base->devindex%26));



	if (base->features & DASD_FEATURE_READONLY ||

	    test_bit(DASD_FLAG_DEVICE_RO, &base->flags))
@@ -111,15 +131,23 @@ int dasd_gendisk_alloc(struct dasd_block *block) 
	return 0;

}



/*

 * Free gendisk structure

 */

static void dasd_gd_free(struct gendisk *gd)

{

	del_gendisk(gd);

	gd->private_data = NULL;

	put_disk(gd);

}



/*

 * Unregister and free gendisk structure for device.

 */

void dasd_gendisk_free(struct dasd_block *block)

{

	if (block->gdp) {

		del_gendisk(block->gdp);

		block->gdp->private_data = NULL;

		put_disk(block->gdp);

		dasd_gd_free(block->gdp);

		block->gdp = NULL;

		blk_mq_free_tag_set(&block->tag_set);

	}