From: Jan Höppner 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 3e1a7ff8a0a7 ("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: Jan Höppner Reviewed-by: Stefan Haberland Signed-off-by: Stefan Haberland --- drivers/s390/block/dasd_genhd.c | 80 ++++++++++++++++++++++----------- 1 file changed, 54 insertions(+), 26 deletions(-) diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c index 28e92fad0ca1..6ee3d952412e 100644 --- a/drivers/s390/block/dasd_genhd.c +++ b/drivers/s390/block/dasd_genhd.c @@ -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); } -- 2.51.0