diff options
author | Tejun Heo <tj@kernel.org> | 2008-08-25 10:56:17 (GMT) |
---|---|---|
committer | Jens Axboe <jens.axboe@oracle.com> | 2008-10-09 06:56:08 (GMT) |
commit | 3e1a7ff8a0a7b948f2684930166954f9e8e776fe (patch) | |
tree | 0a8642f5cdbc6ddfdd66dc7241c915e57b3cb7ff /drivers | |
parent | 689d6fac40b41c7bf154f362deaf442548e4dc81 (diff) | |
download | linux-fsl-qoriq-3e1a7ff8a0a7b948f2684930166954f9e8e776fe.tar.xz |
block: allow disk to have extended device number
Now that disk and partition handlings are mostly unified, it's easy to
allow disk to have extended device number. This patch makes
add_disk() use extended device number if disk->minors is zero. Both
sd and ide-disk are updated to use this.
* sd_format_disk_name() is implemented which can generically determine
the drive name. This removes disk number restriction stemming from
limited device names.
* If sd index goes over SD_MAX_DISKS (which can be increased now BTW),
sd simply doesn't initialize minors letting block layer choose
extended device number.
* If CONFIG_DEBUG_EXT_DEVT is set, both sd and ide-disk always set
minors to 0 and use extended device numbers.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/ide/ide-disk.c | 2 | ||||
-rw-r--r-- | drivers/scsi/sd.c | 74 |
2 files changed, 55 insertions, 21 deletions
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c index 29c8ae7..33ea8c0 100644 --- a/drivers/ide/ide-disk.c +++ b/drivers/ide/ide-disk.c @@ -44,7 +44,7 @@ #if !defined(CONFIG_DEBUG_BLOCK_EXT_DEVT) #define IDE_DISK_MINORS (1 << PARTN_BITS) #else -#define IDE_DISK_MINORS 1 +#define IDE_DISK_MINORS 0 #endif struct ide_disk_obj { diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 6598024..bcb04b2 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -89,7 +89,7 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_RBC); #if !defined(CONFIG_DEBUG_BLOCK_EXT_DEVT) #define SD_MINORS 16 #else -#define SD_MINORS 1 +#define SD_MINORS 0 #endif static int sd_revalidate_disk(struct gendisk *); @@ -1770,6 +1770,52 @@ static int sd_revalidate_disk(struct gendisk *disk) } /** + * sd_format_disk_name - format disk name + * @prefix: name prefix - ie. "sd" for SCSI disks + * @index: index of the disk to format name for + * @buf: output buffer + * @buflen: length of the output buffer + * + * SCSI disk names starts at sda. The 26th device is sdz and the + * 27th is sdaa. The last one for two lettered suffix is sdzz + * which is followed by sdaaa. + * + * This is basically 26 base counting with one extra 'nil' entry + * at the beggining from the second digit on and can be + * determined using similar method as 26 base conversion with the + * index shifted -1 after each digit is computed. + * + * CONTEXT: + * Don't care. + * + * RETURNS: + * 0 on success, -errno on failure. + */ +static int sd_format_disk_name(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; +} + +/** * sd_probe - called during driver initialization and whenever a * new scsi device is attached to the system. It is called once * for each scsi device (not just disks) present. @@ -1821,8 +1867,8 @@ static int sd_probe(struct device *dev) if (error) goto out_put; - error = -EBUSY; - if (index >= SD_MAX_DISKS) + error = sd_format_disk_name("sd", index, gd->disk_name, DISK_NAME_LEN); + if (error) goto out_free_index; sdkp->device = sdp; @@ -1849,24 +1895,12 @@ static int sd_probe(struct device *dev) get_device(&sdp->sdev_gendev); - gd->major = sd_major((index & 0xf0) >> 4); - gd->first_minor = ((index & 0xf) << 4) | (index & 0xfff00); - gd->minors = SD_MINORS; - gd->fops = &sd_fops; - - if (index < 26) { - sprintf(gd->disk_name, "sd%c", 'a' + index % 26); - } else if (index < (26 + 1) * 26) { - sprintf(gd->disk_name, "sd%c%c", - 'a' + index / 26 - 1,'a' + index % 26); - } else { - const unsigned int m1 = (index / 26 - 1) / 26 - 1; - const unsigned int m2 = (index / 26 - 1) % 26; - const unsigned int m3 = index % 26; - sprintf(gd->disk_name, "sd%c%c%c", - 'a' + m1, 'a' + m2, 'a' + m3); + if (index < SD_MAX_DISKS) { + gd->major = sd_major((index & 0xf0) >> 4); + gd->first_minor = ((index & 0xf) << 4) | (index & 0xfff00); + gd->minors = SD_MINORS; } - + gd->fops = &sd_fops; gd->private_data = &sdkp->driver; gd->queue = sdkp->device->request_queue; |