[PATCH 07/09] block: adjust formatting for large minors and add ext_range sysfs attr

Tejun Heo
2008-08-25T10:47:23Z

With extended minors and the soon-to-follow debug feature, large minor
numbers for block devices will be common. This patch does the
followings to make printouts pretty.

* Adapt print formats such that large minors don't break the
formatting.

* For extended MAJ:MIN, %02x%02x for MAJ:MIN used in
printk_all_partitions() doesn't cut it anymore. Update it such that
%03x:%05x is used if either MAJ or MIN doesn't fit in %02x.

* Implement ext_range sysfs attribute which shows total minors the
device can use including both conventional minor space and the
extended one.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
block/genhd.c | 47 +++++++++++++++++++++++++++++++++++------------
include/linux/fs.h | 1 +
2 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index e730dc0..93ebc6c 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -366,6 +366,18 @@ void blk_free_devt(dev_t devt)
}
}

+static char *bdevt_str(dev_t devt, char *buf)
+{
+ if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) {
+ char tbuf[BDEVT_SIZE];
+ snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt));
+ snprintf(buf, BDEVT_SIZE, "%-9s", tbuf);
+ } else
+ snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt));
+
+ return buf;
+}
+
/*
* Register device numbers dev..(dev+range-1)
* range must be nonzero
@@ -523,7 +535,8 @@ void __init printk_all_partitions(void)
struct gendisk *disk = dev_to_disk(dev);
struct disk_part_iter piter;
struct hd_struct *part;
- char buf[BDEVNAME_SIZE];
+ char name_buf[BDEVNAME_SIZE];
+ char devt_buf[BDEVT_SIZE];

/*
* Don't show empty devices or things that have been
@@ -538,10 +551,10 @@ void __init printk_all_partitions(void)
* numbers in hex - the same format as the root=
* option takes.
*/
- printk("%02x%02x %10llu %s",
- MAJOR(disk_devt(disk)), MINOR(disk_devt(disk)),
+ printk("%s %10llu %s",
+ bdevt_str(disk_devt(disk), devt_buf),
(unsigned long long)get_capacity(disk) >> 1,
- disk_name(disk, 0, buf));
+ disk_name(disk, 0, name_buf));
if (disk->driverfs_dev != NULL &&
disk->driverfs_dev->driver != NULL)
printk(" driver: %s\n",
@@ -552,10 +565,10 @@ void __init printk_all_partitions(void)
/* now show the partitions */
disk_part_iter_init(&piter, disk, 0);
while ((part = disk_part_iter_next(&piter)))
- printk(" %02x%02x %10llu %s\n",
- MAJOR(part_devt(part)), MINOR(part_devt(part)),
+ printk(" %s %10llu %s\n",
+ bdevt_str(part_devt(part), devt_buf),
(unsigned long long)part->nr_sects >> 1,
- disk_name(disk, part->partno, buf));
+ disk_name(disk, part->partno, name_buf));
disk_part_iter_exit(&piter);
}
class_dev_iter_exit(&iter);
@@ -612,7 +625,7 @@ static void *show_partition_start(struct seq_file *seqf, loff_t *pos)

p = disk_seqf_start(seqf, pos);
if (!IS_ERR(p) && p)
- seq_puts(part, "major minor #blocks name\n\n");
+ seq_puts(seqf, "major minor #blocks name\n\n");
return p;
}

@@ -631,14 +644,14 @@ static int show_partition(struct seq_file *seqf, void *v)
return 0;

/* show the full disk and all non-0 size partitions of it */
- seq_printf(seqf, "%4d %4d %10llu %s\n",
+ seq_printf(seqf, "%4d %7d %10llu %s\n",
MAJOR(disk_devt(sgp)), MINOR(disk_devt(sgp)),
(unsigned long long)get_capacity(sgp) >> 1,
disk_name(sgp, 0, buf));

disk_part_iter_init(&piter, sgp, 0);
while ((part = disk_part_iter_next(&piter)))
- seq_printf(seqf, "%4d %4d %10llu %s\n",
+ seq_printf(seqf, "%4d %7d %10llu %s\n",
MAJOR(part_devt(part)), MINOR(part_devt(part)),
(unsigned long long)part->nr_sects >> 1,
disk_name(sgp, part->partno, buf));
@@ -692,6 +705,14 @@ static ssize_t disk_range_show(struct device *dev,
return sprintf(buf, "%d\n", disk->minors);
}

+static ssize_t disk_ext_range_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+
+ return sprintf(buf, "%d\n", disk_max_parts(disk) + 1);
+}
+
static ssize_t disk_removable_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -781,6 +802,7 @@ static ssize_t disk_fail_store(struct device *dev,
#endif

static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL);
+static DEVICE_ATTR(ext_range, S_IRUGO, disk_ext_range_show, NULL);
static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL);
static DEVICE_ATTR(ro, S_IRUGO, disk_ro_show, NULL);
static DEVICE_ATTR(size, S_IRUGO, disk_size_show, NULL);
@@ -793,6 +815,7 @@ static struct device_attribute dev_attr_fail =

static struct attribute *disk_attrs[] = {
&dev_attr_range.attr,
+ &dev_attr_ext_range.attr,
&dev_attr_removable.attr,
&dev_attr_ro.attr,
&dev_attr_size.attr,
@@ -859,7 +882,7 @@ static int diskstats_show(struct seq_file *seqf, void *v)
cpu = disk_stat_lock();
disk_round_stats(cpu, gp);
disk_stat_unlock();
- seq_printf(seqf, "%4d %4d %s %lu %lu %llu %u %lu %lu %llu %u %u %u %u\n",
+ seq_printf(seqf, "%4d %7d %s %lu %lu %llu %u %lu %lu %llu %u %u %u %u\n",
MAJOR(disk_devt(gp)), MINOR(disk_devt(gp)),
disk_name(gp, 0, buf),
disk_stat_read(gp, ios[0]), disk_stat_read(gp, merges[0]),
@@ -878,7 +901,7 @@ static int diskstats_show(struct seq_file *seqf, void *v)
cpu = disk_stat_lock();
part_round_stats(cpu, hd);
disk_stat_unlock();
- seq_printf(seqf, "%4d %4d %s %lu %lu %llu "
+ seq_printf(seqf, "%4d %7d %s %lu %lu %llu "
"%u %lu %lu %llu %u %u %u %u\n",
MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
disk_name(gp, hd->partno, buf),
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 860689f..02a9fb5 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1685,6 +1685,7 @@ extern void chrdev_show(struct seq_file *,off_t);

/* fs/block_dev.c */
#define BDEVNAME_SIZE 32 /* Largest string for a blockdev identifier */
+#define BDEVT_SIZE 10 /* Largest string for MAJ:MIN for blkdev */

#ifdef CONFIG_BLOCK
#define BLKDEV_MAJOR_HASH_SIZE 255
--
1.5.4.5