block: don't depend on consecutive minor space
* Implement disk_devt() and part_devt() and use them to directly
access devt instead of computing it from ->major and ->first_minor.
Note that all references to ->major and ->first_minor outside of
block layer is used to determine devt of the disk (the part0) and as
->major and ->first_minor will continue to represent devt for the
disk, converting these users aren't strictly necessary. However,
convert them for consistency.
* Implement disk_max_parts() to avoid directly deferencing
genhd->minors.
* Update bdget_disk() such that it doesn't assume consecutive minor
space.
* Move devt computation from register_disk() to add_disk() and make it
the only one (all other usages use the initially determined value).
These changes clean up the code and will help disk->part dereference
fix and extended block device numbers.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/genhd.c b/block/genhd.c
index dc9ad4c..fa32d09 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -186,13 +186,14 @@
int retval;
disk->flags |= GENHD_FL_UP;
- blk_register_region(MKDEV(disk->major, disk->first_minor),
- disk->minors, NULL, exact_match, exact_lock, disk);
+ disk->dev.devt = MKDEV(disk->major, disk->first_minor);
+ blk_register_region(disk_devt(disk), disk->minors, NULL,
+ exact_match, exact_lock, disk);
register_disk(disk);
blk_register_queue(disk);
bdi = &disk->queue->backing_dev_info;
- bdi_register_dev(bdi, MKDEV(disk->major, disk->first_minor));
+ bdi_register_dev(bdi, disk_devt(disk));
retval = sysfs_create_link(&disk->dev.kobj, &bdi->dev->kobj, "bdi");
WARN_ON(retval);
}
@@ -205,8 +206,7 @@
sysfs_remove_link(&disk->dev.kobj, "bdi");
bdi_unregister(&disk->queue->backing_dev_info);
blk_unregister_queue(disk);
- blk_unregister_region(MKDEV(disk->major, disk->first_minor),
- disk->minors);
+ blk_unregister_region(disk_devt(disk), disk->minors);
}
/**
@@ -225,6 +225,38 @@
return kobj ? dev_to_disk(dev) : NULL;
}
+/**
+ * bdget_disk - do bdget() by gendisk and partition number
+ * @disk: gendisk of interest
+ * @partno: partition number
+ *
+ * Find partition @partno from @disk, do bdget() on it.
+ *
+ * CONTEXT:
+ * Don't care.
+ *
+ * RETURNS:
+ * Resulting block_device on success, NULL on failure.
+ */
+extern struct block_device *bdget_disk(struct gendisk *disk, int partno)
+{
+ dev_t devt = MKDEV(0, 0);
+
+ if (partno == 0)
+ devt = disk_devt(disk);
+ else {
+ struct hd_struct *part = disk->part[partno - 1];
+
+ if (part && part->nr_sects)
+ devt = part_devt(part);
+ }
+
+ if (likely(devt != MKDEV(0, 0)))
+ return bdget(devt);
+ return NULL;
+}
+EXPORT_SYMBOL(bdget_disk);
+
/*
* print a full list of all partitions - intended for places where the root
* filesystem can't be mounted and thus to give the victim some idea of what
@@ -255,7 +287,7 @@
* option takes.
*/
printk("%02x%02x %10llu %s",
- disk->major, disk->first_minor,
+ MAJOR(disk_devt(disk)), MINOR(disk_devt(disk)),
(unsigned long long)get_capacity(disk) >> 1,
disk_name(disk, 0, buf));
if (disk->driverfs_dev != NULL &&
@@ -266,15 +298,15 @@
printk(" (driver?)\n");
/* now show the partitions */
- for (n = 0; n < disk->minors - 1; ++n) {
- if (disk->part[n] == NULL)
- continue;
- if (disk->part[n]->nr_sects == 0)
+ for (n = 0; n < disk_max_parts(disk); ++n) {
+ struct hd_struct *part = disk->part[n];
+
+ if (!part || !part->nr_sects)
continue;
printk(" %02x%02x %10llu %s\n",
- disk->major, n + 1 + disk->first_minor,
- (unsigned long long)disk->part[n]->nr_sects >> 1,
- disk_name(disk, n + 1, buf));
+ MAJOR(part_devt(part)), MINOR(part_devt(part)),
+ (unsigned long long)part->nr_sects >> 1,
+ disk_name(disk, part->partno, buf));
}
}
class_dev_iter_exit(&iter);
@@ -343,26 +375,27 @@
char buf[BDEVNAME_SIZE];
/* Don't show non-partitionable removeable devices or empty devices */
- if (!get_capacity(sgp) ||
- (sgp->minors == 1 && (sgp->flags & GENHD_FL_REMOVABLE)))
+ if (!get_capacity(sgp) || (!disk_max_parts(sgp) &&
+ (sgp->flags & GENHD_FL_REMOVABLE)))
return 0;
if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
return 0;
/* show the full disk and all non-0 size partitions of it */
seq_printf(seqf, "%4d %4d %10llu %s\n",
- sgp->major, sgp->first_minor,
+ MAJOR(disk_devt(sgp)), MINOR(disk_devt(sgp)),
(unsigned long long)get_capacity(sgp) >> 1,
disk_name(sgp, 0, buf));
- for (n = 0; n < sgp->minors - 1; n++) {
- if (!sgp->part[n])
+ for (n = 0; n < disk_max_parts(sgp); n++) {
+ struct hd_struct *part = sgp->part[n];
+ if (!part)
continue;
- if (sgp->part[n]->nr_sects == 0)
+ if (part->nr_sects == 0)
continue;
seq_printf(seqf, "%4d %4d %10llu %s\n",
- sgp->major, n + 1 + sgp->first_minor,
- (unsigned long long)sgp->part[n]->nr_sects >> 1 ,
- disk_name(sgp, n + 1, buf));
+ MAJOR(part_devt(part)), MINOR(part_devt(part)),
+ (unsigned long long)part->nr_sects >> 1,
+ disk_name(sgp, part->partno, buf));
}
return 0;
@@ -578,7 +611,8 @@
disk_round_stats(gp);
preempt_enable();
seq_printf(seqf, "%4d %4d %s %lu %lu %llu %u %lu %lu %llu %u %u %u %u\n",
- gp->major, gp->first_minor, disk_name(gp, 0, buf),
+ 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]),
(unsigned long long)disk_stat_read(gp, sectors[0]),
jiffies_to_msecs(disk_stat_read(gp, ticks[0])),
@@ -590,7 +624,7 @@
jiffies_to_msecs(disk_stat_read(gp, time_in_queue)));
/* now show all non-0 size partitions of it */
- for (n = 0; n < gp->minors - 1; n++) {
+ for (n = 0; n < disk_max_parts(gp); n++) {
struct hd_struct *hd = gp->part[n];
if (!hd || !hd->nr_sects)
@@ -601,8 +635,8 @@
preempt_enable();
seq_printf(seqf, "%4d %4d %s %lu %lu %llu "
"%u %lu %lu %llu %u %u %u %u\n",
- gp->major, n + gp->first_minor + 1,
- disk_name(gp, n + 1, buf),
+ MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
+ disk_name(gp, hd->partno, buf),
part_stat_read(hd, ios[0]),
part_stat_read(hd, merges[0]),
(unsigned long long)part_stat_read(hd, sectors[0]),
@@ -661,11 +695,22 @@
while ((dev = class_dev_iter_next(&iter))) {
struct gendisk *disk = dev_to_disk(dev);
- if (!strcmp(dev->bus_id, name) && partno < disk->minors) {
- devt = MKDEV(MAJOR(dev->devt),
- MINOR(dev->devt) + partno);
- break;
+ if (strcmp(dev->bus_id, name))
+ continue;
+ if (partno < 0 || partno > disk_max_parts(disk))
+ continue;
+
+ if (partno == 0)
+ devt = disk_devt(disk);
+ else {
+ struct hd_struct *part = disk->part[partno - 1];
+
+ if (!part || !part->nr_sects)
+ continue;
+
+ devt = part_devt(part);
}
+ break;
}
class_dev_iter_exit(&iter);
return devt;
@@ -755,7 +800,7 @@
{
int i;
disk->policy = flag;
- for (i = 0; i < disk->minors - 1; i++)
+ for (i = 0; i < disk_max_parts(disk); i++)
if (disk->part[i]) disk->part[i]->policy = flag;
}
diff --git a/block/ioctl.c b/block/ioctl.c
index d77f5e2..403f7d7e 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -29,7 +29,7 @@
if (bdev != bdev->bd_contains)
return -EINVAL;
partno = p.pno;
- if (partno <= 0 || partno >= disk->minors)
+ if (partno <= 0 || partno > disk_max_parts(disk))
return -EINVAL;
switch (a.op) {
case BLKPG_ADD_PARTITION:
@@ -47,7 +47,7 @@
mutex_lock(&bdev->bd_mutex);
/* overlap? */
- for (i = 0; i < disk->minors - 1; i++) {
+ for (i = 0; i < disk_max_parts(disk); i++) {
struct hd_struct *s = disk->part[i];
if (!s)
@@ -96,7 +96,7 @@
struct gendisk *disk = bdev->bd_disk;
int res;
- if (disk->minors == 1 || bdev != bdev->bd_contains)
+ if (!disk_max_parts(disk) || bdev != bdev->bd_contains)
return -EINVAL;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 29b7a64..e1a90bb 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2911,7 +2911,7 @@
if (!disk->queue)
goto out_mem2;
- pd->pkt_dev = MKDEV(disk->major, disk->first_minor);
+ pd->pkt_dev = MKDEV(pktdev_major, idx);
ret = pkt_new_dev(pd, dev);
if (ret)
goto out_new_dev;
diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c
index 4b0d6c7..936466f 100644
--- a/drivers/block/ps3disk.c
+++ b/drivers/block/ps3disk.c
@@ -541,7 +541,7 @@
struct ps3disk_private *priv = dev->sbd.core.driver_data;
mutex_lock(&ps3disk_mask_mutex);
- __clear_bit(priv->gendisk->first_minor / PS3DISK_MINORS,
+ __clear_bit(MINOR(disk_devt(priv->gendisk)) / PS3DISK_MINORS,
&ps3disk_mask);
mutex_unlock(&ps3disk_mask_mutex);
del_gendisk(priv->gendisk);
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 7ce1ac4..6af435b 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -661,10 +661,10 @@
if (!disk || !disk->random)
return;
/* first major is 1, so we get >= 0x200 here */
- DEBUG_ENT("disk event %d:%d\n", disk->major, disk->first_minor);
+ DEBUG_ENT("disk event %d:%d\n",
+ MAJOR(disk_devt(disk)), MINOR(disk_devt(disk)));
- add_timer_randomness(disk->random,
- 0x100 + MKDEV(disk->major, disk->first_minor));
+ add_timer_randomness(disk->random, 0x100 + disk_devt(disk));
}
#endif
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index b262c00..c3de311 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -426,7 +426,7 @@
old_nl->next = (uint32_t) ((void *) nl -
(void *) old_nl);
disk = dm_disk(hc->md);
- nl->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
+ nl->dev = huge_encode_dev(disk_devt(disk));
nl->next = 0;
strcpy(nl->name, hc->name);
@@ -539,7 +539,7 @@
if (dm_suspended(md))
param->flags |= DM_SUSPEND_FLAG;
- param->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
+ param->dev = huge_encode_dev(disk_devt(disk));
/*
* Yes, this will be out of date by the time it gets back
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index 4de90ab..b745d8a 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -284,8 +284,8 @@
memset(major_minor, 0, sizeof(major_minor));
sprintf(major_minor, "%d:%d",
- bio->bi_bdev->bd_disk->major,
- bio->bi_bdev->bd_disk->first_minor);
+ MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
+ MINOR(disk_devt(bio->bi_bdev->bd_disk)));
/*
* Test to see which stripe drive triggered the event
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index ace998c..a78caad 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1146,7 +1146,7 @@
static void free_dev(struct mapped_device *md)
{
- int minor = md->disk->first_minor;
+ int minor = MINOR(disk_devt(md->disk));
if (md->suspended_bdev) {
unlock_fs(md);
@@ -1267,7 +1267,7 @@
md = idr_find(&_minor_idr, minor);
if (md && (md == MINOR_ALLOCED ||
- (dm_disk(md)->first_minor != minor) ||
+ (MINOR(disk_devt(dm_disk(md))) != minor) ||
test_bit(DMF_FREEING, &md->flags))) {
md = NULL;
goto out;
@@ -1318,7 +1318,8 @@
if (atomic_dec_and_lock(&md->holders, &_minor_lock)) {
map = dm_get_table(md);
- idr_replace(&_minor_idr, MINOR_ALLOCED, dm_disk(md)->first_minor);
+ idr_replace(&_minor_idr, MINOR_ALLOCED,
+ MINOR(disk_devt(dm_disk(md))));
set_bit(DMF_FREEING, &md->flags);
spin_unlock(&_minor_lock);
if (!dm_suspended(md)) {
diff --git a/drivers/memstick/core/mspro_block.c b/drivers/memstick/core/mspro_block.c
index d2d2318..82bf649 100644
--- a/drivers/memstick/core/mspro_block.c
+++ b/drivers/memstick/core/mspro_block.c
@@ -197,7 +197,7 @@
static int mspro_block_disk_release(struct gendisk *disk)
{
struct mspro_block_data *msb = disk->private_data;
- int disk_id = disk->first_minor >> MSPRO_BLOCK_PART_SHIFT;
+ int disk_id = MINOR(disk_devt(disk)) >> MSPRO_BLOCK_PART_SHIFT;
mutex_lock(&mspro_block_disk_lock);
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index ebc8b9d..97156b6 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -83,7 +83,7 @@
mutex_lock(&open_lock);
md->usage--;
if (md->usage == 0) {
- int devidx = md->disk->first_minor >> MMC_SHIFT;
+ int devidx = MINOR(disk_devt(md->disk)) >> MMC_SHIFT;
__clear_bit(devidx, dev_use);
put_disk(md->disk);
diff --git a/drivers/s390/block/dasd_proc.c b/drivers/s390/block/dasd_proc.c
index 03c0e40..e3b5c4d 100644
--- a/drivers/s390/block/dasd_proc.c
+++ b/drivers/s390/block/dasd_proc.c
@@ -76,7 +76,8 @@
/* Print kdev. */
if (block->gdp)
seq_printf(m, " at (%3d:%6d)",
- block->gdp->major, block->gdp->first_minor);
+ MAJOR(disk_devt(block->gdp)),
+ MINOR(disk_devt(block->gdp)));
else
seq_printf(m, " at (???:??????)");
/* Print device name. */
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index 711b300..9481e4a 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -114,7 +114,7 @@
found = 0;
// test if minor available
list_for_each_entry(entry, &dcssblk_devices, lh)
- if (minor == entry->gd->first_minor)
+ if (minor == MINOR(disk_devt(entry->gd)))
found++;
if (!found) break; // got unused minor
}
@@ -397,7 +397,7 @@
goto unload_seg;
}
sprintf(dev_info->gd->disk_name, "dcssblk%d",
- dev_info->gd->first_minor);
+ MINOR(disk_devt(dev_info->gd)));
list_add_tail(&dev_info->lh, &dcssblk_devices);
if (!try_module_get(THIS_MODULE)) {
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 27f5bfd..8dbe379 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -878,7 +878,7 @@
struct gendisk *disk = cd->disk;
spin_lock(&sr_index_lock);
- clear_bit(disk->first_minor, sr_index_bits);
+ clear_bit(MINOR(disk_devt(disk)), sr_index_bits);
spin_unlock(&sr_index_lock);
unregister_cdrom(&cd->cdi);
diff --git a/fs/block_dev.c b/fs/block_dev.c
index de0776c..72e0a28 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -892,7 +892,7 @@
if (bdops->revalidate_disk)
bdops->revalidate_disk(bdev->bd_disk);
- if (bdev->bd_disk->minors > 1)
+ if (disk_max_parts(bdev->bd_disk))
bdev->bd_invalidated = 1;
return 1;
}
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index b86aab1..e77fa14 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -134,7 +134,11 @@
const char *bdevname(struct block_device *bdev, char *buf)
{
- int partno = MINOR(bdev->bd_dev) - bdev->bd_disk->first_minor;
+ int partno = 0;
+
+ if (bdev->bd_part)
+ partno = bdev->bd_part->partno;
+
return disk_name(bdev->bd_disk, partno, buf);
}
@@ -169,7 +173,7 @@
if (isdigit(state->name[strlen(state->name)-1]))
sprintf(state->name, "p");
- state->limit = hd->minors;
+ state->limit = disk_max_parts(hd) + 1;
i = res = err = 0;
while (!res && check_part[i]) {
memset(&state->parts, 0, sizeof(state->parts));
@@ -416,7 +420,6 @@
int err;
disk->dev.parent = disk->driverfs_dev;
- disk->dev.devt = MKDEV(disk->major, disk->first_minor);
strlcpy(disk->dev.bus_id, disk->disk_name, BUS_ID_SIZE);
/* ewww... some of these buggers have / in the name... */
@@ -440,7 +443,7 @@
disk_sysfs_add_subdirs(disk);
/* No minors to use for partitions */
- if (disk->minors == 1)
+ if (!disk_max_parts(disk))
goto exit;
/* No such device (e.g., media were just removed) */
@@ -463,8 +466,8 @@
kobject_uevent(&disk->dev.kobj, KOBJ_ADD);
/* announce possible partitions */
- for (i = 1; i < disk->minors; i++) {
- p = disk->part[i-1];
+ for (i = 0; i < disk_max_parts(disk); i++) {
+ p = disk->part[i];
if (!p || !p->nr_sects)
continue;
kobject_uevent(&p->dev.kobj, KOBJ_ADD);
@@ -482,7 +485,7 @@
if (res)
return res;
bdev->bd_invalidated = 0;
- for (p = 1; p < disk->minors; p++)
+ for (p = 1; p <= disk_max_parts(disk); p++)
delete_partition(disk, p);
if (disk->fops->revalidate_disk)
disk->fops->revalidate_disk(disk);
@@ -545,7 +548,7 @@
int p;
/* invalidate stuff */
- for (p = disk->minors - 1; p > 0; p--) {
+ for (p = disk_max_parts(disk); p > 0; p--) {
invalidate_partition(disk, p);
delete_partition(disk, p);
}
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index d1723c0..0ff7532 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -111,10 +111,14 @@
#define GENHD_FL_FAIL 64
struct gendisk {
+ /* major, first_minor and minors are input parameters only,
+ * don't use directly. Use disk_devt() and disk_max_parts().
+ */
int major; /* major number of driver */
int first_minor;
int minors; /* maximum number of minors, =1 for
* disks that can't be partitioned. */
+
char disk_name[32]; /* name of major driver */
struct hd_struct **part; /* [indexed by minor - 1] */
struct block_device_operations *fops;
@@ -152,6 +156,21 @@
return NULL;
}
+static inline int disk_max_parts(struct gendisk *disk)
+{
+ return disk->minors - 1;
+}
+
+static inline dev_t disk_devt(struct gendisk *disk)
+{
+ return disk->dev.devt;
+}
+
+static inline dev_t part_devt(struct hd_struct *part)
+{
+ return part->dev.devt;
+}
+
/*
* Macros to operate on percpu disk statistics:
*
@@ -163,7 +182,7 @@
{
struct hd_struct *part;
int i;
- for (i = 0; i < gendiskp->minors - 1; i++) {
+ for (i = 0; i < disk_max_parts(gendiskp); i++) {
part = gendiskp->part[i];
if (part && part->start_sect <= sector
&& sector < part->start_sect + part->nr_sects)
@@ -366,6 +385,7 @@
extern void del_gendisk(struct gendisk *gp);
extern void unlink_gendisk(struct gendisk *gp);
extern struct gendisk *get_gendisk(dev_t dev, int *partno);
+extern struct block_device *bdget_disk(struct gendisk *disk, int partno);
extern void set_device_ro(struct block_device *bdev, int flag);
extern void set_disk_ro(struct gendisk *disk, int flag);
@@ -553,11 +573,6 @@
void *data);
extern void blk_unregister_region(dev_t devt, unsigned long range);
-static inline struct block_device *bdget_disk(struct gendisk *disk, int partno)
-{
- return bdget(MKDEV(disk->major, disk->first_minor) + partno);
-}
-
#else /* CONFIG_BLOCK */
static inline void printk_all_partitions(void) { }