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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>
This commit is contained in:
Tejun Heo 2008-09-03 09:01:48 +02:00 committed by Jens Axboe
parent cf771cb5a7
commit f331c0296f
16 changed files with 132 additions and 67 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

107
block/genhd.c
View File

@ -186,13 +186,14 @@ void add_disk(struct gendisk *disk)
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 @@ void unlink_gendisk(struct gendisk *disk)
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 @@ struct gendisk *get_gendisk(dev_t devt, int *partno)
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 @@ void __init printk_all_partitions(void)
* 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 @@ void __init printk_all_partitions(void)
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 @@ static int show_partition(struct seq_file *seqf, void *v)
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 @@ static int diskstats_show(struct seq_file *seqf, void *v)
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 @@ static int diskstats_show(struct seq_file *seqf, void *v)
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 @@ static int diskstats_show(struct seq_file *seqf, void *v)
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 @@ dev_t blk_lookup_devt(const char *name, int partno)
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 @@ void set_disk_ro(struct gendisk *disk, int flag)
{
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;
}

6
block/ioctl.c
View File

@ -29,7 +29,7 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
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 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
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 @@ static int blkdev_reread_part(struct block_device *bdev)
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;

2
drivers/block/pktcdvd.c
View File

@ -2911,7 +2911,7 @@ static int pkt_setup_dev(dev_t dev, dev_t* pkt_dev)
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;

2
drivers/block/ps3disk.c
View File

@ -541,7 +541,7 @@ static int ps3disk_remove(struct ps3_system_bus_device *_dev)
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);

6
drivers/char/random.c
View File

@ -661,10 +661,10 @@ void add_disk_randomness(struct gendisk *disk)
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

4
drivers/md/dm-ioctl.c
View File

@ -426,7 +426,7 @@ static int list_devices(struct dm_ioctl *param, size_t param_size)
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 @@ static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
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

4
drivers/md/dm-stripe.c
View File

@ -284,8 +284,8 @@ static int stripe_end_io(struct dm_target *ti, struct bio *bio,
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

7
drivers/md/dm.c
View File

@ -1146,7 +1146,7 @@ static void unlock_fs(struct mapped_device *md);
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 @@ static struct mapped_device *dm_find_md(dev_t dev)
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 @@ void dm_put(struct mapped_device *md)
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)) {

2
drivers/memstick/core/mspro_block.c
View File

@ -197,7 +197,7 @@ static int mspro_block_bd_open(struct inode *inode, struct file *filp)
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);

2
drivers/mmc/card/block.c
View File

@ -83,7 +83,7 @@ static void mmc_blk_put(struct mmc_blk_data *md)
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);

3
drivers/s390/block/dasd_proc.c
View File

@ -76,7 +76,8 @@ dasd_devices_show(struct seq_file *m, void *v)
/* 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. */

4
drivers/s390/block/dcssblk.c
View File

@ -114,7 +114,7 @@ dcssblk_assign_free_minor(struct dcssblk_dev_info *dev_info)
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 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
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)) {

2
drivers/scsi/sr.c
View File

@ -878,7 +878,7 @@ static void sr_kref_release(struct kref *kref)
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);

2
fs/block_dev.c
View File

@ -892,7 +892,7 @@ int check_disk_change(struct block_device *bdev)
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;
}

19
fs/partitions/check.c
View File

@ -134,7 +134,11 @@ char *disk_name(struct gendisk *hd, int partno, char *buf)
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 @@ check_partition(struct gendisk *hd, struct block_device *bdev)
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 @@ void register_disk(struct gendisk *disk)
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 @@ void register_disk(struct gendisk *disk)
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 @@ void register_disk(struct gendisk *disk)
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 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
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 @@ void del_gendisk(struct gendisk *disk)
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);
}

27
include/linux/genhd.h
View File

@ -111,10 +111,14 @@ struct hd_struct {
#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 @@ static inline struct gendisk *part_to_disk(struct hd_struct *part)
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 @@ static inline struct hd_struct *disk_map_sector(struct gendisk *gendiskp,
{
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 add_disk(struct gendisk *disk);
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 @@ extern void blk_register_region(dev_t devt, unsigned long range,
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) { }