Commit f331c029 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

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: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent cf771cb5

block/genhd.c

+76 −31
Original line number Diff line number Diff line
@@ -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;

}

block/ioctl.c

+3 −3
Original line number Diff line number Diff line
@@ -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;

drivers/block/pktcdvd.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

drivers/block/ps3disk.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

drivers/char/random.c

+3 −3
Original line number Diff line number Diff line
@@ -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

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