Commit d27769ec authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

block: add GENHD_FL_NO_PART_SCAN 



There are cases where suppressing partition scan is useful - e.g. for
lo devices and pseudo SATA devices which advertise to be a disk but
get upset on partition scan (some port multiplier control devices show
such behavior).

This patch adds GENHD_FL_NO_PART_SCAN which suppresses partition scan
regardless of the number of possible partitions.  disk_partitionable()
is renamed to disk_part_scan_enabled() as suppressing partition scan
doesn't imply the device can't be partitioned using
BLKPG_ADD/DEL_PARTITION calls from userland.  show_partition() now
directly tests disk_max_parts() to maintain backward-compatibility.

-v2: Updated to make it clear that only partition scan is suppressed
     not partitioning itself as suggested by Kay Sievers.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
parent 322a8b03

block/genhd.c

+2 −2
Original line number Diff line number Diff line
@@ -536,7 +536,7 @@ void register_disk(struct gendisk *disk) 
	disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);



	/* No minors to use for partitions */

	if (!disk_partitionable(disk))

	if (!disk_part_scan_enabled(disk))

		goto exit;



	/* No such device (e.g., media were just removed) */
@@ -841,7 +841,7 @@ 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) || (!disk_partitionable(sgp) &&

	if (!get_capacity(sgp) || (!disk_max_parts(sgp) &&

				   (sgp->flags & GENHD_FL_REMOVABLE)))

		return 0;

	if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)

block/ioctl.c

+1 −1
Original line number Diff line number Diff line
@@ -101,7 +101,7 @@ static int blkdev_reread_part(struct block_device *bdev) 
	struct gendisk *disk = bdev->bd_disk;

	int res;



	if (!disk_partitionable(disk) || bdev != bdev->bd_contains)

	if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)

		return -EINVAL;

	if (!capable(CAP_SYS_ADMIN))

		return -EACCES;

fs/block_dev.c

+1 −1
Original line number Diff line number Diff line
@@ -971,7 +971,7 @@ static void flush_disk(struct block_device *bdev, bool kill_dirty) 


	if (!bdev->bd_disk)

		return;

	if (disk_partitionable(bdev->bd_disk))

	if (disk_part_scan_enabled(bdev->bd_disk))

		bdev->bd_invalidated = 1;

}

include/linux/genhd.h

+4 −2
Original line number Diff line number Diff line
@@ -128,6 +128,7 @@ struct hd_struct { 
#define GENHD_FL_EXT_DEVT			64 /* allow extended devt */

#define GENHD_FL_NATIVE_CAPACITY		128

#define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE	256

#define GENHD_FL_NO_PART_SCAN			512



enum {

	DISK_EVENT_MEDIA_CHANGE			= 1 << 0, /* media changed */
@@ -234,9 +235,10 @@ static inline int disk_max_parts(struct gendisk *disk) 
	return disk->minors;

}



static inline bool disk_partitionable(struct gendisk *disk)

static inline bool disk_part_scan_enabled(struct gendisk *disk)

{

	return disk_max_parts(disk) > 1;

	return disk_max_parts(disk) > 1 &&

		!(disk->flags & GENHD_FL_NO_PART_SCAN);

}



static inline dev_t disk_devt(struct gendisk *disk)

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