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Commit 8892cbaf authored by Namhyung Kim's avatar Namhyung Kim Committed by Jens Axboe
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brd: export module parameters 



Export 'rd_nr', 'rd_size' and 'max_part' parameters to sysfs so user can
know that how many devices are allowed, how big each device is and how
many partitions are supported. If 'max_part' is 0, it means simply the
device doesn't support partitioning.

Also note that 'max_part' can be adjusted to power of 2 minus 1 form if
needed. User should check this value after the module loading if he/she
want to use that number correctly (i.e. fdisk, mknod, etc.).

Signed-off-by: default avatarNamhyung Kim <namhyung@gmail.com>
Cc: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
parent 13868b76

drivers/block/brd.c

+15 −4
Original line number Diff line number Diff line
@@ -436,11 +436,11 @@ static int rd_nr; 
int rd_size = CONFIG_BLK_DEV_RAM_SIZE;

static int max_part;

static int part_shift;

module_param(rd_nr, int, 0);

module_param(rd_nr, int, S_IRUGO);

MODULE_PARM_DESC(rd_nr, "Maximum number of brd devices");

module_param(rd_size, int, 0);

module_param(rd_size, int, S_IRUGO);

MODULE_PARM_DESC(rd_size, "Size of each RAM disk in kbytes.");

module_param(max_part, int, 0);

module_param(max_part, int, S_IRUGO);

MODULE_PARM_DESC(max_part, "Maximum number of partitions per RAM disk");

MODULE_LICENSE("GPL");

MODULE_ALIAS_BLOCKDEV_MAJOR(RAMDISK_MAJOR);
@@ -578,9 +578,20 @@ static int __init brd_init(void) 
	 */



	part_shift = 0;

	if (max_part > 0)

	if (max_part > 0) {

		part_shift = fls(max_part);



		/*

		 * Adjust max_part according to part_shift as it is exported

		 * to user space so that user can decide correct minor number

		 * if [s]he want to create more devices.

		 *

		 * Note that -1 is required because partition 0 is reserved

		 * for the whole disk.

		 */

		max_part = (1UL << part_shift) - 1;

	}



	if ((1UL << part_shift) > DISK_MAX_PARTS)

		return -EINVAL;