From 5988ce239682854d4e632fb58bff000700830394 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Sat, 28 May 2011 14:44:46 +0200 Subject: [PATCH] nbd: adjust 'max_part' according to part_shift The 'max_part' parameter determines how many partitions are supported on each nbd device. However the actual number can be changed to the power of 2 minus 1 form during the module initialization as alloc_disk() is called with (1 << part_shift) for some reason. So adjust 'max_part' also at least for consistency with loop and brd. It is exported via sysfs already, and a user should check this value after module loading if [s]he wants to use that number correctly (i.e. fdisk or something). Signed-off-by: Namhyung Kim Cc: Laurent Vivier Cc: Paul Clements Signed-off-by: Jens Axboe --- drivers/block/nbd.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index fdee7567fd15..f533f3375e24 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -754,9 +754,20 @@ static int __init nbd_init(void) return -ENOMEM; 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 know the max number of + * partition kernel should be able to manage. + * + * 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; -- 2.20.1