Messages in this thread | | | Date | Fri, 27 May 2011 08:59:31 -0400 | Subject | Re: [PATCH 3/3] nbd: adjust 'max_part' according to part_shift | From | Paul Clements <> |
| |
On Fri, May 27, 2011 at 2:00 AM, Namhyung Kim <namhyung@gmail.com> wrote: > 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 <namhyung@gmail.com> > Cc: Laurent Vivier <Laurent.Vivier@bull.net> > Cc: Paul Clements <Paul.Clements@steeleye.com>
Sure, looks good.
Thanks, Paul
> --- > drivers/block/nbd.c | 13 ++++++++++++- > 1 files changed, 12 insertions(+), 1 deletions(-) > > 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; > > -- > 1.7.5.2 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |