Messages in this thread | | | Subject | Re: [PATCH] loop: export module parameters | From | Namhyung Kim <> | Date | Fri, 27 May 2011 13:57:38 +0900 |
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2011-05-25 (수), 14:44 +0900, Namhyung Kim: > Export 'max_loop' and 'max_part' parameters to sysfs so user can know > that how many devices are allowed and how many partitions are supported. > > If 'max_loop' is 0, there is no restriction on the number of loop devices. > User can create/use the devices as many as minor numbers available. 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: Namhyung Kim <namhyung@gmail.com> > Cc: Laurent Vivier <Laurent.Vivier@bull.net> > --- > drivers/block/loop.c | 17 ++++++++++++++--- > 1 files changed, 14 insertions(+), 3 deletions(-) > > diff --git a/drivers/block/loop.c b/drivers/block/loop.c > index c59a672a3de0..76c8da78212b 100644 > --- a/drivers/block/loop.c > +++ b/drivers/block/loop.c > @@ -1540,9 +1540,9 @@ static const struct block_device_operations lo_fops = { > * And now the modules code and kernel interface. > */ > static int max_loop; > -module_param(max_loop, int, 0); > +module_param(max_loop, int, S_IRUGO); > MODULE_PARM_DESC(max_loop, "Maximum number of loop devices"); > -module_param(max_part, int, 0); > +module_param(max_part, int, S_IRUGO); > MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device"); > MODULE_LICENSE("GPL"); > MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR); > @@ -1688,9 +1688,20 @@ static int __init loop_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; >
Hi Jens,
Could you please consider applying this in your tree too? It's exactly the same thing what I did for brd series.
Thanks.
-- Regards, Namhyung Kim
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