osdblk: a Linux block device for OSD objects

Submitted driver exports a block device of the form /dev/osdblkX,
where X is a decimal number.

It does that by mounting a stacking block device on top
of an osd object. For example, if you create a 2G object
on an OSD device, you can then use this module to present
that 2G object as a Linux block device.

See inside patch for exact documentation.

[Sitting at linux-next helped fix proper Kconfig dependency
 for this driver, thanks to Randy Dunlap]

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index 7755a5e2..cdaa3f8 100644
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -23,6 +23,7 @@
 obj-$(CONFIG_CDROM_PKTCDVD)	+= pktcdvd.o
 obj-$(CONFIG_MG_DISK)		+= mg_disk.o
 obj-$(CONFIG_SUNVDC)		+= sunvdc.o
+obj-$(CONFIG_BLK_DEV_OSD)	+= osdblk.o
 
 obj-$(CONFIG_BLK_DEV_UMEM)	+= umem.o
 obj-$(CONFIG_BLK_DEV_NBD)	+= nbd.o