On Thu, 7 Jun 2012, Randy Dunlap wrote:

on x86_64:

  CC [M]  drivers/staging/ccg/ccg.o
In file included from drivers/staging/ccg/../../usb/gadget/f_mass_storage.c:311:0,
                 from drivers/staging/ccg/ccg.c:52:
drivers/staging/ccg/../../usb/gadget/storage_common.c: In function 'fsg_lun_open':
drivers/staging/ccg/../../usb/gadget/storage_common.c:686:3: error: implicit declaration of function 'bdev_logical_block_size'
drivers/staging/ccg/../../usb/gadget/storage_common.c:687:3: error: implicit declaration of function 'blksize_bits'
In file included from drivers/staging/ccg/ccg.c:52:0:
drivers/staging/ccg/../../usb/gadget/f_mass_storage.c: In function 'fsg_main_thread':
drivers/staging/ccg/../../usb/gadget/f_mass_storage.c:2624:2: error: implicit declaration of function 'set_fs'
drivers/staging/ccg/../../usb/gadget/f_mass_storage.c:2624:2: error: implicit declaration of function 'get_ds'

The problems above are caused by the fact that 
drivers/staging/ccg/Kconfig does not make USB_G_CGG dependent on BLOCK.

In file included from drivers/staging/ccg/ccg.c:59:0:
drivers/staging/ccg/../../usb/gadget/f_fs.c: At top level:
drivers/staging/ccg/../../usb/gadget/f_fs.c:40:0: warning: "pr_vdebug" redefined
drivers/staging/ccg/../../usb/gadget/u_serial.c:138:0: note: this is the location of the previous definition

This could be fixed by adding a #ifndef guard to f_fs.c and u_serial.c.  
It's a little awkward to combine independent source files this way.

Alan Stern