On Thu, Mar 10, 2016 at 08:59:28AM +1100, NeilBrown wrote: > When alloc_disk(0) is used, the ->major number is ignored and > irrelevant. Yet several drivers register a major number anyway. > > This series of patches removes the pointless registrations. The pmem > driver also does this, but a patch has already been sent for that > driver. > > Note that I am not in a position to test these beyond simple compile > testing. > > Thanks, > NeilBrown > > > --- > > NeilBrown (4): > nvdimm/blk: don't allocate unused major device number > nvdimm/btt: don't allocate unused major device number > memstick: don't allocate unused major for ms_block > NVMe: don't allocate unused nvme_major > > > drivers/memstick/core/ms_block.c | 17 ++--------------- > drivers/nvdimm/blk.c | 18 +----------------- > drivers/nvdimm/btt.c | 19 ++----------------- > drivers/nvme/host/core.c | 16 +--------------- > 4 files changed, 6 insertions(+), 64 deletions(-)
There are several other drivers that allocate a major, but then use it for some small number of minors (1 for null_blk.c and 16 for virtio_blk.c). They both have GENHD_FL_EXT_DEVT set, so I think what happens is that after we exhaust the allocated minors they hop over to having BLOCK_EXT_MAJOR as a major and a dynamically assigned minor. It seems like these could easily be converted in the same way so they'd use BLOCK_EXT_MAJOR for their major and have a bunch of dynamically assigned minors. Does this break something I'm not seeing? Yay for this series, by the way. :)
