On 05/07/2015 10:26 AM, Christoph Hellwig wrote:
On Mon, May 04, 2015 at 10:43:01AM -0600, Ross Zwisler wrote:
>> Yes, if CONFIG_DEBUG_BLOCK_EXT_DEVT isn't set that code doesn't work at
> I can't figure out a use case that breaks when using dynamically allocated
> minors without CONFIG_DEBUG_BLOCK_EXT_DEVT. The patch that I've been testing
> against is at the bottom of this mail.
> Here are the minors that I get when creating a bunch of partitions using the
> current code with PMEM_MINORS=16, with CONFIG_DEBUG_BLOCK_EXT_DEVT turned off:
FYI, your patch below works fine for me, but the original one certainly
didn't. One big difference was that it also removed the register_blkdev
call and thus assigning a major number.
assigning a major number for what?
That "assigned major number" is then never used *anywhere* in the code at all
until it is unregistered. All the devices come up with the dynamic (259) major
the register_blkdev is just dead code. I have experimented with this a lot,
I have audited the all code stack, that major is never used, when doing the:
disk->flags |= GENHD_FL_EXT_DEVT
disk->major = X
Is completely ignored and is immediately over written. The only relic of that
major registration is the pmem_major global member collecting dust.
Sigh, bad habits die hard, I don't really care you can keep it. Sorry for