On 16/7/21 7:00 am, Miquel Raynal wrote:

Hello,

Desmond Cheong Zhi Xi [off-list ref] wrote on Mon, 12 Jul
2021 16:29:16 +0800:

quoted

On 12/7/21 1:27 pm, Christoph Hellwig wrote:

quoted

On Sat, Jul 10, 2021 at 09:16:38PM +0800, Hillf Danton wrote:

quoted

To break the lock chain, un/register blkdev without mtd_table_mutex held.

Yes, Desmond Cheong Zhi Xi sent pretty much the same patch on June 18th
(mtd: break circular locks in register_mtd_blktrans), but it did not get
picked up.
   

I believe Miquèl was waiting for -rc1 to apply it.

Indeed, I already applied it but did not advertise yet.

Thanks Miquèl!

quoted

But taking a closer look, although the fix for the register path is the same, Hillf Danton's proposed patch additionally avoids inverting the lock hierarchy on the unregister path. So I believe this new patch should be more robust.

We can definitely do this in two steps if you want.

Sounds good, I'll prepare a patch with Hillf's suggestion for the 
unregister path.

Thanks,
Miquèl