[PATCH v2 14/30] cxlflash: Fix to avoid stall while waiting on TMF

[Matthew R. Ochs]

> On Sep 21, 2015, at 1:24 PM, Brian King <brking at linux.vnet.ibm.com> wrote:
> On 09/16/2015 04:30 PM, Matthew R. Ochs wrote:
>> Borrowing the TMF waitq's spinlock causes a stall condition when
>> waiting for the TMF to complete. To remedy, introduce our own spin
>> lock to serialize TMF and use the appropriate wait services.
> 
> Can you clarify what stall condition you were seeing. Its not obvious
> to me what this fixes. Do you have soft lockup logs from the failure?

I believe we saw cascading RCU stalls.

I couldn't find any more details in my notes or development commits.
Unfortunately the logs are long gone as this was fixed in June.