Re: Trying to understand CAM (and the cciss driver)

From: Marek Zarychta <zarychtam_at_plan-b.pwste.edu.pl>
Date: Thu, 23 May 2024 13:19:55 UTC 
Dnia Thu, May 09, 2024 at 07:58:32PM +0200, Peter Eriksson napisał(a):
> Hi,
> 
> I’m trying to fix a bug in the cciss driver that has been there “forever” when using it with an HP H241 SAS HBA card. 
> The driver works fine when all (SAS, spinning rust) drives are behaving well, but when some of them are starting to go bad it often goes into spin and either hangs the kernel or panics. I’ve been trying to add instrumentation to it in order to pin-point the problem and have been attempting some workarounds (like clearing cr_complete since without that hack sometime the driver get many many non-busy repeated requests with the same “tag” and then It panics with: 
(...)
> 
> - Any suggestions? (Probably not but I thought I’d ask anyway :-)
> 

Hello Peter,

I have no suggestion but a question. Does the panic happen with
https://reviews.freebsd.org/D25155 applied ? I am using your patch from
this review with a few drives. It's handy and still builds fine on
15-CURRENT.

Cheers
 
-- 
Marek Zarychta