Re: [PATCHv8 00/10] scsi: EH rework, main part

[Niklas Cassel <cassel@kernel.org>]

Hello Hannes,

On Tue, Nov 05, 2024 at 04:22:40PM +0100, Hannes Reinecke wrote:
> On 11/5/24 10:10, Niklas Cassel wrote:
> > Hello Hannes,
> > 
> > On Mon, Oct 23, 2023 at 11:28:27AM +0200, Hannes Reinecke wrote:
> > > Hi all,
> > > 
> > > (taking up an old thread:)
> > > here's now the main part of my EH rework.
> > > It modifies the reset callbacks for SCSI EH such that
> > > each callback (eh_host_reset_handler, eh_bus_reset_handler,
> > > eh_target_reset_handler, eh_device_reset_handler) only
> > > references the actual entity it needs to work on
> > > (ie 'Scsi_Host', (scsi bus), 'scsi_target', 'scsi_device'),
> > > and the 'struct scsi_cmnd' is dropped from the argument list.
> > > This simplifies the handler themselves as they don't need to
> > > exclude some 'magic' command, and we don't need to allocate
> > > a mock 'struct scsi_cmnd' when issuing a reset via SCSI ioctl.
> > > 
> > > The entire patchset can be found at:
> > > 
> > > https://git.kernel.org/pub/scm/linux/kernel/git/hare/scsi-devel.git
> > > branch eh-rework.v8
> > > 
> > > As usual, comments and reviews are welcome.
> > 
> > This seems to be the latest version of your EH rework.
> > 
> > Do you have any plans to send a v9?
> > 
> Weelll ... I didn't really proceed with that, as that requires
> for some LLDDs to set a side a command tag for TMF.
> 
> It was relatively easy pre-multiqueue times (where you could just
> reduce max_commands by 1), but for blk-mq that now longer works.
> 
> We need to do some really cumbersome things (just look at fnic ...)
> and I hoped I could get the 'reserved commands for TMF' patchset
> in first, so then this one would be easy.

I see, I didn't realize that the series had outstanding dependencies.


For anyone else looking for the actual series in lore, here there are:

EH rework prep patches, part 1:
https://lore.kernel.org/linux-scsi/20231002154328.43718-1-hare@suse.de/
- This series has been merged by Martin, and was included in v6.7.

EH rework prep patches, part 2:
https://lore.kernel.org/linux-scsi/20231023091507.120828-1-hare@suse.de/
- This series has not been merged, and is most likely the
  'reserved commands for TMF' series that Hannes is referring to.

EH rework, main part (or part 3):
https://lore.kernel.org/linux-scsi/20231023092837.33786-1-hare@suse.de/
- Depends on part 2 (which has not been merged yet).


> 
> Alas, this hasn't happened, and so I didn't continue on that work.
> But I'll see if I can resurrect it.