On Wed, Jul 14, 2021 at 05:48:36PM +0100, John Garry wrote:

quoted

quoted

And that looks to solve the deadlock which I was seeing. I'm not sure on
side-effects elsewhere.

We'll test it a bit more.

In the absence of any bad reports, here is a proposal for a patch.

Comments?

Alan Stern

Hi Alan,

Sorry for not getting back to you sooner. Testing so far with the originally
proposed change [0] has not raised any issues and has solved the deadlock.

But we have a list of other problems to deal with in the RPM area related to
the LLDD/libsas, so were waiting to address all of them (or at least have a
plan) before progressing this change.

One such issue is that when we issue the link-reset which causes the device
to be lost in the test, the disk is not found again. The customer may not be
happy with this, so we're investigating solutions.

As for your change itself, I had something similar sitting on our dev
branch:

[0] https://github.com/hisilicon/kernel-dev/commit/3696ca85c1e00257c96e40154d28b936742430c4

For me, I'm happy to hold off on any change, but if you think it's serious
enough to progress your patch, below, now, then I think that should be ok.

No, I don't think it's all that serious.  The scenario is probably 
pretty rare in real life, outside of a few odd circumstances like yours.  
I'm happy to wait until you're comfortable with a full set of changes.

Alan Stern