On Fri, 2021-01-01 at 13:21 -0800, Linus Torvalds wrote: > On Fri, Jan 1, 2021 at 12:19 PM James Bottomley > <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote: > > Originally this change was slated for the merge window but a late > > arriving build problem with CONFIG_PM=n derailed that. > > So I've pulled this, Thanks! > but we need to have a policy for reverting this > quickly if it turns out to cause problems. Sure, we'd have to revert the six patches plus the dependent PM fix. > I'm not worried about any remaining build issues - but I'm simply > worried about some missed case where code depended on the block layer > passing commands through even while suspended. > > The block bits would seem affect non-SCSI stuff too, how extensively > have any random odd special case been tested? The block bits have been in -next since 7 December, so it has had some testing. That said, REQ_PREEMPT doesn't affect much outside of SCSI and IDE because we're where the original concept of at head insertion for "special" error handling commands like request sense came from. I'd expect the biggest field of potential problems to be in USB which does both block/SCSI and PM. That should have been well tested by the PM people (as far as they can, as you know there are tons of non spec devices out there in the space). > So I'm not so much with you on the "the scary case is the spi domain > validation case". I'm more about "what about all the other random > cases for random special drivers" I picked on that because it's the least likely to get any testing for a while. However, you're right, there are other potential problem consumers but hopefully any problem (if there is one) with the rest will show up quickly. James
