Subject: Re: linux-next: build failure after merge of the driver-core tree

From: Mark Brown <[email-masked]>
Date: Wed, 18 Sep 2019 22:55:23 +0100

On Wed, Sep 18, 2019 at 12:03:17PM -0700, Linus Torvalds wrote:
> On Wed, Sep 18, 2019 at 11:53 AM Greg KH <[email-masked]> wrote:
> > On Wed, Sep 18, 2019 at 06:09:52PM +0100, Mark Brown wrote:

> > > After merging the driver-core tree, today's linux-next build
> > > for arm64 allmodconfig failed like this:

> > Wait, I thought Linus said this fixup was now resolved.  What went
> > wrong?

> I think this is purely a linux-next build failure.

> I do full allmodconfig builds between each merge I do, and what
> happened is that as part of the LED merge, I removed the
> no-longer-used 'i2c_acpi_find_match_adapter()' to resolve that build
> warning.

> Then linux-next presumably merged my tree with the driver-core tree,
> and that re-instated the use of i2c_acpi_find_match_adapter() - which
> was now gone.

> But when *I* merged the driver-core tree, I did the merge fixup
> correctly to actually re-instate not only the use, but also re-instate
> the removed function that now had a use again.

Yes, that's exactly what happened - it's purely an issue when Greg's
tree is merged automatically, I was reporting the same thing you fixed
up.  If the initial build of your tree had been broken I'd have been
complaining much more loudy and much earlier!

> > Linus, should I submit a fix for this?

> My tree should be fine, and I really think this is just a temporary
> linux-next effect from the above. I think linux-next only handled the
> actual syntactic conflicts, not the semantic conflict of "function had
> been removed to avoid build error from previous merge, and needed to
> be brought back"

Right, git just sees the code moving about and got confused.  Since
you've merged both trees now tomorrow's -next won't do anything for
driver-core and the automation will handle everything fine.