LinuxKPI: implement dmam_free_coherent()

[bz]

Summary

dmam_free_coherent() is used by an updated mt76 driver at v6.19-rc6.
We need to surgically find the devres information and destroy it before
calling dma_free_coherent.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days

[emaste]

Why do we use linuxkpi prefix sometimes and lkpi others?

But looks fine

[bz]

In D54810#1252993, @emaste wrote:

Why do we use linuxkpi prefix sometimes and lkpi others?

But looks fine

Historically this was mixed. We are trying to use linuxkpi_ for official public LinuxKPi functions now and lkpi_ for internal. Historically there's also linux_ which we shoudl leave to the Linuxolator. Doing the full sweep one day will be tough but at least trying to keep it consistent for new stuff.

Should we add a README somewhere in sys/compat/linuxkpi/ and start writing these things down?

[imp]

In D54810#1253014, @bz wrote:

In D54810#1252993, @emaste wrote:

Why do we use linuxkpi prefix sometimes and lkpi others?

But looks fine

Historically this was mixed. We are trying to use linuxkpi_ for official public LinuxKPi functions now and lkpi_ for internal. Historically there's also linux_ which we shoudl leave to the Linuxolator. Doing the full sweep one day will be tough but at least trying to keep it consistent for new stuff.

Should we add a README somewhere in sys/compat/linuxkpi/ and start writing these things down?

I love that idea

[bz]

Should we add a README somewhere in sys/compat/linuxkpi/ and start writing these things down?

I love that idea

Great. I'll find the version I wrote in ~2021, when people didn't like, the next days it and update it and put it up here.

[emaste]

OK with me

[bz]

sys/compat/linuxkpi/common/src/linux_pci.c

1822

= &dma_handle ; will do before commit.