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Date: Thu, 25 Jan 2024 12:31:07 -0600
From: Bjorn Helgaas <helgaas@kernel.org>
To: Philipp Stanner <pstanner@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>, Arnd Bergmann <arnd@arndb.de>,
	Johannes Berg <johannes@sipsolutions.net>,
	Randy Dunlap <rdunlap@infradead.org>, NeilBrown <neilb@suse.de>,
	John Sanpe <sanpeqf@gmail.com>,
	Kent Overstreet <kent.overstreet@gmail.com>,
	Niklas Schnelle <schnelle@linux.ibm.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Uladzislau Koshchanka <koshchanka@gmail.com>,
	"Masami Hiramatsu (Google)" <mhiramat@kernel.org>,
	David Gow <davidgow@google.com>, Kees Cook <keescook@chromium.org>,
	Rae Moar <rmoar@google.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	"wuqiang.matt" <wuqiang.matt@bytedance.com>,
	Yury Norov <yury.norov@gmail.com>, Jason Baron <jbaron@akamai.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Marco Elver <elver@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ben Dooks <ben.dooks@codethink.co.uk>, dakr@redhat.com,
	linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
	linux-arch@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v5 RESEND 2/5] lib: move pci_iomap.c to drivers/pci/
Message-ID: <20240125183107.GA393314@bhelgaas>
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In-Reply-To: <3abf071d12de5b69e146665dfb57386e3b0ddfe0.camel@redhat.com>

On Thu, Jan 25, 2024 at 03:54:51PM +0100, Philipp Stanner wrote:
> On Tue, 2024-01-23 at 14:20 -0600, Bjorn Helgaas wrote:
> > On Thu, Jan 11, 2024 at 09:55:37AM +0100, Philipp Stanner wrote:
> > > This file is guarded by an #ifdef CONFIG_PCI. It, consequently,
> > > does not
> > > belong to lib/ because it is not generic infrastructure.
> > > 
> > > Move the file to drivers/pci/ and implement the necessary changes
> > > to
> > > Makefiles and Kconfigs.
> > > ...
> > 
> > > --- a/drivers/pci/Kconfig
> > > +++ b/drivers/pci/Kconfig
> > > @@ -13,6 +13,11 @@ config FORCE_PCI
> > >         select HAVE_PCI
> > >         select PCI
> > >  
> > > +# select this to provide a generic PCI iomap,
> > > +# without PCI itself having to be defined
> > > +config GENERIC_PCI_IOMAP
> > > +       bool
> > 
> > > --- a/lib/pci_iomap.c
> > > +++ b/drivers/pci/iomap.c
> > > @@ -9,7 +9,6 @@
> > >  
> > >  #include <linux/export.h>
> > >  
> > > -#ifdef CONFIG_PCI
> > 
> > IIUC, in the case where CONFIG_GENERIC_PCI_IOMAP=y but CONFIG_PCI was
> > not set, pci_iomap.c was compiled but produced no code because the
> > entire file was wrapped with this #ifdef.
> > 
> > But after this patch, it looks like pci_iomap_range(),
> > pci_iomap_wc_range(), etc., *will* be compiled?
> > 
> > Is that what you intend, or did I miss something?
> 
> They *will* be compiled when BOTH, CONFIG_PCI and
> CONFIG_GENERIC_PCI_IOMAP have been set.

I was asking about CONFIG_GENERIC_PCI_IOMAP=y but CONFIG_PCI unset.

But the Makefile contains this:

  ifdef CONFIG_PCI
  obj-$(CONFIG_GENERIC_PCI_IOMAP) += iomap.o
  endif

So iomap.c will not be compiled when CONFIG_PCI is unset, which is
what I missed.

Bjorn