pci_iounmap'2: Electric Boogaloo: try to make sense of it all

Nathan Chancellor reports that the recent change to pci_iounmap in
commit 9caea0007601 ("parisc: Declare pci_iounmap() parisc version only
when CONFIG_PCI enabled") causes build errors on arm64.

It took me about two hours to convince myself that I think I know what
the logic of that mess of #ifdef's in the <asm-generic/io.h> header file
really aim to do, and rewrite it to be easier to follow.

Famous last words.

Anyway, the code has now been lifted from that grotty header file into
lib/pci_iomap.c, and has fairly extensive comments about what the logic
is.  It also avoids indirecting through another confusing (and badly
named) helper function that has other preprocessor config conditionals.

Let's see what odd architecture did something else strange in this area
to break things.  But my arm64 cross build is clean.

Fixes: 9caea0007601 ("parisc: Declare pci_iounmap() parisc version only when CONFIG_PCI enabled")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ulrich Teichert <krypton@ulrich-teichert.org>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 23 deletions

diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index e93375c710b9..cc7338f9e0d1 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -1023,16 +1023,7 @@ static inline void __iomem *ioport_map(unsigned long port, unsigned int nr)
 	port &= IO_SPACE_LIMIT;
 	return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
 }
-#define __pci_ioport_unmap __pci_ioport_unmap
-static inline void __pci_ioport_unmap(void __iomem *p)
-{
-	uintptr_t start = (uintptr_t) PCI_IOBASE;
-	uintptr_t addr = (uintptr_t) p;
-
-	if (addr >= start && addr < start + IO_SPACE_LIMIT)
-		return;
-	iounmap(p);
-}
+#define ARCH_HAS_GENERIC_IOPORT_MAP
 #endif
 
 #ifndef ioport_unmap
@@ -1048,21 +1039,10 @@ extern void ioport_unmap(void __iomem *p);
 #endif /* CONFIG_HAS_IOPORT_MAP */
 
 #ifndef CONFIG_GENERIC_IOMAP
-struct pci_dev;
-extern void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max);
-
-#ifndef __pci_ioport_unmap
-static inline void __pci_ioport_unmap(void __iomem *p) {}
-#endif
-
 #ifndef pci_iounmap
-#define pci_iounmap pci_iounmap
-static inline void pci_iounmap(struct pci_dev *dev, void __iomem *p)
-{
-	__pci_ioport_unmap(p);
-}
+#define ARCH_WANTS_GENERIC_PCI_IOUNMAP
+#endif
 #endif
-#endif /* CONFIG_GENERIC_IOMAP */
 
 #ifndef xlate_dev_mem_ptr
 #define xlate_dev_mem_ptr xlate_dev_mem_ptr