+ io-mapping-remove-fallback-for-writecombine.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     Subject: include/linux/io-mapping.h: remove fallback for writecombine
has been added to the -mm tree.  Its filename is
     io-mapping-remove-fallback-for-writecombine.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/io-mapping-remove-fallback-for-writecombine.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/io-mapping-remove-fallback-for-writecombine.patch

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------------------------------------------------------
From: Lucas De Marchi <lucas.demarchi@intel.com>
Subject: include/linux/io-mapping.h: remove fallback for writecombine

The fallback was introduced in commit 80c33624e472 ("io-mapping: Fixup for
different names of writecombine") to fix the build on microblaze.

5 years later, it seems all archs now provide a pgprot_writecombine(), so
just remove the other possible fallbacks.  For microblaze,
pgprot_writecombine() is available since commit 97ccedd793ac ("microblaze:
Provide pgprot_device/writecombine macros for nommu").

This is build-tested on microblaze with a hack to always build
mm/io-mapping.o and without DIYing on an x86-only macro (_PAGE_CACHE_MASK)

Link: https://lkml.kernel.org/r/20211020204838.1142908-1-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/io-mapping.h |    6 ------
 1 file changed, 6 deletions(-)

--- a/include/linux/io-mapping.h~io-mapping-remove-fallback-for-writecombine
+++ a/include/linux/io-mapping.h
@@ -132,13 +132,7 @@ io_mapping_init_wc(struct io_mapping *io
 
 	iomap->base = base;
 	iomap->size = size;
-#if defined(pgprot_noncached_wc) /* archs can't agree on a name ... */
-	iomap->prot = pgprot_noncached_wc(PAGE_KERNEL);
-#elif defined(pgprot_writecombine)
 	iomap->prot = pgprot_writecombine(PAGE_KERNEL);
-#else
-	iomap->prot = pgprot_noncached(PAGE_KERNEL);
-#endif
 
 	return iomap;
 }
_

Patches currently in -mm which might be from lucas.demarchi@intel.com are

io-mapping-remove-fallback-for-writecombine.patch
lib-string_helpers-add-linux-stringh-for-strlen.patch