linux-kernel - [PATCH v13 01/10] iomap: Use correct endian conversion function in mmio

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Date:   Wed, 21 Mar 2018 10:37:36 -0600
From:   Logan Gunthorpe <logang@...tatee.com>
To:     linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
        linux-ntb@...glegroups.com, linux-crypto@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Horia Geantă <horia.geanta@....com>,
        Logan Gunthorpe <logang@...tatee.com>,
        Philippe Ombredanne <pombredanne@...b.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        Luc Van Oostenryck <luc.vanoostenryck@...il.com>
Subject: [PATCH v13 01/10] iomap: Use correct endian conversion function in mmio_writeXXbe

The semantics of the iowriteXXbe() functions are to write a
value in CPU endianess to an IO register that is known by the
caller to be in Big Endian. The mmio_writeXXbe() macro, which
is called by iowriteXXbe(), should therefore use cpu_to_beXX()
instead of beXX_to_cpu().

Seeing both beXX_to_cpu() and cpu_to_beXX() are both functionally
implemented as either null operations or swabXX operations there
was no noticable bug here. But it is confusing for both developers
and code analysis tools alike.

Signed-off-by: Logan Gunthorpe <logang@...tatee.com>
Cc: Philippe Ombredanne <pombredanne@...b.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Kate Stewart <kstewart@...uxfoundation.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Luc Van Oostenryck <luc.vanoostenryck@...il.com>
---
 lib/iomap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/iomap.c b/lib/iomap.c
index 541d926da95e..be120c13d6cc 100644
--- a/lib/iomap.c
+++ b/lib/iomap.c
@@ -106,8 +106,8 @@ EXPORT_SYMBOL(ioread32be);
 #endif
 
 #ifndef mmio_write16be
-#define mmio_write16be(val,port) __raw_writew(be16_to_cpu(val),port)
-#define mmio_write32be(val,port) __raw_writel(be32_to_cpu(val),port)
+#define mmio_write16be(val,port) __raw_writew(cpu_to_be16(val),port)
+#define mmio_write32be(val,port) __raw_writel(cpu_to_be32(val),port)
 #endif
 
 void iowrite8(u8 val, void __iomem *addr)
-- 
2.11.0