linux-kernel - [PATCH v2] nfc: don't be making arch specific unaligned decisions at driver level.

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Date:   Mon, 9 Jan 2017 12:52:22 -0500
From:   Paul Gortmaker <paul.gortmaker@...driver.com>
To:     <linux-kernel@...r.kernel.org>
CC:     kbuild test robot <lkp@...el.com>,
        Paul Gortmaker <paul.gortmaker@...driver.com>,
        Lauro Ramos Venancio <lauro.venancio@...nbossa.org>,
        Aloisio Almeida Jr <aloisio.almeida@...nbossa.org>,
        Samuel Ortiz <sameo@...ux.intel.com>,
        Tony Luck <tony.luck@...el.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        <linux-ia64@...r.kernel.org>, <linux-wireless@...r.kernel.org>
Subject: [PATCH v2] nfc: don't be making arch specific unaligned decisions at driver level.

Currently ia64 fails building allmodconfig with variations of:

   In file included from drivers/nfc/nxp-nci/i2c.c:39:0:
   ./include/linux/unaligned/access_ok.h:62:29: error: redefinition of ‘put_unaligned_be64’
    static __always_inline void put_unaligned_be64(u64 val, void *p)
                                ^~~~~~~~~~~~~~~~~~
   In file included from ./arch/ia64/include/asm/unaligned.h:5:0,
                    from ./arch/ia64/include/asm/io.h:22,
                    from ./arch/ia64/include/asm/smp.h:20,
                    from ./include/linux/smp.h:59,
                    from ./include/linux/topology.h:33,
                    from ./include/linux/gfp.h:8,
                    from ./include/linux/slab.h:14,
                    from ./include/linux/resource_ext.h:19,
                    from ./include/linux/acpi.h:26,
                    from drivers/nfc/nxp-nci/i2c.c:28:
   ./include/linux/unaligned/be_byteshift.h:65:20: note: previous definition of ‘put_unaligned_be64’ was here
    static inline void put_unaligned_be64(u64 val, void *p)
                       ^~~~~~~~~~~~~~~~~~
   scripts/Makefile.build:293: recipe for target 'drivers/nfc/nxp-nci/i2c.o' failed

The easiest explanation for this is to look at the non-arch users in
the following output:

   linux$git grep include.*access_ok.h
   arch/arm64/crypto/crc32-arm64.c:#include <linux/unaligned/access_ok.h>
   arch/cris/include/asm/unaligned.h:#include <linux/unaligned/access_ok.h>
   arch/m68k/include/asm/unaligned.h:#include <linux/unaligned/access_ok.h>
   arch/mn10300/include/asm/unaligned.h:#include <linux/unaligned/access_ok.h>
   arch/powerpc/include/asm/unaligned.h:#include <linux/unaligned/access_ok.h>
   arch/s390/include/asm/unaligned.h:#include <linux/unaligned/access_ok.h>
   arch/x86/include/asm/unaligned.h:#include <linux/unaligned/access_ok.h>
   drivers/nfc/nfcmrvl/fw_dnld.c:#include <linux/unaligned/access_ok.h>
   drivers/nfc/nxp-nci/firmware.c:#include <linux/unaligned/access_ok.h>
   drivers/nfc/nxp-nci/i2c.c:#include <linux/unaligned/access_ok.h>
   include/asm-generic/unaligned.h:# include <linux/unaligned/access_ok.h>

Note that nfc is essentially the only non-arch user in the above.
When it forces use of access_ok.h, it will break any arch that has
already selected be_byteshift.h (or other conflicting implementations)
at the arch level.

The decision of what variant for unaligned access to use needs to be
left to the arch level and not used at the driver level.  Since not
all arch will have sourced asm/unaligned.h already, we need to call
it out and then the arch can give us just the one definition that
is needed.

See commit 064106a91be5 ("kernel: add common infrastructure for
unaligned access") as a reference.

Cc: Lauro Ramos Venancio <lauro.venancio@...nbossa.org>
Cc: Aloisio Almeida Jr <aloisio.almeida@...nbossa.org>
Cc: Samuel Ortiz <sameo@...ux.intel.com>
Cc: Tony Luck <tony.luck@...el.com>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Cc: linux-ia64@...r.kernel.org
Cc: linux-wireless@...r.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com>
---

[v2: explicitly include asm/uaccess.h since some arch won't be
 getting any variant of an unaligned access header without it.
 Build test allmodconfig on x86-64, i386, arm64, ia64. ]

 drivers/nfc/nfcmrvl/fw_dnld.c  | 2 +-
 drivers/nfc/nxp-nci/firmware.c | 2 +-
 drivers/nfc/nxp-nci/i2c.c      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/nfc/nfcmrvl/fw_dnld.c b/drivers/nfc/nfcmrvl/fw_dnld.c
index f8dcdf4b24f6..f3f246ddae06 100644
--- a/drivers/nfc/nfcmrvl/fw_dnld.c
+++ b/drivers/nfc/nfcmrvl/fw_dnld.c
@@ -17,11 +17,11 @@
  */
 
 #include <linux/module.h>
-#include <linux/unaligned/access_ok.h>
 #include <linux/firmware.h>
 #include <linux/nfc.h>
 #include <net/nfc/nci.h>
 #include <net/nfc/nci_core.h>
+#include <asm/unaligned.h>
 #include "nfcmrvl.h"
 
 #define FW_DNLD_TIMEOUT			15000
diff --git a/drivers/nfc/nxp-nci/firmware.c b/drivers/nfc/nxp-nci/firmware.c
index 5291797324ba..553011f58339 100644
--- a/drivers/nfc/nxp-nci/firmware.c
+++ b/drivers/nfc/nxp-nci/firmware.c
@@ -24,7 +24,7 @@
 #include <linux/completion.h>
 #include <linux/firmware.h>
 #include <linux/nfc.h>
-#include <linux/unaligned/access_ok.h>
+#include <asm/unaligned.h>
 
 #include "nxp-nci.h"
 
diff --git a/drivers/nfc/nxp-nci/i2c.c b/drivers/nfc/nxp-nci/i2c.c
index 36099e557730..20243dafea21 100644
--- a/drivers/nfc/nxp-nci/i2c.c
+++ b/drivers/nfc/nxp-nci/i2c.c
@@ -36,9 +36,9 @@
 #include <linux/of_gpio.h>
 #include <linux/of_irq.h>
 #include <linux/platform_data/nxp-nci.h>
-#include <linux/unaligned/access_ok.h>
 
 #include <net/nfc/nfc.h>
+#include <asm/unaligned.h>
 
 #include "nxp-nci.h"
 
-- 
2.11.0