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Message-ID: <51F8818C.7030703@gmail.com>
Date: Wed, 31 Jul 2013 11:16:28 +0800
From: Chen Gang F T <chen.gang.flying.transformer@...il.com>
To: Chen Gang <gang.chen@...anux.com>
CC: Joe Perches <joe@...ches.com>, 'Jiri Kosina' <trivial@...nel.org>,
jaharkes@...cmu.edu, coda@...cmu.edu, codalist@...a.cs.cmu.edu,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH trivial] include/linux/coda.h: remove useless '#else'
On 07/31/2013 09:53 AM, Chen Gang wrote:
> On 07/31/2013 09:44 AM, Chen Gang wrote:
>> On 07/30/2013 08:29 PM, Joe Perches wrote:
>>> On Tue, 2013-07-30 at 15:30 +0800, Chen Gang wrote:
>>>> '#else' is useless, need remove.
>>>>
>>>> Signed-off-by: Chen Gang <gang.chen@...anux.com>
>>>> ---
>>>> include/linux/coda.h | 1 -
>>>> 1 files changed, 0 insertions(+), 1 deletions(-)
>>>>
>>>> diff --git a/include/linux/coda.h b/include/linux/coda.h
>>>> index cff544f..d30209b 100644
>>>> --- a/include/linux/coda.h
>>>> +++ b/include/linux/coda.h
>>>> @@ -60,7 +60,6 @@ Mellon the rights to redistribute these changes without encumbrance.
>>>>
>>>> #if defined(__linux__)
>>>> typedef unsigned long long u_quad_t;
>>>> -#else
>>>> #endif
>>>> #include <uapi/linux/coda.h>
>>>> #endif
>>>
>>> Why have the #if at all?
>>>
>>>
>>>
>>
OH, sorry, what I said about openrisc cross-compiler is not precise.
Need a patch for openrisc (just like another architectures have done):
-------------------------------diff begin-------------------------------
diff --git a/arch/openrisc/Makefile b/arch/openrisc/Makefile
index 4739b83..89076a6 100644
--- a/arch/openrisc/Makefile
+++ b/arch/openrisc/Makefile
@@ -24,7 +24,7 @@ OBJCOPYFLAGS := -O binary -R .note -R .comment -S
LDFLAGS_vmlinux :=
LIBGCC := $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
-KBUILD_CFLAGS += -pipe -ffixed-r10
+KBUILD_CFLAGS += -pipe -ffixed-r10 -D__linux__
ifeq ($(CONFIG_OPENRISC_HAVE_INST_MUL),y)
KBUILD_CFLAGS += $(call cc-option,-mhard-mul)
-------------------------------diff end---------------------------------
But for "include/linux/coda.h", I still suggest to check __linux__
whether defined, at least it can find the building issues.
And next, I will send the related patch to openrisc mailing list.
:-)
Thanks.
>> Hmm... some old version compilers do not define __linux__ automatically
>> (e.g. or32-linux-gcc 4.5.1-or32-1.0rc1, which is the latest cross
>> compiler for openrisc, though).
>>
>> If not define __linux__, the compiler will report error (u_quad_t is
>> not defined).
>>
>> When we remove "#if defined(__linux__)" from "include/linux/coda.h",
>> the compiler will not report error, and 'cdev_t' will be defined as
>> 'dev_t', not 'u_quad_t' (I guess, it is an implicit bug).
>>
>>
>> In "uapi/include/*", only "coda.h" has "#if defined(__linux__)", maybe
>> they want multiple OS can share the same "coda.h" file (at least, we
>> can not say it is a bad idea).
>>
>> Neither suitable to define __linux__ in "include/linux/coda.h".
>>
>>
>> All together, I think:
>>
>> the direct cause:
>> "uapi/include/coda.h" wants to share itself for multiple OS (so they need check __linux__).
>> (in "uapi/include/*", only coda.h need check __linux__)
>>
>> the root cause:
>> the compiler for linux should define __linux__ automatically, the latest version of gcc has done, but some of the old version is not.
>> most of cross compilers have merged their code into gcc main tree, but still left some (e.g. openrisc).
>> (at least, I can not build openrisc from gcc main tree correctly, but most of others can)
>> some of latest cross compilers still use old version of gcc, (still not define __linux__ automatically).
>>
>
> Maybe what I said is incorrect (it is just my current understanding).
>
> Welcome any other members' suggestions or completions for discussing and
> checking.
>
> Thanks.
>
>>
>> The related code in "uapi/linux/coda.h" is below:
>>
>> -------------------------------code begin-------------------------------
>>
>> 73 #if defined(DJGPP) || defined(__CYGWIN32__)
>> 74 #ifdef KERNEL
>> 75 typedef unsigned long u_long;
>> 76 typedef unsigned int u_int;
>> 77 typedef unsigned short u_short;
>> 78 typedef u_long ino_t;
>> 79 typedef u_long dev_t;
>> 80 typedef void * caddr_t;
>> 81 #ifdef DOS
>> 82 typedef unsigned __int64 u_quad_t;
>> 83 #else
>> 84 typedef unsigned long long u_quad_t;
>> 85 #endif
>> 86
>> 87 #define inline
>> 88
>> 89 struct timespec {
>> 90 long ts_sec;
>> 91 long ts_nsec;
>> 92 };
>> 93 #else /* DJGPP but not KERNEL */
>> 94 #include <sys/time.h>
>> 95 typedef unsigned long long u_quad_t;
>> 96 #endif /* !KERNEL */
>> 97 #endif /* !DJGPP */
>> 98
>> 99
>> 100 #if defined(__linux__)
>> 101 #include <linux/time.h>
>> 102 #define cdev_t u_quad_t
>> 103 #ifndef __KERNEL__
>> 104 #if !defined(_UQUAD_T_) && (!defined(__GLIBC__) || __GLIBC__ < 2)
>> 105 #define _UQUAD_T_ 1
>> 106 typedef unsigned long long u_quad_t;
>> 107 #endif
>> 108 #endif /* __KERNEL__ */
>> 109 #else
>> 110 #define cdev_t dev_t
>> 111 #endif
>> 112
>>
>> -------------------------------code end---------------------------------
>>
>>
>> Thanks.
>>
>
>
--
Chen Gang
--
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