[PATCH] libc: posix_fadvise: Fix build breakage for !LFS

[Vineet Gupta]

On Thursday 12 June 2014 09:40 PM, Bernhard Reutner-Fischer wrote:
> On Tue, Apr 01, 2014 at 10:53:29AM +0530, Vineet Gupta wrote:
>> Ping ^ 2
>>
>> On Tuesday 04 February 2014 10:02 AM, Vineet Gupta wrote:
>>> Ping !
>>>
>>> On Thursday 09 January 2014 03:05 PM, Vineet Gupta wrote:
>>>> commit 00571b43df2e "libc: posix_fadvise: restore implementation for xtensa"
>>>> enabled posix_fadvise() for all arches (it was just not generated
>>>> before).
>>>>
>>>> However this also unearthed an issue introduced by ee84b8b400
>>>> "linux: posix_fadvise: use new SYSCALL_ALIGN_64BIT" which is to
>>>> referencing LFS'ish code (off64_t) w/o proper checks which causes build
>>>> to break for !LFS.
>>>>
>>>> Fix this by calling posix_fadvise64() only for LFS case and open-code
>>>> it's equivalent for !LFS.
> 
> I do not like the open-coding, can we avoid it?

I don't like it too however I don't see how it will work. W/o LFS we can't call
any *64 stuff.

> I.e. let the __NR_fadvise64_64 based impl live in posix_fadvise64.c,
> __WORDSIZE == 64 ?

I don't think I understand.

1. My patch doesn't touch wordsize == 64 case, it handles the size 32 case.
2. I agree that current code is open coding posix_fadvise64 inside posix_fadvise,
but I don't know a better way of doing it - ideas / suggestions welcome !

Thx,
-Vineet

> 
> thanks,
>>>>
>>>> Signed-off-by: Vineet Gupta <vgupta at synopsys.com>
>>>> Cc: Mike Frysinger <vapier at gentoo.org>
>>>> Cc: Baruch Siach <baruch at tkos.co.il>
>>>> Cc: Khem Raj <raj.khem at gmail.com>
>>>> Cc: markos Chandras <markos.chandras at gmail.com>
>>>> Cc: Bernhard Reutner-Fischer <rep.dot.nop at gmail.com>
>>>> ---
>>>>  libc/sysdeps/linux/common/posix_fadvise.c | 30 ++++++++++++++++++++++++------
>>>>  1 file changed, 24 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/libc/sysdeps/linux/common/posix_fadvise.c b/libc/sysdeps/linux/common/posix_fadvise.c
>>>> index 25c294178e5e..14bbeeea13bc 100644
>>>> --- a/libc/sysdeps/linux/common/posix_fadvise.c
>>>> +++ b/libc/sysdeps/linux/common/posix_fadvise.c
>>>> @@ -22,17 +22,34 @@
>>>>  # include <endian.h>
>>>>  # include <bits/wordsize.h>
>>>>  
>>>> -# ifdef __NR_fadvise64_64
>>>> -int posix_fadvise64(int fd, off64_t offset, off64_t len, int advice);
>>>> -# endif
>>>> +# if defined(__NR_fadvise64_64) && defined(__UCLIBC_HAS_LFS__)
>>>> +#include <_lfs_64.h>
>>>>  
>>>> +int posix_fadvise64(int fd, off64_t offset, off64_t len, int advice);
>>>>  int posix_fadvise(int fd, off_t offset, off_t len, int advice)
>>>>  {
>>>> -# ifdef __NR_fadvise64_64
>>>>  	return posix_fadvise64(fd, offset, len, advice);
>>>> -# else
>>>> +}
>>>> +#else
>>>> +
>>>> +int posix_fadvise(int fd, off_t offset, off_t len, int advice)
>>>> +{
>>>>  	int ret;
>>>>  	INTERNAL_SYSCALL_DECL(err);
>>>> +
>>>> +# ifdef __NR_fadvise64_64
>>>> +#  if __WORDSIZE == 64
>>>> +	ret = INTERNAL_SYSCALL(fadvise64_64, err, 4, fd, offset, len, advice);
>>>> +#  else
>>>> +#   if defined(__UCLIBC_SYSCALL_ALIGN_64BIT__) || defined(__arm__)
>>>> +	ret = INTERNAL_SYSCALL(fadvise64_64, err, 6, fd, advice,
>>>> +			OFF_HI_LO (offset), OFF_HI_LO (len));
>>>> +#   else
>>>> +	ret = INTERNAL_SYSCALL(fadvise64_64, err, 6, fd,
>>>> +			OFF_HI_LO (offset), OFF_HI_LO (len), advice);
>>>> +#   endif
>>>> +#  endif
>>>> +# else  /* __NR_fadvise64 */
>>>>  #  if __WORDSIZE == 64
>>>>  	ret = INTERNAL_SYSCALL(fadvise64, err, 4, fd, offset, len, advice);
>>>>  #  else
>>>> @@ -43,12 +60,13 @@ int posix_fadvise(int fd, off_t offset, off_t len, int advice)
>>>>  #   endif
>>>>  			OFF_HI_LO (offset), len, advice);
>>>>  #  endif
>>>> +#  endif
>>>>  	if (INTERNAL_SYSCALL_ERROR_P (ret, err))
>>>>  		return INTERNAL_SYSCALL_ERRNO (ret, err);
>>>>  	return 0;
>>>> -#  endif
>>>>  }
>>>>  # if defined __UCLIBC_HAS_LFS__ && (!defined __NR_fadvise64_64 || __WORDSIZE == 64)
>>>>  strong_alias(posix_fadvise,posix_fadvise64)
>>>>  # endif
>>>>  #endif
>>>> +#endif
>>>>
>>
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