On Fri, Apr 07, 2017 at 04:42:18PM -0500, Eric Sandeen wrote:
> Long ago, all this gunk was added with a lament about problems
> with gcc's do_div, and a fun recommendation in the changelog:
>
> egcs-2.91.66 is the recommended compiler version for building XFS.
>
> All this special stuff was needed to work around an old gcc bug,
> apparently, and it's been there ever since.
>
> There should be no need for this anymore, so remove it.
>
> Remove the special 32-bit xfs_do_mod as well; just let the
> kernel's do_div() handle all this.
>
> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> ---
Looks Ok to me:
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
>
> I'm currently running through xfstests on a 32-bit box with
> no issues, so going ahead & sending it out.
>
> Darrick, please queue this for -rc7. (I KID!) ;)
>
> diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
> index 592fdf7..044fb0e 100644
> --- a/fs/xfs/xfs_linux.h
> +++ b/fs/xfs/xfs_linux.h
> @@ -212,88 +212,6 @@ static inline kgid_t xfs_gid_to_kgid(__uint32_t gid)
> #define xfs_sort(a,n,s,fn) sort(a,n,s,fn,NULL)
> #define xfs_stack_trace() dump_stack()
>
> -
> -/* Move the kernel do_div definition off to one side */
> -
> -#if defined __i386__
> -/* For ia32 we need to pull some tricks to get past various versions
> - * of the compiler which do not like us using do_div in the middle
> - * of large functions.
> - */
> -static inline __u32 xfs_do_div(void *a, __u32 b, int n)
> -{
> - __u32 mod;
> -
> - switch (n) {
> - case 4:
> - mod = *(__u32 *)a % b;
> - *(__u32 *)a = *(__u32 *)a / b;
> - return mod;
> - case 8:
> - {
> - unsigned long __upper, __low, __high, __mod;
> - __u64 c = *(__u64 *)a;
> - __upper = __high = c >> 32;
> - __low = c;
> - if (__high) {
> - __upper = __high % (b);
> - __high = __high / (b);
> - }
> - asm("divl %2":"=a" (__low), "=d" (__mod):"rm" (b), "0" (__low), "1" (__upper));
> - asm("":"=A" (c):"a" (__low),"d" (__high));
> - *(__u64 *)a = c;
> - return __mod;
> - }
> - }
> -
> - /* NOTREACHED */
> - return 0;
> -}
> -
> -/* Side effect free 64 bit mod operation */
> -static inline __u32 xfs_do_mod(void *a, __u32 b, int n)
> -{
> - switch (n) {
> - case 4:
> - return *(__u32 *)a % b;
> - case 8:
> - {
> - unsigned long __upper, __low, __high, __mod;
> - __u64 c = *(__u64 *)a;
> - __upper = __high = c >> 32;
> - __low = c;
> - if (__high) {
> - __upper = __high % (b);
> - __high = __high / (b);
> - }
> - asm("divl %2":"=a" (__low), "=d" (__mod):"rm" (b), "0" (__low), "1" (__upper));
> - asm("":"=A" (c):"a" (__low),"d" (__high));
> - return __mod;
> - }
> - }
> -
> - /* NOTREACHED */
> - return 0;
> -}
> -#else
> -static inline __u32 xfs_do_div(void *a, __u32 b, int n)
> -{
> - __u32 mod;
> -
> - switch (n) {
> - case 4:
> - mod = *(__u32 *)a % b;
> - *(__u32 *)a = *(__u32 *)a / b;
> - return mod;
> - case 8:
> - mod = do_div(*(__u64 *)a, b);
> - return mod;
> - }
> -
> - /* NOTREACHED */
> - return 0;
> -}
> -
> /* Side effect free 64 bit mod operation */
> static inline __u32 xfs_do_mod(void *a, __u32 b, int n)
> {
> @@ -310,10 +228,7 @@ static inline __u32 xfs_do_mod(void *a, __u32 b, int n)
> /* NOTREACHED */
> return 0;
> }
> -#endif
>
> -#undef do_div
> -#define do_div(a, b) xfs_do_div(&(a), (b), sizeof(a))
> #define do_mod(a, b) xfs_do_mod(&(a), (b), sizeof(a))
>
> static inline __uint64_t roundup_64(__uint64_t x, __uint32_t y)
>
> --
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