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SubjectRe: [PATCH 1/2] [CIFS] Fix signed/unsigned pointer warning
On Mon, Nov 10, 2014 at 1:09 PM, Kevin Cernekee <cernekee@gmail.com> wrote:
> Commit 2ae83bf93882d1 ("[CIFS] Fix setting time before epoch (negative
> time values)") changed "u64 t" to "s64 t", which makes do_div() complain
> about a pointer signedness mismatch:
>
> CC fs/cifs/netmisc.o
> In file included from ./arch/mips/include/asm/div64.h:12:0,
> from include/linux/kernel.h:124,
> from include/linux/list.h:8,
> from include/linux/wait.h:6,
> from include/linux/net.h:23,
> from fs/cifs/netmisc.c:25:
> fs/cifs/netmisc.c: In function ‘cifs_NTtimeToUnix’:
> include/asm-generic/div64.h:43:28: warning: comparison of distinct pointer types lacks a cast [enabled by default]
> (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
> ^
> fs/cifs/netmisc.c:941:22: note: in expansion of macro ‘do_div’
> ts.tv_nsec = (long)do_div(t, 10000000) * 100;
>
> Introduce a temporary "u64 abs_t" variable to fix this.
>
> Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
> ---
> fs/cifs/netmisc.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
>
> Note: this is compile-tested only (on a 32-bit build).
>
>
> diff --git a/fs/cifs/netmisc.c b/fs/cifs/netmisc.c
> index b333ff6..abae6dd 100644
> --- a/fs/cifs/netmisc.c
> +++ b/fs/cifs/netmisc.c
> @@ -926,6 +926,7 @@ cifs_NTtimeToUnix(__le64 ntutc)
>
> /* Subtract the NTFS time offset, then convert to 1s intervals. */
> s64 t = le64_to_cpu(ntutc) - NTFS_TIME_OFFSET;
> + u64 abs_t;
>
> /*
> * Unfortunately can not use normal 64 bit division on 32 bit arch, but
> @@ -933,13 +934,14 @@ cifs_NTtimeToUnix(__le64 ntutc)
> * to special case them
> */
> if (t < 0) {
> - t = -t;
> - ts.tv_nsec = (long)(do_div(t, 10000000) * 100);
> + abs_t = -t;
> + ts.tv_nsec = (long)(do_div(abs_t, 10000000) * 100);
> ts.tv_nsec = -ts.tv_nsec;
> - ts.tv_sec = -t;
> + ts.tv_sec = -abs_t;
> } else {
> - ts.tv_nsec = (long)do_div(t, 10000000) * 100;
> - ts.tv_sec = t;
> + abs_t = t;
> + ts.tv_nsec = (long)do_div(abs_t, 10000000) * 100;
> + ts.tv_sec = abs_t;
> }
>
> return ts;
> --
> 2.1.1
>

Hi guys,

I am still seeing this warning on Linus' head of tree. Do you think
this is something we can pull in for 3.19?

Thanks!


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