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| author | Leon Romanovsky <leonro@mellanox.com> | 2019-03-17 13:11:14 +0300 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@mellanox.com> | 2019-03-27 16:23:03 +0300 |
| commit | dc7fe518b0493faa0af0568d6d8c2a33c00f58d0 (patch) | |
| tree | 0f25a8b3718704d8e8bb55a74b56f265f26bb193 /include/linux/overflow.h | |
| parent | 9513ea4f67280a17365f5adfa31fac7d344150c6 (diff) | |
| download | linux-dc7fe518b0493faa0af0568d6d8c2a33c00f58d0.tar.xz | |
overflow: Fix -Wtype-limits compilation warnings
Attempt to use check_shl_overflow() with inputs of unsigned type
produces the following compilation warnings.
drivers/infiniband/hw/mlx5/qp.c: In function _set_user_rq_size_:
./include/linux/overflow.h:230:6: warning: comparison of unsigned
expression >= 0 is always true [-Wtype-limits]
_s >= 0 && _s < 8 * sizeof(*d) ? _s : 0; \
^~
drivers/infiniband/hw/mlx5/qp.c:5820:6: note: in expansion of macro _check_shl_overflow_
if (check_shl_overflow(rwq->wqe_count, rwq->wqe_shift,
&rwq->buf_size))
^~~~~~~~~~~~~~~~~~
./include/linux/overflow.h:232:26: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits]
(_to_shift != _s || *_d < 0 || _a < 0 || \
^
drivers/infiniband/hw/mlx5/qp.c:5820:6: note: in expansion of macro _check_shl_overflow_
if (check_shl_overflow(rwq->wqe_count, rwq->wqe_shift, &rwq->buf_size))
^~~~~~~~~~~~~~~~~~
./include/linux/overflow.h:232:36: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits]
(_to_shift != _s || *_d < 0 || _a < 0 || \
^
drivers/infiniband/hw/mlx5/qp.c:5820:6: note: in expansion of macro _check_shl_overflow_
if (check_shl_overflow(rwq->wqe_count, rwq->wqe_shift,&rwq->buf_size))
^~~~~~~~~~~~~~~~~~
Fixes: 0c66847793d1 ("overflow.h: Add arithmetic shift helper")
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'include/linux/overflow.h')
| -rw-r--r-- | include/linux/overflow.h | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/include/linux/overflow.h b/include/linux/overflow.h index 40b48e2133cb..15eb85de9226 100644 --- a/include/linux/overflow.h +++ b/include/linux/overflow.h @@ -36,6 +36,12 @@ #define type_max(T) ((T)((__type_half_max(T) - 1) + __type_half_max(T))) #define type_min(T) ((T)((T)-type_max(T)-(T)1)) +/* + * Avoids triggering -Wtype-limits compilation warning, + * while using unsigned data types to check a < 0. + */ +#define is_non_negative(a) ((a) > 0 || (a) == 0) +#define is_negative(a) (!(is_non_negative(a))) #ifdef COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW /* @@ -227,10 +233,10 @@ typeof(d) _d = d; \ u64 _a_full = _a; \ unsigned int _to_shift = \ - _s >= 0 && _s < 8 * sizeof(*d) ? _s : 0; \ + is_non_negative(_s) && _s < 8 * sizeof(*d) ? _s : 0; \ *_d = (_a_full << _to_shift); \ - (_to_shift != _s || *_d < 0 || _a < 0 || \ - (*_d >> _to_shift) != _a); \ + (_to_shift != _s || is_negative(*_d) || is_negative(_a) || \ + (*_d >> _to_shift) != _a); \ }) /** |