include: util: fix division by zero in DIV_ROUND macros #95303
Conversation
zephyrbot
requested review from
aaronemassey,
andyross,
asemjonovs,
dcpleung,
jeremybettis,
nashif,
peter-mitsis and
yperess
Also fix DIV_ROUND_UP(n, d) in cases where at least one parameter is negative. Added unit tests to check for assserts and wrong calculation. Signed-off-by: Lucas Ribeiro <[email protected]>
LucasRibeiro-Zuhlke
force-pushed
the
bugfix/div_round_macros
branch
from
3bc1061 to
787da83
Compare
|
| */ | ||
| #define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d)) | ||
| #define DIV_ROUND_UP(n, d) ((d == 0) \ | ||
| ? __ASSERT_NO_MSG(false) \ |
There was a problem hiding this comment.
Looking closer at this, this won't work. The ternary operator won't be able to expand the macro for asserts here.
There was a problem hiding this comment.
We will have to use a static inline function then, but that needs a fixed type for return and parameters.
There was a problem hiding this comment.
You might need to resort to _Generic to make it work.
| * @return The result of @p n / @p d, rounded up. | ||
| */ | ||
| #define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d)) | ||
| #define DIV_ROUND_UP(n, d) ((d == 0) \ |
There was a problem hiding this comment.
How about:
#define DIV_ROUND_UP(n, d) ({ \
__typeof__(n) un = (n); \
__typeof__(d) ud = (d); \
__ASSERT_NO_MSG(ud != 0); \
((un + ud - 1) / ud); \
})Inspired by #96478
There was a problem hiding this comment.
Nah :-(
include/zephyr/drivers/can.h: uint32_t data_32[DIV_ROUND_UP(CAN_MAX_DLEN, sizeof(uint32_t))];
include/zephyr/logging/log_msg.h: long long _ll_buf[DIV_ROUND_UP(len, sizeof(long long))]; \
include/zephyr/logging/log_msg.h: long double _ld_buf[DIV_ROUND_UP(len, sizeof(long double))]; \
and plenty more, I think we should have a DIV_ROUND_UP and div_round_up, once you do the ({ thing it effectively becomes a function
6 participants
Also fix DIV_ROUND_UP(n, d) in cases where at least one parameter is negative.
Fixes #95302.