Trent Piepho 0ef6f97839 lib/math/rational.c: fix divide by zero ... [ Upstream commit 65a0d3c146 ] If the input is out of the range of the allowed values, either larger than the largest value or closer to zero than the smallest non-zero allowed value, then a division by zero would occur. In the case of input too large, the division by zero will occur on the first iteration. The best result (largest allowed value) will be found by always choosing the semi-convergent and excluding the denominator based limit when finding it. In the case of the input too small, the division by zero will occur on the second iteration. The numerator based semi-convergent should not be calculated to avoid the division by zero. But the semi-convergent vs previous convergent test is still needed, which effectively chooses between 0 (the previous convergent) vs the smallest allowed fraction (best semi-convergent) as the result. Link: https://lkml.kernel.org/r/20210525144250.214670-1-tpiepho@gmail.com Fixes: 323dd2c3ed ("lib/math/rational.c: fix possible incorrect result from rational fractions helper") Signed-off-by: Trent Piepho <tpiepho@gmail.com> Reported-by: Yiyuan Guo <yguoaz@gmail.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Oskar Schirmer <oskar@scara.com> Cc: Daniel Latypov <dlatypov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2021-07-14 17:07:48 +02:00
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cordic.c
div64.c	math: Export mul_u64_u64_div_u64	2021-03-24 16:42:54 -07:00
gcd.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
int_pow.c	kernel.h: split out mathematical helpers	2020-12-15 22:46:15 -08:00
int_sqrt.c	kernel.h: split out mathematical helpers	2020-12-15 22:46:15 -08:00
Kconfig	lib: Make prime number generator independently selectable	2020-06-02 10:25:20 -06:00
lcm.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
Makefile	lib/math: Add a `do_div' test module	2021-04-21 13:45:36 +02:00
prime_numbers.c	lib/math: avoid trailing newline hidden in pr_fmt()	2020-06-04 19:06:24 -07:00
rational.c	lib/math/rational.c: fix divide by zero	2021-07-14 17:07:48 +02:00
reciprocal_div.c	kernel.h: split out mathematical helpers	2020-12-15 22:46:15 -08:00
test_div64.c	lib/math/test_div64: Correct the spelling of "dividend"	2021-04-23 13:40:05 +02:00