diff options
| author | Vinod Koul <vkoul@kernel.org> | 2019-06-28 21:07:21 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-06-29 10:43:45 +0200 |
| commit | 8f9fab480c7a87b10bb5440b5555f370272a5d59 (patch) | |
| tree | a7980854d30c6713bfc9ca225fb1f79fc6274327 | |
| parent | mm, swap: fix THP swap out (diff) | |
| download | linux-8f9fab480c7a87b10bb5440b5555f370272a5d59.tar.xz linux-8f9fab480c7a87b10bb5440b5555f370272a5d59.zip | |
linux/kernel.h: fix overflow for DIV_ROUND_UP_ULL
DIV_ROUND_UP_ULL adds the two arguments and then invokes
DIV_ROUND_DOWN_ULL. But on a 32bit system the addition of two 32 bit
values can overflow. DIV_ROUND_DOWN_ULL does it correctly and stashes
the addition into a unsigned long long so cast the result to unsigned
long long here to avoid the overflow condition.
[akpm@linux-foundation.org: DIV_ROUND_UP_ULL must be an rval]
Link: http://lkml.kernel.org/r/20190625100518.30753-1-vkoul@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/kernel.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 74b1ee9027f5..0c9bc231107f 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -93,7 +93,8 @@ #define DIV_ROUND_DOWN_ULL(ll, d) \ ({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; }) -#define DIV_ROUND_UP_ULL(ll, d) DIV_ROUND_DOWN_ULL((ll) + (d) - 1, (d)) +#define DIV_ROUND_UP_ULL(ll, d) \ + DIV_ROUND_DOWN_ULL((unsigned long long)(ll) + (d) - 1, (d)) #if BITS_PER_LONG == 32 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d) |