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Subject[PATCH] netfilter: xt_hashlimit: avoid 64-bit division
Date
64-bit division is expensive on 32-bit architectures, and
requires a special function call to avoid a link error like:

net/netfilter/xt_hashlimit.o: In function `hashlimit_mt_common':
xt_hashlimit.c:(.text+0x1328): undefined reference to `__aeabi_uldivmod'

In the case of hashlimit_mt_common, we don't actually need a
64-bit operation, we can simply rewrite the function slightly
to make that clear to the compiler.

Fixes: bea74641e378 ("netfilter: xt_hashlimit: add rate match mode")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
net/netfilter/xt_hashlimit.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index 10d48234f5f4..50b53d86eef5 100644
--- a/net/netfilter/xt_hashlimit.c
+++ b/net/netfilter/xt_hashlimit.c
@@ -531,7 +531,10 @@ static u64 user2rate_bytes(u64 user)
{
u64 r;

- r = user ? 0xFFFFFFFFULL / user : 0xFFFFFFFFULL;
+ if (user > 0xFFFFFFFFULL)
+ return 0;
+
+ r = user ? 0xFFFFFFFFULL / (u32)user : 0xFFFFFFFFULL;
r = (r - 1) << 4;
return r;
}
--
2.9.0
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