Messages in this thread | | | Date | Sat, 07 Jul 2018 21:17:07 +0900 (KST) | Subject | Re: [PATCH net-next] stmmac: fix signed 64-bit division | From | David Miller <> |
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From: Arnd Bergmann <arnd@arndb.de> Date: Fri, 6 Jul 2018 15:36:07 +0200
> I link error on 32-bit ARM points to yet another arithmetic bug: > > drivers/net/ethernet/stmicro/stmmac/stmmac_tc.o: In function `tc_setup_cbs': > stmmac_tc.c:(.text+0x148): undefined reference to `__aeabi_uldivmod' > stmmac_tc.c:(.text+0x1fc): undefined reference to `__aeabi_uldivmod' > stmmac_tc.c:(.text+0x308): undefined reference to `__aeabi_uldivmod' > stmmac_tc.c:(.text+0x320): undefined reference to `__aeabi_uldivmod' > stmmac_tc.c:(.text+0x33c): undefined reference to `__aeabi_uldivmod' > drivers/net/ethernet/stmicro/stmmac/stmmac_tc.o:stmmac_tc.c:(.text+0x3a4): more undefined references to `__aeabi_uldivmod' follow > > I observe that the last change to add the 'ul' prefix was incorrect, > as it did not turn the result of the multiplication into a 64-bit > expression on 32-bit architectures. Further, it seems that the > do_div() macro gets confused by the fact that we pass a signed > variable rather than unsigned into it. > > This changes the code to instead use the div_s64() helper that is > meant for signed division, along with changing the constant suffix > to 'll' to actually make it a 64-bit argument everywhere, fixing > both of the issues I pointed out. > > I'm not completely convinced that this makes the code correct, but > I'm fairly sure that we have two problems less than before. > > Fixes: 1f705bc61aee ("net: stmmac: Add support for CBS QDISC") > Fixes: c18a9c096683 ("net: stmmac_tc: use 64-bit arithmetic instead of 32-bit") > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Applied, thank you.
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