Ob Tue, Dec 04, 2007 at 12:17:23AM +1100, Herbert Xu wrote: > > Never mind, we already have that in local_t and as Alexey correctly > points out, USER is still going to be the expensive variant with the > preempt_disable (well until BH gets threaded). So how about this patch?
I didn't hear any objections so here is the patch again. [SNMP]: Fix SNMP counters with PREEMPT The SNMP macros use raw_smp_processor_id() in process context which is illegal because the process may be preempted and then migrated to another CPU. This patch makes it use get_cpu/put_cpu to disable preemption. Signed-off-by: Herbert Xu <[EMAIL PROTECTED]> Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} <[EMAIL PROTECTED]> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- diff --git a/include/net/snmp.h b/include/net/snmp.h index ea206bf..9444b54 100644 --- a/include/net/snmp.h +++ b/include/net/snmp.h @@ -23,6 +23,7 @@ #include <linux/cache.h> #include <linux/snmp.h> +#include <linux/smp.h> /* * Mibs are stored in array of unsigned long. @@ -137,7 +138,10 @@ struct linux_mib { #define SNMP_INC_STATS_OFFSET_BH(mib, field, offset) \ (per_cpu_ptr(mib[0], raw_smp_processor_id())->mibs[field + (offset)]++) #define SNMP_INC_STATS_USER(mib, field) \ - (per_cpu_ptr(mib[1], raw_smp_processor_id())->mibs[field]++) + do { \ + per_cpu_ptr(mib[1], get_cpu())->mibs[field]++; \ + put_cpu(); \ + } while (0) #define SNMP_INC_STATS(mib, field) \ (per_cpu_ptr(mib[!in_softirq()], raw_smp_processor_id())->mibs[field]++) #define SNMP_DEC_STATS(mib, field) \ @@ -145,6 +149,9 @@ struct linux_mib { #define SNMP_ADD_STATS_BH(mib, field, addend) \ (per_cpu_ptr(mib[0], raw_smp_processor_id())->mibs[field] += addend) #define SNMP_ADD_STATS_USER(mib, field, addend) \ - (per_cpu_ptr(mib[1], raw_smp_processor_id())->mibs[field] += addend) + do { \ + per_cpu_ptr(mib[1], get_cpu())->mibs[field] += addend; \ + put_cpu(); \ + } while (0) #endif -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
