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[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 <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Herbert Xu 2007-12-20 04:13:21 -08:00 committed by David S. Miller
parent 2caf62f6ca
commit d647b36a69
1 changed files with 17 additions and 4 deletions
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21
include/net/snmp.h
View File

@ -23,6 +23,7 @@
#include <linux/cache.h>
#include <linux/snmp.h>
#include <linux/smp.h>
/*
* Mibs are stored in array of unsigned long.
@ -135,14 +136,26 @@ struct linux_mib {
#define SNMP_INC_STATS_BH(mib, field) \
(per_cpu_ptr(mib[0], raw_smp_processor_id())->mibs[field]++)
#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]++)
do { \
per_cpu_ptr(mib[!in_softirq()], get_cpu())->mibs[field]++; \
put_cpu(); \
} while (0)
#define SNMP_DEC_STATS(mib, field) \
(per_cpu_ptr(mib[!in_softirq()], raw_smp_processor_id())->mibs[field]--)
do { \
per_cpu_ptr(mib[!in_softirq()], get_cpu())->mibs[field]--; \
put_cpu(); \
} while (0)
#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