This is going to be used by irqtime accounting. The scheduler accesses irqtime from fast-path where preemption is already disabled.
Cc: Benjamin Herrenschmidt <[email protected]> Cc: Heiko Carstens <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Martin Schwidefsky <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Tony Luck <[email protected]> Cc: Wu Fengguang <[email protected]> Signed-off-by: Frederic Weisbecker <[email protected]> --- include/linux/u64_stats_sync.h | 35 +++++++++++++++++++++++------------ 1 file changed, 23 insertions(+), 12 deletions(-) diff --git a/include/linux/u64_stats_sync.h b/include/linux/u64_stats_sync.h index 4b4439e..20c26dc 100644 --- a/include/linux/u64_stats_sync.h +++ b/include/linux/u64_stats_sync.h @@ -88,29 +88,40 @@ static inline void u64_stats_update_end(struct u64_stats_sync *syncp) #endif } +/* Preempt-unsafe version of u64_stats_fetch_begin */ +static inline unsigned int __u64_stats_fetch_begin(const struct u64_stats_sync *syncp) +{ +#if BITS_PER_LONG==32 && defined(CONFIG_SMP) + return read_seqcount_begin(&syncp->seq); +#endif + return 0; +} + +/* Preempt-unsafe version of u64_stats_fetch_retry */ +static inline bool __u64_stats_fetch_retry(const struct u64_stats_sync *syncp, + unsigned int start) +{ +#if BITS_PER_LONG==32 && defined(CONFIG_SMP) + return read_seqcount_retry(&syncp->seq, start); +#endif + return false; +} + static inline unsigned int u64_stats_fetch_begin(const struct u64_stats_sync *syncp) { -#if BITS_PER_LONG==32 && defined(CONFIG_SMP) - return read_seqcount_begin(&syncp->seq); -#else -#if BITS_PER_LONG==32 +#if BITS_PER_LONG==32 && !defined(CONFIG_SMP) preempt_disable(); #endif - return 0; -#endif + return __u64_stats_fetch_begin(syncp); } static inline bool u64_stats_fetch_retry(const struct u64_stats_sync *syncp, unsigned int start) { -#if BITS_PER_LONG==32 && defined(CONFIG_SMP) - return read_seqcount_retry(&syncp->seq, start); -#else -#if BITS_PER_LONG==32 +#if BITS_PER_LONG==32 && !defined(CONFIG_SMP) preempt_enable(); #endif - return false; -#endif + return __u64_stats_fetch_retry(syncp, start); } /* -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
