This is going to be used by irqtime accounting. The scheduler accesses
irqtime from fast-path where preemption is already disabled.
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carst...@de.ibm.com>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Martin Schwidefsky <schwidef...@de.ibm.com>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Rik van Riel <r...@redhat.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Tony Luck <tony.l...@intel.com>
Cc: Wu Fengguang <fengguang...@intel.com>
Signed-off-by: Frederic Weisbecker <fweis...@gmail.com>
---
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
--
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