Commit-ID:  68107df5f2cb5dc3785be40162bfe2f19a178bbb
Gitweb:     http://git.kernel.org/tip/68107df5f2cb5dc3785be40162bfe2f19a178bbb
Author:     Frederic Weisbecker <[email protected]>
AuthorDate: Mon, 26 Sep 2016 02:29:19 +0200
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 30 Sep 2016 11:46:40 +0200

u64_stats: Introduce IRQs disabled helpers

Introduce light versions of u64_stats helpers for context where
either preempt or IRQs are disabled. This way we can make this library
usable by scheduler irqtime accounting which currenty implement its
ad-hoc version.

Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Wanpeng Li <[email protected]>
Link: 
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
 include/linux/u64_stats_sync.h | 45 ++++++++++++++++++++++--------------------
 1 file changed, 24 insertions(+), 21 deletions(-)

diff --git a/include/linux/u64_stats_sync.h b/include/linux/u64_stats_sync.h
index d3a2bb7..650f3dd 100644
--- a/include/linux/u64_stats_sync.h
+++ b/include/linux/u64_stats_sync.h
@@ -103,31 +103,42 @@ static inline void u64_stats_update_end_raw(struct 
u64_stats_sync *syncp)
 #endif
 }
 
-static inline unsigned int u64_stats_fetch_begin(const struct u64_stats_sync 
*syncp)
+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
-       preempt_disable();
-#endif
        return 0;
 #endif
 }
 
-static inline bool u64_stats_fetch_retry(const struct u64_stats_sync *syncp,
+static inline unsigned int u64_stats_fetch_begin(const struct u64_stats_sync 
*syncp)
+{
+#if BITS_PER_LONG==32 && !defined(CONFIG_SMP)
+       preempt_disable();
+#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
-       preempt_enable();
-#endif
        return false;
 #endif
 }
 
+static inline bool u64_stats_fetch_retry(const struct u64_stats_sync *syncp,
+                                        unsigned int start)
+{
+#if BITS_PER_LONG==32 && !defined(CONFIG_SMP)
+       preempt_enable();
+#endif
+       return __u64_stats_fetch_retry(syncp, start);
+}
+
 /*
  * In case irq handlers can update u64 counters, readers can use following 
helpers
  * - SMP 32bit arches use seqcount protection, irq safe.
@@ -136,27 +147,19 @@ static inline bool u64_stats_fetch_retry(const struct 
u64_stats_sync *syncp,
  */
 static inline unsigned int u64_stats_fetch_begin_irq(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)
        local_irq_disable();
 #endif
-       return 0;
-#endif
+       return __u64_stats_fetch_begin(syncp);
 }
 
 static inline bool u64_stats_fetch_retry_irq(const struct u64_stats_sync 
*syncp,
-                                        unsigned int start)
+                                            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)
        local_irq_enable();
 #endif
-       return false;
-#endif
+       return __u64_stats_fetch_retry(syncp, start);
 }
 
 #endif /* _LINUX_U64_STATS_SYNC_H */

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