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author | Thomas Gleixner <tglx@linutronix.de> | 2011-05-14 14:06:36 +0400 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2011-05-14 14:06:36 +0400 |
commit | a18f22a968de17b29f2310cdb7ba69163e65ec15 (patch) | |
tree | a7d56d88fad5e444d7661484109758a2f436129e /include/linux/rcupdate.h | |
parent | a1c57e0fec53defe745e64417eacdbd3618c3e66 (diff) | |
parent | 798778b8653f64b7b2162ac70eca10367cff6ce8 (diff) | |
download | linux-a18f22a968de17b29f2310cdb7ba69163e65ec15.tar.xz |
Merge branch 'consolidate-clksrc-i8253' of master.kernel.org:~rmk/linux-2.6-arm into timers/clocksource
Conflicts:
arch/ia64/kernel/cyclone.c
arch/mips/kernel/i8253.c
arch/x86/kernel/i8253.c
Reason: Resolve conflicts so further cleanups do not conflict further
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/linux/rcupdate.h')
-rw-r--r-- | include/linux/rcupdate.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index af5614856285..ff422d2b7f90 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -339,6 +339,12 @@ extern int rcu_my_thread_group_empty(void); ((typeof(*p) __force __kernel *)(p)); \ }) +#define __rcu_access_index(p, space) \ + ({ \ + typeof(p) _________p1 = ACCESS_ONCE(p); \ + rcu_dereference_sparse(p, space); \ + (_________p1); \ + }) #define __rcu_dereference_index_check(p, c) \ ({ \ typeof(p) _________p1 = ACCESS_ONCE(p); \ @@ -429,6 +435,20 @@ extern int rcu_my_thread_group_empty(void); #define rcu_dereference_raw(p) rcu_dereference_check(p, 1) /*@@@ needed? @@@*/ /** + * rcu_access_index() - fetch RCU index with no dereferencing + * @p: The index to read + * + * Return the value of the specified RCU-protected index, but omit the + * smp_read_barrier_depends() and keep the ACCESS_ONCE(). This is useful + * when the value of this index is accessed, but the index is not + * dereferenced, for example, when testing an RCU-protected index against + * -1. Although rcu_access_index() may also be used in cases where + * update-side locks prevent the value of the index from changing, you + * should instead use rcu_dereference_index_protected() for this use case. + */ +#define rcu_access_index(p) __rcu_access_index((p), __rcu) + +/** * rcu_dereference_index_check() - rcu_dereference for indices with debug checking * @p: The pointer to read, prior to dereferencing * @c: The conditions under which the dereference will take place |