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McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu, patches@linaro.org, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 04/17] rcu: Add a gcc-style structure initializer for RCU pointers Date: Fri, 22 Jun 2012 08:34:59 -0700 Message-Id: <1340379312-6684-4-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.8 In-Reply-To: <1340379312-6684-1-git-send-email-paulmck@linux.vnet.ibm.com> References: <20120622153501.GA6626@linux.vnet.ibm.com> <1340379312-6684-1-git-send-email-paulmck@linux.vnet.ibm.com> X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12062215-4242-0000-0000-0000021531F7 X-Gm-Message-State: ALoCoQkUTRMgOnXsB60vYeCTLjCDIoMx0SkPnP8GDa+AeJiqA25nri83rnvShfYmzphDugYVRGYa From: "Paul E. McKenney" RCU_INIT_POINTER() returns a value that is never used, and which should be abolished due to terminal ugliness: q = RCU_INIT_POINTER(global_p, p); However, there are two uses that cannot be handled by a do-while formulation because they do gcc-style initialization: RCU_INIT_POINTER(.real_cred, &init_cred), RCU_INIT_POINTER(.cred, &init_cred), This usage is clever, but not necessarily the nicest approach. This commit therefore creates an RCU_POINTER_INITIALIZER() macro that is specifically designed for gcc-style initialization. Signed-off-by: Paul E. McKenney Acked-by: David Howells --- include/linux/rcupdate.h | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 26d1a47..88e4e08 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -906,6 +906,14 @@ static inline notrace void rcu_read_unlock_sched_notrace(void) #define RCU_INIT_POINTER(p, v) \ p = (typeof(*v) __force __rcu *)(v) +/** + * RCU_POINTER_INITIALIZER() - statically initialize an RCU protected pointer + * + * GCC-style initialization for an RCU-protected pointer in a structure field. + */ +#define RCU_POINTER_INITIALIZER(p, v) \ + .p = (typeof(*v) __force __rcu *)(v) + static __always_inline bool __is_kfree_rcu_offset(unsigned long offset) { return offset < 4096;