Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933071Ab1FAA6Q (ORCPT ); Tue, 31 May 2011 20:58:16 -0400 Received: from outmail008.snc4.facebook.com ([66.220.144.140]:54165 "EHLO mx-out.facebook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932638Ab1FAA6O (ORCPT ); Tue, 31 May 2011 20:58:14 -0400 From: Arun Sharma To: linux-kernel@vger.kernel.org Cc: Arun Sharma , Ingo Molnar , David Miller , Andrew Morton , Eric Dumazet Subject: [PATCH] atomic: generalize atomic_add_unless_return Date: Tue, 31 May 2011 17:57:56 -0700 Message-Id: <1306889876-5327-1-git-send-email-asharma@fb.com> X-Mailer: git-send-email 1.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2502 Lines: 84 commit 686a7e3 added this primitive to get something going for the stable branch. Move the primitive to Signed-off-by: Arun Sharma Cc: Ingo Molnar Cc: David Miller Cc: Andrew Morton Cc: Eric Dumazet LKML-Reference: <20110531105019.GF24172@elte.hu> --- include/linux/atomic.h | 14 ++++++++++++++ net/ipv4/inetpeer.c | 17 ++--------------- 2 files changed, 16 insertions(+), 15 deletions(-) diff --git a/include/linux/atomic.h b/include/linux/atomic.h index fc31190..4e2c272 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -17,6 +17,20 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u) } /** + * atomic_add_unless - add unless the number is already a given value + * @v: pointer of type atomic_t + * @a: the amount to add to v... + * @u: ...unless v is equal to u. + * + * Atomically adds @a to @v, so long as @v was not already @u. + * Returns the old value of @v + @a. + */ +static inline int atomic_add_unless_return(atomic_t *v, int a, int u) +{ + return __atomic_add_unless(v, a, u) + a; +} + +/** * atomic_inc_not_zero - increment unless the number is zero * @v: pointer of type atomic_t * diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c index ce616d9..d4190ae 100644 --- a/net/ipv4/inetpeer.c +++ b/net/ipv4/inetpeer.c @@ -203,20 +203,6 @@ static int addr_compare(const struct inetpeer_addr *a, u; \ }) -static bool atomic_add_unless_return(atomic_t *ptr, int a, int u, int *newv) -{ - int cur, old = atomic_read(ptr); - - while (old != u) { - *newv = old + a; - cur = atomic_cmpxchg(ptr, old, *newv); - if (cur == old) - return true; - old = cur; - } - return false; -} - /* * Called with rcu_read_lock() * Because we hold no lock against a writer, its quite possible we fall @@ -239,7 +225,8 @@ static struct inet_peer *lookup_rcu(const struct inetpeer_addr *daddr, * distinction between an unused entry (refcnt=0) and * a freed one. */ - if (!atomic_add_unless_return(&u->refcnt, 1, -1, newrefcnt)) + *newrefcnt = atomic_add_unless_return(&u->refcnt, 1, -1); + if (*newrefcnt == 0) u = NULL; return u; } -- 1.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/