Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751362Ab1E1Fle (ORCPT ); Sat, 28 May 2011 01:41:34 -0400 Received: from mail-wy0-f174.google.com ([74.125.82.174]:56349 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751039Ab1E1Flc (ORCPT ); Sat, 28 May 2011 01:41:32 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; b=XElcNHjElvvrB4GN0k6e7O71rUcO2dKorav+g2bj2OcwucDl8EQGoOEVh57gMjvLjc imGZOBGdg0d8KEs6S/Mm6dr2W9W7U5NL3MPTJD9513CgteiXOYxkmNUPDstRUAzpHAR1 dtRqPeoUyaK9zg1KXS0OdtSJ3F8M//sPshmB0= Subject: Re: Kernel crash after using new Intel NIC (igb) From: Eric Dumazet To: Arun Sharma Cc: David Miller , Maximilian Engelhardt , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, StuStaNet Vorstand , Yann Dupont , Denys Fedoryshchenko , Ingo Molnar , Thomas Gleixner In-Reply-To: <20110527211419.GA6793@dev1756.snc6.facebook.com> References: <20110525060609.GA32244@dev1756.snc6.facebook.com> <1306305331.3305.22.camel@edumazet-laptop> <4DDEAA3C.7020502@fb.com> <1306439246.2543.10.camel@edumazet-laptop> <4DDECA9B.8080206@fb.com> <1306447292.2543.32.camel@edumazet-laptop> <4DDEEBC5.80804@fb.com> <1306466831.2543.58.camel@edumazet-laptop> <4DDFE4D6.4010000@fb.com> <1306526219.2533.3.camel@edumazet-laptop> <20110527211419.GA6793@dev1756.snc6.facebook.com> Content-Type: text/plain; charset="UTF-8" Date: Sat, 28 May 2011 07:41:25 +0200 Message-ID: <1306561285.2533.9.camel@edumazet-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2649 Lines: 78 Le vendredi 27 mai 2011 à 14:14 -0700, Arun Sharma a écrit : > The attached works for me for x86_64. Cc'ing Ingo/Thomas for comment. > > -Arun > > atomic: Refactor atomic_add_unless > > Commit 686a7e3 (inetpeer: fix race in unused_list manipulations) > in net-2.6 added a atomic_add_unless_return() variant that tries > to detect 0->1 transitions of an atomic reference count. > > This sounds like a generic functionality that could be expressed > in terms of an __atomic_add_unless() that returned the old value > instead of a bool. > > Signed-off-by: Arun Sharma > --- > arch/x86/include/asm/atomic.h | 22 ++++++++++++++++++---- > 1 files changed, 18 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h > index 952a826..bbdbffe 100644 > --- a/arch/x86/include/asm/atomic.h > +++ b/arch/x86/include/asm/atomic.h > @@ -221,15 +221,15 @@ static inline int atomic_xchg(atomic_t *v, int new) > } > > /** > - * atomic_add_unless - add unless the number is already a given value > + * __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 non-zero if @v was not @u, and zero otherwise. > + * Returns the old value of v > */ > -static inline int atomic_add_unless(atomic_t *v, int a, int u) > +static inline int __atomic_add_unless(atomic_t *v, int a, int u) > { > int c, old; > c = atomic_read(v); > @@ -241,7 +241,21 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u) > break; > c = old; > } > - return c != (u); > + return c; > +} > + > +/** > + * 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 non-zero if @v was not @u, and zero otherwise. > + */ > +static inline int atomic_add_unless(atomic_t *v, int a, int u) > +{ > + return __atomic_add_unless(v, a, u) != u; > } > > #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) As I said, atomic_add_unless() has several implementations in various arches. You must take care of all, not only x86. -- 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/