Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755586AbbFBLmt (ORCPT ); Tue, 2 Jun 2015 07:42:49 -0400 Received: from mailapp01.imgtec.com ([195.59.15.196]:36148 "EHLO imgpgp01.kl.imgtec.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753116AbbFBLmn (ORCPT ); Tue, 2 Jun 2015 07:42:43 -0400 X-PGP-Universal: processed; by imgpgp01.kl.imgtec.org on Tue, 02 Jun 2015 12:42:41 +0100 Message-ID: <556D96B0.3050409@imgtec.com> Date: Tue, 2 Jun 2015 12:42:40 +0100 From: James Hogan User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Leonid Yegoshin , , , , , , , , , , Subject: Re: [PATCH 3/3] MIPS: bugfix - replace smp_mb with release barrier function in unlocks References: <20150602000818.6668.76632.stgit@ubuntu-yegoshin> <20150602000952.6668.82483.stgit@ubuntu-yegoshin> In-Reply-To: <20150602000952.6668.82483.stgit@ubuntu-yegoshin> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="BUOk0tpjh3b3SKxRuMKslWrcXeCrNGoBj" X-Originating-IP: [192.168.154.110] X-ESG-ENCRYPT-TAG: e4aa9c8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3161 Lines: 93 --BUOk0tpjh3b3SKxRuMKslWrcXeCrNGoBj Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 02/06/15 01:09, Leonid Yegoshin wrote: > Repleace smp_mb() in arch_write_unlock() and __clear_bit_unlock() to Replace. > smp_mb__before_llsc() call which does "release" barrier functionality. >=20 > It seems like it was missed in commit f252ffd50c97dae87b45f1dbad24f7135= 8ccfbd6 > during introduction of "acquire" and "release" semantics. >=20 > Signed-off-by: Leonid Yegoshin > --- > arch/mips/include/asm/bitops.h | 2 +- > arch/mips/include/asm/spinlock.h | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) >=20 > diff --git a/arch/mips/include/asm/bitops.h b/arch/mips/include/asm/bit= ops.h > index 0cf29bd5dc5c..ce9666cf1499 100644 > --- a/arch/mips/include/asm/bitops.h > +++ b/arch/mips/include/asm/bitops.h > @@ -469,7 +469,7 @@ static inline int test_and_change_bit(unsigned long= nr, > */ > static inline void __clear_bit_unlock(unsigned long nr, volatile unsig= ned long *addr) > { > - smp_mb(); > + smp_mb__before_llsc(); > __clear_bit(nr, addr); > } > =20 > diff --git a/arch/mips/include/asm/spinlock.h b/arch/mips/include/asm/s= pinlock.h > index 1fca2e0793dc..7c7f3b2bd3de 100644 > --- a/arch/mips/include/asm/spinlock.h > +++ b/arch/mips/include/asm/spinlock.h > @@ -317,7 +317,7 @@ static inline void arch_write_lock(arch_rwlock_t *r= w) > =20 > static inline void arch_write_unlock(arch_rwlock_t *rw) > { > - smp_mb(); > + smp_mb__before_llsc(); arch_write_unlock appears to just use sw, not sc, and __clear_bit appears to be implemented in plain C, so is smp_mb__before_llsc() really appropriate? Would smp_release() be more accurate/correct in both cases? Cheers James > =20 > __asm__ __volatile__( > " # arch_write_unlock \n" >=20 >=20 --BUOk0tpjh3b3SKxRuMKslWrcXeCrNGoBj Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJVbZawAAoJEGwLaZPeOHZ69DUP/1vPsYAvYTqrU+eyuE9/6vaL o5kqgWNGsdVKgfHaV9jRNU4n/FAWgapLBs+Xod7YgrKxhPFBepTtWTJxXvG7H7NT xsf0xqew71nTczPBln6kA4CppUi4ia88BvHfiXFEtfu2s3Fc5FCnaEO7RQznoqVn i3XtwYxYeS8JVhT7vqMMJJijlNUa0Hy0clpA/TM3UB9kWuN71SebuUeE1ZOWRha4 i1lp4HE8MWbUj3pkWrxdx/HUHrUWKgwDPH97JTjtXsq+lT6FLYMAZ0iZvWn74jPy 7fwrs5mY0yYcsjnGFaRG1yK8gGvzC3yZG7AKPj7Nx2Nlr84QYg/XpDbgc4gxdN+8 kYYtXQcLgnA6zX/lAJeuTcuymgUUNRl4DRJDiRvFU0W5ufp9MyUjHiIPyiO1R+QN 3T0uOj4KSGKkINIEp5hXI/qGrM+uHYE9FyP8qvRuNCi/I+C0kV5MkvVDBOyU43Mh XKKmLIK2uK/k21LEXcUMJPiGiY7/Zd8WQguujNZo9YiD0K+NGMMzxYuZpZPmx6FK kW38MmV9FgVg44yXQKqW+0z+JrgFNFy1BN/P3Kq2x5x7IH3eIxBNwOgBidMm8wDb psK34fYmvqU5cnVZRgxdwdFn/ZEc76feuHp747qPCH/+/GC6W6qVWAMlH//HWtfG fWhMUCEOsvb0SWBCi7pO =Crqs -----END PGP SIGNATURE----- --BUOk0tpjh3b3SKxRuMKslWrcXeCrNGoBj-- -- 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/