From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f70.google.com (mail-wm0-f70.google.com [74.125.82.70]) by kanga.kvack.org (Postfix) with ESMTP id 39B6D6B026D for ; Wed, 20 Dec 2017 16:58:43 -0500 (EST) Received: by mail-wm0-f70.google.com with SMTP id 194so3171806wmv.9 for ; Wed, 20 Dec 2017 13:58:43 -0800 (PST) Received: from Galois.linutronix.de (Galois.linutronix.de. [2a01:7a0:2:106d:700::1]) by mx.google.com with ESMTPS id v5si3602837wmg.198.2017.12.20.13.58.42 for (version=TLS1_2 cipher=AES128-SHA bits=128/128); Wed, 20 Dec 2017 13:58:42 -0800 (PST) Message-Id: <20171220215441.852602011@linutronix.de> Date: Wed, 20 Dec 2017 22:35:18 +0100 From: Thomas Gleixner Subject: [patch V181 15/54] x86/mm: Remove superfluous barriers References: <20171220213503.672610178@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0061-x86-mm-Remove-superfluous-barriers.patch Sender: owner-linux-mm@kvack.org List-ID: To: LKML Cc: x86@kernel.org, Linus Torvalds , Andy Lutomirsky , Peter Zijlstra , Dave Hansen , Borislav Petkov , Greg KH , keescook@google.com, hughd@google.com, Brian Gerst , Josh Poimboeuf , Denys Vlasenko , Rik van Riel , Boris Ostrovsky , Juergen Gross , David Laight , Eduardo Valentin , aliguori@amazon.com, Will Deacon , Vlastimil Babka , daniel.gruss@iaik.tugraz.at, Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , linux-mm@kvack.org From: Peter Zijlstra atomic64_inc_return() already implies smp_mb() before and after. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Cc: linux-mm@kvack.org --- arch/x86/include/asm/tlbflush.h | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -60,19 +60,13 @@ static inline void invpcid_flush_all_non static inline u64 inc_mm_tlb_gen(struct mm_struct *mm) { - u64 new_tlb_gen; - /* * Bump the generation count. This also serves as a full barrier * that synchronizes with switch_mm(): callers are required to order * their read of mm_cpumask after their writes to the paging * structures. */ - smp_mb__before_atomic(); - new_tlb_gen = atomic64_inc_return(&mm->context.tlb_gen); - smp_mb__after_atomic(); - - return new_tlb_gen; + return atomic64_inc_return(&mm->context.tlb_gen); } #ifdef CONFIG_PARAVIRT -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org