From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9923C43331 for ; Wed, 1 Apr 2020 13:46:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 79ADA20776 for ; Wed, 1 Apr 2020 13:46:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="y6eQIehs" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 79ADA20776 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 11E148E0005; Wed, 1 Apr 2020 09:46:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0A8528E0001; Wed, 1 Apr 2020 09:46:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ED8AC8E0005; Wed, 1 Apr 2020 09:46:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0025.hostedemail.com [216.40.44.25]) by kanga.kvack.org (Postfix) with ESMTP id D1CA68E0001 for ; Wed, 1 Apr 2020 09:46:48 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id A65263A97 for ; Wed, 1 Apr 2020 13:46:48 +0000 (UTC) X-FDA: 76659411696.24.idea41_759ef54d9fc07 X-HE-Tag: idea41_759ef54d9fc07 X-Filterd-Recvd-Size: 3988 Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by imf08.hostedemail.com (Postfix) with ESMTP for ; Wed, 1 Apr 2020 13:46:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=bTIg9/frqj0tTmLnxet1vx3Kwof9z52T8v82iLta588=; b=y6eQIehsd2lZKBw1GndVjHgXhl vWkm5POiPtUDt57kOlC7uLCeVBM6X1K7RdasXLf2u8Njydm09956qElYR5pDt15OJtr+bZs5y74tO XApkXUNA98fOOyXuKaDa+sAZ+kZYdKTafno0qXG2AHWhEETysieDAZpfYo2PigDDCcV6d3ZPAZlkK fcsDaG/9FI8an+McCvzI/hfHmtPr1IGBN6kpiFwgfQygtv/uS69LKENzXhyGEC5RSGDNFcpFqqT4C 7KRhSsAHCG6qFH5yQ+IeC0ObsAwoSf0HWQQ9HFcGskVEqKjd8z7EdqBgynfsz1Gk2BvGtTB5e9aGi LTgdf+cQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jJdhU-0005xz-CH; Wed, 01 Apr 2020 13:46:36 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 1AF6930610E; Wed, 1 Apr 2020 15:46:34 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 0456F29D86172; Wed, 1 Apr 2020 15:46:33 +0200 (CEST) Date: Wed, 1 Apr 2020 15:46:33 +0200 From: Peter Zijlstra To: Michel Lespinasse Cc: Andrew Morton , linux-mm , LKML , Laurent Dufour , Vlastimil Babka , Matthew Wilcox , Liam Howlett , Jerome Glisse , Davidlohr Bueso , David Rientjes , Hugh Dickins , Ying Han , Jason Gunthorpe , Markus Elfring Subject: Re: [PATCH v3 07/10] mmap locking API: add mmap_read_release() and mmap_read_unlock_non_owner() Message-ID: <20200401134633.GS20696@hirez.programming.kicks-ass.net> References: <20200327225102.25061-1-walken@google.com> <20200327225102.25061-8-walken@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200327225102.25061-8-walken@google.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Mar 27, 2020 at 03:50:59PM -0700, Michel Lespinasse wrote: > Add a couple APIs to allow splitting mmap_read_unlock() into two calls: > - mmap_read_release(), called by the task that had taken the mmap lock; > - mmap_read_unlock_non_owner(), called from a work queue. > > These apis are used by kernel/bpf/stackmap.c only. That code is an absolute abomination and should never have gotten merged. That said; I would prefer a mmap_read_trylock_nonowner() over mmap_read_release() existing. > Signed-off-by: Michel Lespinasse > --- > include/linux/mmap_lock.h | 10 ++++++++++ > kernel/bpf/stackmap.c | 9 ++++----- > 2 files changed, 14 insertions(+), 5 deletions(-) > > diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h > index 36fb758401d6..a80cf9695514 100644 > --- a/include/linux/mmap_lock.h > +++ b/include/linux/mmap_lock.h > @@ -62,4 +62,14 @@ static inline void mmap_read_unlock(struct mm_struct *mm) > up_read(&mm->mmap_sem); > } > > +static inline void mmap_read_release(struct mm_struct *mm, unsigned long ip) > +{ > + rwsem_release(&mm->mmap_sem.dep_map, ip); > +} > + > +static inline void mmap_read_unlock_non_owner(struct mm_struct *mm) > +{ > + up_read_non_owner(&mm->mmap_sem); > +} > + > #endif /* _LINUX_MMAP_LOCK_H */