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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 40206C10F0E for ; Mon, 15 Apr 2019 09:04:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0D6B920693 for ; Mon, 15 Apr 2019 09:04:13 +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="ADBYsgvk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727159AbfDOJEL (ORCPT ); Mon, 15 Apr 2019 05:04:11 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:35680 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726408AbfDOJEL (ORCPT ); Mon, 15 Apr 2019 05:04:11 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=6Y1sUvSp25DQUSecTY7gB5Ablwg7tJmCYsxXPYXaofY=; b=ADBYsgvkhZHBuKug0QJGHq1ci T4phB6d8iXS+K9iwMq0c4QH5FByAtv8lmLBqR1Q7S055rBrdZ9FptfWpLAy7ythGFqk41ryTvAyMR +tTBVnE7M9Gvn2vkoFrqv4iknZejfJW/zZOttiYsmzk/yp+4bQMF4IUYVicI+KSP+PBSMLkitrYym 22i8swNam3A85L9f/PyqzxfnnIbmzdaq70F5xjjeWSJUYjQSHUZ/kj/hxdlqgYvSA1QRk2jvKX+ZF sycKqJeyf51iUug0NgOYIM7auyF7kE7khecj9M1QHKyp9vowF7gIOmkURGGNPDVp+akmrOdehUwB4 Opk8QKURA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hFxX7-00005c-Uk; Mon, 15 Apr 2019 09:04:10 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 44B53981E5B; Mon, 15 Apr 2019 11:04:06 +0200 (CEST) Date: Mon, 15 Apr 2019 11:04:06 +0200 From: Peter Zijlstra To: Alexei Starovoitov Cc: Al Viro , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, tj@kernel.org Subject: Re: misuse of fget_raw() in perf_event_get() Message-ID: <20190415090406.GJ2490@worktop.programming.kicks-ass.net> References: <20190413210242.GP2217@ZenIV.linux.org.uk> <20190415044158.5goa2je57j63kwaz@ast-mbp.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190415044158.5goa2je57j63kwaz@ast-mbp.dhcp.thefacebook.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Apr 14, 2019 at 09:42:00PM -0700, Alexei Starovoitov wrote: > On Sat, Apr 13, 2019 at 10:02:42PM +0100, Al Viro wrote: > > What's the point of using fget_raw(), if you do > > _not_ accept O_PATH descriptors? That should be fget()... > > I think you're talking about commit e03e7ee34fdd ("perf/bpf: Convert perf_event_array to use struct file") > I don't really remember why we went with this instead of fget(). > There was a bunch of back and forth back then with Peter. That was mostly on what refcount to use, you wanted to use the event refcount, and I suggested using the file refcount. If you look at: lkml.kernel.org/r/20160126161637.GF6357@twins.programming.kicks-ass.net I too wondered about the fget_raw() at the time, whatever Al wants though, I never quite remember how that file stuff works :/