From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Kuo Subject: Re: [PATCH 4/6] Hexagon: check to if we will overflow the signal stack Date: Thu, 04 Apr 2013 11:58:58 -0500 Message-ID: <515DB152.603@codeaurora.org> References: <1365033776-21804-1-git-send-email-rkuo@codeaurora.org> <1365033776-21804-5-git-send-email-rkuo@codeaurora.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: linasvepstas@gmail.com Cc: linux-arch@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk On 04/04/2013 11:25 AM, Linas Vepstas wrote: > On 3 April 2013 19:02, Richard Kuo wrote: > >> + /* check if we would overflow the alt stack */ >> + if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size))) >> + return (void __user __force *)-1UL; > I found the !likely construction confusing, as its doing both a > 'unlikely' (right?) and inverting the argument. It seems clearer, > to idiots like me, to write this as: > > if (on_sig_stack(sp) && unlikely(!on_sig_stack(sp - frame_size))) > > since where checking for overflow, and its unlikely that the overflow happened. > > -- Linas I'm not sure if putting a double negative in there will make it less not easy to understand... -- Sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation