From: Richard Knutsson Date: Fri, 04 Jan 2008 06:46:44 +0000 Subject: Re: [PATCH 1/3] ipc: Convert handmade 'max' to max(). Message-Id: <477DD654.1010709@student.ltu.se> List-Id: References: <20071217023555.24944.62155.sendpatchset@thinktank.campus.ltu.se> <20071222022701.1ddd2ae2.akpm@linux-foundation.org> In-Reply-To: <20071222022701.1ddd2ae2.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Andrew Morton Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Sorry for the late response, have been away during the holidays. Andrew Morton wrote: > On Mon, 17 Dec 2007 03:35:55 +0100 (MET) Richard Knutsson wrote: > > >> Convert handmade 'max' to max(). >> >> ... >> >> --- a/ipc/msg.c >> +++ b/ipc/msg.c >> @@ -473,7 +473,7 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf) >> up_read(&msg_ids(ns).rw_mutex); >> if (copy_to_user(buf, &msginfo, sizeof(struct msginfo))) >> return -EFAULT; >> - return (max_id < 0) ? 0 : max_id; >> + return max(max_id, 0); >> > > I don't think I like that much. > > I tend to think of max() as being an arithmetic sort of thing: pick the > largest of two scalars. > > But the code which you're changing is a _logical_ operation. It says "if > ipc_get_maxid() returned an error, then return zero. Otherwise return > whatever ipc_get_maxid() returned". > > Yes, max() will do the right thing here, but I think it's a bit of weird > trick? > > > I mean, if ipc_get_maxid() were a better function, it would return a -ve > errno when something failed rather than the present dopey hard-coded -1. > In which case the code would read > > return IS_ERR_VALUE(max_id) ? 0 : max_id; > > in which case, converting it to max() would be even less appropriate. If > you see what I mean... > Yes, have to agree. Were too quick with the changing... Thanks Richard Knutsson