Return-path: Received: from mail-pa0-f48.google.com ([209.85.220.48]:42794 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752045AbaBRURn (ORCPT ); Tue, 18 Feb 2014 15:17:43 -0500 Received: by mail-pa0-f48.google.com with SMTP id kx10so17158566pab.7 for ; Tue, 18 Feb 2014 12:17:42 -0800 (PST) MIME-Version: 1.0 Reply-To: andrea.merello@gmail.com In-Reply-To: <20140218192239.GP26776@mwanda> References: <1392685846-10116-1-git-send-email-andrea.merello@gmail.com> <1392685846-10116-4-git-send-email-andrea.merello@gmail.com> <20140218093135.GJ26776@mwanda> <20140218182714.GO26776@mwanda> <20140218192239.GP26776@mwanda> From: Andrea Merello Date: Tue, 18 Feb 2014 21:17:22 +0100 Message-ID: (sfid-20140218_211746_510945_181B535F) Subject: Re: [PATCH 3/7] rtl818x: check for pci_map_single() success when initializing RX ring To: Dan Carpenter Cc: John Linville , Linux Wireless List , Larry Finger , Bernhard Schiffner , Huqiu Liu Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: Ok, I will fix my patch in this way. I will resend it. Should I also rebase following patches in the patch serie and resent them also? Thanks Andrea On Tue, Feb 18, 2014 at 8:22 PM, Dan Carpenter wrote: > On Tue, Feb 18, 2014 at 08:06:51PM +0100, Andrea Merello wrote: >> Thank for pointing out this. Yes, I probably exaggerated trying hard >> to allocate memory. >> >> If your point is about if pci_map_single may or not ever fail in real >> life (that is was I thought you meant in your first mail), then I >> think that it's worth to keep the check anyway (I think it could >> happen). > > Please keep the check. > >> >> If your point is that it can be not so much useful to try and retry >> hard the allocation (I must admit I'm not even sure that after freeing >> the skb the kernel will not likely re-allocate the same one at the >> next try), then I will keep the error check, but I can remove code >> that retries allocation (failing at the first error as you suggested). > > Yes. Please remove the retry code unless there is some real life > justification for it where you have seen partial allocations before. > >> >> BTW consider that the allocation is done in ieee80211 start callback, >> that is called every time the interface is brought down/up, and not >> once at the begining. >> > > You are right. I didn't realize that. > >> On one hand I cared avoiding wasting memory when the interface is not up. >> On the other hand I had thought also to move memory allocation in >> initialization, exactly to increase success probability as you pointed >> out.. >> >> I chosen the first option because after the interface is brought up, >> the RX ant TX processes will start to perform a lot of other skb >> allocations and dma maps. >> If we assume, as you pointed out, they will likely ALL fail or >> succeeds, not just few of them, then probably even if we allocated >> some memory at init time, we have gained not advantage. >> >> Do you agree ? > > Yes. > > regards, > dan carpenter > >