From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx198.postini.com [74.125.245.198]) by kanga.kvack.org (Postfix) with SMTP id 3EA8C6B002B for ; Tue, 16 Oct 2012 13:47:11 -0400 (EDT) Received: by mail-da0-f41.google.com with SMTP id i14so3851344dad.14 for ; Tue, 16 Oct 2012 10:47:10 -0700 (PDT) Date: Tue, 16 Oct 2012 23:17:05 +0530 From: Raghavendra D Prabhu Subject: Re: Re: Re: [PATCH 1/5] mm/readahead: Check return value of read_pages Message-ID: <20121016174705.GC2826@Archie> References: <20120922124337.GA17562@localhost> <20120926012503.GA24218@Archie> <20120928115405.GA1525@localhost> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="IMjqdzrDRly81ofr" Content-Disposition: inline In-Reply-To: <20120928115405.GA1525@localhost> Sender: owner-linux-mm@kvack.org List-ID: To: Fengguang Wu Cc: linux-mm@kvack.org, viro@zeniv.linux.org.uk, akpm@linux-foundation.org --IMjqdzrDRly81ofr Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, * On Fri, Sep 28, 2012 at 07:54:05PM +0800, Fengguang Wu wrote: >On Wed, Sep 26, 2012 at 06:55:03AM +0530, Raghavendra D Prabhu wrote: >> >> Hi, >> >> >> * On Sat, Sep 22, 2012 at 08:43:37PM +0800, Fengguang Wu wrote: >> >On Sat, Sep 22, 2012 at 04:03:10PM +0530, raghu.prabhu13@gmail.com wrot= e: >> >>From: Raghavendra D Prabhu >> >> >> >>Return value of a_ops->readpage will be propagated to return value of = read_pages >> >>and __do_page_cache_readahead. >> > >> >That does not explain the intention and benefit of this patch.. >> >> I noticed that force_page_cache_readahead checks return value of >> __do_page_cache_readahead but the actual error if any is never >> propagated. > >force_page_cache_readahead()'s return value, in turn, is never used by >its callers.. Yes, it is not called by its callers, however, since it is called=20 in a loop, shouldn't we bail out if force_page_cache_readahead=20 fails once? Without the appropriate return value, it will=20 continue and in=20 force_page_cache_readahead if (err < 0) { ret =3D err; break; } is never hit. Nor does the other __do_page_cache_readahead() callers >care about the error state. So until we find an actual user of the >error code, I'd recommend to avoid changing the current code. > >Thanks, >Fengguang > Regards, --=20 Raghavendra Prabhu GPG Id : 0xD72BE977 Fingerprint: B93F EBCB 8E05 7039 CD3C A4B8 A616 DCA1 D72B E977 www: wnohang.net --IMjqdzrDRly81ofr Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iQEcBAEBAgAGBQJQfZ2ZAAoJEKYW3KHXK+l3BI0H/2VNkvjgy/bDvjBiKK4CVZLH 61A+s6TVd4Por2P5YvusOt4v9QU+zF6A9XgGQ4Vtss5cqDDg+q1l105ujyeR+tVS ynXpgxAAanGCSMndQDsp0HPRpWOhiaIpsv6b1AFwYLRUQNtOBU4RsdvFu+UudiQw wb+T+Y0PZCnOa7PUqZayXsuQpj2pfTP/od8uQuJod3Py46p8vXH8SqmYlMMaZDi8 tAaMBYE7fIDPFJa8V03z6L8U5RDNrrFcBsfjjEdS4Aek6bjUbU5tesmWcYzpNEj5 +VLwh6isT5S0InfAHA6+5iLCzEp2Ngh5dCxvEO9jopZehP7Uw0r+SLdgjQpqLp4= =Ucuh -----END PGP SIGNATURE----- --IMjqdzrDRly81ofr-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org