From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752989AbbJGLtb (ORCPT ); Wed, 7 Oct 2015 07:49:31 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:48813 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751104AbbJGLta (ORCPT ); Wed, 7 Oct 2015 07:49:30 -0400 X-IronPort-AV: E=Sophos;i="5.17,648,1437436800"; d="scan'208";a="308623735" Subject: Re: [PATCH v3 8/9] xen/blkback: pseudo support for multi hardware queues/rings To: Bob Liu References: <1441456782-31318-1-git-send-email-bob.liu@oracle.com> <1441456782-31318-9-git-send-email-bob.liu@oracle.com> <56129282.2060709@citrix.com> <5614F904.3080509@oracle.com> CC: , , , , , , , , , , From: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Message-ID: <561506C5.9050304@citrix.com> Date: Wed, 7 Oct 2015 13:49:25 +0200 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <5614F904.3080509@oracle.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org El 07/10/15 a les 12.50, Bob Liu ha escrit: > > On 10/05/2015 11:08 PM, Roger Pau Monné wrote: >> El 05/09/15 a les 14.39, Bob Liu ha escrit: >>> Prepare patch for multi hardware queues/rings, the ring number was set to 1 by >>> force. >> >> This should be: >> >> Preparatory patch for multiple hardware queues (rings). The number of >> rings is unconditionally set to 1. >> >> But frankly this description is not helpful at all, you should describe >> the preparatory changes and why you need them. >> > > Will update, the purpose is just to make each patch smaller and more readable. > >>> >>> Signed-off-by: Arianna Avanzini >>> Signed-off-by: Bob Liu >>> --- >>> drivers/block/xen-blkback/common.h | 3 +- >>> drivers/block/xen-blkback/xenbus.c | 328 +++++++++++++++++++++++------------- >>> 2 files changed, 209 insertions(+), 122 deletions(-) >>> >>> diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h >>> index cc253d4..ba058a0 100644 >>> --- a/drivers/block/xen-blkback/common.h >>> +++ b/drivers/block/xen-blkback/common.h >>> @@ -339,7 +339,8 @@ struct xen_blkif { >>> unsigned long long st_wr_sect; >>> unsigned int nr_ring_pages; >>> /* All rings for this device */ >>> - struct xen_blkif_ring ring; >>> + struct xen_blkif_ring *rings; >>> + unsigned int nr_rings; >>> }; >>> >>> struct seg_buf { >>> diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c >>> index 6482ee3..04b8d0d 100644 >>> --- a/drivers/block/xen-blkback/xenbus.c >>> +++ b/drivers/block/xen-blkback/xenbus.c >>> @@ -26,6 +26,7 @@ >>> /* Enlarge the array size in order to fully show blkback name. */ >>> #define BLKBACK_NAME_LEN (20) >>> #define RINGREF_NAME_LEN (20) >>> +#define RINGREF_NAME_LEN (20) >> >> Duplicate define? >> > > Will update. > >>> >>> struct backend_info { >>> struct xenbus_device *dev; >>> @@ -84,11 +85,13 @@ static int blkback_name(struct xen_blkif *blkif, char *buf) >>> >>> static void xen_update_blkif_status(struct xen_blkif *blkif) >>> { >>> - int err; >>> + int err, i; >>> char name[BLKBACK_NAME_LEN]; >>> + struct xen_blkif_ring *ring; >>> + char per_ring_name[BLKBACK_NAME_LEN + 2]; >> >> Hm, why don't you just add + 2 to the place where BLKBACK_NAME_LEN is >> defined and use the same character array ("name")? This is just a waste >> of stack. >> > > per_ring_name = name + 'queue number'; > If reuse name[], I'm not sure whether > snprintf(name, BLKBACK_NAME_LEN + 2, "%s-%d", name, i); can work. What I would like to avoid is having two character arrays in the stack when IMHO we can achieve the same with a single array that's long enough. Roger.