From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751257AbdCOFIw (ORCPT ); Wed, 15 Mar 2017 01:08:52 -0400 Received: from mx2.suse.de ([195.135.220.15]:45202 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751000AbdCOFIv (ORCPT ); Wed, 15 Mar 2017 01:08:51 -0400 Subject: Re: [PATCH v3 4/7] xen/9pfs: connect to the backend To: Stefano Stabellini References: <1489449019-13343-1-git-send-email-sstabellini@kernel.org> <1489449019-13343-4-git-send-email-sstabellini@kernel.org> Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, boris.ostrovsky@oracle.com, Stefano Stabellini , Eric Van Hensbergen , Ron Minnich , Latchesar Ionkov , v9fs-developer@lists.sourceforge.net From: Juergen Gross Message-ID: Date: Wed, 15 Mar 2017 06:08:46 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/03/17 22:22, Stefano Stabellini wrote: > Hi Juergen, > > thank you for the review! > > On Tue, 14 Mar 2017, Juergen Gross wrote: >> On 14/03/17 00:50, Stefano Stabellini wrote: >>> Implement functions to handle the xenbus handshake. Upon connection, >>> allocate the rings according to the protocol specification. >>> >>> Initialize a work_struct and a wait_queue. The work_struct will be used >>> to schedule work upon receiving an event channel notification from the >>> backend. The wait_queue will be used to wait when the ring is full and >>> we need to send a new request. >>> >>> Signed-off-by: Stefano Stabellini >>> CC: boris.ostrovsky@oracle.com >>> CC: jgross@suse.com >>> CC: Eric Van Hensbergen >>> CC: Ron Minnich >>> CC: Latchesar Ionkov >>> CC: v9fs-developer@lists.sourceforge.net >>> --- >> Did you think about using request_threaded_irq() instead of a workqueue? >> For an example see e.g. drivers/scsi/xen-scsifront.c > > I like workqueues :-) It might come down to personal preferences, but I > think workqueues are more flexible and a better fit for this use case. > Not only it is easy to schedule work in a workqueue from the interrupt > handler, but also they can be used for sleeping in the request function > if there is not enough room on the ring. Besides, they can easily be > configured to share a single thread or to have multiple independent > threads. I'm fine with the workqueues as long as you have decided to use them considering the alternatives. :-) >> Can't you use xenbus_read_unsigned() instead of xenbus_read()? > > I can use xenbus_read_unsigned in the other cases below, but not here, > because versions is in the form: "1,3,4" Is this documented somewhere? Hmm, are any of the Xenstore entries documented? Shouldn't this be done in xen_9pfs.h ? Juergen