From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Blunck Subject: Re: [PATCH v6 05/11] bus: introduce hotplug functionality Date: Wed, 28 Jun 2017 13:58:32 +0200 Message-ID: References: <4639959.eMbdazoqpE@xps> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: dev , Gaetan Rivet To: Thomas Monjalon Return-path: Received: from mail-wr0-f181.google.com (mail-wr0-f181.google.com [209.85.128.181]) by dpdk.org (Postfix) with ESMTP id 635C12C13 for ; Wed, 28 Jun 2017 13:58:33 +0200 (CEST) Received: by mail-wr0-f181.google.com with SMTP id c11so173268651wrc.3 for ; Wed, 28 Jun 2017 04:58:33 -0700 (PDT) In-Reply-To: <4639959.eMbdazoqpE@xps> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Wed, Jun 28, 2017 at 1:44 PM, Thomas Monjalon wrote: > 27/06/2017 21:03, Jan Blunck: >> On Tue, Jun 27, 2017 at 6:11 PM, Gaetan Rivet wrote: >> > --- a/lib/librte_eal/common/include/rte_bus.h >> > +++ b/lib/librte_eal/common/include/rte_bus.h >> > /** >> > + * Implementation specific probe function which is responsible for linking >> > + * devices on that bus with applicable drivers. >> > + * The plugged device might already have been used previously by the bus, >> > + * in which case some buses might prefer to detect and re-use the relevant >> > + * information pertaining to this device. >> > + * >> > + * @param da >> > + * Device declaration. >> > + * >> > + * @return >> > + * The pointer to a valid rte_device usable by the bus on success. >> > + * NULL on error. rte_errno is then set. >> > + */ >> > +typedef struct rte_device * (*rte_bus_plug_t)(struct rte_devargs *da); >> >> Shouldn't this be orthogonal to unplug() and take a rte_device. You >> should only be able to plug devices that have been found by scan >> before. > > Plugging a device that has been scanned before is a special case. > In a true hotplug scenario, we could use this plug function passing > a devargs. > I don't see any issue passing rte_devargs to plug and rte_device to unplug. What do you mean by "true hotplug"? The problem with this is that passing just rte_devargs to plug() requires the bus to parse and enrich the rte_devargs with bus specifics. From there it gets folded into the to-be-created bus specific rte_XXX_device. This makes it unnecessarily complicated and even worse it adds a second code path how devices come alive. When we get notified about a hotplug event we already know which bus this event belongs to: 1. scan the bus for incoming devices 2. plug single device with devargs and probe for drivers Makes sense?