From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Monjalon Subject: Re: [PATCH v4 18/23] ethdev: Helper to map to struct rte_pci_device Date: Fri, 23 Dec 2016 13:47:42 +0100 Message-ID: <1921808.Bo5Y97VPPb@xps13> References: <1482332986-7599-1-git-send-email-jblunck@infradead.org> <4070328.Wvu0M6jAFZ@xps13> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: dev@dpdk.org, Shreyansh Jain , David Marchand , Stephen Hemminger To: Jan Blunck Return-path: Received: from mail-wm0-f42.google.com (mail-wm0-f42.google.com [74.125.82.42]) by dpdk.org (Postfix) with ESMTP id 7807E201 for ; Fri, 23 Dec 2016 13:47:45 +0100 (CET) Received: by mail-wm0-f42.google.com with SMTP id m1so3566567wme.0 for ; Fri, 23 Dec 2016 04:47:45 -0800 (PST) In-Reply-To: List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 2016-12-23 11:27, Jan Blunck: > On Fri, Dec 23, 2016 at 9:30 AM, Thomas Monjalon > wrote: > > 2016-12-22 19:13, Jan Blunck: > >> On Thu, Dec 22, 2016 at 4:21 PM, Thomas Monjalon > >> wrote: > >> > 2016-12-21 16:09, Jan Blunck: > >> >> PCI drivers could use this helper instead of directly accessing fields of > >> >> rte_eth_dev to map to rte_pci_device. > >> > [...] > >> >> +/** > >> >> + * @internal > >> >> + * Helper for drivers that need to convert from rte_eth_dev to rte_pci_device. > >> >> + */ > >> >> +static inline struct rte_pci_device *__attribute__((always_inline)) > >> >> +rte_eth_dev_to_pci(struct rte_eth_dev *eth_dev) > >> >> +{ > >> >> + return eth_dev->pci_dev; > >> >> +} > >> > > >> > Why adding this function instead of just using DEV_PCI_DEV(eth_dev->device)? > >> > > >> > I think we must try to avoid any PCI (or other bus) reference inside ethdev.h. > >> > >> David requested to move it from rte_pci.h to rte_ethdev.h. > >> > >> It could get forward declared here if one doesn't use it. On the other > >> hand the rte_pci.h would be required to include rte_ethdev.h if we > >> move it. > > > > I think there is a misunderstanding. > > I was just suggesting to drop this function. > > But that would undo the whole purpose of adding a helper. The purpose > of the helper is to map from ethdev to the low-level rte_pci_device. > If we remove this helper all users still need to know how to map to > the embedded device structure. What you ask for also means that the > patch "ethdev: Decouple struct rte_eth_dev from struct rte_pci_device" > needs to change all users of the DEV_PCI_DEV() instead of changing the > helper introduced in this patch. Yes, using RTE_PCI_DEV(eth_dev->device) instead of rte_eth_dev_to_pci(eth_dev). Is it a problem to know that the field name is "device" to access the underlying device characteristics? > Let me summarize the workable options from my perspective: > 1. helper macro to map from eth_dev to pci_dev in rte_pci.h > 2. helper inline function to map from eth_dev to pci_dev in rte_ethdev.h > 3. put helpers into new header file rte_ethdrv.h > > I'm still in favor of the first option but David suggested to remove > it from eal. I could also counter the type-safety argument from > Stephen by adding a type check to it. My proposal is: 4. no helper, use eth_dev->device