From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by dpdk.org (Postfix) with ESMTP id 815BBE5D for ; Mon, 18 Dec 2017 16:53:50 +0100 (CET) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Dec 2017 07:53:49 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.45,422,1508828400"; d="scan'208";a="159791024" Received: from fmsmsx106.amr.corp.intel.com ([10.18.124.204]) by orsmga004.jf.intel.com with ESMTP; 18 Dec 2017 07:53:48 -0800 Received: from fmsmsx155.amr.corp.intel.com (10.18.116.71) by FMSMSX106.amr.corp.intel.com (10.18.124.204) with Microsoft SMTP Server (TLS) id 14.3.319.2; Mon, 18 Dec 2017 07:53:39 -0800 Received: from shsmsx152.ccr.corp.intel.com (10.239.6.52) by FMSMSX155.amr.corp.intel.com (10.18.116.71) with Microsoft SMTP Server (TLS) id 14.3.319.2; Mon, 18 Dec 2017 07:53:38 -0800 Received: from shsmsx101.ccr.corp.intel.com ([169.254.1.159]) by SHSMSX152.ccr.corp.intel.com ([169.254.6.93]) with mapi id 14.03.0319.002; Mon, 18 Dec 2017 23:53:37 +0800 From: "Wang, Xiao W" To: Stephen Hemminger CC: "Yigit, Ferruh" , "dev@dpdk.org" Thread-Topic: [dpdk-dev] [PATCH] igb_uio: allow multi-process access Thread-Index: AQHTcJDERXZz4GzGOEmIIDhNzAQk8aM+bLOAgArg3YA= Date: Mon, 18 Dec 2017 15:53:36 +0000 Message-ID: References: <1512784653-128951-1-git-send-email-xiao.w.wang@intel.com> <20171211173855.3eed4623@xeon-e3> In-Reply-To: <20171211173855.3eed4623@xeon-e3> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ctpclassification: CTP_IC x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiNDAyZjEyM2EtMjU4My00ZWYxLTg1MGItOTI3Y2Y1ODE2MWM0IiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX0lDIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE3LjIuNS4xOCIsIlRydXN0ZWRMYWJlbEhhc2giOiJ5VnMwUjFLMHBzcXNwS1BOcWFLQVhBZHJnR29OdWhONHVjVU1HSU5SUE5qRWlzWHozMWlKQjBVRTdKeXZxNHlKIn0= dlp-product: dlpe-windows dlp-version: 11.0.0.116 dlp-reaction: no-action x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH] igb_uio: allow multi-process access X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 18 Dec 2017 15:53:50 -0000 Hi, > -----Original Message----- > From: Stephen Hemminger [mailto:stephen@networkplumber.org] > Sent: Tuesday, December 12, 2017 9:39 AM > To: Wang, Xiao W > Cc: Yigit, Ferruh ; dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH] igb_uio: allow multi-process access >=20 > On Fri, 8 Dec 2017 17:57:33 -0800 > Xiao Wang wrote: >=20 > > In some case, one device are accessed by different processes via > > different BARs, so one uio device may be opened by more than one > > process, for this case we just need to enable interrupt once, and > > pci_clear_master only when the last process closed. > > > > Fixes: 5f6ff30dc507 ("igb_uio: fix interrupt enablement after FLR in VM= ") >=20 >=20 > Yes, this makes sense. >=20 > > > > Signed-off-by: Xiao Wang > > --- > > lib/librte_eal/linuxapp/igb_uio/igb_uio.c | 7 +++++++ > > 1 file changed, 7 insertions(+) > > > > diff --git a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c > b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c > > index a3a98c1..c239d98 100644 > > --- a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c > > +++ b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c > > @@ -45,6 +45,7 @@ struct rte_uio_pci_dev { > > struct uio_info info; > > struct pci_dev *pdev; > > enum rte_intr_mode mode; > > + uint32_t ref_cnt; >=20 > Simple unsigned reference count is not SMP safe on all architectures. > In kernel it is recommended to use refcount_t and associated API's. > Note: refcount_t was introduced in last 2 years and some DPDK users > still have ancient kernels. I think atomic_t associated API will be enough, without worry about kernel = version. >=20 > > }; > > > > static char *intr_mode; > > @@ -336,6 +337,9 @@ struct rte_uio_pci_dev { > > struct pci_dev *dev =3D udev->pdev; > > int err; > > > > + if (++(udev->ref_cnt) > 1) > > + return 0; >=20 > Do not use (unnecessary) parenthesis. C precedence order is well defined. Agree. Will change it in v2. Thanks for your comments, Xiao