From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f67.google.com (mail-pg0-f67.google.com [74.125.83.67]) by dpdk.org (Postfix) with ESMTP id 7AF13201 for ; Tue, 12 Dec 2017 02:38:59 +0100 (CET) Received: by mail-pg0-f67.google.com with SMTP id e14so12287505pgr.9 for ; Mon, 11 Dec 2017 17:38:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=E5EvYCwaUsFHJsf+PDwTqAW0gj7Ga3PknMqkGDQx+4E=; b=Nj38vYdyTO9EgRtBxtnTfajw9Hp3VZ3RtZN5bQyfSSAiwt7OK7EC8Z7BVH+Gur/ZXm ulNHGh3K9OdvF5nxJl7LBfTmX8LZWRUwFupWuD8vxiezegCH/KBokiV/Sl+gPm2PhAGV SyTr2Nwkpc0zzitXFmV+Kub126/L/VkiuP3EQ4lUjd/G62Lyzk3PUmS+gL3tflnEgrxo EqlDJ38k0+gsM8D4IO/HOegdGDZk/WVBCfRknD4iM9LgjM7DFFRBvG1rYVmX4IdlK9F/ ODxwSOKtGxEhl8N+eZuH7fVrYXfC4WbptivY9MBkbhZ6MZZHqEORFPw68GVv4bgyN0Ll Hi3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=E5EvYCwaUsFHJsf+PDwTqAW0gj7Ga3PknMqkGDQx+4E=; b=F870jLQU0gbCeorx06LezWmbUtWJErycrh1e095ZYrTl1To7EMypx6J8gW5s0MUdIV 5fgo5/Jn4O2ZfsYHiJIhmIs0XrsnluCYOozTY1g4PFuoesEEQ69+Dk0erelM05qhDElb SlZesBavDZk0292ncMKUQAYkRQ6W5zUCLgErA0bfsAMIevrTgkfdTWqLe63cy+AXY2Tg sK9URxXXFoOx9ya73z0OMJJDKXZy2R3jIiyEKiJonZqNdV/3wUDftPYBMLR8w4K3/Jve R566V+IyTwin8ZJ0a65qv6xD/VUxNyDMrX+s8woJI5pElpfao6F9lB0ooIuacyH0E9BB 8ZiQ== X-Gm-Message-State: AKGB3mLa4ebHkn8rVZagylGGkE+nZYk2sq7QAcUPvXnuBhudt+ThACXt /aXjyyAyoxVZz1Sy4MEs/2+N+pJeBQA= X-Google-Smtp-Source: ACJfBotOlfGCI86QdlVMaomDZ7Mr+C6Ed+ESmaxr5isn2wJ/HxSk1RpED8EGJOaDXyws4sSMyh6EGQ== X-Received: by 10.99.115.79 with SMTP id d15mr497059pgn.340.1513042738519; Mon, 11 Dec 2017 17:38:58 -0800 (PST) Received: from xeon-e3 (76-14-207-240.or.wavecable.com. [76.14.207.240]) by smtp.gmail.com with ESMTPSA id s73sm29215191pfi.167.2017.12.11.17.38.58 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 11 Dec 2017 17:38:58 -0800 (PST) Date: Mon, 11 Dec 2017 17:38:55 -0800 From: Stephen Hemminger To: Xiao Wang Cc: ferruh.yigit@intel.com, dev@dpdk.org Message-ID: <20171211173855.3eed4623@xeon-e3> In-Reply-To: <1512784653-128951-1-git-send-email-xiao.w.wang@intel.com> References: <1512784653-128951-1-git-send-email-xiao.w.wang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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: Tue, 12 Dec 2017 01:38:59 -0000 On Fri, 8 Dec 2017 17:57:33 -0800 Xiao Wang wrote: > 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") Yes, this makes sense. > > 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; 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. > }; > > static char *intr_mode; > @@ -336,6 +337,9 @@ struct rte_uio_pci_dev { > struct pci_dev *dev = udev->pdev; > int err; > > + if (++(udev->ref_cnt) > 1) > + return 0; Do not use (unnecessary) parenthesis. C precedence order is well defined. > /* set bus master, which was cleared by the reset function */ > pci_set_master(dev); > > @@ -354,6 +358,9 @@ struct rte_uio_pci_dev { > struct rte_uio_pci_dev *udev = info->priv; > struct pci_dev *dev = udev->pdev; > > + if (--(udev->ref_cnt) > 0) > + return 0; > + > /* disable interrupts */ > igbuio_pci_disable_interrupts(udev); >