From: Tiwei Bie <tiwei.bie@intel.com>
To: Xiao Wang <xiao.w.wang@intel.com>
Cc: ferruh.yigit@intel.com, dev@dpdk.org, stephen@networkplumber.org
Subject: Re: [dpdk-dev] [PATCH v2] igb_uio: allow multi-process access
Date: Tue, 19 Dec 2017 17:04:34 +0800 [thread overview]
Message-ID: <20171219090433.3jymojar7of3mkdm@debian-xvivbkq> (raw)
In-Reply-To: <1513698140-92837-1-git-send-email-xiao.w.wang@intel.com>
Hi,
On Tue, Dec 19, 2017 at 07:42:20AM -0800, Xiao Wang wrote:
> @@ -336,6 +337,10 @@ struct rte_uio_pci_dev {
> struct pci_dev *dev = udev->pdev;
> int err;
>
> + atomic_inc(&udev->refcnt);
> + if (atomic_read(&udev->refcnt) > 1)
The "inc and read" should be atomic. Otherwise below
sequence may happen:
P1: atomic_inc(&udev->refcnt);
P2: atomic_inc(&udev->refcnt);
P1: if (atomic_read(&udev->refcnt) > 1)
P2: if (atomic_read(&udev->refcnt) > 1)
> + return 0;
> +
> /* set bus master, which was cleared by the reset function */
> pci_set_master(dev);
>
> @@ -354,6 +359,10 @@ struct rte_uio_pci_dev {
> struct rte_uio_pci_dev *udev = info->priv;
> struct pci_dev *dev = udev->pdev;
>
> + atomic_dec(&udev->refcnt);
> + if (atomic_read(&udev->refcnt) > 0)
> + return 0;
Ditto.
Best regards,
Tiwei Bie
> +
> /* disable interrupts */
> igbuio_pci_disable_interrupts(udev);
>
> --
> 1.8.3.1
>
next prev parent reply other threads:[~2017-12-19 9:05 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-09 1:57 [dpdk-dev] [PATCH] " Xiao Wang
2017-12-12 1:38 ` Stephen Hemminger
2017-12-18 15:53 ` Wang, Xiao W
2017-12-19 15:42 ` [dpdk-dev] [PATCH v2] " Xiao Wang
2017-12-19 9:04 ` Tiwei Bie [this message]
2017-12-19 9:23 ` Wang, Xiao W
2017-12-19 15:39 ` Stephen Hemminger
2017-12-19 17:58 ` [dpdk-dev] [PATCH v3] " Xiao Wang
2017-12-20 2:17 ` Tiwei Bie
2018-01-01 22:00 ` [dpdk-dev] [PATCH v4] " Xiao Wang
2018-01-16 19:43 ` Ferruh Yigit
2018-01-16 23:37 ` Thomas Monjalon
2018-03-08 21:17 ` [dpdk-dev] [PATCH] " Stephen Hemminger
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