From: Stephen Hemminger <stephen@networkplumber.org>
To: Xiao Wang <xiao.w.wang@intel.com>
Cc: ferruh.yigit@intel.com, dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH] igb_uio: allow multi-process access
Date: Thu, 8 Mar 2018 13:17:00 -0800 [thread overview]
Message-ID: <20180308131700.1569797c@xeon-e3> (raw)
In-Reply-To: <1512784653-128951-1-git-send-email-xiao.w.wang@intel.com>
On Fri, 8 Dec 2017 17:57:33 -0800
Xiao Wang <xiao.w.wang@intel.com> 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")
>
> Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
> ---
> 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;
> };
>
> 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)
Minor nit: Parenthesis is unnecessary here.
> + return 0;
> +
> /* 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);
>
You might consider using new reference counting (refcnt_t) in kernel which
protects against accidental under/overflow.
prev parent reply other threads:[~2018-03-08 21:17 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-09 1:57 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
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 ` Stephen Hemminger [this message]
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