[dpdk-stable] patch 'igb_uio: allow multi-process access' has been queued to LTS release 17.11.1

[Yuanhan Liu]

Hi,

FYI, your patch has been queued to LTS release 17.11.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 01/26/18. So please
shout if anyone has objections.

Thanks.

	--yliu

---
>From caedec7911c6f04ceb41a777ca3665b8df44e329 Mon Sep 17 00:00:00 2001
From: Xiao Wang <xiao.w.wang at intel.com>
Date: Mon, 1 Jan 2018 14:00:10 -0800
Subject: [PATCH] igb_uio: allow multi-process access

[ upstream commit 19685d5aa79c2f86486b0afee6db4c7a280ea7b3 ]

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 at intel.com>
Acked-by: Ferruh Yigit <ferruh.yigit at intel.com>
---
 lib/librte_eal/linuxapp/igb_uio/igb_uio.c | 18 ++++++++++++++++++
 1 file changed, 18 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..1826adb 100644
--- a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
+++ b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
@@ -45,6 +45,8 @@ struct rte_uio_pci_dev {
 	struct uio_info info;
 	struct pci_dev *pdev;
 	enum rte_intr_mode mode;
+	struct mutex lock;
+	int refcnt;
 };
 
 static char *intr_mode;
@@ -336,11 +338,18 @@ igbuio_pci_open(struct uio_info *info, struct inode *inode)
 	struct pci_dev *dev = udev->pdev;
 	int err;
 
+	mutex_lock(&udev->lock);
+	if (++udev->refcnt > 1) {
+		mutex_unlock(&udev->lock);
+		return 0;
+	}
+
 	/* set bus master, which was cleared by the reset function */
 	pci_set_master(dev);
 
 	/* enable interrupts */
 	err = igbuio_pci_enable_interrupts(udev);
+	mutex_unlock(&udev->lock);
 	if (err) {
 		dev_err(&dev->dev, "Enable interrupt fails\n");
 		return err;
@@ -354,12 +363,19 @@ igbuio_pci_release(struct uio_info *info, struct inode *inode)
 	struct rte_uio_pci_dev *udev = info->priv;
 	struct pci_dev *dev = udev->pdev;
 
+	mutex_lock(&udev->lock);
+	if (--udev->refcnt > 0) {
+		mutex_unlock(&udev->lock);
+		return 0;
+	}
+
 	/* disable interrupts */
 	igbuio_pci_disable_interrupts(udev);
 
 	/* stop the device from further DMA */
 	pci_clear_master(dev);
 
+	mutex_unlock(&udev->lock);
 	return 0;
 }
 
@@ -480,6 +496,7 @@ igbuio_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	if (!udev)
 		return -ENOMEM;
 
+	mutex_init(&udev->lock);
 	/*
 	 * enable device: ask low-level code to enable I/O and
 	 * memory
@@ -570,6 +587,7 @@ igbuio_pci_remove(struct pci_dev *dev)
 {
 	struct rte_uio_pci_dev *udev = pci_get_drvdata(dev);
 
+	mutex_destroy(&udev->lock);
 	sysfs_remove_group(&dev->dev.kobj, &dev_attr_grp);
 	uio_unregister_device(&udev->info);
 	igbuio_pci_release_iomem(&udev->info);
-- 
2.7.4