diff mbox

[dpdk-dev,v3] igb_uio: allow multi-process access

Message ID 1513706293-133528-1-git-send-email-xiao.w.wang@intel.com (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK

Commit Message

Xiao Wang Dec. 19, 2017, 5:58 p.m. UTC 
  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>
---
v3:
- Use atomic_inc_return instead of atomic_inc and atomic_read.
- Ditto for atomic_dec.

v2:
- Make uio reference counter operation atomic.
---
 lib/librte_eal/linuxapp/igb_uio/igb_uio.c | 7 +++++++
 1 file changed, 7 insertions(+)

Comments

Tiwei Bie Dec. 20, 2017, 2:17 a.m. UTC | #1 
On Tue, Dec 19, 2017 at 09:58:13AM -0800, Xiao Wang wrote:
[...]
>  static char *intr_mode;
> @@ -336,6 +337,9 @@ struct rte_uio_pci_dev {
>  	struct pci_dev *dev = udev->pdev;
>  	int err;
>  
> +	if (atomic_inc_return(&udev->refcnt) > 1)
> +		return 0;
> +

Hmm, ideally, you also need to make sure that other calls
won't return until the setup is actually done.

Best regards,
Tiwei Bie

>  	/* 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 (atomic_dec_return(&udev->refcnt) > 0)
> +		return 0;
> +
>  	/* disable interrupts */
>  	igbuio_pci_disable_interrupts(udev);
>  
> -- 
> 1.8.3.1
>
diff mbox

Patch

diff --git a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
index a3a98c1..8f40c01 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;
+	atomic_t refcnt;
 };
 
 static char *intr_mode;
@@ -336,6 +337,9 @@  struct rte_uio_pci_dev {
 	struct pci_dev *dev = udev->pdev;
 	int err;
 
+	if (atomic_inc_return(&udev->refcnt) > 1)
+		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 (atomic_dec_return(&udev->refcnt) > 0)
+		return 0;
+
 	/* disable interrupts */
 	igbuio_pci_disable_interrupts(udev);