[PATCH v19 net-next 1/9] octeontx2-af: Enforce single RVU AF probe

[Ratheesh Kannoth]

There is only one admin-function PCI device per system.
Reject any additional AF probe with -EBUSY so the driver model matches
hardware and automated reviewers can rely on a single bound instance.

Signed-off-by: Ratheesh Kannoth <rkannoth@xxxxxxxxxxx>
---
 drivers/net/ethernet/marvell/octeontx2/af/rvu.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
index 3cf131508ecf..1f0c962e10f4 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
@@ -3542,12 +3542,19 @@ static void rvu_update_module_params(struct rvu *rvu)
 		kpu_profile ? kpu_profile : default_pfl_name, KPU_NAME_LEN);
 }
 
+static atomic_t device_bound = ATOMIC_INIT(0);
+
 static int rvu_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	struct device *dev = &pdev->dev;
 	struct rvu *rvu;
 	int    err;
 
+	if (atomic_cmpxchg(&device_bound, 0, 1) != 0) {
+		dev_warn(dev, "Only one af device is supported.\n");
+		return -EBUSY;
+	}
+
 	rvu = devm_kzalloc(dev, sizeof(*rvu), GFP_KERNEL);
 	if (!rvu)
 		return -ENOMEM;
-- 
2.43.0