[dpdk-dev] [PATCH] mlx4: avoid init errors when kernel modules are not loaded

[Adrien Mazarguil <adrien.mazarguil@6wind.com>]

Mimic UIO/VFIO drivers behavior by not causing errors when a device cannot
be initialized due to missing or mismatching kernel modules. Display helpful
messages instead, such as:

 [...]
 EAL: PCI device 0000:83:00.0 on NUMA socket 1
 EAL:   probe driver: 15b3:1007 librte_pmd_mlx4
 PMD: librte_pmd_mlx4: PCI information matches, using device "mlx4_0" (VF: false)
 PMD: librte_pmd_mlx4: cannot use device, are drivers up to date?
 EAL: PCI device 0000:84:00.0 on NUMA socket 1
 EAL:   probe driver: 15b3:1007 librte_pmd_mlx4
 PMD: librte_pmd_mlx4: PCI information matches, using device "mlx4_1" (VF: false)
 PMD: librte_pmd_mlx4: cannot use device, are drivers up to date?
 EAL: No probed ethernet devices
 [...]

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
---
 lib/librte_pmd_mlx4/mlx4.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/lib/librte_pmd_mlx4/mlx4.c b/lib/librte_pmd_mlx4/mlx4.c
index 492cbbf..12d9379 100644
--- a/lib/librte_pmd_mlx4/mlx4.c
+++ b/lib/librte_pmd_mlx4/mlx4.c
@@ -4425,6 +4425,10 @@ mlx4_pci_devinit(struct rte_pci_driver *pci_drv, struct rte_pci_device *pci_dev)
 	list = ibv_get_device_list(&i);
 	if (list == NULL) {
 		assert(errno);
+		if (errno == ENOSYS) {
+			WARN("cannot list devices, is ib_uverbs loaded?");
+			return 0;
+		}
 		return -errno;
 	}
 	assert(i >= 0);
@@ -4453,9 +4457,15 @@ mlx4_pci_devinit(struct rte_pci_driver *pci_drv, struct rte_pci_device *pci_dev)
 		break;
 	}
 	if (attr_ctx == NULL) {
-		if (err == 0)
-			err = ENODEV;
 		ibv_free_device_list(list);
+		switch (err) {
+		case 0:
+			WARN("cannot access device, is mlx4_ib loaded?");
+			return 0;
+		case EINVAL:
+			WARN("cannot use device, are drivers up to date?");
+			return 0;
+		}
 		assert(err > 0);
 		return -err;
 	}
-- 
2.1.0