net: mana: Fix debugfs directory naming and file lifecycle

This series fixes two pre-existing debugfs issues in the MANA driver.

Patch 1 fixes the per-device debugfs directory naming to use the unique PCI BDF address via pci_name(), avoiding a potential NULL pointer dereference when pdev->slot is NULL (e.g. VFIO passthrough, nested KVM) and preventing name collisions across multiple PFs or VFs.

Patch 2 moves the current_speed debugfs file creation from mana_probe_port() to mana_init_port() so it survives detach/attach cycles triggered by MTU changes or XDP program changes.

Erni Sri Satya Vennela (2):
net: mana: Use pci_name() for debugfs directory naming
net: mana: Move current_speed debugfs file to mana_init_port()

 drivers/net/ethernet/microsoft/mana/gdma_main.c | 7 ++-----
 drivers/net/ethernet/microsoft/mana/mana_en.c   | 4 ++--
 2 files changed, 4 insertions(+), 7 deletions(-)

2.34.1

Use pci_name(pdev) for the per-device debugfs directory instead of hardcoded "0" for PFs and pci_slot_name(pdev->slot) for VFs. The previous approach had two issues:

1. pci_slot_name() dereferences pdev->slot, which can be NULL for VFs in environments like generic VFIO passthrough or nested KVM, causing a NULL pointer dereference.

2. Multiple PFs would all use "0", and VFs across different PCI domains or buses could share the same slot name, leading to -EEXIST errors from debugfs_create_dir().

pci_name(pdev) returns the unique BDF address, is always valid, and is unique across the system.

---
 drivers/net/ethernet/microsoft/mana/gdma_main.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

index 43741cd35af8..098fbda0d128 100644
@@ -2065,11 +2065,8 @@ static int mana_gd_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	gc->dev = &pdev->dev;
 	xa_init(&gc->irq_contexts);
 
-	if (gc->is_pf)
-		gc->mana_pci_debugfs = debugfs_create_dir("0", mana_debugfs_root);
-	else
-		gc->mana_pci_debugfs = debugfs_create_dir(pci_slot_name(pdev->slot),
-							  mana_debugfs_root);
+	gc->mana_pci_debugfs = debugfs_create_dir(pci_name(pdev),
+						  mana_debugfs_root);
 
 	err = mana_gd_setup(pdev);
 	if (err)

2.34.1

Move the current_speed debugfs file creation from mana_probe_port() to mana_init_port(). The file was previously created only during initial probe, but mana_cleanup_port_context() removes the entire vPort debugfs directory during detach/attach cycles. Since mana_init_port() recreates the directory on re-attach, moving current_speed here ensures it survives these cycles.

---
 drivers/net/ethernet/microsoft/mana/mana_en.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 07630322545f..6302432b9bf6 100644
@@ -3154,6 +3154,8 @@ static int mana_init_port(struct net_device *ndev)
 	eth_hw_addr_set(ndev, apc->mac_addr);
 	sprintf(vport, "vport%d", port_idx);
 	apc->mana_port_debugfs = debugfs_create_dir(vport, gc->mana_pci_debugfs);
+	debugfs_create_u32("current_speed", 0400, apc->mana_port_debugfs,
+			   &apc->speed);
 	return 0;
 
 reset_apc:

@@ -3432,8 +3434,6 @@ static int mana_probe_port(struct mana_context *ac, int port_idx,
 
 	netif_carrier_on(ndev);
 
-	debugfs_create_u32("current_speed", 0400, apc->mana_port_debugfs, &apc->speed);
-
 	return 0;
 
 free_indir:

2.34.1