PCI/sysfs: Suppress FW_BUG warning when NUMA node already matches

The numa_node sysfs interface allows users to manually override a PCI
device's NUMA node assignment. Currently, every write triggers a FW_BUG
warning and taints the kernel, even when writing the same value that is
already set.

Check if the requested node is already assigned to the device. If it
matches, return success immediately without tainting the kernel or printing
a warning.

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20260317002803.2353-1-lirongqing@baidu.com

Author: lrq-max

drivers/pci/pci-sysfs.c

@@ -378,6 +378,9 @@ static ssize_t numa_node_store(struct device *dev,
 	if (node != NUMA_NO_NODE && !node_online(node))
 		return -EINVAL;
 
+	if (node == dev->numa_node)
+		return count;
+
 	add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
 	pci_alert(pdev, FW_BUG "Overriding NUMA node to %d.  Contact your vendor for updates.",
 		  node);