diff mbox series

[net,1/5] net: lan966x: Fix taking rtnl_lock while holding spin_lock

Message ID 20220714194040.231651-2-horatiu.vultur@microchip.com (mailing list archive)
State Accepted
Commit 45533a534a45cb12c20c81615d17306176cb1c57
Delegated to: Netdev Maintainers
Headers show
Series net: lan966x: Fix issues with MAC table | expand

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Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 7 of 7 maintainers
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning WARNING: line length of 82 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Horatiu Vultur July 14, 2022, 7:40 p.m. UTC
When the HW deletes an entry in MAC table then it generates an
interrupt. The SW will go through it's own list of MAC entries and if it
is not found then it would notify the listeners about this. The problem
is that when the SW will go through it's own list it would take a spin
lock(lan966x->mac_lock) and when it notifies that the entry is deleted.
But to notify the listeners it taking the rtnl_lock which is illegal.

This is fixed by instead of notifying right away that the entry is
deleted, move the entry on a temp list and once, it checks all the
entries then just notify that the entries from temp list are deleted.

Fixes: 5ccd66e01cbe ("net: lan966x: add support for interrupts from analyzer")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
---
 .../ethernet/microchip/lan966x/lan966x_mac.c  | 27 ++++++++++++-------
 1 file changed, 18 insertions(+), 9 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
index 005e56ea5da1..2d2b83c03796 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
@@ -325,10 +325,13 @@  static void lan966x_mac_irq_process(struct lan966x *lan966x, u32 row,
 {
 	struct lan966x_mac_entry *mac_entry, *tmp;
 	unsigned char mac[ETH_ALEN] __aligned(2);
+	struct list_head mac_deleted_entries;
 	u32 dest_idx;
 	u32 column;
 	u16 vid;
 
+	INIT_LIST_HEAD(&mac_deleted_entries);
+
 	spin_lock(&lan966x->mac_lock);
 	list_for_each_entry_safe(mac_entry, tmp, &lan966x->mac_entries, list) {
 		bool found = false;
@@ -362,20 +365,26 @@  static void lan966x_mac_irq_process(struct lan966x *lan966x, u32 row,
 		}
 
 		if (!found) {
-			/* Notify the bridge that the entry doesn't exist
-			 * anymore in the HW and remove the entry from the SW
-			 * list
-			 */
-			lan966x_mac_notifiers(SWITCHDEV_FDB_DEL_TO_BRIDGE,
-					      mac_entry->mac, mac_entry->vid,
-					      lan966x->ports[mac_entry->port_index]->dev);
-
 			list_del(&mac_entry->list);
-			kfree(mac_entry);
+			/* Move the entry from SW list to a tmp list such that
+			 * it would be deleted later
+			 */
+			list_add_tail(&mac_entry->list, &mac_deleted_entries);
 		}
 	}
 	spin_unlock(&lan966x->mac_lock);
 
+	list_for_each_entry_safe(mac_entry, tmp, &mac_deleted_entries, list) {
+		/* Notify the bridge that the entry doesn't exist
+		 * anymore in the HW
+		 */
+		lan966x_mac_notifiers(SWITCHDEV_FDB_DEL_TO_BRIDGE,
+				      mac_entry->mac, mac_entry->vid,
+				      lan966x->ports[mac_entry->port_index]->dev);
+		list_del(&mac_entry->list);
+		kfree(mac_entry);
+	}
+
 	/* Now go to the list of columns and see if any entry was not in the SW
 	 * list, then that means that the entry is new so it needs to notify the
 	 * bridge.