diff mbox series

[net,5/5] igb: Always call igb_xdp_ring_update_tail() under Tx lock

Message ID 20240909203842.3109822-6-anthony.l.nguyen@intel.com (mailing list archive)
State Accepted
Commit 27717f8b17c098c4373ddb8fe89e1a1899c7779d
Delegated to: Netdev Maintainers
Headers show
Series Intel Wired LAN Driver Updates 2024-09-09 (ice, igb) | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 16 this patch: 16
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 10 of 10 maintainers
netdev/build_clang success Errors and warnings before: 16 this patch: 16
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
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: 16 this patch: 16
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 57 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 38 this patch: 38
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-09-10--06-00 (tests: 722)

Commit Message

Tony Nguyen Sept. 9, 2024, 8:38 p.m. UTC 
From: Sriram Yagnaraman <sriram.yagnaraman@est.tech>

Always call igb_xdp_ring_update_tail() under __netif_tx_lock, add a comment
and lockdep assert to indicate that. This is needed to share the same TX
ring between XDP, XSK and slow paths. Furthermore, the current XDP
implementation is racy on tail updates.

Fixes: 9cbc948b5a20 ("igb: add XDP support")
Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
[Kurt: Add lockdep assert and fixes tag]
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: George Kuruvinakunnel <george.kuruvinakunnel@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
---
 drivers/net/ethernet/intel/igb/igb_main.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 9dc7c60838ed..1ef4cb871452 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -33,6 +33,7 @@ 
 #include <linux/bpf_trace.h>
 #include <linux/pm_runtime.h>
 #include <linux/etherdevice.h>
+#include <linux/lockdep.h>
 #ifdef CONFIG_IGB_DCA
 #include <linux/dca.h>
 #endif
@@ -2914,8 +2915,11 @@  static int igb_xdp(struct net_device *dev, struct netdev_bpf *xdp)
 	}
 }
 
+/* This function assumes __netif_tx_lock is held by the caller. */
 static void igb_xdp_ring_update_tail(struct igb_ring *ring)
 {
+	lockdep_assert_held(&txring_txq(ring)->_xmit_lock);
+
 	/* Force memory writes to complete before letting h/w know there
 	 * are new descriptors to fetch.
 	 */
@@ -3000,11 +3004,11 @@  static int igb_xdp_xmit(struct net_device *dev, int n,
 		nxmit++;
 	}
 
-	__netif_tx_unlock(nq);
-
 	if (unlikely(flags & XDP_XMIT_FLUSH))
 		igb_xdp_ring_update_tail(tx_ring);
 
+	__netif_tx_unlock(nq);
+
 	return nxmit;
 }
 
@@ -8864,12 +8868,14 @@  static void igb_put_rx_buffer(struct igb_ring *rx_ring,
 
 static int igb_clean_rx_irq(struct igb_q_vector *q_vector, const int budget)
 {
+	unsigned int total_bytes = 0, total_packets = 0;
 	struct igb_adapter *adapter = q_vector->adapter;
 	struct igb_ring *rx_ring = q_vector->rx.ring;
-	struct sk_buff *skb = rx_ring->skb;
-	unsigned int total_bytes = 0, total_packets = 0;
 	u16 cleaned_count = igb_desc_unused(rx_ring);
+	struct sk_buff *skb = rx_ring->skb;
+	int cpu = smp_processor_id();
 	unsigned int xdp_xmit = 0;
+	struct netdev_queue *nq;
 	struct xdp_buff xdp;
 	u32 frame_sz = 0;
 	int rx_buf_pgcnt;
@@ -8997,7 +9003,10 @@  static int igb_clean_rx_irq(struct igb_q_vector *q_vector, const int budget)
 	if (xdp_xmit & IGB_XDP_TX) {
 		struct igb_ring *tx_ring = igb_xdp_tx_queue_mapping(adapter);
 
+		nq = txring_txq(tx_ring);
+		__netif_tx_lock(nq, cpu);
 		igb_xdp_ring_update_tail(tx_ring);
+		__netif_tx_unlock(nq);
 	}
 
 	u64_stats_update_begin(&rx_ring->rx_syncp);