diff mbox series

[1/5] net: thunderbolt: Enable DMA paths only after rings are enabled

Message ID 20220830153250.15496-2-mika.westerberg@linux.intel.com (mailing list archive)
State Accepted
Commit ff7cd07f306406493f7b78890475e85b6d0811ed
Delegated to: Netdev Maintainers
Headers show
Series thunderbolt: net: Enable full end-to-end flow control | expand

Checks

Context Check Description
netdev/tree_selection success Guessed tree name to be net-next
netdev/fixes_present success Fixes tag not required for -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: 18 this patch: 18
netdev/cc_maintainers fail 2 blamed authors not CCed: amir.jer.levy@intel.com andriy.shevchenko@linux.intel.com; 2 maintainers not CCed: amir.jer.levy@intel.com andriy.shevchenko@linux.intel.com
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: 18 this patch: 18
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 45 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Mika Westerberg Aug. 30, 2022, 3:32 p.m. UTC
If the other host starts sending packets early on it is possible that we
are still in the middle of populating the initial Rx ring packets to the
ring. This causes the tbnet_poll() to mess over the queue and causes
list corruption. This happens specifically when connected with macOS as
it seems start sending various IP discovery packets as soon as its side
of the paths are configured.

To prevent this we move the DMA path enabling to happen after we have
primed the Rx ring. This makes sure no incoming packets can arrive
before we are ready to handle them.

Fixes: e69b6c02b4c3 ("net: Add support for networking over Thunderbolt cable")
Cc: stable@vger.kernel.org
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/net/thunderbolt.c | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/thunderbolt.c b/drivers/net/thunderbolt.c
index ff5d0e98a088..ab3f04562980 100644
--- a/drivers/net/thunderbolt.c
+++ b/drivers/net/thunderbolt.c
@@ -612,18 +612,13 @@  static void tbnet_connected_work(struct work_struct *work)
 		return;
 	}
 
-	/* Both logins successful so enable the high-speed DMA paths and
-	 * start the network device queue.
+	/* Both logins successful so enable the rings, high-speed DMA
+	 * paths and start the network device queue.
+	 *
+	 * Note we enable the DMA paths last to make sure we have primed
+	 * the Rx ring before any incoming packets are allowed to
+	 * arrive.
 	 */
-	ret = tb_xdomain_enable_paths(net->xd, net->local_transmit_path,
-				      net->rx_ring.ring->hop,
-				      net->remote_transmit_path,
-				      net->tx_ring.ring->hop);
-	if (ret) {
-		netdev_err(net->dev, "failed to enable DMA paths\n");
-		return;
-	}
-
 	tb_ring_start(net->tx_ring.ring);
 	tb_ring_start(net->rx_ring.ring);
 
@@ -635,10 +630,21 @@  static void tbnet_connected_work(struct work_struct *work)
 	if (ret)
 		goto err_free_rx_buffers;
 
+	ret = tb_xdomain_enable_paths(net->xd, net->local_transmit_path,
+				      net->rx_ring.ring->hop,
+				      net->remote_transmit_path,
+				      net->tx_ring.ring->hop);
+	if (ret) {
+		netdev_err(net->dev, "failed to enable DMA paths\n");
+		goto err_free_tx_buffers;
+	}
+
 	netif_carrier_on(net->dev);
 	netif_start_queue(net->dev);
 	return;
 
+err_free_tx_buffers:
+	tbnet_free_buffers(&net->tx_ring);
 err_free_rx_buffers:
 	tbnet_free_buffers(&net->rx_ring);
 err_stop_rings: