Thread (5 messages) 5 messages, 2 authors, 1d ago
WARM1d
Revisions (2)
  1. v2 [diff vs current]
  2. v3 current

[PATCH net v3 0/2] Drop in-flight Tx SKBs on MACB close

From: Théo Lebrun <theo.lebrun@bootlin.com>
Date: 2026-06-17 09:17:53
Also in: lkml, stable

The first patch is here to allow giving a drop reason.
We dissociate consumed packets from dropped ones that way.

Second patch is the main one: it drops unsent packets on close.
MACB driver forgot freeing its SKBs (and associated DMA mappings).

---
Changes in v3:
- Drop stats fixing. A proper fix deserves its own net-next refactoring
  series to migrate to netdev_stat_ops (ynltool uAPI), which will come
  in later. We keep the tx_dropped++ because they are safe as every
  other context is disabled when macb_free_consistent() is called.
- Rebased to latest net/main (406e8a651a7b), nothing to report.
- Link to v2: https://patch.msgid.link/20260428-macb-drop-tx-v2-0-647f5199d8df@bootlin.com

Changes in v2:
- Increment tx_dropped stat once per SKB, not once per frame.
- Reset tx_head & tx_tail to avoid keeping stalled cursors.
- Fix SKB dropped reasons throughout by adding the reason as parameter
  to macb_tx_unmap(). This is a new patch. Then the drop-all-on-close
  fix can use this ability to report we are not consuming SKBs.
- Add increment to stats->tx_dropped on DMA mapping failure and
  tx_error_task. Done as separate patches (3 and 4).
- Rebase upon net/main @ 46f74a3f7d57, nothing to report.
- Link to v1: https://patch.msgid.link/20260424-macb-drop-tx-v1-1-b3ecb787d84d@bootlin.com

To: Nicolas Ferre <nicolas.ferre@microchip.com>
To: Claudiu Beznea <claudiu.beznea@tuxon.dev>
To: Andrew Lunn <andrew+netdev@lunn.ch>
To: "David S. Miller" <davem@davemloft.net>
To: Eric Dumazet <edumazet@google.com>
To: Jakub Kicinski <kuba@kernel.org>
To: Paolo Abeni <pabeni@redhat.com>
To: Haavard Skinnemoen <redacted>
To: Jeff Garzik <redacted>
To: Conor Dooley <conor.dooley@microchip.com>
Cc: Paolo Valerio <redacted>
Cc: Nicolai Buchwitz <redacted>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Vladimir Kondratiev <vladimir.kondratiev@mobileye.com>
Cc: Gregory CLEMENT <gregory.clement@bootlin.com>
Cc: Benoît Monin <benoit.monin@bootlin.com>
Cc: Tawfik Bayouk <redacted>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>

---
Théo Lebrun (2):
      net: macb: give reasons for Tx SKB kfree
      net: macb: drop in-flight Tx SKBs on close

 drivers/net/ethernet/cadence/macb_main.c | 46 +++++++++++++++++++++++++-------
 1 file changed, 37 insertions(+), 9 deletions(-)
---
base-commit: 712927eaa34199bb62cf370af591c0550ba977de
change-id: 20260423-macb-drop-tx-f9ce72720d05

Best regards,
--  
Théo Lebrun [off-list ref]
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