[PATCH net v3 1/2] net: ngbe: propagate resume errors to the PM core

[Zhang Yunfei]

After a failed resume from suspend, the device stays detached from
the networking stack: every attempt to bring the interface up fails
the netif_device_present() check in __dev_open() with -ENODEV,
while the PM core is told that resume succeeded.

ngbe_resume() declares err as u32 and unconditionally returns 0:
the return value of ngbe_reset_hw() is ignored entirely, and
failures of wx_init_interrupt_scheme() and ngbe_open() are silently
swallowed. The interrupt scheme torn down at suspend is never
rebuilt, so the device cannot self-heal.

Fix the type to int and propagate the errors, making the whole tail
of the resume path consistent with the pci_enable_device_mem()
failure path at the top. If the hardware reset fails, return early:
the remaining resume steps cannot succeed. The suspend path may
already have torn the interface down (ngbe_close() and
wx_clear_interrupt_scheme()), leaving freed rings and IRQs behind
while netif_running() still reports true, so set WX_STATE_RES_FREED
on every failing return, the same mark ngbe_down_suspend() uses for
the PCI error recovery path: a later ngbe_close() skips the
teardown of the already-freed state, and ngbe_up_complete() clears
the bit again so later opens are unaffected. This is safe on the
wx_init_interrupt_scheme() failure path too, as it cleans up after
itself.

Found by manual code inspection of the PM error paths; the missing
ngbe_reset_hw() propagation was reported by Sashiko in its review
of v1. The failure paths are unreachable without fault injection:
a loadable test module injects failures into ngbe_reset_hw(),
wx_init_interrupt_scheme() and ngbe_open(). In a QEMU VM the
unfixed driver hits the kernel "Trying to free already-free IRQ"
warning on the post-suspend close; with the fix, the error is
reported and no warning appears. No physical ngbe device is
involved.

Fixes: 6963e463256e ("net: ngbe: add Wake on Lan support")
Reported-by: Sashiko <sashiko-bot@xxxxxxxxxx>
Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260917090050.1927999-1-zhangyunfei1%40kylinos.cn
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Zhang Yunfei <zhangyunfei1@xxxxxxxxxx>
---
Changes in v3:
- set WX_STATE_RES_FREED on every failing return of ngbe_resume()
  (the pci_enable_device_mem() failure, the reset failure early return
  and the wx_init_interrupt_scheme()/ngbe_open() failures), so that a
  later ngbe_close() skips re-running the teardown on the already-freed
  post-suspend state (Sashiko review of v2);

Changes in v2:
- also propagate the ngbe_reset_hw() failure, so the whole tail of
  ngbe_resume() reports errors to the PM core;
- drop the inaccurate "device can be re-probed" claim: the PM core
  records and logs the failure, there is no re-probe.

 drivers/net/ethernet/wangxun/ngbe/ngbe_main.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/wangxun/ngbe/ngbe_main.c b/drivers/net/ethernet/wangxun/ngbe/ngbe_main.c
index 855dc963c610..8247f6c14be0 100644
--- a/drivers/net/ethernet/wangxun/ngbe/ngbe_main.c
+++ b/drivers/net/ethernet/wangxun/ngbe/ngbe_main.c
@@ -954,13 +954,14 @@ static int ngbe_resume(struct pci_dev *pdev)
 {
 	struct net_device *netdev;
 	struct wx *wx;
-	u32 err;
+	int err;
 
 	wx = pci_get_drvdata(pdev);
 	netdev = wx->netdev;
 
 	err = pci_enable_device_mem(pdev);
 	if (err) {
+		set_bit(WX_STATE_RES_FREED, wx->state);
 		wx_err(wx, "Cannot enable PCI device from suspend\n");
 		return err;
 	}
@@ -968,16 +969,23 @@ static int ngbe_resume(struct pci_dev *pdev)
 	pci_set_master(pdev);
 	device_wakeup_disable(&pdev->dev);
 
-	ngbe_reset_hw(wx);
+	err = ngbe_reset_hw(wx);
+	if (err) {
+		set_bit(WX_STATE_RES_FREED, wx->state);
+		wx_err(wx, "Hardware reset failed: %d\n", err);
+		return err;
+	}
 	rtnl_lock();
 	err = wx_init_interrupt_scheme(wx);
 	if (!err && netif_running(netdev))
 		err = ngbe_open(netdev);
 	if (!err)
 		netif_device_attach(netdev);
+	else
+		set_bit(WX_STATE_RES_FREED, wx->state);
 	rtnl_unlock();
 
-	return 0;
+	return err;
 }
 
 static struct pci_driver ngbe_driver = {
-- 
2.25.1