It was <2021-10-01 pią 15:39>, when Jakub Kicinski wrote: > On Wed, 29 Sep 2021 16:08:54 +0200 Łukasz Stelmach wrote: >> +static char *no_regs_list = "80018001,e1918001,8001a001,fc0d0000"; > > static const char ... > >> +static int >> +ax88796c_close(struct net_device *ndev) >> +{ >> + struct ax88796c_device *ax_local = to_ax88796c_device(ndev); >> + >> + netif_stop_queue(ndev); > > This can run concurrently with the work which restarts the queue. > You should take the mutex and purge the queue here, so that there > is no chance queue will get restarted by the work right after. >> + phy_stop(ndev->phydev); >> + >> + mutex_lock(&ax_local->spi_lock); This was a bit tricky. The function now looks like this (details in the comments). In theory there is a chance of dropping a packet if the ax88796c_work() runs between phy_stop() and mutex_lock(), but I'd say the overall risk is negligible. --8<---------------cut here---------------start------------->8--- static int ax88796c_close(struct net_device *ndev) { struct ax88796c_device *ax_local = to_ax88796c_device(ndev); phy_stop(ndev->phydev); /* We lock the mutex early not only to protect the device * against concurrent access, but also avoid waking up the * queue in ax88796c_work(). phy_stop() needs to be called * before because it locks the mutex to access SPI. */ mutex_lock(&ax_local->spi_lock); netif_stop_queue(ndev); /* No more work can be scheduled now. Make any pending work, * including one already waiting for the mutex to be unlocked, * NOP. */ clear_bit(EVENT_SET_MULTI, &ax_local->flags); clear_bit(EVENT_INTR, &ax_local->flags); clear_bit(EVENT_TX, &ax_local->flags); /* Disable MAC interrupts */ AX_WRITE(&ax_local->ax_spi, IMR_MASKALL, P0_IMR); __skb_queue_purge(&ax_local->tx_wait_q); ax88796c_soft_reset(ax_local); mutex_unlock(&ax_local->spi_lock); cancel_work_sync(&ax_local->ax_work); free_irq(ndev->irq, ndev); return 0; } --8<---------------cut here---------------end--------------->8--- >> +MODULE_AUTHOR("ASIX"); > > You can drop this, author should be human. I looked at diff --stat and decided it is OK to put my name there (-; -- Łukasz Stelmach Samsung R&D Institute Poland Samsung Electronics