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
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