On 4/2/22 15:47, Michael Straube wrote:
> Hi all,
>
> smatch reported a sleeping in atomic context.
>
> rtw_set_802_11_disassociate() <- disables preempt
> -> _rtw_pwr_wakeup()
> -> ips_leave()
>
> rtw_set_802_11_disassociate() takes a spinlock and ips_leave() uses a
> mutex.
>
> I'm fairly new to the locking stuff, but as far as I know this is not a
> false positive since mutex can sleep, but that's not allowed under a
> spinlock.
>
> What is the best way to handle this?
> I'm not sure if converting the mutex to a spinlock (including all the
> other places where the mutex is used) is the right thing to do?
In drivers/net/wireless/realtek/rtlwifi, we had a similar problem. There it was
handled by putting the lps_enter() and lps_leave() operations in a separate
workqueue. In this case, the routines were rtl_lps_enter() and rtl_lps_leave().
Each of them sets a variable to indicate whether enter_ps is true or false, and
schedules the workqueue. In the workqueue's callback routine, the routines to
start/stop ps mode are called. The code is in
drivers/net/wireless/realtek/rtlwifi/ps.c.
This solution is only one of many, and there may be a better one.
Larry
On 4/2/22 23:32, Larry Finger wrote:
> In drivers/net/wireless/realtek/rtlwifi, we had a similar problem. There
> it was handled by putting the lps_enter() and lps_leave() operations in
> a separate workqueue. In this case, the routines were rtl_lps_enter()
> and rtl_lps_leave(). Each of them sets a variable to indicate whether
> enter_ps is true or false, and schedules the workqueue. In the
> workqueue's callback routine, the routines to start/stop ps mode are
> called. The code is in drivers/net/wireless/realtek/rtlwifi/ps.c.
>
> This solution is only one of many, and there may be a better one.
>
> Larry
>
Thank you for the explanation Larry.
Michael