Re: [PATCH v2 11/25] usb: gadget: f_tcm: Execute command on write completion

Sebastian Andrzej Siewior
2022-08-26T07:01:29Z

On 2022-07-18 18:27:12 [-0700], Thinh Nguyen wrote:
> index 6fea80afe2d7..ec83f2f9a858 100644
> --- a/drivers/usb/gadget/function/f_tcm.c
> +++ b/drivers/usb/gadget/function/f_tcm.c
> @@ -955,7 +949,7 @@ static void usbg_data_write_cmpl(struct usb_ep *ep, struct usb_request *req)
> se_cmd->data_length);
> }
>
> - complete(&cmd->write_complete);
> + target_execute_cmd(se_cmd);

usbg_data_write_cmpl() is invoked from interrupt service routing which
may run with disabled interrupts. From looking at target_execute_cmd():
| void target_execute_cmd(struct se_cmd *cmd)
| {
…
| spin_lock_irq(&cmd->t_state_lock);
…
| spin_unlock_irq(&cmd->t_state_lock);
…
| }

which means interrupts will remain open after leaving
target_execute_cmd(). Now, why didn't the WARN_ONCE() in
__handle_irq_event_percpu() trigger? Am I missing something?

> return;

Sebastian