> David Miller [mailto:davem@xxxxxxxxxxxxx] > > Sent: Sunday, January 25, 2015 2:44 PM > > What keeps rtl_start_rx() from running in parallel with > > r8152_submit_rx(), or any other accessor of the RX agg->list? > > Forgive my poor English. I would try to describe them clearly. > The steps about the rx agg->list would be > 1. carrier on or autoresume occurs. > 2. Call rtl_start_rx(). > 3. Rx agg->list flows between device and tp->rx_done. > 4. carrier off or autosuspend occurs. > 5. call rtl_stop_rx(). > > The rtl_start_rx() would only be called when the linking > status is changed from off to on or the auto resume occurs. > And rtl_start_rx() would reinitialize the tp->rx_done and > all of the rx agg->list. After step 2, the rx agg->list > would flow between the usb host controller and the driver. > If r8152_submit_rx() is success, the driver wouldn't own the > rx agg->list until it is returned from the usb host controller. > If r8152_submit_rx() is fail, the driver would still own the > rx agg->list, and queue it to the tp->rx_done with spin lock > for next try. > > If the status stays in step 3, only the rx_bottom() would submit > the rx agg. The rtl_start_rx() wouldn't be called suddenly, > unless the linking down or auto suspend occur first and linking > on or auto resume occur again. If linking down or auto suspend > occur, rtl_stop_rx() would be called (step 5). After this step, > rx_bottom() wouldn't submit rx, and all rx agg->list would stop > flowing. That is, the tp->rx_done and all rx agg->list wouldn't > be changed until the next rtl_start_rx() is called. > > Therefore, the flow for each rx agg->list would be > a. submittd by rtl_start_rx(). > b. goto step c if success, otherwise goto step d. > c. completed by usb host controller. > d. queued to tp->rx_done with spin lock. > e. dequeue from tp->rx_done with spin lock by rx_botoom(). > f. goto step i if link down, otherwise goto step g. > g. submitted by rx_botoom(). > h. goto step b. > i. goto step a if link on. > > And the patch change the step g to g1. > g1. submitted by rx_botoom() if (!ret), otherwise goto step d. Excuse me. Any other question or suggestion for this patch? Best Regards, Hayes -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
