On Wed, Nov 23, 2016 at 02:24:27PM +0200, Mathias Nyman wrote:
> the tt_info provided by a HS hub might be in use to by a child device
> Make sure we free the devices in the correct order.
>
> This is needed in special cases such as when xhci controller is
> reset when resuming from hibernate, and all virt_devices are freed.
>
> Also free the virt_devices starting from max slot_id as children
> more commonly have higher slot_id than parent.
>
> CC: <sta...@vger.kernel.org>
> Signed-off-by: Mathias Nyman <mathias.ny...@linux.intel.com>
>
> ---
>
> Guenter Roeck, does this work for you?
>
Yes, it does.
Tested-by: Guenter Roeck <gro...@chromium.org>
Thanks,
Guenter
> A rework of how tt_info is stored and used might be needed,
> but that will take some time and won't go to stable as easily.
> ---
> drivers/usb/host/xhci-mem.c | 38 ++++++++++++++++++++++++++++++++++++--
> 1 file changed, 36 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
> index 6afe323..b3a5cd8 100644
> --- a/drivers/usb/host/xhci-mem.c
> +++ b/drivers/usb/host/xhci-mem.c
> @@ -979,6 +979,40 @@ void xhci_free_virt_device(struct xhci_hcd *xhci, int
> slot_id)
> xhci->devs[slot_id] = NULL;
> }
>
> +/*
> + * Free a virt_device structure.
> + * If the virt_device added a tt_info (a hub) and has children pointing to
> + * that tt_info, then free the child first. Recursive.
> + * We can't rely on udev at this point to find child-parent relationships.
> + */
> +void xhci_free_virt_devices_depth_first(struct xhci_hcd *xhci, int slot_id)
> +{
> + struct xhci_virt_device *vdev;
> + struct list_head *tt_list_head;
> + struct xhci_tt_bw_info *tt_info, *next;
> + int i;
> +
> + vdev = xhci->devs[slot_id];
> + if (!vdev)
> + return;
> +
> + tt_list_head = &(xhci->rh_bw[vdev->real_port - 1].tts);
> + list_for_each_entry_safe(tt_info, next, tt_list_head, tt_list) {
> + /* is this a hub device that added a tt_info to the tts list */
> + if (tt_info->slot_id == slot_id) {
> + /* are any devices using this tt_info? */
> + for (i = 1; i < HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
> + vdev = xhci->devs[i];
> + if (vdev && (vdev->tt_info == tt_info))
> + xhci_free_virt_devices_depth_first(
> + xhci, i);
> + }
> + }
> + }
> + /* we are now at a leaf device */
> + xhci_free_virt_device(xhci, slot_id);
> +}
> +
> int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id,
> struct usb_device *udev, gfp_t flags)
> {
> @@ -1829,8 +1863,8 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci)
> }
> }
>
> - for (i = 1; i < MAX_HC_SLOTS; ++i)
> - xhci_free_virt_device(xhci, i);
> + for (i = HCS_MAX_SLOTS(xhci->hcs_params1); i > 0; i--)
> + xhci_free_virt_devices_depth_first(xhci, i);
>
> dma_pool_destroy(xhci->segment_pool);
> xhci->segment_pool = NULL;
> --
> 1.9.1
>
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