usb: assign default peer ports for root hubs
Assume that the peer of a superspeed port is the port with the same id
on the shared_hcd root hub. This identification scheme is required of
external hubs by the USB3 spec [1]. However, for root hubs, tier mismatch
may be in effect [2]. Tier mismatch can only be enumerated via platform
firmware. For now, simply perform the nominal association.
A new lock 'usb_port_peer_mutex' is introduced to synchronize port
device add/remove with peer lookups. It protects peering against
changes to hcd->shared_hcd, hcd->self.root_hub, hdev->maxchild, and
port_dev->child pointers.
[1]: usb 3.1 section 10.3.3
[2]: xhci 1.1 appendix D
Cc: Alan Stern <stern@rowland.harvard.edu>
[alan: usb_port_peer_mutex locking scheme]
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 2912925..5a909ba 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -55,6 +55,9 @@
static struct task_struct *khubd_task;
+/* synchronize hub-port add/remove and peering operations */
+DEFINE_MUTEX(usb_port_peer_mutex);
+
/* cycle leds on hubs that aren't blinking for attention */
static bool blinkenlights = 0;
module_param (blinkenlights, bool, S_IRUGO);
@@ -1323,6 +1326,7 @@
char *message = "out of memory";
unsigned unit_load;
unsigned full_load;
+ unsigned maxchild;
hub->buffer = kmalloc(sizeof(*hub->buffer), GFP_KERNEL);
if (!hub->buffer) {
@@ -1361,12 +1365,11 @@
goto fail;
}
- hdev->maxchild = hub->descriptor->bNbrPorts;
- dev_info (hub_dev, "%d port%s detected\n", hdev->maxchild,
- (hdev->maxchild == 1) ? "" : "s");
+ maxchild = hub->descriptor->bNbrPorts;
+ dev_info(hub_dev, "%d port%s detected\n", maxchild,
+ (maxchild == 1) ? "" : "s");
- hub->ports = kzalloc(hdev->maxchild * sizeof(struct usb_port *),
- GFP_KERNEL);
+ hub->ports = kzalloc(maxchild * sizeof(struct usb_port *), GFP_KERNEL);
if (!hub->ports) {
ret = -ENOMEM;
goto fail;
@@ -1387,11 +1390,11 @@
int i;
char portstr[USB_MAXCHILDREN + 1];
- for (i = 0; i < hdev->maxchild; i++)
+ for (i = 0; i < maxchild; i++)
portstr[i] = hub->descriptor->u.hs.DeviceRemovable
[((i + 1) / 8)] & (1 << ((i + 1) % 8))
? 'F' : 'R';
- portstr[hdev->maxchild] = 0;
+ portstr[maxchild] = 0;
dev_dbg(hub_dev, "compound device; port removable status: %s\n", portstr);
} else
dev_dbg(hub_dev, "standalone hub\n");
@@ -1503,7 +1506,7 @@
if (hcd->power_budget > 0)
hdev->bus_mA = hcd->power_budget;
else
- hdev->bus_mA = full_load * hdev->maxchild;
+ hdev->bus_mA = full_load * maxchild;
if (hdev->bus_mA >= full_load)
hub->mA_per_port = full_load;
else {
@@ -1518,7 +1521,7 @@
hub->descriptor->bHubContrCurrent);
hub->limited_power = 1;
- if (remaining < hdev->maxchild * unit_load)
+ if (remaining < maxchild * unit_load)
dev_warn(hub_dev,
"insufficient power available "
"to use all downstream ports\n");
@@ -1586,15 +1589,19 @@
if (hub->has_indicators && blinkenlights)
hub->indicator[0] = INDICATOR_CYCLE;
- for (i = 0; i < hdev->maxchild; i++) {
+ mutex_lock(&usb_port_peer_mutex);
+ for (i = 0; i < maxchild; i++) {
ret = usb_hub_create_port_device(hub, i + 1);
if (ret < 0) {
dev_err(hub->intfdev,
"couldn't create port%d device.\n", i + 1);
- hdev->maxchild = i;
- goto fail_keep_maxchild;
+ break;
}
}
+ hdev->maxchild = i;
+ mutex_unlock(&usb_port_peer_mutex);
+ if (ret < 0)
+ goto fail;
usb_hub_adjust_deviceremovable(hdev, hub->descriptor);
@@ -1602,8 +1609,6 @@
return 0;
fail:
- hdev->maxchild = 0;
-fail_keep_maxchild:
dev_err (hub_dev, "config failed, %s (err %d)\n",
message, ret);
/* hub_disconnect() frees urb and descriptor */
@@ -1639,6 +1644,8 @@
hub->error = 0;
hub_quiesce(hub, HUB_DISCONNECT);
+ mutex_lock(&usb_port_peer_mutex);
+
/* Avoid races with recursively_mark_NOTATTACHED() */
spin_lock_irq(&device_state_lock);
port1 = hdev->maxchild;
@@ -1649,6 +1656,8 @@
for (; port1 > 0; --port1)
usb_hub_remove_port_device(hub, port1);
+ mutex_unlock(&usb_port_peer_mutex);
+
if (hub->hdev->speed == USB_SPEED_HIGH)
highspeed_hubs--;
@@ -4608,6 +4617,8 @@
*/
status = 0;
+ mutex_lock(&usb_port_peer_mutex);
+
/* We mustn't add new devices if the parent hub has
* been disconnected; we would race with the
* recursively_mark_NOTATTACHED() routine.
@@ -4618,14 +4629,17 @@
else
port_dev->child = udev;
spin_unlock_irq(&device_state_lock);
+ mutex_unlock(&usb_port_peer_mutex);
/* Run it through the hoops (find a driver, etc) */
if (!status) {
status = usb_new_device(udev);
if (status) {
+ mutex_lock(&usb_port_peer_mutex);
spin_lock_irq(&device_state_lock);
port_dev->child = NULL;
spin_unlock_irq(&device_state_lock);
+ mutex_unlock(&usb_port_peer_mutex);
}
}