USB: hub: fix SS max number of ports

commit 93491ced3c87c94b12220dbac0527e1356702179 upstream.

Add define for the maximum number of ports on a SuperSpeed hub as per
USB 3.1 spec Table 10-5, and use it when verifying the retrieved hub
descriptor.

This specifically avoids benign attempts to update the DeviceRemovable
mask for non-existing ports (should we get that far).

Fixes: dbe79bbe9dcb ("USB 3.0 Hub Changes")
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2:
 - Add maxchild variable in hub_configure(), which was added separately upstream
 - Adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 9da5981..7c59466 100644 (file)
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1108,6 +1108,7 @@ static int hub_configure(struct usb_hub *hub,
        unsigned int pipe;
        int maxp, ret;
        char *message = "out of memory";
+       unsigned maxchild;
 
        hub->buffer = kmalloc(sizeof(*hub->buffer), GFP_KERNEL);
        if (!hub->buffer) {
@@ -1136,7 +1137,13 @@ static int hub_configure(struct usb_hub *hub,
        if (ret < 0) {
                message = "can't read hub descriptor";
                goto fail;
-       } else if (hub->descriptor->bNbrPorts > USB_MAXCHILDREN) {
+       }
+
+       maxchild = USB_MAXCHILDREN;
+       if (hub_is_superspeed(hdev))
+               maxchild = min_t(unsigned, maxchild, USB_SS_MAXPORTS);
+
+       if (hub->descriptor->bNbrPorts > maxchild) {
                message = "hub has too many ports!";
                ret = -ENODEV;
                goto fail;

diff --git a/include/linux/usb/ch11.h b/include/linux/usb/ch11.h
index 1eb735b..5c62734 100644 (file)
--- a/include/linux/usb/ch11.h
+++ b/include/linux/usb/ch11.h
@@ -11,6 +11,9 @@
 
 #include <linux/types.h>       /* __u8 etc */
 
+/* See USB 3.1 spec Table 10-5 */
+#define USB_SS_MAXPORTS                15
+
 /*
  * Hub request types
  */