USB: check serial-number string after device reset
This patch (as1048) extends the descriptor checking after a device is
reset. Now the SerialNumber string descriptor is compared to its old
value, in addition to the device and configuration descriptors.
As a consequence, the kmalloc() call in usb_string() is now on the
error-handling pathway for usb-storage. Hence its allocation type is
changed to GFO_NOIO.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/Documentation/usb/persist.txt b/Documentation/usb/persist.txt
index bea58db..d56cb1a 100644
--- a/Documentation/usb/persist.txt
+++ b/Documentation/usb/persist.txt
@@ -136,10 +136,10 @@
If you replace one USB device with another of the same type (same
manufacturer, same IDs, and so on) there's an excellent chance the
-kernel won't detect the change. Serial numbers and other strings are
-not compared. In many cases it wouldn't help if they were, because
-manufacturers frequently omit serial numbers entirely in their
-devices.
+kernel won't detect the change. The serial number string and other
+descriptors are compared with the kernel's stored values, but this
+might not help since manufacturers frequently omit serial numbers
+entirely in their devices.
Furthermore it's quite possible to leave a USB device exactly the same
while changing its media. If you replace the flash memory card in a
