[PATCH] USB: Remove USB private semaphore
This patch (as605) removes the private udev->serialize semaphore,
relying instead on the locking provided by the embedded struct device's
semaphore. The changes are confined to the core, except that the
usb_trylock_device routine now uses the return convention of
down_trylock rather than down_read_trylock (they return opposite values
for no good reason).
A couple of other associated changes are included as well:
Now that we aren't concerned about HCDs that avoid using the
hcd glue layer, usb_disconnect no longer needs to acquire the
usb_bus_lock -- that can be done by usb_remove_hcd where it
belongs.
Devices aren't locked over the same scope of code in
usb_new_device and hub_port_connect_change as they used to be.
This shouldn't cause any trouble.
Along with the preceding driver core patch, this needs a lot of testing.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/core/devices.c b/drivers/usb/core/devices.c
index 83e815d..55bc563 100644
--- a/drivers/usb/core/devices.c
+++ b/drivers/usb/core/devices.c
@@ -545,10 +545,10 @@
struct usb_device *childdev = usbdev->children[chix];
if (childdev) {
- down(&childdev->serialize);
+ usb_lock_device(childdev);
ret = usb_device_dump(buffer, nbytes, skip_bytes, file_offset, childdev,
bus, level + 1, chix, ++cnt);
- up(&childdev->serialize);
+ usb_unlock_device(childdev);
if (ret == -EFAULT)
return total_written;
total_written += ret;
