• Alan Stern's avatar
    usb-storage: implement "soft" unbinding · 543f7810
    Alan Stern authored
    This patch (as1092) implements "soft" unbinding for usb-storage.  When
    the disconnect routine is called, all commands and reset delays are
    allowed to complete normally until after scsi_remove_host() returns.
    This means that the commands needed for an orderly shutdown will be
    sent through to the device.
    
    Unlike before, the driver will now execute every command that it
    accepts.  Hence there's no need for special code to catch unexecuted
    commands and fail them.
    
    The new sequence of events when disconnect runs goes as follows:
    
    	If the device is truly unplugged, set the DISCONNECTING
    	flag so we won't try to access it any more.
    
    	If the SCSI-scanning thread hasn't started up yet, prevent
    	it from doing anything by setting the new DONT_SCAN flag.
    	Then wake it up and wait for it to terminate.
    
    	Remove the SCSI host.  This unbinds the upper-level drivers,
    	doing an orderly shutdown.  Commands sent to quiesce the
    	device will be transmitted normally, unless the device is
    	unplugged.
    
    	Set the DISCONNECTING flag so that we won't accept any new
    	commands that might get submitted (there aren't supposed to be
    	any) and we won't try to access the device for resets.
    
    	Tell the control thread to exit by waking it up with no
    	pending command, and wait for it to terminate.
    
    	Go on to do all the other normal stuff: releasing resources,
    	freeing memory, and so on.
    Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
    543f7810
usb.c 29.4 KB