usb-storage: report underflow with no sense data
authorAlan Stern <stern@rowland.harvard.edu>
Tue, 2 Sep 2008 14:12:11 +0000 (10:12 -0400)
committerGreg Kroah-Hartman <gregkh@suse.de>
Fri, 17 Oct 2008 21:40:54 +0000 (14:40 -0700)
commit8bfa24727087d7252f9ecfb5fea2dfc92d797fbd
treef7155136c8a9353e4058b416ffff60512b266020
parent3948f0e0c999a6201e9898bb8fbe3c6cc1199276
usb-storage: report underflow with no sense data

This patch (as1118) addresses a problem with certain USB mass-storage
devices.  These devices sometimes return less data than asked for and
then provide no sense data to explain the problem.  Currently
usb-storage leaves it up to the SCSI layer to decide how this should
be handled, and the SCSI layer interprets the lack of sense data to
mean that nothing went wrong.  But if we got less data than required
then something definitely _did_ go wrong, and we should say so.

The patch tells the SCSI layer to retry the command when this sort of
thing happens.  Retrying may not solve the underlying problem, but
it's better than believing that data was transferred when it wasn't.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/usb/storage/transport.c