On Thu, Aug 18, 2011 at 02:29:00PM -0400, Alan Stern wrote: > This patch (as1481) fixes a problem affecting g_file_storage and > g_mass_storage when running at SuperSpeed. The two drivers currently > assume that the bulk-out maxpacket size can evenly divide the SCSI > block size, which is 512 bytes. But SuperSpeed bulk endpoints have a > maxpacket size of 1024, so the assumption is no longer true. > > This patch removes that assumption from the drivers, by getting rid of > a small optimization (they try to align VFS reads and writes on page > cache boundaries). If a command's starting logical block address is > 512 bytes below the end of a page, it's not okay to issue a USB > command for just those 512 bytes when the maxpacket size is 1024 -- it > would result in either babble (for an OUT transfer) or a short packet > (for an IN transfer). > > Also, for backward compatibility, the test for writes extending beyond > the end of the backing storage has to be changed. If the host tries > to do this, we should accept the data that fits in the backing storage > and ignore the rest. Because the storage's end may not align with a > USB packet boundary, this means we may have to accept a USB OUT > transfer that extends beyond the end of the storage and then write out > only the part of the data that fits. > > Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > CC: Michal Nazarewicz <mina86@xxxxxxxxxx> applied, thanks -- balbi
Attachment:
signature.asc
Description: Digital signature
