On Wed, 20 Nov 2013, David Laight wrote: > > From: Sarah Sharp > ... > > (Also, usb-storage aligns the block sizes to 512K, which explains why > > we've never had an issue with TD fragments with that driver.) > > What is a 'block' in that context?
I think Sarah means that usb-storage requires the block layer to align its data buffers to 512-byte boundaries. (Note: 512 bytes, not 512K.) Disk I/O naturally tends to be done in units of the page size, anyway, although raw I/O can involve single sectors. If a user supplies an unaligned buffer, the block layer will set up a bounce buffer. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
