On Sat, 2009-06-20 at 19:35 +0530, Ravish Tayal wrote: > I am debugging Filesystem code for USB mass storage devices. I need > help to figure out after generic_make_request how the request is > placed to scsi disk (sd) requeset queue and than how sd qeueuecommand > to usb_storeage thread. (in which context, is it system call context) requests out of the lower end of block come from the elevators. The elevators can operate in a variety of contexts: user, kernel thread or softirq depending on state. The mechanism for queueing to the USB thread is in scsiglue.c:queuecommand() it's basically a simple single command consumer model: fill in slot and wake thread. James -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html