On Tue, 15 May 2018, Tushar Nimkar wrote: > Everyone, > > Please help me in understanding sd_probe| storage_probe/1/2 and > uas_probe | scsi_scan_host :) > Basically want to know the correct sequence for them? How > sd_probe_async() is called (ASYNC_DOMAIN(scsi_sd_probe_domain))?
Very briefly: The probe routine for usb-storage is storage_probe(), which calls usb_stor_probe1() and usb_stor_probe2(). Similarly, the probe routine for uas is uas_probe(). Each driver's probe routine is called by the driver core (drivers/base/dd.c) when a new device of the appropriate type is detected. usb_stor_probe2() starts a workqueue routine, usb_stor_scan_dwork(), which calls scsi_scan_host(), whereas uas_probe() calls scsi_scan_host() directly. Either way, scsi_scan_host() usually sets up an async worker to carry out the actual scanning. The scanning is started by scsi_scan_target() and the various routines it calls. When the scanning procedure registers a SCSI device that is a disk-drive-like device, the sd driver's sd_probe() routine is called by the driver core. sd_probe() does some of the initial work needed to probe the device, and it defers the rest of the work to the async worker routine sd_probe_async(). > Is there any document which say it in detail ? No. UTSL. You might concentrate on include/linux/async.h and kernel/async.c (and you should be able to figure that much out for yourself without asking the mailing list). Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
