On Fri, Sep 25, 2015 at 10:31:18AM -0700, James Bottomley wrote: > So the warning seems to be because scsi_dh_find_driver() is not quite > consistent. For everything except alua, it scans the dh driver list to > see what might attach to the device. It returns "alua" if the TPGS > field is anything other than zero, regardless of whether the alua driver > is loaded. We could fix the problem by returning NULL if the alua > driver isn't present ... would that have any other adverse consequences?
It's not inconsistent - to autoload a driver we cant't require it to be loaded. For alua we check the TPGS bit per the standard, and for the non-standard drivers we use a whitelist in scsi_dh.c now. The problem is that async probing deadlocks vs a synchronous request_module, as Tejun figured out based on the thrad in http://thread.gmane.org/gmane.linux.kernel/1420814 Tejun, if I understand the thread and your patch right there really isn't any good altenative to a synchronous request_module, and you thus disabled autoloading elevator modules, right? For SCSI device handlers we could do this by switching from scsi_dh_lookup to __scsi_dh_lookup in scsi_dh_add_device, but autoloading the device handlers is a really useful feature that I'd love to keep if possible. Given that before 4.3-rc we could not autoload them the switch to __scsi_dh_lookup migt be the required band aid for now until we can come up with something better. Paul, can you try the trivial one liner below? diff --git a/drivers/scsi/scsi_dh.c b/drivers/scsi/scsi_dh.c index edb044a..fbc9502 100644 --- a/drivers/scsi/scsi_dh.c +++ b/drivers/scsi/scsi_dh.c @@ -391,7 +391,7 @@ int scsi_dh_attach(struct request_queue *q, const char *name) if (!sdev) return -ENODEV; - scsi_dh = scsi_dh_lookup(name); + scsi_dh = __scsi_dh_lookup(name); if (!scsi_dh) { err = -EINVAL; goto out_put_device; -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
