On Mon, Dec 19, 2011 at 12:50 AM, David Dillow <dillowda@xxxxxxxx> wrote: > On Thu, 2011-12-01 at 20:11 +0100, Bart Van Assche wrote: >> Add a time-based transport layer test such that fail-over in a multipath >> setup can happen quickly. > > Why should this be done in the kernel? multipathd already verifies all > paths to a SCSI device are up and that the device is reachable. I'm afraid it's impossible to make a transport layer check work reliably from user space. As an example, srp_reset_host() blocks the SCSI host before reconnecting. Before starting to attempt to reconnect, that action does block the SCSI host and hence also all transport layer checks issued from user space. I doubt it's possible to fix the resulting race between a transport layer reconnect issued from srp_reset_host() and a transport layer reconnect triggered from user space. Bart. -- 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
