On 07/03/2014 07:11 PM, Christoph Hellwig wrote:
On Thu, Jul 03, 2014 at 10:05:57AM -0500, Stephen M. Cameron wrote:
From: Stephen M. Cameron <scameron@xxxxxxxxxxxxxxxxxx>
Don't loop through all the devices even after
finding the one we're looking for
The comments in the code seem to indicate that we want to modify
the queue depth for all LUNs on a given target.
Ccing Mike and Vasu as they wrote this code.
Indeed, that was the idea.
This piece of code tries to keep track of the remote port queue
depth, which isn't represented at all.
Thing is, each remote target has a target queue depth which can hold
only so many outstanding SCSI requests. If that is full it'll return
BUSY for _all_ LUNs served from that port.
And the very _next_ command after the one which filled the target
queue will get the BUSY status.
So we need to decrease the queue depth on _all_ LUNs here to avoid
starvation of individual devices.
Hence I guess this is not the correct fix.
Cheers,
Hannes
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Dr. Hannes Reinecke zSeries & Storage
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