[lkml]   [2011]   [Apr]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: Strange block/scsi/workqueue issue
Hello, James.

On Mon, Apr 11, 2011 at 07:47:56PM -0500, James Bottomley wrote:
> Actually, I don't think it's anything to do with the user process stuff.
> The problem seems to be that the block delay function ends up being the
> last user of the SCSI device, so it does the final put of the sdev when
> it's finished processing. This will trigger queue destruction
> (blk_cleanup_queue) and so on with your analysis.

Hmm... this I can understand.

> The problem seems to be that with the new workqueue changes, the queue
> itself may no longer be the last holder of a reference on the sdev
> because the queue destruction is in the sdev release function and a
> queue cannot now be destroyed from its own delayed work. This is a bit
> contrary to the principles SCSI was using, which was that we drive queue
> lifetime from the sdev, not vice versa.

But confused here. Why does it make any difference whether the
release operation is in the request_fn context or not? What makes
SCSI refcounting different from others?



 \ /
  Last update: 2011-04-12 04:55    [W:0.097 / U:1.152 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site