[PATCH] elevator: move clearing of unplug flag earlier
authorLinas Vepstas <linas@austin.ibm.com>
Tue, 23 Jan 2007 18:40:54 +0000 (19:40 +0100)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Tue, 23 Jan 2007 19:01:17 +0000 (11:01 -0800)
commit95543179f158b4891c5dc49004853ce081e8d794
tree39cc1ae27c53bc7ac7cc6401afc8ecee69b76b0f
parent3a7122923e87fc5cdf8affa1845924a0def4657d
[PATCH] elevator: move clearing of unplug flag earlier

A flag was recently added to the elevator code to avoid
performing an unplug when reuests are being re-queued.
The goal of this flag was to avoid a deep recursion that
can occur when re-queueing requests after a SCSI device/host
reset.  See http://lkml.org/lkml/2006/5/17/254

However, that fix added the flag near the bottom of a case
statement, where an earlier break (in an if statement) could
transport one out of the case, without setting the flag.
This patch sets the flag earlier in the case statement.

I re-discovered the deep recursion recently during testing;
I was told that it was a known problem, and the fix to it was
in the kernel I was testing. Indeed it was ... but it didn't
fix the bug. With the patch below, I no longer see the bug.

Signed-off by: Linas Vepstas <linas@austin.ibm.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
block/elevator.c