cfq-iosched: fix RCU problem in cfq_cic_lookup()
authorJens Axboe <jens.axboe@oracle.com>
Wed, 28 May 2008 12:46:59 +0000 (14:46 +0200)
committerJens Axboe <jens.axboe@oracle.com>
Wed, 28 May 2008 12:49:28 +0000 (14:49 +0200)
commitd6de8be711b28049a5cb93c954722c311c7d3f7f
tree001dfc1147a64bd05798e29b15ce5d995486a6fa
parent64565911cdb57c2f512a9715b985b5617402cc67
cfq-iosched: fix RCU problem in cfq_cic_lookup()

cfq_cic_lookup() needs to properly protect ioc->ioc_data before
dereferencing it and also exclude updaters of ioc->ioc_data as well.

Also add a number of comments documenting why the existing RCU usage
is OK.

Thanks a lot to "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> for
review and comments!

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
block/cfq-iosched.c