Date: Sat, 29 Nov 2008 14:55:47 +0100 (CET) From: Stefan Richter Subject: ieee1394: sbp2: fix race condition in state change An intermediate transition from _RUNNING to _IN_SHUTDOWN could have been missed by the former code. Signed-off-by: Stefan Richter --- drivers/ieee1394/sbp2.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) Index: linux/drivers/ieee1394/sbp2.c =================================================================== --- linux.orig/drivers/ieee1394/sbp2.c +++ linux/drivers/ieee1394/sbp2.c @@ -895,12 +895,13 @@ static void sbp2_host_reset(struct hpsb_ return; read_lock_irqsave(&sbp2_hi_logical_units_lock, flags); + list_for_each_entry(lu, &hi->logical_units, lu_list) - if (likely(atomic_read(&lu->state) != - SBP2LU_STATE_IN_SHUTDOWN)) { - atomic_set(&lu->state, SBP2LU_STATE_IN_RESET); + if (atomic_cmpxchg(&lu->state, + SBP2LU_STATE_RUNNING, SBP2LU_STATE_IN_RESET) + == SBP2LU_STATE_RUNNING) scsi_block_requests(lu->shost); - } + read_unlock_irqrestore(&sbp2_hi_logical_units_lock, flags); }