Messages in this thread Patch in this message | | | From | Zach Brown <> | Subject | [PATCH] mthca: initialize send and receive queue locks separately | Date | Mon, 3 Jul 2006 15:50:20 -0700 (PDT) |
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mthca: initialize send and receive queue locks separately
lockdep identifies a lock by the call site of its initialization. By initializing the send and receive queue locks in mthca_wq_init() we confuse lockdep. It warns that that the ordered acquiry of both locks in mthca_modify_qp() is recursive acquiry of one lock:
============================================= [ INFO: possible recursive locking detected ] --------------------------------------------- modprobe/1192 is trying to acquire lock: (&wq->lock){....}, at: [<f892b4db>] mthca_modify_qp+0x60/0xa7b [ib_mthca] but task is already holding lock: (&wq->lock){....}, at: [<f892b4ce>] mthca_modify_qp+0x53/0xa7b [ib_mthca]
Initializing the locks separately in mthca_alloc_qp_common() stops the warning and will let lockdep enforce proper ordering on paths that acquire both locks.
Signed-off-by: Zach Brown <zach.brown@oracle.com> ---
drivers/infiniband/hw/mthca/mthca_qp.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
Index: 2.6.17-mm6/drivers/infiniband/hw/mthca/mthca_qp.c =================================================================== --- 2.6.17-mm6.orig/drivers/infiniband/hw/mthca/mthca_qp.c 2006-07-03 08:41:16.000000000 -0400 +++ 2.6.17-mm6/drivers/infiniband/hw/mthca/mthca_qp.c 2006-07-03 10:05:52.000000000 -0400 @@ -224,7 +224,7 @@ static void mthca_wq_init(struct mthca_wq *wq) { - spin_lock_init(&wq->lock); + /* mthca_alloc_qp_common() initializes the locks */ wq->next_ind = 0; wq->last_comp = wq->max - 1; wq->head = 0; @@ -1114,6 +1114,9 @@ qp->sq_policy = send_policy; mthca_wq_init(&qp->sq); mthca_wq_init(&qp->rq); + /* these are initialized separately so lockdep can tell them apart */ + spin_lock_init(&qp->sq.lock); + spin_lock_init(&qp->rq.lock); ret = mthca_map_memfree(dev, qp); if (ret) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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