From: Zach Brown Date: Tue, 4 Jul 2006 09:57:52 +0000 (-0700) Subject: [PATCH] mthca: initialize send and receive queue locks separately X-Git-Tag: v2.6.18-rc1~14 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a46f9484f8926aacb2e79a0e1676de3a6a6fbae8;p=linux-2.6 [PATCH] mthca: initialize send and receive queue locks separately 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: [] mthca_modify_qp+0x60/0xa7b [ib_mthca] but task is already holding lock: (&wq->lock){....}, at: [] 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 Cc: Roland Dreier Cc: Arjan van de Ven Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/infiniband/hw/mthca/mthca_qp.c b/drivers/infiniband/hw/mthca/mthca_qp.c index 16c387d817..490fc783bb 100644 --- a/drivers/infiniband/hw/mthca/mthca_qp.c +++ b/drivers/infiniband/hw/mthca/mthca_qp.c @@ -224,7 +224,7 @@ static void *get_send_wqe(struct mthca_qp *qp, int n) 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 @@ static int mthca_alloc_qp_common(struct mthca_dev *dev, 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)