From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roland Dreier Subject: [PATCH 1/2] IB/cm: Fix sleeping in atomic when RoCE is used Date: Tue, 29 Aug 2017 10:34:43 -0700 Message-ID: <20170829173444.4289-1-roland@kernel.org> Return-path: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Doug Ledford , Sean Hefty Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org From: Roland Dreier A couple of places in the CM do spin_lock_irq(&cm_id_priv->lock); ... if (cm_alloc_response_msg(work->port, work->mad_recv_wc, &msg)) However when the underlying transport is RoCE, this leads to a sleeping function being called with the lock held - the callchain is cm_alloc_response_msg() -> ib_create_ah_from_wc() -> ib_init_ah_from_wc() -> rdma_addr_find_l2_eth_by_grh() -> rdma_resolve_ip() and rdma_resolve_ip() starts out by doing req = kzalloc(sizeof *req, GFP_KERNEL); not to mention rdma_addr_find_l2_eth_by_grh() doing wait_for_completion(&ctx.comp); to wait for the task that rdma_resolve_ip() queues up. Fix this by moving the AH creation out of the lock. Signed-off-by: Roland Dreier --- drivers/infiniband/core/cm.c | 63 +++++++++++++++++++++++++++++++------------- 1 file changed, 44 insertions(+), 19 deletions(-) diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c index 2b4d613a3474..f814c5035c74 100644 --- a/drivers/infiniband/core/cm.c +++ b/drivers/infiniband/core/cm.c @@ -373,11 +373,19 @@ static int cm_alloc_msg(struct cm_id_private *cm_id_priv, return ret; } -static int cm_alloc_response_msg(struct cm_port *port, - struct ib_mad_recv_wc *mad_recv_wc, - struct ib_mad_send_buf **msg) +static struct ib_mad_send_buf *cm_alloc_response_msg_no_ah(struct cm_port *port, + struct ib_mad_recv_wc *mad_recv_wc) +{ + return ib_create_send_mad(port->mad_agent, 1, mad_recv_wc->wc->pkey_index, + 0, IB_MGMT_MAD_HDR, IB_MGMT_MAD_DATA, + GFP_ATOMIC, + IB_MGMT_BASE_VERSION); +} + +static int cm_create_response_msg_ah(struct cm_port *port, + struct ib_mad_recv_wc *mad_recv_wc, + struct ib_mad_send_buf *msg) { - struct ib_mad_send_buf *m; struct ib_ah *ah; ah = ib_create_ah_from_wc(port->mad_agent->qp->pd, mad_recv_wc->wc, @@ -385,27 +393,40 @@ static int cm_alloc_response_msg(struct cm_port *port, if (IS_ERR(ah)) return PTR_ERR(ah); - m = ib_create_send_mad(port->mad_agent, 1, mad_recv_wc->wc->pkey_index, - 0, IB_MGMT_MAD_HDR, IB_MGMT_MAD_DATA, - GFP_ATOMIC, - IB_MGMT_BASE_VERSION); - if (IS_ERR(m)) { - rdma_destroy_ah(ah); - return PTR_ERR(m); - } - m->ah = ah; - *msg = m; + msg->ah = ah; return 0; } static void cm_free_msg(struct ib_mad_send_buf *msg) { - rdma_destroy_ah(msg->ah); + if (msg->ah) + rdma_destroy_ah(msg->ah); if (msg->context[0]) cm_deref_id(msg->context[0]); ib_free_send_mad(msg); } +static int cm_alloc_response_msg(struct cm_port *port, + struct ib_mad_recv_wc *mad_recv_wc, + struct ib_mad_send_buf **msg) +{ + struct ib_mad_send_buf *m; + int ret; + + m = cm_alloc_response_msg_no_ah(port, mad_recv_wc); + if (IS_ERR(m)) + return PTR_ERR(m); + + ret = cm_create_response_msg_ah(port, mad_recv_wc, m); + if (ret) { + cm_free_msg(m); + return ret; + } + + *msg = m; + return 0; +} + static void * cm_copy_private_data(const void *private_data, u8 private_data_len) { @@ -2424,7 +2445,8 @@ static int cm_dreq_handler(struct cm_work *work) case IB_CM_TIMEWAIT: atomic_long_inc(&work->port->counter_group[CM_RECV_DUPLICATES]. counter[CM_DREQ_COUNTER]); - if (cm_alloc_response_msg(work->port, work->mad_recv_wc, &msg)) + msg = cm_alloc_response_msg_no_ah(work->port, work->mad_recv_wc); + if (IS_ERR(msg)) goto unlock; cm_format_drep((struct cm_drep_msg *) msg->mad, cm_id_priv, @@ -2432,7 +2454,8 @@ static int cm_dreq_handler(struct cm_work *work) cm_id_priv->private_data_len); spin_unlock_irq(&cm_id_priv->lock); - if (ib_post_send_mad(msg, NULL)) + if (cm_create_response_msg_ah(work->port, work->mad_recv_wc, msg) || + ib_post_send_mad(msg, NULL)) cm_free_msg(msg); goto deref; case IB_CM_DREQ_RCVD: @@ -2980,7 +3003,8 @@ static int cm_lap_handler(struct cm_work *work) case IB_CM_MRA_LAP_SENT: atomic_long_inc(&work->port->counter_group[CM_RECV_DUPLICATES]. counter[CM_LAP_COUNTER]); - if (cm_alloc_response_msg(work->port, work->mad_recv_wc, &msg)) + msg = cm_alloc_response_msg_no_ah(work->port, work->mad_recv_wc); + if (IS_ERR(msg)) goto unlock; cm_format_mra((struct cm_mra_msg *) msg->mad, cm_id_priv, @@ -2990,7 +3014,8 @@ static int cm_lap_handler(struct cm_work *work) cm_id_priv->private_data_len); spin_unlock_irq(&cm_id_priv->lock); - if (ib_post_send_mad(msg, NULL)) + if (cm_create_response_msg_ah(work->port, work->mad_recv_wc, msg) || + ib_post_send_mad(msg, NULL)) cm_free_msg(msg); goto deref; case IB_CM_LAP_RCVD: -- 2.14.1 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html