From: Steve Wise <sw...@opengridcomputing.com>

There is a race between ULP threads doing an accept/reject, and the
ingress processing thread handling close/abort for the same connection.
The accept/reject path needs to hold the lock to serialize these paths.

Signed-off-by: Steve Wise <sw...@opengridcomputing.com>
---
 drivers/infiniband/hw/cxgb4/cm.c | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/drivers/infiniband/hw/cxgb4/cm.c b/drivers/infiniband/hw/cxgb4/cm.c
index 95b3c01..f4a9ebe 100644
--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c
@@ -775,7 +775,7 @@ static void send_mpa_req(struct c4iw_ep *ep, struct sk_buff 
*skb,
        ep->mpa_skb = skb;
        c4iw_l2t_send(&ep->com.dev->rdev, skb, ep->l2t);
        start_ep_timer(ep);
-       state_set(&ep->com, MPA_REQ_SENT);
+       __state_set(&ep->com, MPA_REQ_SENT);
        ep->mpa_attr.initiator = 1;
        ep->snd_seq += mpalen;
        return;
@@ -941,7 +941,7 @@ static int send_mpa_reply(struct c4iw_ep *ep, const void 
*pdata, u8 plen)
        skb_get(skb);
        t4_set_arp_err_handler(skb, NULL, arp_failure_discard);
        ep->mpa_skb = skb;
-       state_set(&ep->com, MPA_REP_SENT);
+       __state_set(&ep->com, MPA_REP_SENT);
        ep->snd_seq += mpalen;
        return c4iw_l2t_send(&ep->com.dev->rdev, skb, ep->l2t);
 }
@@ -959,6 +959,7 @@ static int act_establish(struct c4iw_dev *dev, struct 
sk_buff *skb)
        PDBG("%s ep %p tid %u snd_isn %u rcv_isn %u\n", __func__, ep, tid,
             be32_to_cpu(req->snd_isn), be32_to_cpu(req->rcv_isn));
 
+       mutex_lock(&ep->com.mutex);
        dst_confirm(ep->dst);
 
        /* setup the hwtid for this connection */
@@ -982,7 +983,7 @@ static int act_establish(struct c4iw_dev *dev, struct 
sk_buff *skb)
                send_mpa_req(ep, skb, 1);
        else
                send_mpa_req(ep, skb, mpa_rev);
-
+       mutex_unlock(&ep->com.mutex);
        return 0;
 }
 
@@ -2566,22 +2567,28 @@ static int fw4_ack(struct c4iw_dev *dev, struct sk_buff 
*skb)
 
 int c4iw_reject_cr(struct iw_cm_id *cm_id, const void *pdata, u8 pdata_len)
 {
-       int err;
+       int err = 0;
+       int disconnect = 0;
        struct c4iw_ep *ep = to_ep(cm_id);
        PDBG("%s ep %p tid %u\n", __func__, ep, ep->hwtid);
 
-       if (state_read(&ep->com) == DEAD) {
+
+       mutex_lock(&ep->com.mutex);
+       if (ep->com.state == DEAD) {
                c4iw_put_ep(&ep->com);
                return -ECONNRESET;
        }
        set_bit(ULP_REJECT, &ep->com.history);
-       BUG_ON(state_read(&ep->com) != MPA_REQ_RCVD);
+       BUG_ON(ep->com.state != MPA_REQ_RCVD);
        if (mpa_rev == 0)
                abort_connection(ep, NULL, GFP_KERNEL);
        else {
                err = send_mpa_reject(ep, pdata, pdata_len);
-               err = c4iw_ep_disconnect(ep, 0, GFP_KERNEL);
+               disconnect = 1;
        }
+       mutex_unlock(&ep->com.mutex);
+       if (disconnect)
+               err = c4iw_ep_disconnect(ep, 0, GFP_KERNEL);
        c4iw_put_ep(&ep->com);
        return 0;
 }
@@ -2596,12 +2603,14 @@ int c4iw_accept_cr(struct iw_cm_id *cm_id, struct 
iw_cm_conn_param *conn_param)
        struct c4iw_qp *qp = get_qhp(h, conn_param->qpn);
 
        PDBG("%s ep %p tid %u\n", __func__, ep, ep->hwtid);
-       if (state_read(&ep->com) == DEAD) {
+
+       mutex_lock(&ep->com.mutex);
+       if (ep->com.state == DEAD) {
                err = -ECONNRESET;
                goto err;
        }
 
-       BUG_ON(state_read(&ep->com) != MPA_REQ_RCVD);
+       BUG_ON(ep->com.state != MPA_REQ_RCVD);
        BUG_ON(!qp);
 
        set_bit(ULP_ACCEPT, &ep->com.history);
@@ -2670,14 +2679,16 @@ int c4iw_accept_cr(struct iw_cm_id *cm_id, struct 
iw_cm_conn_param *conn_param)
        if (err)
                goto err1;
 
-       state_set(&ep->com, FPDU_MODE);
+       __state_set(&ep->com, FPDU_MODE);
        established_upcall(ep);
+       mutex_unlock(&ep->com.mutex);
        c4iw_put_ep(&ep->com);
        return 0;
 err1:
        ep->com.cm_id = NULL;
        cm_id->rem_ref(cm_id);
 err:
+       mutex_unlock(&ep->com.mutex);
        c4iw_put_ep(&ep->com);
        return err;
 }
-- 
1.8.4

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