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RDMA/cxgb4: Fix race in fini path 

There exists a race condition where the app disconnects, which
initiates an orderly close (via rdma_fini()), concurrently with an
ingress abort condition, which initiates an abortive close operation.
Since rdma_fini() must be called without IRQs disabled, the fini can
be called after the QP has been transitioned to ERROR.  This is ok,
but we need to protect against qp->ep getting NULLed.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Steve Wise 2010-07-23 19:12:27 +00:00 committed by Roland Dreier
parent d37ac31ddc
commit 73d6fcad2a
1 changed files with 7 additions and 7 deletions
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14
drivers/infiniband/hw/cxgb4/qp.c
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@ -961,7 +961,8 @@ static void flush_qp(struct c4iw_qp *qhp, unsigned long *flag)
__flush_qp(qhp, rchp, schp, flag);
}
static int rdma_fini(struct c4iw_dev *rhp, struct c4iw_qp *qhp)
static int rdma_fini(struct c4iw_dev *rhp, struct c4iw_qp *qhp,
struct c4iw_ep *ep)
{
struct fw_ri_wr *wqe;
int ret;
@ -969,12 +970,12 @@ static int rdma_fini(struct c4iw_dev *rhp, struct c4iw_qp *qhp)
struct sk_buff *skb;
PDBG("%s qhp %p qid 0x%x tid %u\n", __func__, qhp, qhp->wq.sq.qid,
qhp->ep->hwtid);
ep->hwtid);
skb = alloc_skb(sizeof *wqe, GFP_KERNEL);
if (!skb)
return -ENOMEM;
set_wr_txq(skb, CPL_PRIORITY_DATA, qhp->ep->txq_idx);
set_wr_txq(skb, CPL_PRIORITY_DATA, ep->txq_idx);
wqe = (struct fw_ri_wr *)__skb_put(skb, sizeof(*wqe));
memset(wqe, 0, sizeof *wqe);
@ -982,7 +983,7 @@ static int rdma_fini(struct c4iw_dev *rhp, struct c4iw_qp *qhp)
FW_WR_OP(FW_RI_INIT_WR) |
FW_WR_COMPL(1));
wqe->flowid_len16 = cpu_to_be32(
FW_WR_FLOWID(qhp->ep->hwtid) |
FW_WR_FLOWID(ep->hwtid) |
FW_WR_LEN16(DIV_ROUND_UP(sizeof *wqe, 16)));
wqe->cookie = (u64)&wr_wait;
@ -1212,17 +1213,16 @@ int c4iw_modify_qp(struct c4iw_dev *rhp, struct c4iw_qp *qhp,
case C4IW_QP_STATE_CLOSING:
BUG_ON(atomic_read(&qhp->ep->com.kref.refcount) < 2);
qhp->attr.state = C4IW_QP_STATE_CLOSING;
ep = qhp->ep;
if (!internal) {
abort = 0;
disconnect = 1;
ep = qhp->ep;
c4iw_get_ep(&ep->com);
}
spin_unlock_irqrestore(&qhp->lock, flag);
ret = rdma_fini(rhp, qhp);
ret = rdma_fini(rhp, qhp, ep);
spin_lock_irqsave(&qhp->lock, flag);
if (ret) {
ep = qhp->ep;
c4iw_get_ep(&ep->com);
disconnect = abort = 1;
goto err;