diff options
| author | Ralph Campbell <ralph.campbell@qlogic.com> | 2007-10-19 15:04:10 -0700 |
|---|---|---|
| committer | Roland Dreier <rolandd@cisco.com> | 2007-10-30 10:57:24 -0700 |
| commit | fffbfeaa680e2b87a591e141f2aa7e9e91184956 (patch) | |
| tree | 6a087d79165f626e6ad13dddf4dfb17ba128d1f4 | |
| parent | 96db0e0335c7981911bd7efc5c79e82d2358c0fc (diff) | |
IB/ipath: Fix a race where s_last is updated without lock held
There is a small window where a send work queue entry could be
overwritten by ib_post_send() because s_last is updated before the
entry is read.
This patch closes the window by acquiring the lock and updating
the last send work queue entry index after reading the wr_id.
Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
| -rw-r--r-- | drivers/infiniband/hw/ipath/ipath_ruc.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/drivers/infiniband/hw/ipath/ipath_ruc.c b/drivers/infiniband/hw/ipath/ipath_ruc.c index 4b6b7ee8e5c..54c61a972de 100644 --- a/drivers/infiniband/hw/ipath/ipath_ruc.c +++ b/drivers/infiniband/hw/ipath/ipath_ruc.c @@ -630,11 +630,8 @@ bail:; void ipath_send_complete(struct ipath_qp *qp, struct ipath_swqe *wqe, enum ib_wc_status status) { - u32 last = qp->s_last; - - if (++last == qp->s_size) - last = 0; - qp->s_last = last; + unsigned long flags; + u32 last; /* See ch. 11.2.4.1 and 10.7.3.1 */ if (!(qp->s_flags & IPATH_S_SIGNAL_REQ_WR) || @@ -658,4 +655,11 @@ void ipath_send_complete(struct ipath_qp *qp, struct ipath_swqe *wqe, wc.port_num = 0; ipath_cq_enter(to_icq(qp->ibqp.send_cq), &wc, 0); } + + spin_lock_irqsave(&qp->s_lock, flags); + last = qp->s_last; + if (++last >= qp->s_size) + last = 0; + qp->s_last = last; + spin_unlock_irqrestore(&qp->s_lock, flags); } |