4.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mike Marciniszyn <mike.marcinis...@intel.com>

commit 2aee309d3e01447c55fdf89cef05a0e2be372655 upstream.

A failure in the get_txreq() inline will result in a
slow path retry using __get_txreq().

__get_txreq() attempts to procure the qp s_lock, which
is already held in all callers.

Fix by deleting the s_lock maintenance in __get_txreq()
and add sparse syntax hooks to future proof the code.

Cc: Stable <sta...@vger.kernel.org> # 4.6+
Reviewed-by: Dennis Dalessandro <dennis.dalessan...@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marcinis...@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessan...@intel.com>
Signed-off-by: Doug Ledford <dledf...@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/staging/rdma/hfi1/verbs_txreq.c |    4 +---
 drivers/staging/rdma/hfi1/verbs_txreq.h |    1 +
 2 files changed, 2 insertions(+), 3 deletions(-)

--- a/drivers/staging/rdma/hfi1/verbs_txreq.c
+++ b/drivers/staging/rdma/hfi1/verbs_txreq.c
@@ -92,11 +92,10 @@ void hfi1_put_txreq(struct verbs_txreq *
 
 struct verbs_txreq *__get_txreq(struct hfi1_ibdev *dev,
                                struct rvt_qp *qp)
+       __must_hold(&qp->s_lock)
 {
        struct verbs_txreq *tx = ERR_PTR(-EBUSY);
-       unsigned long flags;
 
-       spin_lock_irqsave(&qp->s_lock, flags);
        write_seqlock(&dev->iowait_lock);
        if (ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK) {
                struct hfi1_qp_priv *priv;
@@ -116,7 +115,6 @@ struct verbs_txreq *__get_txreq(struct h
        }
 out:
        write_sequnlock(&dev->iowait_lock);
-       spin_unlock_irqrestore(&qp->s_lock, flags);
        return tx;
 }
 
--- a/drivers/staging/rdma/hfi1/verbs_txreq.h
+++ b/drivers/staging/rdma/hfi1/verbs_txreq.h
@@ -73,6 +73,7 @@ struct verbs_txreq *__get_txreq(struct h
 
 static inline struct verbs_txreq *get_txreq(struct hfi1_ibdev *dev,
                                            struct rvt_qp *qp)
+       __must_hold(&qp->slock)
 {
        struct verbs_txreq *tx;
        struct hfi1_qp_priv *priv = qp->priv;


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