IB/qib: Remove s_lock around header validation

Review of qib_ruc_check_hdr() shows that the s_lock is not required in
the normal case.  The r_lock is held in all cases, and protects the qp
fields that are read.

The s_lock will be needed to around the call to qib_migrate_qp() to
insure that the send engine sees a consistent set of fields.

Signed-off-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

4 files changed, 8 insertions, 15 deletions

diff --git a/drivers/infiniband/hw/qib/qib_driver.c b/drivers/infiniband/hw/qib/qib_driver.c
index d35c9d38ceee..9a9047f385ae 100644
--- a/drivers/infiniband/hw/qib/qib_driver.c
+++ b/drivers/infiniband/hw/qib/qib_driver.c
@@ -310,7 +310,6 @@ static u32 qib_rcv_hdrerr(struct qib_ctxtdata *rcd, struct qib_pportdata *ppd,
                 u32 opcode;
                 u32 psn;
                 int diff;
-                unsigned long flags;
 
                 /* Sanity check packet */
                 if (tlen < 24)
@@ -365,7 +364,6 @@ static u32 qib_rcv_hdrerr(struct qib_ctxtdata *rcd, struct qib_pportdata *ppd,
 
                         switch (qp->ibqp.qp_type) {
                         case IB_QPT_RC:
-                                spin_lock_irqsave(&qp->s_lock, flags);
                                 ruc_res =
                                         qib_ruc_check_hdr(
                                                 ibp, hdr,
@@ -373,11 +371,8 @@ static u32 qib_rcv_hdrerr(struct qib_ctxtdata *rcd, struct qib_pportdata *ppd,
                                                 qp,
                                                 be32_to_cpu(ohdr->bth[0]));
                                 if (ruc_res) {
-                                        spin_unlock_irqrestore(&qp->s_lock,
-                                                               flags);
                                         goto unlock;
                                 }
-                                spin_unlock_irqrestore(&qp->s_lock, flags);
 
                                 /* Only deal with RDMA Writes for now */
                                 if (opcode <
diff --git a/drivers/infiniband/hw/qib/qib_rc.c b/drivers/infiniband/hw/qib/qib_rc.c
index ecfa087ad45e..afaf4ac79f42 100644
--- a/drivers/infiniband/hw/qib/qib_rc.c
+++ b/drivers/infiniband/hw/qib/qib_rc.c
@@ -1889,10 +1889,8 @@ void qib_rc_rcv(struct qib_ctxtdata *rcd, struct qib_ib_header *hdr,
         }
 
         opcode = be32_to_cpu(ohdr->bth[0]);
-        spin_lock_irqsave(&qp->s_lock, flags);
         if (qib_ruc_check_hdr(ibp, hdr, has_grh, qp, opcode))
-                goto sunlock;
-        spin_unlock_irqrestore(&qp->s_lock, flags);
+                return;
 
         psn = be32_to_cpu(ohdr->bth[2]);
         opcode >>= 24;
diff --git a/drivers/infiniband/hw/qib/qib_ruc.c b/drivers/infiniband/hw/qib/qib_ruc.c
index eb78d9367f06..b4b37e47321a 100644
--- a/drivers/infiniband/hw/qib/qib_ruc.c
+++ b/drivers/infiniband/hw/qib/qib_ruc.c
@@ -260,12 +260,15 @@ static int gid_ok(union ib_gid *gid, __be64 gid_prefix, __be64 id)
 
 /*
  *
- * This should be called with the QP s_lock held.
+ * This should be called with the QP r_lock held.
+ *
+ * The s_lock will be acquired around the qib_migrate_qp() call.
  */
 int qib_ruc_check_hdr(struct qib_ibport *ibp, struct qib_ib_header *hdr,
                       int has_grh, struct qib_qp *qp, u32 bth0)
 {
         __be64 guid;
+        unsigned long flags;
 
         if (qp->s_mig_state == IB_MIG_ARMED && (bth0 & IB_BTH_MIG_REQ)) {
                 if (!has_grh) {
@@ -295,7 +298,9 @@ int qib_ruc_check_hdr(struct qib_ibport *ibp, struct qib_ib_header *hdr,
                 if (be16_to_cpu(hdr->lrh[3]) != qp->alt_ah_attr.dlid ||
                     ppd_from_ibp(ibp)->port != qp->alt_ah_attr.port_num)
                         goto err;
+                spin_lock_irqsave(&qp->s_lock, flags);
                 qib_migrate_qp(qp);
+                spin_unlock_irqrestore(&qp->s_lock, flags);
         } else {
                 if (!has_grh) {
                         if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
diff --git a/drivers/infiniband/hw/qib/qib_uc.c b/drivers/infiniband/hw/qib/qib_uc.c
index 9a4630f8276f..847e7afdfd94 100644
--- a/drivers/infiniband/hw/qib/qib_uc.c
+++ b/drivers/infiniband/hw/qib/qib_uc.c
@@ -243,7 +243,6 @@ void qib_uc_rcv(struct qib_ibport *ibp, struct qib_ib_header *hdr,
                 int has_grh, void *data, u32 tlen, struct qib_qp *qp)
 {
         struct qib_other_headers *ohdr;
-        unsigned long flags;
         u32 opcode;
         u32 hdrsize;
         u32 psn;
@@ -263,10 +262,8 @@ void qib_uc_rcv(struct qib_ibport *ibp, struct qib_ib_header *hdr,
         }
 
         opcode = be32_to_cpu(ohdr->bth[0]);
-        spin_lock_irqsave(&qp->s_lock, flags);
         if (qib_ruc_check_hdr(ibp, hdr, has_grh, qp, opcode))
-                goto sunlock;
-        spin_unlock_irqrestore(&qp->s_lock, flags);
+                return;
 
         psn = be32_to_cpu(ohdr->bth[2]);
         opcode >>= 24;
@@ -554,6 +551,4 @@ op_err:
         qib_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
         return;
 
-sunlock:
-        spin_unlock_irqrestore(&qp->s_lock, flags);
 }