IB/mthca: Avoid alignment traps when writing doorbells

Architectures such as ia64 see alignment traps when doing a 64-bit 
read from __be32 doorbell[2] arrays to do doorbell writes in 
mthca_write64().  Fix this by just passing the two halves of the 
doorbell value into mthca_write64().  This actually improves the 
generated code by allowing the compiler to see what's going on better.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 19 insertions, 34 deletions

diff --git a/drivers/infiniband/hw/mthca/mthca_cq.c b/drivers/infiniband/hw/mthca/mthca_cq.c
index be6e1e03bdab..6bd9f1393349 100644
--- a/drivers/infiniband/hw/mthca/mthca_cq.c
+++ b/drivers/infiniband/hw/mthca/mthca_cq.c
@@ -204,16 +204,11 @@ static void dump_cqe(struct mthca_dev *dev, void *cqe_ptr)
 static inline void update_cons_index(struct mthca_dev *dev, struct mthca_cq *cq,
                                      int incr)
 {
-        __be32 doorbell[2];
-
         if (mthca_is_memfree(dev)) {
                 *cq->set_ci_db = cpu_to_be32(cq->cons_index);
                 wmb();
         } else {
-                doorbell[0] = cpu_to_be32(MTHCA_TAVOR_CQ_DB_INC_CI | cq->cqn);
-                doorbell[1] = cpu_to_be32(incr - 1);
-
-                mthca_write64(doorbell,
+                mthca_write64(MTHCA_TAVOR_CQ_DB_INC_CI | cq->cqn, incr - 1,
                               dev->kar + MTHCA_CQ_DOORBELL,
                               MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
                 /*
@@ -731,17 +726,12 @@ repoll:
 
 int mthca_tavor_arm_cq(struct ib_cq *cq, enum ib_cq_notify_flags flags)
 {
-        __be32 doorbell[2];
+        u32 dbhi = ((flags & IB_CQ_SOLICITED_MASK) == IB_CQ_SOLICITED ?
+                    MTHCA_TAVOR_CQ_DB_REQ_NOT_SOL :
+                    MTHCA_TAVOR_CQ_DB_REQ_NOT) |
+                to_mcq(cq)->cqn;
 
-        doorbell[0] = cpu_to_be32(((flags & IB_CQ_SOLICITED_MASK) ==
-                                   IB_CQ_SOLICITED ?
-                                   MTHCA_TAVOR_CQ_DB_REQ_NOT_SOL :
-                                   MTHCA_TAVOR_CQ_DB_REQ_NOT)      |
-                                  to_mcq(cq)->cqn);
-        doorbell[1] = (__force __be32) 0xffffffff;
-
-        mthca_write64(doorbell,
-                      to_mdev(cq->device)->kar + MTHCA_CQ_DOORBELL,
+        mthca_write64(dbhi, 0xffffffff, to_mdev(cq->device)->kar + MTHCA_CQ_DOORBELL,
                       MTHCA_GET_DOORBELL_LOCK(&to_mdev(cq->device)->doorbell_lock));
 
         return 0;
@@ -750,19 +740,16 @@ int mthca_tavor_arm_cq(struct ib_cq *cq, enum ib_cq_notify_flags flags)
 int mthca_arbel_arm_cq(struct ib_cq *ibcq, enum ib_cq_notify_flags flags)
 {
         struct mthca_cq *cq = to_mcq(ibcq);
-        __be32 doorbell[2];
-        u32 sn;
-        __be32 ci;
-
-        sn = cq->arm_sn & 3;
-        ci = cpu_to_be32(cq->cons_index);
+        __be32 db_rec[2];
+        u32 dbhi;
+        u32 sn = cq->arm_sn & 3;
 
-        doorbell[0] = ci;
-        doorbell[1] = cpu_to_be32((cq->cqn << 8) | (2 << 5) | (sn << 3) |
-                                  ((flags & IB_CQ_SOLICITED_MASK) ==
-                                   IB_CQ_SOLICITED ? 1 : 2));
+        db_rec[0] = cpu_to_be32(cq->cons_index);
+        db_rec[1] = cpu_to_be32((cq->cqn << 8) | (2 << 5) | (sn << 3) |
+                                ((flags & IB_CQ_SOLICITED_MASK) ==
+                                 IB_CQ_SOLICITED ? 1 : 2));
 
-        mthca_write_db_rec(doorbell, cq->arm_db);
+        mthca_write_db_rec(db_rec, cq->arm_db);
 
         /*
          * Make sure that the doorbell record in host memory is
@@ -770,14 +757,12 @@ int mthca_arbel_arm_cq(struct ib_cq *ibcq, enum ib_cq_notify_flags flags)
          */
         wmb();
 
-        doorbell[0] = cpu_to_be32((sn << 28)                       |
-                                  ((flags & IB_CQ_SOLICITED_MASK) == IB_CQ_SOLICITED ?
-                                   MTHCA_ARBEL_CQ_DB_REQ_NOT_SOL :
-                                   MTHCA_ARBEL_CQ_DB_REQ_NOT)      |
-                                  cq->cqn);
-        doorbell[1] = ci;
+        dbhi = (sn << 28) |
+                ((flags & IB_CQ_SOLICITED_MASK) == IB_CQ_SOLICITED ?
+                 MTHCA_ARBEL_CQ_DB_REQ_NOT_SOL :
+                 MTHCA_ARBEL_CQ_DB_REQ_NOT) | cq->cqn;
 
-        mthca_write64(doorbell,
+        mthca_write64(dbhi, cq->cons_index,
                       to_mdev(ibcq->device)->kar + MTHCA_CQ_DOORBELL,
                       MTHCA_GET_DOORBELL_LOCK(&to_mdev(ibcq->device)->doorbell_lock));