IB/ehca: Change idr spinlocks into rwlocks

This eliminates lock contention among IRQs as well as the need to
disable IRQs around idr_find, because there are no IRQ writers.

Signed-off-by: Joachim Fenkes <fenkes@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 8 insertions, 11 deletions

diff --git a/drivers/infiniband/hw/ehca/ehca_irq.c b/drivers/infiniband/hw/ehca/ehca_irq.c
index 3e790a326d97..02b73c84c49b 100644
--- a/drivers/infiniband/hw/ehca/ehca_irq.c
+++ b/drivers/infiniband/hw/ehca/ehca_irq.c
@@ -180,12 +180,11 @@ static void qp_event_callback(struct ehca_shca *shca,
 {
         struct ib_event event;
         struct ehca_qp *qp;
-        unsigned long flags;
         u32 token = EHCA_BMASK_GET(EQE_QP_TOKEN, eqe);
 
-        spin_lock_irqsave(&ehca_qp_idr_lock, flags);
+        read_lock(&ehca_qp_idr_lock);
         qp = idr_find(&ehca_qp_idr, token);
-        spin_unlock_irqrestore(&ehca_qp_idr_lock, flags);
+        read_unlock(&ehca_qp_idr_lock);
 
 
         if (!qp)
@@ -209,14 +208,13 @@ static void cq_event_callback(struct ehca_shca *shca,
                               u64 eqe)
 {
         struct ehca_cq *cq;
-        unsigned long flags;
         u32 token = EHCA_BMASK_GET(EQE_CQ_TOKEN, eqe);
 
-        spin_lock_irqsave(&ehca_cq_idr_lock, flags);
+        read_lock(&ehca_cq_idr_lock);
         cq = idr_find(&ehca_cq_idr, token);
         if (cq)
                 atomic_inc(&cq->nr_events);
-        spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
+        read_unlock(&ehca_cq_idr_lock);
 
         if (!cq)
                 return;
@@ -411,7 +409,6 @@ static inline void process_eqe(struct ehca_shca *shca, struct ehca_eqe *eqe)
 {
         u64 eqe_value;
         u32 token;
-        unsigned long flags;
         struct ehca_cq *cq;
 
         eqe_value = eqe->entry;
@@ -419,11 +416,11 @@ static inline void process_eqe(struct ehca_shca *shca, struct ehca_eqe *eqe)
         if (EHCA_BMASK_GET(EQE_COMPLETION_EVENT, eqe_value)) {
                 ehca_dbg(&shca->ib_device, "Got completion event");
                 token = EHCA_BMASK_GET(EQE_CQ_TOKEN, eqe_value);
-                spin_lock_irqsave(&ehca_cq_idr_lock, flags);
+                read_lock(&ehca_cq_idr_lock);
                 cq = idr_find(&ehca_cq_idr, token);
                 if (cq)
                         atomic_inc(&cq->nr_events);
-                spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
+                read_unlock(&ehca_cq_idr_lock);
                 if (cq == NULL) {
                         ehca_err(&shca->ib_device,
                                  "Invalid eqe for non-existing cq token=%x",
@@ -480,11 +477,11 @@ void ehca_process_eq(struct ehca_shca *shca, int is_irq)
                 eqe_value = eqe_cache[eqe_cnt].eqe->entry;
                 if (EHCA_BMASK_GET(EQE_COMPLETION_EVENT, eqe_value)) {
                         token = EHCA_BMASK_GET(EQE_CQ_TOKEN, eqe_value);
-                        spin_lock(&ehca_cq_idr_lock);
+                        read_lock(&ehca_cq_idr_lock);
                         eqe_cache[eqe_cnt].cq = idr_find(&ehca_cq_idr, token);
                         if (eqe_cache[eqe_cnt].cq)
                                 atomic_inc(&eqe_cache[eqe_cnt].cq->nr_events);
-                        spin_unlock(&ehca_cq_idr_lock);
+                        read_unlock(&ehca_cq_idr_lock);
                         if (!eqe_cache[eqe_cnt].cq) {
                                 ehca_err(&shca->ib_device,
                                          "Invalid eqe for non-existing cq "