IB/ehca: Rework irq handler

Rework ehca interrupt handling to avoid/reduce missed irq events.

Signed-off-by: Hoang-Nam Nguyen <hnguyen@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 136 insertions, 80 deletions

diff --git a/drivers/infiniband/hw/ehca/ehca_irq.c b/drivers/infiniband/hw/ehca/ehca_irq.c
index 6c4f9f91b15d..b923b5d5de68 100644
--- a/drivers/infiniband/hw/ehca/ehca_irq.c
+++ b/drivers/infiniband/hw/ehca/ehca_irq.c
@@ -206,7 +206,7 @@ static void qp_event_callback(struct ehca_shca *shca,
 }
 
 static void cq_event_callback(struct ehca_shca *shca,
-                                          u64 eqe)
+                              u64 eqe)
 {
         struct ehca_cq *cq;
         unsigned long flags;
@@ -318,7 +318,7 @@ static void parse_ec(struct ehca_shca *shca, u64 eqe)
                           "disruptive port %x configuration change", port);
 
                 ehca_info(&shca->ib_device,
-                         "port %x is inactive.", port);
+                          "port %x is inactive.", port);
                 event.device = &shca->ib_device;
                 event.event = IB_EVENT_PORT_ERR;
                 event.element.port_num = port;
@@ -326,7 +326,7 @@ static void parse_ec(struct ehca_shca *shca, u64 eqe)
                 ib_dispatch_event(&event);
 
                 ehca_info(&shca->ib_device,
-                         "port %x is active.", port);
+                          "port %x is active.", port);
                 event.device = &shca->ib_device;
                 event.event = IB_EVENT_PORT_ACTIVE;
                 event.element.port_num = port;
@@ -401,87 +401,143 @@ irqreturn_t ehca_interrupt_eq(int irq, void *dev_id)
         return IRQ_HANDLED;
 }
 
-void ehca_tasklet_eq(unsigned long data)
-{
-        struct ehca_shca *shca = (struct ehca_shca*)data;
-        struct ehca_eqe *eqe;
-        int int_state;
-        int query_cnt = 0;
 
-        do {
-                eqe = (struct ehca_eqe *)ehca_poll_eq(shca, &shca->eq);
-
-                if ((shca->hw_level >= 2) && eqe)
-                        int_state = 1;
-                else
-                        int_state = 0;
-
-                while ((int_state == 1) || eqe) {
-                        while (eqe) {
-                                u64 eqe_value = eqe->entry;
-
-                                ehca_dbg(&shca->ib_device,
-                                         "eqe_value=%lx", eqe_value);
-
-                                /* TODO: better structure */
-                                if (EHCA_BMASK_GET(EQE_COMPLETION_EVENT,
-                                                   eqe_value)) {
-                                        unsigned long flags;
-                                        u32 token;
-                                        struct ehca_cq *cq;
-
-                                        ehca_dbg(&shca->ib_device,
-                                                 "... completion event");
-                                        token =
-                                                EHCA_BMASK_GET(EQE_CQ_TOKEN,
-                                                               eqe_value);
-                                        spin_lock_irqsave(&ehca_cq_idr_lock,
-                                                          flags);
-                                        cq = idr_find(&ehca_cq_idr, token);
-
-                                        if (cq == NULL) {
-                                                spin_unlock_irqrestore(&ehca_cq_idr_lock,
-                                                                       flags);
-                                                break;
-                                        }
-
-                                        reset_eq_pending(cq);
+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;
+        ehca_dbg(&shca->ib_device, "eqe_value=%lx", eqe_value);
+        if (EHCA_BMASK_GET(EQE_COMPLETION_EVENT, eqe_value)) {
+                ehca_dbg(&shca->ib_device, "... completion event");
+                token = EHCA_BMASK_GET(EQE_CQ_TOKEN, eqe_value);
+                spin_lock_irqsave(&ehca_cq_idr_lock, flags);
+                cq = idr_find(&ehca_cq_idr, token);
+                if (cq == NULL) {
+                        spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
+                        ehca_err(&shca->ib_device,
+                                 "Invalid eqe for non-existing cq token=%x",
+                                 token);
+                        return;
+                }
+                reset_eq_pending(cq);
 #ifdef CONFIG_INFINIBAND_EHCA_SCALING
-                                        queue_comp_task(cq);
-                                        spin_unlock_irqrestore(&ehca_cq_idr_lock,
-                                                               flags);
+                queue_comp_task(cq);
+                spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
 #else
-                                        spin_unlock_irqrestore(&ehca_cq_idr_lock,
-                                                               flags);
-                                        comp_event_callback(cq);
+                spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
+                comp_event_callback(cq);
 #endif
-                                } else {
-                                        ehca_dbg(&shca->ib_device,
-                                                 "... non completion event");
-                                        parse_identifier(shca, eqe_value);
-                                }
-                                eqe =
-                                        (struct ehca_eqe *)ehca_poll_eq(shca,
-                                                                    &shca->eq);
-                        }
+        } else {
+                ehca_dbg(&shca->ib_device,
+                         "Got non completion event");
+                parse_identifier(shca, eqe_value);
+        }
+}
 
-                        if (shca->hw_level >= 2) {
-                                int_state =
-                                    hipz_h_query_int_state(shca->ipz_hca_handle,
-                                                           shca->eq.ist);
-                                query_cnt++;
-                                iosync();
-                                if (query_cnt >= 100) {
-                                        query_cnt = 0;
-                                        int_state = 0;
-                                }
-                        }
-                        eqe = (struct ehca_eqe *)ehca_poll_eq(shca, &shca->eq);
+void ehca_process_eq(struct ehca_shca *shca, int is_irq)
+{
+        struct ehca_eq *eq = &shca->eq;
+        struct ehca_eqe_cache_entry *eqe_cache = eq->eqe_cache;
+        u64 eqe_value;
+        unsigned long flags;
+        int eqe_cnt, i;
+        int eq_empty = 0;
+
+        spin_lock_irqsave(&eq->irq_spinlock, flags);
+        if (is_irq) {
+                const int max_query_cnt = 100;
+                int query_cnt = 0;
+                int int_state = 1;
+                do {
+                        int_state = hipz_h_query_int_state(
+                                shca->ipz_hca_handle, eq->ist);
+                        query_cnt++;
+                        iosync();
+                } while (int_state && query_cnt < max_query_cnt);
+                if (unlikely((query_cnt == max_query_cnt)))
+                        ehca_dbg(&shca->ib_device, "int_state=%x query_cnt=%x",
+                                 int_state, query_cnt);
+        }
 
+        /* read out all eqes */
+        eqe_cnt = 0;
+        do {
+                u32 token;
+                eqe_cache[eqe_cnt].eqe =
+                        (struct ehca_eqe *)ehca_poll_eq(shca, eq);
+                if (!eqe_cache[eqe_cnt].eqe)
+                        break;
+                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);
+                        eqe_cache[eqe_cnt].cq = idr_find(&ehca_cq_idr, token);
+                        if (!eqe_cache[eqe_cnt].cq) {
+                                spin_unlock(&ehca_cq_idr_lock);
+                                ehca_err(&shca->ib_device,
+                                         "Invalid eqe for non-existing cq "
+                                         "token=%x", token);
+                                continue;
+                        }
+                        spin_unlock(&ehca_cq_idr_lock);
+                } else
+                        eqe_cache[eqe_cnt].cq = NULL;
+                eqe_cnt++;
+        } while (eqe_cnt < EHCA_EQE_CACHE_SIZE);
+        if (!eqe_cnt) {
+                if (is_irq)
+                        ehca_dbg(&shca->ib_device,
+                                 "No eqe found for irq event");
+                goto unlock_irq_spinlock;
+        } else if (!is_irq)
+                ehca_dbg(&shca->ib_device, "deadman found %x eqe", eqe_cnt);
+        if (unlikely(eqe_cnt == EHCA_EQE_CACHE_SIZE))
+                ehca_dbg(&shca->ib_device, "too many eqes for one irq event");
+        /* enable irq for new packets */
+        for (i = 0; i < eqe_cnt; i++) {
+                if (eq->eqe_cache[i].cq)
+                        reset_eq_pending(eq->eqe_cache[i].cq);
+        }
+        /* check eq */
+        spin_lock(&eq->spinlock);
+        eq_empty = (!ipz_eqit_eq_peek_valid(&shca->eq.ipz_queue));
+        spin_unlock(&eq->spinlock);
+        /* call completion handler for cached eqes */
+        for (i = 0; i < eqe_cnt; i++)
+                if (eq->eqe_cache[i].cq) {
+#ifdef CONFIG_INFINIBAND_EHCA_SCALING
+                        spin_lock(&ehca_cq_idr_lock);
+                        queue_comp_task(eq->eqe_cache[i].cq);
+                        spin_unlock(&ehca_cq_idr_lock);
+#else
+                        comp_event_callback(eq->eqe_cache[i].cq);
+#endif
+                } else {
+                        ehca_dbg(&shca->ib_device, "Got non completion event");
+                        parse_identifier(shca, eq->eqe_cache[i].eqe->entry);
                 }
-        } while (int_state != 0);
+        /* poll eq if not empty */
+        if (eq_empty)
+                goto unlock_irq_spinlock;
+        do {
+                struct ehca_eqe *eqe;
+                eqe = (struct ehca_eqe *)ehca_poll_eq(shca, &shca->eq);
+                if (!eqe)
+                        break;
+                process_eqe(shca, eqe);
+                eqe_cnt++;
+        } while (1);
+
+unlock_irq_spinlock:
+        spin_unlock_irqrestore(&eq->irq_spinlock, flags);
+}
 
-        return;
+void ehca_tasklet_eq(unsigned long data)
+{
+        ehca_process_eq((struct ehca_shca*)data, 1);
 }
 
 #ifdef CONFIG_INFINIBAND_EHCA_SCALING
@@ -654,11 +710,11 @@ static void take_over_work(struct ehca_comp_pool *pool,
         list_splice_init(&cct->cq_list, &list);
 
         while(!list_empty(&list)) {
-               cq = list_entry(cct->cq_list.next, struct ehca_cq, entry);
+                cq = list_entry(cct->cq_list.next, struct ehca_cq, entry);
 
-               list_del(&cq->entry);
-               __queue_comp_task(cq, per_cpu_ptr(pool->cpu_comp_tasks,
-                                                 smp_processor_id()));
+                list_del(&cq->entry);
+                __queue_comp_task(cq, per_cpu_ptr(pool->cpu_comp_tasks,
+                                                  smp_processor_id()));
         }
 
         spin_unlock_irqrestore(&cct->task_lock, flags_cct);