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>

6 files changed, 183 insertions, 92 deletions

diff --git a/drivers/infiniband/hw/ehca/ehca_classes.h b/drivers/infiniband/hw/ehca/ehca_classes.h
index cf95ee474b0f..f08ad6f9c132 100644
--- a/drivers/infiniband/hw/ehca/ehca_classes.h
+++ b/drivers/infiniband/hw/ehca/ehca_classes.h
@@ -42,8 +42,6 @@
 #ifndef __EHCA_CLASSES_H__
 #define __EHCA_CLASSES_H__
 
-#include "ehca_classes.h"
-#include "ipz_pt_fn.h"
 
 struct ehca_module;
 struct ehca_qp;
@@ -54,14 +52,22 @@ struct ehca_mw;
 struct ehca_pd;
 struct ehca_av;
 
+#include <rdma/ib_verbs.h>
+#include <rdma/ib_user_verbs.h>
+
 #ifdef CONFIG_PPC64
 #include "ehca_classes_pSeries.h"
 #endif
+#include "ipz_pt_fn.h"
+#include "ehca_qes.h"
+#include "ehca_irq.h"
 
-#include <rdma/ib_verbs.h>
-#include <rdma/ib_user_verbs.h>
+#define EHCA_EQE_CACHE_SIZE 20
 
-#include "ehca_irq.h"
+struct ehca_eqe_cache_entry {
+        struct ehca_eqe *eqe;
+        struct ehca_cq *cq;
+};
 
 struct ehca_eq {
         u32 length;
@@ -74,6 +80,8 @@ struct ehca_eq {
         spinlock_t spinlock;
         struct tasklet_struct interrupt_task;
         u32 ist;
+        spinlock_t irq_spinlock;
+        struct ehca_eqe_cache_entry eqe_cache[EHCA_EQE_CACHE_SIZE];
 };
 
 struct ehca_sport {
diff --git a/drivers/infiniband/hw/ehca/ehca_eq.c b/drivers/infiniband/hw/ehca/ehca_eq.c
index 24ceab0bae4a..4961eb88827c 100644
--- a/drivers/infiniband/hw/ehca/ehca_eq.c
+++ b/drivers/infiniband/hw/ehca/ehca_eq.c
@@ -61,6 +61,7 @@ int ehca_create_eq(struct ehca_shca *shca,
         struct ib_device *ib_dev = &shca->ib_device;
 
         spin_lock_init(&eq->spinlock);
+        spin_lock_init(&eq->irq_spinlock);
         eq->is_initialized = 0;
 
         if (type != EHCA_EQ && type != EHCA_NEQ) {
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);
diff --git a/drivers/infiniband/hw/ehca/ehca_irq.h b/drivers/infiniband/hw/ehca/ehca_irq.h
index be579cc0adf6..6ed06ee033ed 100644
--- a/drivers/infiniband/hw/ehca/ehca_irq.h
+++ b/drivers/infiniband/hw/ehca/ehca_irq.h
@@ -56,6 +56,7 @@ void ehca_tasklet_neq(unsigned long data);
 
 irqreturn_t ehca_interrupt_eq(int irq, void *dev_id);
 void ehca_tasklet_eq(unsigned long data);
+void ehca_process_eq(struct ehca_shca *shca, int is_irq);
 
 struct ehca_cpu_comp_task {
         wait_queue_head_t wait_queue;
diff --git a/drivers/infiniband/hw/ehca/ehca_main.c b/drivers/infiniband/hw/ehca/ehca_main.c
index 1155bcf48212..579053421472 100644
--- a/drivers/infiniband/hw/ehca/ehca_main.c
+++ b/drivers/infiniband/hw/ehca/ehca_main.c
@@ -52,7 +52,7 @@
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_AUTHOR("Christoph Raisch <raisch@de.ibm.com>");
 MODULE_DESCRIPTION("IBM eServer HCA InfiniBand Device Driver");
-MODULE_VERSION("SVNEHCA_0020");
+MODULE_VERSION("SVNEHCA_0021");
 
 int ehca_open_aqp1     = 0;
 int ehca_debug_level   = 0;
@@ -432,8 +432,8 @@ static int ehca_destroy_aqp1(struct ehca_sport *sport)
 
 static ssize_t ehca_show_debug_level(struct device_driver *ddp, char *buf)
 {
-        return  snprintf(buf, PAGE_SIZE, "%d\n",
-                         ehca_debug_level);
+        return snprintf(buf, PAGE_SIZE, "%d\n",
+                        ehca_debug_level);
 }
 
 static ssize_t ehca_store_debug_level(struct device_driver *ddp,
@@ -778,8 +778,24 @@ void ehca_poll_eqs(unsigned long data)
 
         spin_lock(&shca_list_lock);
         list_for_each_entry(shca, &shca_list, shca_list) {
-                if (shca->eq.is_initialized)
-                        ehca_tasklet_eq((unsigned long)(void*)shca);
+                if (shca->eq.is_initialized) {
+                        /* call deadman proc only if eq ptr does not change */
+                        struct ehca_eq *eq = &shca->eq;
+                        int max = 3;
+                        volatile u64 q_ofs, q_ofs2;
+                        u64 flags;
+                        spin_lock_irqsave(&eq->spinlock, flags);
+                        q_ofs = eq->ipz_queue.current_q_offset;
+                        spin_unlock_irqrestore(&eq->spinlock, flags);
+                        do {
+                                spin_lock_irqsave(&eq->spinlock, flags);
+                                q_ofs2 = eq->ipz_queue.current_q_offset;
+                                spin_unlock_irqrestore(&eq->spinlock, flags);
+                                max--;
+                        } while (q_ofs == q_ofs2 && max > 0);
+                        if (q_ofs == q_ofs2)
+                                ehca_process_eq(shca, 0);
+                }
         }
         mod_timer(&poll_eqs_timer, jiffies + HZ);
         spin_unlock(&shca_list_lock);
@@ -790,7 +806,7 @@ int __init ehca_module_init(void)
         int ret;
 
         printk(KERN_INFO "eHCA Infiniband Device Driver "
-                         "(Rel.: SVNEHCA_0020)\n");
+               "(Rel.: SVNEHCA_0021)\n");
         idr_init(&ehca_qp_idr);
         idr_init(&ehca_cq_idr);
         spin_lock_init(&ehca_qp_idr_lock);
diff --git a/drivers/infiniband/hw/ehca/ipz_pt_fn.h b/drivers/infiniband/hw/ehca/ipz_pt_fn.h
index dc3bda2634b7..8199c45768a3 100644
--- a/drivers/infiniband/hw/ehca/ipz_pt_fn.h
+++ b/drivers/infiniband/hw/ehca/ipz_pt_fn.h
@@ -79,7 +79,7 @@ static inline void *ipz_qeit_calc(struct ipz_queue *queue, u64 q_offset)
         if (q_offset >= queue->queue_length)
                 return NULL;
         current_page = (queue->queue_pages)[q_offset >> EHCA_PAGESHIFT];
-        return  &current_page->entries[q_offset & (EHCA_PAGESIZE - 1)];
+        return &current_page->entries[q_offset & (EHCA_PAGESIZE - 1)];
 }
 
 /*
@@ -247,6 +247,15 @@ static inline void *ipz_eqit_eq_get_inc_valid(struct ipz_queue *queue)
         return ret;
 }
 
+static inline void *ipz_eqit_eq_peek_valid(struct ipz_queue *queue)
+{
+        void *ret = ipz_qeit_get(queue);
+        u32 qe = *(u8 *) ret;
+        if ((qe >> 7) != (queue->toggle_state & 1))
+                return NULL;
+        return ret;
+}
+
 /* returns address (GX) of first queue entry */
 static inline u64 ipz_qpt_get_firstpage(struct ipz_qpt *qpt)
 {