3 files changed, 56 insertions, 103 deletions

diff --git a/drivers/s390/cio/qdio.h b/drivers/s390/cio/qdio.h
index c60f2566d28c..42f2b09631b6 100644
--- a/drivers/s390/cio/qdio.h
+++ b/drivers/s390/cio/qdio.h
@@ -14,7 +14,6 @@
 #include "chsc.h"
 
 #define QDIO_BUSY_BIT_PATIENCE          100     /* 100 microseconds */
-#define QDIO_BUSY_BIT_GIVE_UP           2000000 /* 2 seconds = eternity */
 #define QDIO_INPUT_THRESHOLD            500     /* 500 microseconds */
 
 /*
@@ -195,12 +194,6 @@ struct qdio_input_q {
 };
 
 struct qdio_output_q {
-        /* failed siga-w attempts*/
-        atomic_t busy_siga_counter;
-
-        /* start time of busy condition */
-        u64 timestamp;
-
         /* PCIs are enabled for the queue */
         int pci_out_enabled;
 
@@ -251,6 +244,7 @@ struct qdio_q {
 
         struct qdio_irq *irq_ptr;
         struct tasklet_struct tasklet;
+        spinlock_t lock;
 
         /* error condition during a data transfer */
         unsigned int qdio_error;
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 0b4c09cf6a47..744f928a59ea 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -74,7 +74,7 @@ static inline int do_siga_input(struct subchannel_id schid, unsigned int mask)
  * Note: For IQDC unicast queues only the highest priority queue is processed.
  */
 static inline int do_siga_output(unsigned long schid, unsigned long mask,
-                                 u32 *bb, unsigned int fc)
+                                 unsigned int *bb, unsigned int fc)
 {
         register unsigned long __fc asm("0") = fc;
         register unsigned long __schid asm("1") = schid;
@@ -284,8 +284,7 @@ static int qdio_siga_sync(struct qdio_q *q, unsigned int output,
         if (!need_siga_sync(q))
                 return 0;
 
-        DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-s:");
-        DBF_DEV_HEX(DBF_INFO, q->irq_ptr, q, sizeof(void *));
+        DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-s:%1d", q->nr);
         qdio_perf_stat_inc(&perf_stats.siga_sync);
 
         cc = do_siga_sync(q->irq_ptr->schid, output, input);
@@ -312,46 +311,37 @@ static inline int qdio_siga_sync_all(struct qdio_q *q)
         return qdio_siga_sync(q, ~0U, ~0U);
 }
 
-static inline int qdio_do_siga_output(struct qdio_q *q, unsigned int *busy_bit)
+static int qdio_siga_output(struct qdio_q *q, unsigned int *busy_bit)
 {
-        unsigned int fc = 0;
         unsigned long schid;
+        unsigned int fc = 0;
+        u64 start_time = 0;
+        int cc;
 
-        if (q->u.out.use_enh_siga) {
+        if (q->u.out.use_enh_siga)
                 fc = 3;
-        }
-        if (!is_qebsm(q))
-                schid = *((u32 *)&q->irq_ptr->schid);
-        else {
+
+        if (is_qebsm(q)) {
                 schid = q->irq_ptr->sch_token;
                 fc |= 0x80;
         }
-        return do_siga_output(schid, q->mask, busy_bit, fc);
-}
-
-static int qdio_siga_output(struct qdio_q *q)
-{
-        int cc;
-        u32 busy_bit;
-        u64 start_time = 0;
+        else
+                schid = *((u32 *)&q->irq_ptr->schid);
 
-        DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-w:%1d", q->nr);
-        qdio_perf_stat_inc(&perf_stats.siga_out);
 again:
-        cc = qdio_do_siga_output(q, &busy_bit);
-        if (queue_type(q) == QDIO_IQDIO_QFMT && cc == 2 && busy_bit) {
-                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-w bb:%2d", q->nr);
+        cc = do_siga_output(schid, q->mask, busy_bit, fc);
+
+        /* hipersocket busy condition */
+        if (*busy_bit) {
+                WARN_ON(queue_type(q) != QDIO_IQDIO_QFMT || cc != 2);
 
-                if (!start_time)
+                if (!start_time) {
                         start_time = get_usecs();
-                else if ((get_usecs() - start_time) < QDIO_BUSY_BIT_PATIENCE)
+                        goto again;
+                }
+                if ((get_usecs() - start_time) < QDIO_BUSY_BIT_PATIENCE)
                         goto again;
         }
-
-        if (cc == 2 && busy_bit)
-                cc |= QDIO_ERROR_SIGA_BUSY;
-        if (cc)
-                DBF_ERROR("%4x SIGA-W:%2d", SCH_NO(q), cc);
         return cc;
 }
 
@@ -399,7 +389,7 @@ inline void qdio_stop_polling(struct qdio_q *q)
 
 static void announce_buffer_error(struct qdio_q *q, int count)
 {
-        q->qdio_error = QDIO_ERROR_SLSB_STATE;
+        q->qdio_error |= QDIO_ERROR_SLSB_STATE;
 
         /* special handling for no target buffer empty */
         if ((!q->is_input_q &&
@@ -716,68 +706,36 @@ static inline int qdio_outbound_q_moved(struct qdio_q *q)
                 return 0;
 }
 
-/*
- * VM could present us cc=2 and busy bit set on SIGA-write
- * during reconfiguration of their Guest LAN (only in iqdio mode,
- * otherwise qdio is asynchronous and cc=2 and busy bit there will take
- * the queues down immediately).
- *
- * Therefore qdio_siga_output will try for a short time constantly,
- * if such a condition occurs. If it doesn't change, it will
- * increase the busy_siga_counter and save the timestamp, and
- * schedule the queue for later processing. qdio_outbound_processing
- * will check out the counter. If non-zero, it will call qdio_kick_outbound_q
- * as often as the value of the counter. This will attempt further SIGA
- * instructions. For each successful SIGA, the counter is
- * decreased, for failing SIGAs the counter remains the same, after
- * all. After some time of no movement, qdio_kick_outbound_q will
- * finally fail and reflect corresponding error codes to call
- * the upper layer module and have it take the queues down.
- *
- * Note that this is a change from the original HiperSockets design
- * (saying cc=2 and busy bit means take the queues down), but in
- * these days Guest LAN didn't exist... excessive cc=2 with busy bit
- * conditions will still take the queues down, but the threshold is
- * higher due to the Guest LAN environment.
- *
- * Called from outbound tasklet and do_QDIO handler.
- */
 static void qdio_kick_outbound_q(struct qdio_q *q)
 {
-        int rc;
-
-        DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "kickoutq:%1d", q->nr);
+        unsigned int busy_bit;
+        int cc;
 
         if (!need_siga_out(q))
                 return;
 
-        rc = qdio_siga_output(q);
-        switch (rc) {
+        DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-w:%1d", q->nr);
+        qdio_perf_stat_inc(&perf_stats.siga_out);
+
+        cc = qdio_siga_output(q, &busy_bit);
+        switch (cc) {
         case 0:
-                /* TODO: improve error handling for CC=0 case */
-                if (q->u.out.timestamp)
-                        DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "cc2 rslv:%4x",
-                                      atomic_read(&q->u.out.busy_siga_counter));
-                /* went smooth this time, reset timestamp */
-                q->u.out.timestamp = 0;
                 break;
-        /* cc=2 and busy bit */
-        case (2 | QDIO_ERROR_SIGA_BUSY):
-                atomic_inc(&q->u.out.busy_siga_counter);
-
-                /* if the last siga was successful, save timestamp here */
-                if (!q->u.out.timestamp)
-                        q->u.out.timestamp = get_usecs();
-
-                /* if we're in time, don't touch qdio_error */
-                if (get_usecs() - q->u.out.timestamp < QDIO_BUSY_BIT_GIVE_UP) {
-                        tasklet_schedule(&q->tasklet);
-                        break;
+        case 2:
+                if (busy_bit) {
+                        DBF_ERROR("%4x cc2 REP:%1d", SCH_NO(q), q->nr);
+                        q->qdio_error = cc | QDIO_ERROR_SIGA_BUSY;
+                } else {
+                        DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-w cc2:%1d",
+                                      q->nr);
+                        q->qdio_error = cc;
                 }
-                DBF_ERROR("%4x cc2 REP:%1d", SCH_NO(q), q->nr);
-        default:
-                /* for plain cc=1, 2 or 3 */
-                q->qdio_error = rc;
+                break;
+        case 1:
+        case 3:
+                DBF_ERROR("%4x SIGA-W:%1d", SCH_NO(q), cc);
+                q->qdio_error = cc;
+                break;
         }
 }
 
@@ -808,22 +766,18 @@ static void qdio_kick_outbound_handler(struct qdio_q *q)
 
 static void __qdio_outbound_processing(struct qdio_q *q)
 {
-        int siga_attempts;
+        unsigned long flags;
 
         qdio_perf_stat_inc(&perf_stats.tasklet_outbound);
-
-        /* see comment in qdio_kick_outbound_q */
-        siga_attempts = atomic_read(&q->u.out.busy_siga_counter);
-        while (siga_attempts--) {
-                atomic_dec(&q->u.out.busy_siga_counter);
-                qdio_kick_outbound_q(q);
-        }
+        spin_lock_irqsave(&q->lock, flags);
 
         BUG_ON(atomic_read(&q->nr_buf_used) < 0);
 
         if (qdio_outbound_q_moved(q))
                 qdio_kick_outbound_handler(q);
 
+        spin_unlock_irqrestore(&q->lock, flags);
+
         if (queue_type(q) == QDIO_ZFCP_QFMT) {
                 if (!pci_out_supported(q) && !qdio_outbound_q_done(q))
                         tasklet_schedule(&q->tasklet);
@@ -1491,7 +1445,7 @@ static inline int buf_in_between(int bufnr, int start, int count)
 static void handle_inbound(struct qdio_q *q, unsigned int callflags,
                            int bufnr, int count)
 {
-        int used, rc, diff;
+        int used, cc, diff;
 
         if (!q->u.in.polling)
                 goto set;
@@ -1532,9 +1486,9 @@ set:
                 return;
 
         if (need_siga_in(q)) {
-                rc = qdio_siga_input(q);
-                if (rc)
-                        q->qdio_error = rc;
+                cc = qdio_siga_input(q);
+                if (cc)
+                        q->qdio_error = cc;
         }
 }
 
@@ -1581,6 +1535,10 @@ static void handle_outbound(struct qdio_q *q, unsigned int callflags,
                                 while (count--)
                                         qdio_kick_outbound_q(q);
                         }
+
+                /* report CC=2 conditions synchronously */
+                if (q->qdio_error)
+                        __qdio_outbound_processing(q);
                 goto out;
         }
 
diff --git a/drivers/s390/cio/qdio_setup.c b/drivers/s390/cio/qdio_setup.c
index 18d54fc21ce9..c08356b95bf5 100644
--- a/drivers/s390/cio/qdio_setup.c
+++ b/drivers/s390/cio/qdio_setup.c
@@ -117,6 +117,7 @@ static void setup_queues_misc(struct qdio_q *q, struct qdio_irq *irq_ptr,
         q->mask = 1 << (31 - i);
         q->nr = i;
         q->handler = handler;
+        spin_lock_init(&q->lock);
 }
 
 static void setup_storage_lists(struct qdio_q *q, struct qdio_irq *irq_ptr,