Reenabled linux-xen and xen-image build

[people/pmueller/ipfire-2.x.git] / src / patches / suse-2.6.27.25 / patches.arch / s390-11-05-qdio_error_reporting_hs.patch

From: Gerald Schaefer <geraldsc@de.ibm.com>
Subject: qdio: fix hipersocket busy error handling
References: bnc#484767,LTC#52204

Symptom:     Lower performance of hipersocket connections in case of
             busy errors.
Problem:     The immediate retry for a busy condition is missing and the
             qeth notification about a failed send operation may indicate
             a wrong buffer position since a temporary SIGA error is not
             reported immediately.
Solution:    Retry immediately after a busy condition and report SIGA errors
             directly to qeth.

Acked-by: John Jolly <jjolly@suse.de>
---
 drivers/s390/cio/qdio.h      |    7 -
 drivers/s390/cio/qdio_main.c |  181 ++++++++++++++-----------------------------
 2 files changed, 63 insertions(+), 125 deletions(-)

Index: linux-2.6.27-SLE11_BRANCH/drivers/s390/cio/qdio.h
===================================================================
--- linux-2.6.27-SLE11_BRANCH.orig/drivers/s390/cio/qdio.h
+++ linux-2.6.27-SLE11_BRANCH/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;
 
Index: linux-2.6.27-SLE11_BRANCH/drivers/s390/cio/qdio_main.c
===================================================================
--- linux-2.6.27-SLE11_BRANCH.orig/drivers/s390/cio/qdio_main.c
+++ linux-2.6.27-SLE11_BRANCH/drivers/s390/cio/qdio_main.c
@@ -74,7 +74,7 @@ static inline int do_siga_input(struct s
  * 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;
@@ -278,8 +278,7 @@ static int qdio_siga_sync(struct qdio_q 
 	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);
@@ -306,43 +305,34 @@ static inline int qdio_siga_sync_all(str
 	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 (!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);
 
-		if (!start_time)
+	/* hipersocket busy condition */
+	if (*busy_bit) {
+		WARN_ON(queue_type(q) != QDIO_IQDIO_QFMT || cc != 2);
+
+		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;
 }
 
@@ -390,7 +380,7 @@ inline void qdio_stop_polling(struct qdi
 
 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 &&
@@ -707,69 +697,34 @@ static inline int qdio_outbound_q_moved(
 		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)
+static int 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;
+		return 0;
 
-	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;
-		}
-		DBF_ERROR("%4x cc2 REP:%1d", SCH_NO(q), q->nr);
-	default:
-		/* for plain cc=1, 2 or 3 */
-		q->qdio_error = rc;
+	case 2:
+		if (busy_bit) {
+			DBF_ERROR("%4x cc2 REP:%1d", SCH_NO(q), q->nr);
+			cc |= QDIO_ERROR_SIGA_BUSY;
+		} else
+			DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-w cc2:%1d", q->nr);
+		break;
+	case 1:
+	case 3:
+		DBF_ERROR("%4x SIGA-W:%1d", SCH_NO(q), cc);
+		break;
 	}
+	return cc;
 }
 
 static void qdio_kick_outbound_handler(struct qdio_q *q)
@@ -799,17 +754,7 @@ static void qdio_kick_outbound_handler(s
 
 static void __qdio_outbound_processing(struct qdio_q *q)
 {
-	int siga_attempts;
-
 	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);
-	}
-
 	BUG_ON(atomic_read(&q->nr_buf_used) < 0);
 
 	if (qdio_outbound_q_moved(q))
@@ -1478,10 +1423,10 @@ static inline int buf_in_between(int buf
  * @bufnr: first buffer to process
  * @count: how many buffers are emptied
  */
-static void handle_inbound(struct qdio_q *q, unsigned int callflags,
-			   int bufnr, int count)
+static int handle_inbound(struct qdio_q *q, unsigned int callflags,
+			  int bufnr, int count)
 {
-	int used, rc, diff;
+	int used, diff;
 
 	if (!q->u.in.polling)
 		goto set;
@@ -1519,13 +1464,11 @@ set:
 
 	/* no need to signal as long as the adapter had free buffers */
 	if (used)
-		return;
+		return 0;
 
-	if (need_siga_in(q)) {
-		rc = qdio_siga_input(q);
-		if (rc)
-			q->qdio_error = rc;
-	}
+	if (need_siga_in(q))
+		return qdio_siga_input(q);
+	return 0;
 }
 
 /**
@@ -1535,11 +1478,11 @@ set:
  * @bufnr: first buffer to process
  * @count: how many buffers are filled
  */
-static void handle_outbound(struct qdio_q *q, unsigned int callflags,
-			    int bufnr, int count)
+static int handle_outbound(struct qdio_q *q, unsigned int callflags,
+			   int bufnr, int count)
 {
 	unsigned char state;
-	int used;
+	int used, rc = 0;
 
 	qdio_perf_stat_inc(&perf_stats.outbound_handler);
 
@@ -1554,14 +1497,17 @@ static void handle_outbound(struct qdio_
 
 	if (queue_type(q) == QDIO_IQDIO_QFMT) {
 		if (multicast_outbound(q))
-			qdio_kick_outbound_q(q);
+			rc = qdio_kick_outbound_q(q);
 		else
 			/*
 			 * One siga-w per buffer required for unicast
 			 * HiperSockets.
 			 */
-			while (count--)
-				qdio_kick_outbound_q(q);
+			while (count--) {
+				rc = qdio_kick_outbound_q(q);
+				if (rc)
+					goto out;
+			}
 		goto out;
 	}
 
@@ -1573,7 +1519,7 @@ static void handle_outbound(struct qdio_
 	/* try to fast requeue buffers */
 	get_buf_state(q, prev_buf(bufnr), &state, 0);
 	if (state != SLSB_CU_OUTPUT_PRIMED)
-		qdio_kick_outbound_q(q);
+		rc = qdio_kick_outbound_q(q);
 	else {
 		DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "fast-req");
 		qdio_perf_stat_inc(&perf_stats.fast_requeue);
@@ -1581,6 +1527,7 @@ static void handle_outbound(struct qdio_
 out:
 	/* Fixme: could wait forever if called from process context */
 	tasklet_schedule(&q->tasklet);
+	return rc;
 }
 
 /**
@@ -1619,14 +1566,12 @@ int do_QDIO(struct ccw_device *cdev, uns
 		return -EBUSY;
 
 	if (callflags & QDIO_FLAG_SYNC_INPUT)
-		handle_inbound(irq_ptr->input_qs[q_nr], callflags, bufnr,
-			       count);
+		return handle_inbound(irq_ptr->input_qs[q_nr],
+				      callflags, bufnr, count);
 	else if (callflags & QDIO_FLAG_SYNC_OUTPUT)
-		handle_outbound(irq_ptr->output_qs[q_nr], callflags, bufnr,
-				count);
-	else
-		return -EINVAL;
-	return 0;
+		return handle_outbound(irq_ptr->output_qs[q_nr],
+				       callflags, bufnr, count);
+	return -EINVAL;
 }
 EXPORT_SYMBOL_GPL(do_QDIO);