Revert "Move xen patchset to new version's subdir."

[people/pmueller/ipfire-2.x.git] / src / patches / suse-2.6.27.25 / patches.arch / s390-06-06-qdio_inbound_ack.patch

From: Gerald Schaefer <geraldsc@de.ibm.com>
Subject: qdio: rework inbound buffer acknowledgement
References: bnc#458339

Symptom:     Inbound network traffic stall.
Problem:     Under high load the qdio buffer that specifies the acknowledge
	     mode can be overwritten.
Solution:    Use automatic acknowledgement of incoming buffers in QEBSM mode
	     to improve performance with QIOASSIST. 
	     Move ACK for non-QEBSM mode always to the newest buffer to prevent
  	     a race with qdio_stop_polling.
	     Remove the polling spinlock, the upper layer drivers return new
	     buffers in the same code path and could not run in parallel.
	     Don't flood the error log in case of no-target-buffer-empty.
	     In handle_inbound we check if we would overwrite an ACK'ed buffer,
	     if so advance the pointer to the oldest ACK'ed buffer so we don't
	     overwrite an empty buffer in qdio_stop_polling.

Acked-by: John Jolly <jjolly@suse.de>

---
 drivers/s390/cio/qdio.h         |   19 ++--
 drivers/s390/cio/qdio_debug.c   |    7 +
 drivers/s390/cio/qdio_main.c    |  181 ++++++++++++++++++++++++++--------------
 drivers/s390/cio/qdio_perf.c    |    2 
 drivers/s390/cio/qdio_perf.h    |    1 
 drivers/s390/cio/qdio_setup.c   |    1 
 drivers/s390/cio/qdio_thinint.c |    2 
 7 files changed, 139 insertions(+), 74 deletions(-)

Index: linux-sles11/drivers/s390/cio/qdio.h
===================================================================
--- linux-sles11.orig/drivers/s390/cio/qdio.h
+++ linux-sles11/drivers/s390/cio/qdio.h
@@ -112,12 +112,12 @@ static inline int do_sqbs(u64 token, uns
 }
 
 static inline int do_eqbs(u64 token, unsigned char *state, int queue,
-			  int *start, int *count)
+			  int *start, int *count, int ack)
 {
 	register unsigned long _ccq asm ("0") = *count;
 	register unsigned long _token asm ("1") = token;
 	unsigned long _queuestart = ((unsigned long)queue << 32) | *start;
-	unsigned long _state = 0;
+	unsigned long _state = (unsigned long)ack << 63;
 
 	asm volatile(
 		"	.insn	rrf,0xB99c0000,%1,%2,0,0"
@@ -134,7 +134,7 @@ static inline int do_eqbs(u64 token, uns
 static inline int do_sqbs(u64 token, unsigned char state, int queue,
 			  int *start, int *count) { return 0; }
 static inline int do_eqbs(u64 token, unsigned char *state, int queue,
-			  int *start, int *count) { return 0; }
+			  int *start, int *count, int ack) { return 0; }
 #endif /* CONFIG_64BIT */
 
 struct qdio_irq;
@@ -187,11 +187,11 @@ struct qdio_input_q {
 	/* input buffer acknowledgement flag */
 	int polling;
 
+	/* how much sbals are acknowledged with qebsm */
+	int ack_count;
+
 	/* last time of noticing incoming data */
 	u64 timestamp;
-
-	/* lock for clearing the acknowledgement */
-	spinlock_t lock;
 };
 
 struct qdio_output_q {
@@ -348,10 +348,13 @@ static inline unsigned long long get_use
 	((bufnr + 1) & QDIO_MAX_BUFFERS_MASK)
 #define add_buf(bufnr, inc) \
 	((bufnr + inc) & QDIO_MAX_BUFFERS_MASK)
+#define sub_buf(bufnr, dec) \
+	((bufnr - dec) & QDIO_MAX_BUFFERS_MASK)
 
 /* prototypes for thin interrupt */
 void qdio_sync_after_thinint(struct qdio_q *q);
-int get_buf_state(struct qdio_q *q, unsigned int bufnr, unsigned char *state);
+int get_buf_state(struct qdio_q *q, unsigned int bufnr, unsigned char *state,
+		  int auto_ack);
 void qdio_check_outbound_after_thinint(struct qdio_q *q);
 int qdio_inbound_q_moved(struct qdio_q *q);
 void qdio_kick_inbound_handler(struct qdio_q *q);
@@ -385,6 +388,8 @@ int qdio_setup_irq(struct qdio_initializ
 void qdio_print_subchannel_info(struct qdio_irq *irq_ptr,
 				struct ccw_device *cdev);
 void qdio_release_memory(struct qdio_irq *irq_ptr);
+int qdio_setup_create_sysfs(struct ccw_device *cdev);
+void qdio_setup_destroy_sysfs(struct ccw_device *cdev);
 int qdio_setup_init(void);
 void qdio_setup_exit(void);
 
Index: linux-sles11/drivers/s390/cio/qdio_debug.c
===================================================================
--- linux-sles11.orig/drivers/s390/cio/qdio_debug.c
+++ linux-sles11/drivers/s390/cio/qdio_debug.c
@@ -59,16 +59,18 @@ static int qstat_show(struct seq_file *m
 	if (!q)
 		return 0;
 
-	seq_printf(m, "device state indicator: %d\n", *q->irq_ptr->dsci);
+	seq_printf(m, "device state indicator: %d\n", *(u32 *)q->irq_ptr->dsci);
 	seq_printf(m, "nr_used: %d\n", atomic_read(&q->nr_buf_used));
 	seq_printf(m, "ftc: %d\n", q->first_to_check);
 	seq_printf(m, "last_move_ftc: %d\n", q->last_move_ftc);
 	seq_printf(m, "polling: %d\n", q->u.in.polling);
+	seq_printf(m, "ack count: %d\n", q->u.in.ack_count);
 	seq_printf(m, "slsb buffer states:\n");
+	seq_printf(m, "|0      |8      |16     |24     |32     |40     |48     |56  63|\n");
 
 	qdio_siga_sync_q(q);
 	for (i = 0; i < QDIO_MAX_BUFFERS_PER_Q; i++) {
-		get_buf_state(q, i, &state);
+		get_buf_state(q, i, &state, 0);
 		switch (state) {
 		case SLSB_P_INPUT_NOT_INIT:
 		case SLSB_P_OUTPUT_NOT_INIT:
@@ -100,6 +102,7 @@ static int qstat_show(struct seq_file *m
 			seq_printf(m, "\n");
 	}
 	seq_printf(m, "\n");
+	seq_printf(m, "|64     |72     |80     |88     |96     |104    |112    |   127|\n");
 	return 0;
 }
 
Index: linux-sles11/drivers/s390/cio/qdio_main.c
===================================================================
--- linux-sles11.orig/drivers/s390/cio/qdio_main.c
+++ linux-sles11/drivers/s390/cio/qdio_main.c
@@ -112,12 +112,13 @@ static inline int qdio_check_ccq(struct 
  * @state: state of the extracted buffers
  * @start: buffer number to start at
  * @count: count of buffers to examine
+ * @auto_ack: automatically acknowledge buffers
  *
  * Returns the number of successfull extracted equal buffer states.
  * Stops processing if a state is different from the last buffers state.
  */
 static int qdio_do_eqbs(struct qdio_q *q, unsigned char *state,
-			int start, int count)
+			int start, int count, int auto_ack)
 {
 	unsigned int ccq = 0;
 	int tmp_count = count, tmp_start = start;
@@ -129,7 +130,8 @@ static int qdio_do_eqbs(struct qdio_q *q
 	if (!q->is_input_q)
 		nr += q->irq_ptr->nr_input_qs;
 again:
-	ccq = do_eqbs(q->irq_ptr->sch_token, state, nr, &tmp_start, &tmp_count);
+	ccq = do_eqbs(q->irq_ptr->sch_token, state, nr, &tmp_start, &tmp_count,
+		      auto_ack);
 	rc = qdio_check_ccq(q, ccq);
 
 	/* At least one buffer was processed, return and extract the remaining
@@ -172,6 +174,9 @@ static int qdio_do_sqbs(struct qdio_q *q
 	int nr = q->nr;
 	int rc;
 
+	if (!count)
+		return 0;
+
 	BUG_ON(!q->irq_ptr->sch_token);
 
 	if (!q->is_input_q)
@@ -197,7 +202,8 @@ again:
 
 /* returns number of examined buffers and their common state in *state */
 static inline int get_buf_states(struct qdio_q *q, unsigned int bufnr,
-				 unsigned char *state, unsigned int count)
+				 unsigned char *state, unsigned int count,
+				 int auto_ack)
 {
 	unsigned char __state = 0;
 	int i;
@@ -206,7 +212,7 @@ static inline int get_buf_states(struct 
 	BUG_ON(count > QDIO_MAX_BUFFERS_PER_Q);
 
 	if (is_qebsm(q))
-		return qdio_do_eqbs(q, state, bufnr, count);
+		return qdio_do_eqbs(q, state, bufnr, count, auto_ack);
 
 	for (i = 0; i < count; i++) {
 		if (!__state)
@@ -220,9 +226,9 @@ static inline int get_buf_states(struct 
 }
 
 inline int get_buf_state(struct qdio_q *q, unsigned int bufnr,
-		  unsigned char *state)
+		  unsigned char *state, int auto_ack)
 {
-	return get_buf_states(q, bufnr, state, 1);
+	return get_buf_states(q, bufnr, state, 1, auto_ack);
 }
 
 /* wrap-around safe setting of slsb states, returns number of changed buffers */
@@ -367,29 +373,91 @@ void qdio_sync_after_thinint(struct qdio
 
 inline void qdio_stop_polling(struct qdio_q *q)
 {
-	spin_lock_bh(&q->u.in.lock);
-	if (!q->u.in.polling) {
-		spin_unlock_bh(&q->u.in.lock);
+	if (!q->u.in.polling)
 		return;
-	}
+
 	q->u.in.polling = 0;
 	qdio_perf_stat_inc(&perf_stats.debug_stop_polling);
 
 	/* show the card that we are not polling anymore */
-	set_buf_state(q, q->last_move_ftc, SLSB_P_INPUT_NOT_INIT);
-	spin_unlock_bh(&q->u.in.lock);
+	if (is_qebsm(q)) {
+		set_buf_states(q, q->last_move_ftc, SLSB_P_INPUT_NOT_INIT,
+			       q->u.in.ack_count);
+		q->u.in.ack_count = 0;
+	} else
+		set_buf_state(q, q->last_move_ftc, SLSB_P_INPUT_NOT_INIT);
 }
 
-static void announce_buffer_error(struct qdio_q *q)
+static void announce_buffer_error(struct qdio_q *q, int count)
 {
+	q->qdio_error = QDIO_ERROR_SLSB_STATE;
+
+	/* special handling for no target buffer empty */
+	if ((!q->is_input_q &&
+	    (q->sbal[q->first_to_check]->element[15].flags & 0xff) == 0x10)) {
+		qdio_perf_stat_inc(&perf_stats.outbound_target_full);
+		DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "OUTFULL FTC:%3d",
+			      q->first_to_check);
+		return;
+	}
+
 	DBF_ERROR("%4x BUF ERROR", SCH_NO(q));
 	DBF_ERROR((q->is_input_q) ? "IN:%2d" : "OUT:%2d", q->nr);
-	DBF_ERROR("FTC:%3d", q->first_to_check);
+	DBF_ERROR("FTC:%3d C:%3d", q->first_to_check, count);
 	DBF_ERROR("F14:%2x F15:%2x",
 		  q->sbal[q->first_to_check]->element[14].flags & 0xff,
 		  q->sbal[q->first_to_check]->element[15].flags & 0xff);
+}
 
-	q->qdio_error = QDIO_ERROR_SLSB_STATE;
+static inline void inbound_primed(struct qdio_q *q, int count)
+{
+	int new;
+
+	DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "in prim: %3d", count);
+
+	/* for QEBSM the ACK was already set by EQBS */
+	if (is_qebsm(q)) {
+		if (!q->u.in.polling) {
+			q->u.in.polling = 1;
+			q->u.in.ack_count = count;
+			q->last_move_ftc = q->first_to_check;
+			return;
+		}
+
+		/* delete the previous ACK's */
+		set_buf_states(q, q->last_move_ftc, SLSB_P_INPUT_NOT_INIT,
+			       q->u.in.ack_count);
+		q->u.in.ack_count = count;
+		q->last_move_ftc = q->first_to_check;
+		return;
+	}
+
+	/*
+	 * ACK the newest buffer. The ACK will be removed in qdio_stop_polling
+	 * or by the next inbound run.
+	 */
+	new = add_buf(q->first_to_check, count - 1);
+	if (q->u.in.polling) {
+		/* reset the previous ACK but first set the new one */
+		set_buf_state(q, new, SLSB_P_INPUT_ACK);
+		set_buf_state(q, q->last_move_ftc, SLSB_P_INPUT_NOT_INIT);
+	}
+	else {
+		q->u.in.polling = 1;
+		set_buf_state(q, q->first_to_check, SLSB_P_INPUT_ACK);
+	}
+
+	q->last_move_ftc = new;
+	count--;
+	if (!count)
+		return;
+
+	/*
+	 * Need to change all PRIMED buffers to NOT_INIT, otherwise
+	 * we're loosing initiative in the thinint code.
+	 */
+	set_buf_states(q, next_buf(q->first_to_check), SLSB_P_INPUT_NOT_INIT,
+		       count);
 }
 
 static int get_inbound_buffer_frontier(struct qdio_q *q)
@@ -398,13 +466,6 @@ static int get_inbound_buffer_frontier(s
 	unsigned char state;
 
 	/*
-	 * If we still poll don't update last_move_ftc, keep the
-	 * previously ACK buffer there.
-	 */
-	if (!q->u.in.polling)
-		q->last_move_ftc = q->first_to_check;
-
-	/*
 	 * Don't check 128 buffers, as otherwise qdio_inbound_q_moved
 	 * would return 0.
 	 */
@@ -424,34 +485,13 @@ check_next:
 	if (q->first_to_check == stop)
 		goto out;
 
-	count = get_buf_states(q, q->first_to_check, &state, count);
+	count = get_buf_states(q, q->first_to_check, &state, count, 1);
 	if (!count)
 		goto out;
 
 	switch (state) {
 	case SLSB_P_INPUT_PRIMED:
-		DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "in prim: %3d", count);
-
-		/*
-		 * Only ACK the first buffer. The ACK will be removed in
-		 * qdio_stop_polling.
-		 */
-		if (q->u.in.polling)
-			state = SLSB_P_INPUT_NOT_INIT;
-		else {
-			q->u.in.polling = 1;
-			state = SLSB_P_INPUT_ACK;
-		}
-		set_buf_state(q, q->first_to_check, state);
-
-		/*
-		 * Need to change all PRIMED buffers to NOT_INIT, otherwise
-		 * we're loosing initiative in the thinint code.
-		 */
-		if (count > 1)
-			set_buf_states(q, next_buf(q->first_to_check),
-				       SLSB_P_INPUT_NOT_INIT, count - 1);
-
+		inbound_primed(q, count);
 		/*
 		 * No siga-sync needed for non-qebsm here, as the inbound queue
 		 * will be synced on the next siga-r, resp.
@@ -461,7 +501,7 @@ check_next:
 		atomic_sub(count, &q->nr_buf_used);
 		goto check_next;
 	case SLSB_P_INPUT_ERROR:
-		announce_buffer_error(q);
+		announce_buffer_error(q, count);
 		/* process the buffer, the upper layer will take care of it */
 		q->first_to_check = add_buf(q->first_to_check, count);
 		atomic_sub(count, &q->nr_buf_used);
@@ -507,7 +547,7 @@ static int qdio_inbound_q_done(struct qd
 	 */
 	qdio_siga_sync_q(q);
 
-	get_buf_state(q, q->first_to_check, &state);
+	get_buf_state(q, q->first_to_check, &state, 0);
 	if (state == SLSB_P_INPUT_PRIMED)
 		/* we got something to do */
 		return 0;
@@ -610,7 +650,7 @@ check_next:
 	if (q->first_to_check == stop)
 		return q->first_to_check;
 
-	count = get_buf_states(q, q->first_to_check, &state, count);
+	count = get_buf_states(q, q->first_to_check, &state, count, 0);
 	if (!count)
 		return q->first_to_check;
 
@@ -629,7 +669,7 @@ check_next:
 			break;
 		goto check_next;
 	case SLSB_P_OUTPUT_ERROR:
-		announce_buffer_error(q);
+		announce_buffer_error(q, count);
 		/* process the buffer, the upper layer will take care of it */
 		q->first_to_check = add_buf(q->first_to_check, count);
 		atomic_sub(count, &q->nr_buf_used);
@@ -1441,23 +1481,38 @@ static inline int buf_in_between(int buf
 static void handle_inbound(struct qdio_q *q, unsigned int callflags,
 			   int bufnr, int count)
 {
-	unsigned long flags;
-	int used, rc;
+	int used, rc, diff;
 
-	/*
-	 * do_QDIO could run in parallel with the queue tasklet so the
-	 * upper-layer programm could empty the ACK'ed buffer here.
-	 * If that happens we must clear the polling flag, otherwise
-	 * qdio_stop_polling() could set the buffer to NOT_INIT after
-	 * it was set to EMPTY which would kill us.
-	 */
-	spin_lock_irqsave(&q->u.in.lock, flags);
-	if (q->u.in.polling)
-		if (buf_in_between(q->last_move_ftc, bufnr, count))
+	if (!q->u.in.polling)
+		goto set;
+
+	/* protect against stop polling setting an ACK for an emptied slsb */
+	if (count == QDIO_MAX_BUFFERS_PER_Q) {
+		/* overwriting everything, just delete polling status */
+		q->u.in.polling = 0;
+		q->u.in.ack_count = 0;
+		goto set;
+	} else if (buf_in_between(q->last_move_ftc, bufnr, count)) {
+		if (is_qebsm(q)) {
+			/* partial overwrite, just update last_move_ftc */
+			diff = add_buf(bufnr, count);
+			diff = sub_buf(diff, q->last_move_ftc);
+			q->u.in.ack_count -= diff;
+			if (q->u.in.ack_count <= 0) {
+				q->u.in.polling = 0;
+				q->u.in.ack_count = 0;
+				/* TODO: must we set last_move_ftc to something meaningful? */
+				goto set;
+			}
+			q->last_move_ftc = add_buf(q->last_move_ftc, diff);
+		}
+		else
+			/* the only ACK will be deleted, so stop polling */
 			q->u.in.polling = 0;
+	}
 
+set:
 	count = set_buf_states(q, bufnr, SLSB_CU_INPUT_EMPTY, count);
-	spin_unlock_irqrestore(&q->u.in.lock, flags);
 
 	used = atomic_add_return(count, &q->nr_buf_used) - count;
 	BUG_ON(used + count > QDIO_MAX_BUFFERS_PER_Q);
@@ -1516,7 +1571,7 @@ static void handle_outbound(struct qdio_
 	}
 
 	/* try to fast requeue buffers */
-	get_buf_state(q, prev_buf(bufnr), &state);
+	get_buf_state(q, prev_buf(bufnr), &state, 0);
 	if (state != SLSB_CU_OUTPUT_PRIMED)
 		qdio_kick_outbound_q(q);
 	else {
Index: linux-sles11/drivers/s390/cio/qdio_perf.c
===================================================================
--- linux-sles11.orig/drivers/s390/cio/qdio_perf.c
+++ linux-sles11/drivers/s390/cio/qdio_perf.c
@@ -74,6 +74,8 @@ static int qdio_perf_proc_show(struct se
 	seq_printf(m, "\n");
 	seq_printf(m, "Number of fast requeues (outg. SBAL w/o SIGA)\t: %li\n",
 		   (long)atomic_long_read(&perf_stats.fast_requeue));
+	seq_printf(m, "Number of outbound target full condition\t: %li\n",
+		   (long)atomic_long_read(&perf_stats.outbound_target_full));
 	seq_printf(m, "Number of outbound tasklet mod_timer calls\t: %li\n",
 		   (long)atomic_long_read(&perf_stats.debug_tl_out_timer));
 	seq_printf(m, "Number of stop polling calls\t\t\t: %li\n",
Index: linux-sles11/drivers/s390/cio/qdio_perf.h
===================================================================
--- linux-sles11.orig/drivers/s390/cio/qdio_perf.h
+++ linux-sles11/drivers/s390/cio/qdio_perf.h
@@ -36,6 +36,7 @@ struct qdio_perf_stats {
 	atomic_long_t inbound_handler;
 	atomic_long_t outbound_handler;
 	atomic_long_t fast_requeue;
+	atomic_long_t outbound_target_full;
 
 	/* for debugging */
 	atomic_long_t debug_tl_out_timer;
Index: linux-sles11/drivers/s390/cio/qdio_setup.c
===================================================================
--- linux-sles11.orig/drivers/s390/cio/qdio_setup.c
+++ linux-sles11/drivers/s390/cio/qdio_setup.c
@@ -167,7 +167,6 @@ static void setup_queues(struct qdio_irq
 		setup_queues_misc(q, irq_ptr, qdio_init->input_handler, i);
 
 		q->is_input_q = 1;
-		spin_lock_init(&q->u.in.lock);
 		setup_storage_lists(q, irq_ptr, input_sbal_array, i);
 		input_sbal_array += QDIO_MAX_BUFFERS_PER_Q;
 
Index: linux-sles11/drivers/s390/cio/qdio_thinint.c
===================================================================
--- linux-sles11.orig/drivers/s390/cio/qdio_thinint.c
+++ linux-sles11/drivers/s390/cio/qdio_thinint.c
@@ -131,7 +131,7 @@ static inline int tiqdio_inbound_q_done(
 		return 1;
 
 	qdio_siga_sync_q(q);
-	get_buf_state(q, q->first_to_check, &state);
+	get_buf_state(q, q->first_to_check, &state, 0);
 
 	if (state == SLSB_P_INPUT_PRIMED)
 		/* more work coming */