[S390] qdio: improve inbound buffer acknowledgement

- Use automatic acknowledgement of incoming buffers in QEBSM mode
- 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

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/qdio.h

@@ -112,12 +112,12 @@ static inline int do_sqbs(u64 token, unsigned char state, int queue,
 }
 
 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, unsigned char *state, int queue,
 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 {
@@ -351,10 +351,13 @@ static inline unsigned long long get_usecs(void)
 	((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);
@@ -388,6 +391,8 @@ int qdio_setup_irq(struct qdio_initialize *init_data);
 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);
 

drivers/s390/cio/qdio_debug.c

@@ -60,16 +60,18 @@ static int qstat_show(struct seq_file *m, void *v)
 	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:
@@ -101,6 +103,7 @@ static int qstat_show(struct seq_file *m, void *v)
 			seq_printf(m, "\n");
 	}
 	seq_printf(m, "\n");
+	seq_printf(m, "|64     |72     |80     |88     |96     |104    |112    |   127|\n");
 	return 0;
 }