[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>

1 files changed, 12 insertions, 7 deletions

diff --git a/drivers/s390/cio/qdio.h b/drivers/s390/cio/qdio.h
index 7b50882577d5..c60f2566d28c 100644
--- a/drivers/s390/cio/qdio.h
+++ b/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);