[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, 1 insertions, 0 deletions

diff --git a/drivers/s390/cio/qdio_perf.h b/drivers/s390/cio/qdio_perf.h
index d16c1c67160f..7821ac4fa517 100644
--- a/drivers/s390/cio/qdio_perf.h
+++ b/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;