s390/qdio: remove 'merge_pending' mechanism

For non-QEBSM devices, get_buf_states() merges PENDING and EMPTY buffers
into a single group of finished buffers. To allow the upper-layer driver
to differentiate between the two states, qdio_check_pending() looks at
each buffer's state again and sets the sbal_state flag to
QDIO_OUTBUF_STATE_FLAG_PENDING accordingly.

So effectively we're spending overhead on _every_ Output Queue
inspection, just to avoid some additional TX completion calls in case
a group of buffers has completed with mixed EMPTY / PENDING state.
Given that PENDING buffers should rarely occur, this is a bad trade-off.
In particular so as the additional checks in get_buf_states() affect
_all_ device types (even those that don't use the PENDING state).

Rip it all out, and just report the PENDING completions separately as
we already do for QEBSM devices.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

1 files changed, 0 insertions, 4 deletions

diff --git a/arch/s390/include/asm/qdio.h b/arch/s390/include/asm/qdio.h
index c85f75a3d452..d9215c7106f0 100644
--- a/arch/s390/include/asm/qdio.h
+++ b/arch/s390/include/asm/qdio.h
@@ -250,17 +250,13 @@ struct slsb {
  * struct qdio_outbuf_state - SBAL related asynchronous operation information
  *   (for communication with upper layer programs)
  *   (only required for use with completion queues)
- * @flags: flags indicating state of buffer
  * @user: pointer to upper layer program's state information related to SBAL
  *        (stored in user1 data of QAOB)
  */
 struct qdio_outbuf_state {
-	u8 flags;
 	void *user;
 };
 
-#define QDIO_OUTBUF_STATE_FLAG_PENDING	0x01
-
 #define CHSC_AC1_INITIATE_INPUTQ	0x80