qeth: Reduce CPU consumption through less SIGA-r calls

Patch avoids SIGA-r calls in case of SIGA-r required. It only calls
SIGA-r if a threshold of free buffer is reached. CPU consumption is
reduced as a consequence.
Signed-off-by: NEinar Lueck <elelueck@de.ibm.com>
Signed-off-by: NFrank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_core.h

@@ -236,8 +236,7 @@ static inline int qeth_is_ipa_enabled(struct qeth_ipa_info *ipa,
 #define QETH_IN_BUF_COUNT_MAX 128
 #define QETH_MAX_BUFFER_ELEMENTS(card) ((card)->qdio.in_buf_size >> 12)
 #define QETH_IN_BUF_REQUEUE_THRESHOLD(card) \
-		((card)->ssqd.qdioac1 & AC1_SIGA_INPUT_NEEDED ? 1 : \
-		 ((card)->qdio.in_buf_pool.buf_count / 2))
+		 ((card)->qdio.in_buf_pool.buf_count / 2)
 
 /* buffers we have to be behind before we get a PCI */
 #define QETH_PCI_THRESHOLD_A(card) ((card)->qdio.in_buf_pool.buf_count+1)