[patch 03/10] qdio: fix EQBS handling on CCQ96

Martin Schwidefsky
2007-08-22T12:34:15Z

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From: Klaus D. Wacker <kdwacker@de.ibm.com>

QDIO returned from EQBS instruction in any case after return code
CCQ=96 was issued regardless whether buffer states for at least one
buffer were extracted or not.
This caused FCP devices to hang when running under z/VM and having
QIOASSASIST=ON and having high I/O rates.
In order to fix this qdio return code processing of EQBS instruction
after CCQ=96 is changed that buffers are returned and if no buffers
where extracted the instruction is repeated at once.

Signed-off-by: Klaus D. Wacker <kdwacker@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
---

drivers/s390/cio/qdio.c | 2 ++
1 file changed, 2 insertions(+)

Index: quilt-2.6/drivers/s390/cio/qdio.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/qdio.c
+++ quilt-2.6/drivers/s390/cio/qdio.c
@@ -195,6 +195,8 @@ qdio_do_eqbs(struct qdio_q *q, unsigned
again:
ccq = do_eqbs(irq->sch_token, state, q_no, start, cnt);
rc = qdio_check_ccq(q, ccq);
+ if ((ccq == 96) && (tmp_cnt != *cnt))
+ rc = 0;
if (rc == 1) {
QDIO_DBF_TEXT5(1,trace,"eqAGAIN");
goto again;