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authorJulian Wiedmann <jwi@linux.ibm.com>2019-07-11 18:17:36 +0200
committerHeiko Carstens <heiko.carstens@de.ibm.com>2019-07-23 10:43:55 +0200
commita6ec414a4dd529eeac5c3ea51c661daba3397108 (patch)
tree777ed0945b271b076af78d01b4f04b4da34d7f91 /drivers/s390/cio/qdio_main.c
parents390: enable detection of kernel version from bzImage (diff)
downloadlinux-dev-a6ec414a4dd529eeac5c3ea51c661daba3397108.tar.xz
linux-dev-a6ec414a4dd529eeac5c3ea51c661daba3397108.zip
s390/qdio: add sanity checks to the fast-requeue path
If the device driver were to send out a full queue's worth of SBALs, current code would end up discovering the last of those SBALs as PRIMED and erroneously skip the SIGA-w. This immediately stalls the queue. Add a check to not attempt fast-requeue in this case. While at it also make sure that the state of the previous SBAL was successfully extracted before inspecting it. Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com> Reviewed-by: Jens Remus <jremus@linux.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Diffstat (limited to '')
-rw-r--r--drivers/s390/cio/qdio_main.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 730c4e68094b..7f5adf02f095 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -1558,13 +1558,13 @@ static int handle_outbound(struct qdio_q *q, unsigned int callflags,
rc = qdio_kick_outbound_q(q, phys_aob);
} else if (need_siga_sync(q)) {
rc = qdio_siga_sync_q(q);
+ } else if (count < QDIO_MAX_BUFFERS_PER_Q &&
+ get_buf_state(q, prev_buf(bufnr), &state, 0) > 0 &&
+ state == SLSB_CU_OUTPUT_PRIMED) {
+ /* The previous buffer is not processed yet, tack on. */
+ qperf_inc(q, fast_requeue);
} else {
- /* try to fast requeue buffers */
- get_buf_state(q, prev_buf(bufnr), &state, 0);
- if (state != SLSB_CU_OUTPUT_PRIMED)
- rc = qdio_kick_outbound_q(q, 0);
- else
- qperf_inc(q, fast_requeue);
+ rc = qdio_kick_outbound_q(q, 0);
}
/* in case of SIGA errors we must process the error immediately */