[PATCH 3.16 006/328] s390/qdio: reset old sbal_state flags

Ben Hutchings
2018-12-09T22:29:36Z

From: Julian Wiedmann <jwi@linux.ibm.com>

commit 64e03ff72623b8c2ea89ca3cb660094e019ed4ae upstream.

When allocating a new AOB fails, handle_outbound() is still capable of
transmitting the selected buffer (just without async completion).

But if a previous transfer on this queue slot used async completion, its
sbal_state flags field is still set to QDIO_OUTBUF_STATE_FLAG_PENDING.
So when the upper layer driver sees this stale flag, it expects an async
completion that never happens.

Fix this by unconditionally clearing the flags field.

Fixes: 104ea556ee7f ("qdio: support asynchronous delivery of storage blocks")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/s390/include/asm/qdio.h | 1 -
drivers/s390/cio/qdio_main.c | 5 ++---
2 files changed, 2 insertions(+), 4 deletions(-)

--- a/arch/s390/include/asm/qdio.h
+++ b/arch/s390/include/asm/qdio.h
@@ -271,7 +271,6 @@ struct qdio_outbuf_state {
void *user;
};

-#define QDIO_OUTBUF_STATE_FLAG_NONE 0x00
#define QDIO_OUTBUF_STATE_FLAG_PENDING 0x01

#define CHSC_AC1_INITIATE_INPUTQ 0x80
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -640,21 +640,20 @@ static inline unsigned long qdio_aob_for
unsigned long phys_aob = 0;

if (!q->use_cq)
- goto out;
+ return 0;

if (!q->aobs[bufnr]) {
struct qaob *aob = qdio_allocate_aob();
q->aobs[bufnr] = aob;
}
if (q->aobs[bufnr]) {
- q->sbal_state[bufnr].flags = QDIO_OUTBUF_STATE_FLAG_NONE;
q->sbal_state[bufnr].aob = q->aobs[bufnr];
q->aobs[bufnr]->user1 = (u64) q->sbal_state[bufnr].user;
phys_aob = virt_to_phys(q->aobs[bufnr]);
WARN_ON_ONCE(phys_aob & 0xFF);
}

-out:
+ q->sbal_state[bufnr].flags = 0;
return phys_aob;
}