[SRU][Bionic][PATCH 1/1] s390/qdio: reset old sbal_state flags

Frank Heimes frank.heimes at canonical.com
Mon Nov 5 18:22:47 UTC 2018

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

BugLink: http://bugs.launchpad.net/bugs/1801686

s390/qdio: reset old sbal_state flags

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
Cc: <stable at vger.kernel.org> #v3.2+
Signed-off-by: Julian Wiedmann <jwi at linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky at de.ibm.com>
(cherry picked from commit 64e03ff72623b8c2ea89ca3cb660094e019ed4ae)
Signed-off-by: Frank Heimes <frank.heimes at canonical.com>


diff --git a/arch/s390/include/asm/qdio.h b/arch/s390/include/asm/qdio.h
index de11ecc..9c9970a 100644
--- a/arch/s390/include/asm/qdio.h
+++ b/arch/s390/include/asm/qdio.h
@@ -262,7 +262,6 @@ struct qdio_outbuf_state {
        void *user;


 #define CHSC_AC1_INITIATE_INPUTQ       0x80
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index f4ca72d..9c7d9da 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -631,21 +631,20 @@ static inline unsigned long
qdio_aob_for_buffer(struct qdio_output_q *q,
        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);

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