[PATCH 13/33] scsi: qla2xxx: Fix response queue over-consumption in __qla_consume_iocb()

qla24xx_process_response_queue() advances ring_ptr past the head IOCB
before dispatching, so by the time __qla_consume_iocb() runs, ring_ptr
already points at the first continuation IOCB. The function however
looped purex->entry_count times starting at ring_ptr. As entry_count
includes the head, this consumed one entry too many: it stamped
RESPONSE_PROCESSED on the next, unrelated IOCB and advanced the ring
past it, silently dropping a legitimate firmware response. The head
IOCB's signature was also never marked.

Mark the head processed and account for it, then consume only the
entry_count - 1 continuation IOCBs, matching __qla_copy_purex_to_buffer().

Fixes: fac2807946c1 ("scsi: qla2xxx: edif: Add extraction of auth_els from the wire")
Cc: [email protected]
Reported-by: Sashiko <[email protected]>
Signed-off-by: Nilesh Javali <[email protected]>
---
 drivers/scsi/qla2xxx/qla_isr.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index 86e1e8428f2a..6375c18fe392 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -259,6 +259,17 @@ void __qla_consume_iocb(struct scsi_qla_host *vha,
 	struct purex_entry_24xx *purex = *pkt;
 
 	entry_count_remaining = purex->entry_count;
+
+	/*
+	 * The caller already advanced ring_ptr past the head IOCB, so mark
+	 * the head processed and account for it here, then consume only the
+	 * continuation IOCBs that follow.
+	 */
+	((response_t *)purex)->signature = RESPONSE_PROCESSED;
+	/* flush signature */
+	wmb();
+	--entry_count_remaining;
+
 	while (entry_count_remaining > 0) {
 		new_pkt = rsp_q->ring_ptr;
 		*pkt = new_pkt;
-- 
2.47.3