block/nvme: nvme_process_completion() fix bound for cid

NVMeQueuePair::reqs has length NVME_NUM_REQS, which less than
NVME_QUEUE_SIZE by 1.

Fixes: 1086e95 ("block/nvme: switch to a NVMeRequest freelist")
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Maksim Davydov <davydov-max@yandex-team.ru>
Message-id: 20231017125941.810461-5-vsementsov@yandex-team.ru
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
(cherry picked from commit cc8fb0c)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

block/nvme.c

@@ -416,9 +416,10 @@ static bool nvme_process_completion(NVMeQueuePair *q)
             q->cq_phase = !q->cq_phase;
         }
         cid = le16_to_cpu(c->cid);
-        if (cid == 0 || cid > NVME_QUEUE_SIZE) {
-            warn_report("NVMe: Unexpected CID in completion queue: %"PRIu32", "
-                        "queue size: %u", cid, NVME_QUEUE_SIZE);
+        if (cid == 0 || cid > NVME_NUM_REQS) {
+            warn_report("NVMe: Unexpected CID in completion queue: %" PRIu32
+                        ", should be within: 1..%u inclusively", cid,
+                        NVME_NUM_REQS);
             continue;
         }
         trace_nvme_complete_command(s, q->index, cid);