nvme: Slight reworking this loop to match FreeBSD style

Update the comment for the code, and slightly rework the code in the
'fast exit' paradigm that FreeBSD generally tries to do.

Sponsored by:		Netflix

sys/dev/nvme/nvme_qpair.c

@@ -953,27 +953,26 @@ nvme_admin_qpair_abort_aers(struct nvme_qpair *qpair)
 	/*
 	 * nvme_complete_tracker must be called without the qpair lock held. It
 	 * takes the lock to adjust outstanding_tr list, so make sure we don't
-	 * have it yet (since this is a general purpose routine). We take the
-	 * lock to make the list traverse safe, but have to drop the lock to
-	 * complete any AER. We restart the list scan when we do this to make
-	 * this safe. There's interlock with the ISR so we know this tracker
-	 * won't be completed twice.
+	 * have it yet. We need the lock to make the list traverse safe, but
+	 * have to drop the lock to complete any AER. We restart the list scan
+	 * when we do this to make this safe. There's interlock with the ISR so
+	 * we know this tracker won't be completed twice.
 	 */
 	mtx_assert(&qpair->lock, MA_NOTOWNED);
 
 	mtx_lock(&qpair->lock);
 	tr = TAILQ_FIRST(&qpair->outstanding_tr);
 	while (tr != NULL) {
-		if (tr->req->cmd.opc == NVME_OPC_ASYNC_EVENT_REQUEST) {
-			mtx_unlock(&qpair->lock);
-			nvme_qpair_manual_complete_tracker(tr,
-			    NVME_SCT_GENERIC, NVME_SC_ABORTED_SQ_DELETION, 0,
-			    ERROR_PRINT_NONE);
-			mtx_lock(&qpair->lock);
-			tr = TAILQ_FIRST(&qpair->outstanding_tr);
-		} else {
+		if (tr->req->cmd.opc != NVME_OPC_ASYNC_EVENT_REQUEST) {
 			tr = TAILQ_NEXT(tr, tailq);
+			continue;
 		}
+		mtx_unlock(&qpair->lock);
+		nvme_qpair_manual_complete_tracker(tr,
+		    NVME_SCT_GENERIC, NVME_SC_ABORTED_SQ_DELETION, 0,
+		    ERROR_PRINT_NONE);
+		mtx_lock(&qpair->lock);
+		tr = TAILQ_FIRST(&qpair->outstanding_tr);
 	}
 	mtx_unlock(&qpair->lock);
 }