Refactor fellow_busy_body_seg_next(): Introduce fdsl variable

src/fellow_cache.c

@@ -3977,27 +3977,30 @@ static struct fellow_cache_res
 fellow_busy_body_seg_next(struct fellow_busy *fbo)
 {
 	struct fellow_cache_seglist *fcsl;
+	struct fellow_disk_seglist *fdsl;
 	struct fellow_cache_seg *fcs;
 	struct fellow_cache_res fcr;
 
 	CHECK_OBJ_NOTNULL(fbo, FELLOW_BUSY_MAGIC);
 	fcsl = fbo->body_seglist;
 	CHECK_OBJ_NOTNULL(fcsl, FELLOW_CACHE_SEGLIST_MAGIC);
-	CHECK_OBJ_NOTNULL(fcsl->fdsl, FELLOW_DISK_SEGLIST_MAGIC);
-	assert(fcsl->fdsl->nsegs <= fcsl->lsegs);
-	if (fcsl->fdsl->nsegs == fcsl->lsegs ||
-	    fcsl->segs[fcsl->fdsl->nsegs].state == FCS_INIT) {
+	fdsl = fcsl->fdsl;
+	CHECK_OBJ_NOTNULL(fdsl, FELLOW_DISK_SEGLIST_MAGIC);
+	assert(fdsl->nsegs <= fcsl->lsegs);
+	if (fdsl->nsegs == fcsl->lsegs ||
+	    fcsl->segs[fdsl->nsegs].state == FCS_INIT) {
 		fcr = fellow_busy_body_seglist_alloc(fbo, fcsl);
 		if (fcr.status != fcr_ok)
 			return (fcr);
 		CAST_OBJ_NOTNULL(fcsl, fcr.r.ptr, FELLOW_CACHE_SEGLIST_MAGIC);
 		fbo->body_seglist = fcsl;
+		fdsl = fcsl->fdsl;
 	}
 
-	AN(fcsl->fdsl);
-	assert(fcsl->fdsl->nsegs < fcsl->lsegs);
+	CHECK_OBJ_NOTNULL(fdsl, FELLOW_DISK_SEGLIST_MAGIC);
+	assert(fdsl->nsegs < fcsl->lsegs);
 
-	fcs = &fcsl->segs[fcsl->fdsl->nsegs];
+	fcs = &fcsl->segs[fdsl->nsegs];
 	fbo->body_seg = fcs;
 	assert(fcs->state == FCS_USABLE);
 	assert(fcs->fco == fbo->fco);