SWBIO_READ
bio->bio_caller_info1.index = SWBIO_READ;
((bio->bio_caller_info1.index & SWBIO_READ) ?
if (bio->bio_caller_info1.index & SWBIO_READ) {
} else if (bio->bio_caller_info1.index & SWBIO_READ) {
if (bio->bio_caller_info1.index & SWBIO_READ)