BIO_GET_NR_VECS(9) The Linux VFS BIO_GET_NR_VECS(9)NAMEbio_get_nr_vecs - return approx number of vecs
int bio_get_nr_vecs(struct block_device * bdev);
Return the approximate number of pages we can send to this target.
There's no guarantee that you will be able to fit this number of pages
into a bio, it does not account for dynamic restrictions that vary on
COPYRIGHTKernel Hackers Manual 3.8. June 2014 BIO_GET_NR_VECS(9)