bio_add_page

Hi, On the block device driver i am writing : I have a bio such that the bvec has a page with bvec->bv_len = 4096. I want to create two bios with this bvec such that bio1 --> contains 7 sectors(len1) bio2 --> contiains 1 sector(len2) I tried using bio_add_page as follows : bio_add_page(bio1, bvec->bv_page, len1, bvec->bv_offset) bio_add_page(bio2, bvec->bv_page, len2, bvec->bv_offset + len1) But my second 'bio_add_page' returns 0 and not len2 indicating that there is something wrong. Is there some other way to do this??? Regards, Neha