After bio is submitted, bio->bi_next is used for IO merge for request based queue only. Reuse the filed for bio based driver for storing driver data, and name it as .bi_bio_drv_data. Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> --- include/linux/blk_types.h | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 6e6c2af48d74..acb45213338c 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -220,7 +220,16 @@ typedef unsigned int blk_qc_t; * stacking drivers) */ struct bio { - struct bio *bi_next; /* request queue link */ + union { + /* request queue link */ + struct bio *bi_next; + + /* + * once bio is submitted to bio based queue, driver can use + * this field to store its own data + */ + void *bi_bio_drv_data; + }; struct block_device *bi_bdev; unsigned int bi_opf; /* bottom bits req flags, * top bits REQ_OP. Use -- 2.31.1 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/dm-devel