Hello Gurus, Please disregard my earlier mail due to poor formatting and readability. I'm developing a block driver using the make_request method, effectively bypassing existing scsi or request stack in block layer. So that means im directly working with bios. As prescribed in linux documentation and from referring to similar drivers in kernel, you close a session with a bio with the bio_endio function. I usually invoke bio_endio during successful I/O completion, meaning with an error code of zero. But there are cases that this is not fulfilled or there are error cases. My question is, what are the valid error codes that can be used with it? My initial impression is that other than zero as error code, bio_endio will fail. I've read somewhere that -EBUSY is not recognized, and I tried -EIO but my driver crashed. I got a panic in some dio_xxx function leading from bio_endio(bio,-EIO). I would like to block subsequent bios sent to me after reaching my queue depth and with no tags left, and so I want to use bio_endio with an error code. What are those error codes, and will they work for my intended function? Or is there a better way aside from bio_endio? Thanks! Sent from Samsung Mobile