On Mon, Mar 20, 2023 at 04:49:04PM -0700, Bart Van Assche wrote:
> Submit the bio fragment with the lowest LBA first. This approach prevents
> write errors when submitting large bios to host-managed zoned block devices.
> This patch only modifies the behavior of drivers that call
> bio_split_to_limits() directly. This includes DRBD, pktcdvd, dm, md and
> the NVMe multipath code.
Umm, doesn't it also change how blk-mq splits, which is the prime
reason why you're looking into that?
> + if (current->bio_list) {
> + /*
> + * The caller will submit the first half ('split')
> + * before the second half ('bio').
> + */
> + bio_chain(split, bio);
> + submit_bio_noacct(bio);
> + return split;
> + }
> + /*
> + * Submit the first half ('split') let the caller submit the
> + * second half ('bio').
> + */
> + *nr_segs = bio_chain_nr_segments(bio, lim);
> + bio_chain(split, bio);
> + submit_bio_noacct(split);
I'm really confused on why you want to change the behavior here
for the case where run in a stacking context vs not, and neither
the comments nor the commit log help me trying to figure out why.
