On Wed, Aug 24, 2022 at 09:45:57AM +0300, Alvaro Karsz wrote:
> > What about max_secure_erase_seg and secure_erase_sector_alignment?
>
> Hi Stefan,
> If I understand correctly, the Linux kernel uses the same "max
> segments" value for a discard and a secure erase command.
>
> > unsigned int blk_recalc_rq_segments(struct request *rq)
> > {
> > unsigned int nr_phys_segs = 0;
> > unsigned int bytes = 0;
> > struct req_iterator iter;
> > struct bio_vec bv;
> >
> >
> > if (!rq->bio)
> > return 0;
> >
> >
> > switch (bio_op(rq->bio)) {
> > case REQ_OP_DISCARD:
> > case REQ_OP_SECURE_ERASE:
> > if (queue_max_discard_segments(rq->q) > 1) {
> > struct bio *bio = rq->bio;
> >
> >
> > for_each_bio(bio)
> > nr_phys_segs++;
> > return nr_phys_segs;
> > }
> >
> > ....
>
>
> > struct bio *__bio_split_to_limits(struct bio *bio, struct queue_limits *lim,
> > unsigned int *nr_segs)
> > {
> > struct bio_set *bs = &bio->bi_bdev->bd_disk->bio_split;
> > struct bio *split;
> >
> >
> > switch (bio_op(bio)) {
> > case REQ_OP_DISCARD:
> > case REQ_OP_SECURE_ERASE:
> > split = bio_split_discard(bio, lim, nr_segs, bs);
> >
> > break;
> >
> > ...
>
> What do you suggest?
>
> BTW, the same happens for the write zeros command implementation.
> max_write_zeroes_seg and write_zeroes_may_unmap are ignored in the Linux kernel.
How about calculating the minimum of the limits?
Stefan
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