Commit 6842d264 authored by Damien Le Moal's avatar Damien Le Moal Committed by Mike Snitzer
Browse files

dm: Fix dm_accept_partial_bio() relative to zone management commands 



Fix dm_accept_partial_bio() to actually check that zone management
commands are not passed as explained in the function documentation
comment. Also, since a zone append operation cannot be split, add
REQ_OP_ZONE_APPEND as a forbidden command.

White lines are added around the group of BUG_ON() calls to make the
code more legible.

Signed-off-by: default avatarDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent bab68499

drivers/md/dm.c

+6 −2
Original line number Diff line number Diff line
@@ -1237,8 +1237,8 @@ static int dm_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, 


/*

 * A target may call dm_accept_partial_bio only from the map routine.  It is

 * allowed for all bio types except REQ_PREFLUSH, REQ_OP_ZONE_RESET,

 * REQ_OP_ZONE_OPEN, REQ_OP_ZONE_CLOSE and REQ_OP_ZONE_FINISH.

 * allowed for all bio types except REQ_PREFLUSH, REQ_OP_ZONE_* zone management

 * operations and REQ_OP_ZONE_APPEND (zone append writes).

 *

 * dm_accept_partial_bio informs the dm that the target only wants to process

 * additional n_sectors sectors of the bio and the rest of the data should be
@@ -1268,9 +1268,13 @@ void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors) 
{

	struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);

	unsigned bi_size = bio->bi_iter.bi_size >> SECTOR_SHIFT;



	BUG_ON(bio->bi_opf & REQ_PREFLUSH);

	BUG_ON(op_is_zone_mgmt(bio_op(bio)));

	BUG_ON(bio_op(bio) == REQ_OP_ZONE_APPEND);

	BUG_ON(bi_size > *tio->len_ptr);

	BUG_ON(n_sectors > bi_size);



	*tio->len_ptr -= bi_size - n_sectors;

	bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT;

}