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dm: update dm_process_bio() to split bio if in ->make_request_fn() 

Must call blk_queue_split() otherwise queue_limits for abnormal requests
(e.g. discard, writesame, etc) won't be imposed.

In addition, add dm_queue_split() to simplify DM specific splitting that
is needed for targets that impose ti->max_io_len.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
hifive-unleashed-5.1
Mike Snitzer 2019-01-18 14:10:37 -05:00
parent 4ae280b4ee
commit 568c73a355
1 changed files with 66 additions and 27 deletions
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93
drivers/md/dm.c
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@ -1533,6 +1533,22 @@ static int __send_write_zeroes(struct clone_info *ci, struct dm_target *ti)
return __send_changing_extent_only(ci, ti, get_num_write_zeroes_bios(ti), false);
}
static bool is_abnormal_io(struct bio *bio)
{
bool r = false;
switch (bio_op(bio)) {
case REQ_OP_DISCARD:
case REQ_OP_SECURE_ERASE:
case REQ_OP_WRITE_SAME:
case REQ_OP_WRITE_ZEROES:
r = true;
break;
}
return r;
}
static bool __process_abnormal_io(struct clone_info *ci, struct dm_target *ti,
int *result)
{
@ -1565,7 +1581,7 @@ static int __split_and_process_non_flush(struct clone_info *ci)
if (!dm_target_is_valid(ti))
return -EIO;
if (unlikely(__process_abnormal_io(ci, ti, &r)))
if (__process_abnormal_io(ci, ti, &r))
return r;
len = min_t(sector_t, max_io_len(ci->sector, ti), ci->sector_count);
@ -1601,13 +1617,6 @@ static blk_qc_t __split_and_process_bio(struct mapped_device *md,
blk_qc_t ret = BLK_QC_T_NONE;
int error = 0;
if (unlikely(!map)) {
bio_io_error(bio);
return ret;
}
blk_queue_split(md->queue, &bio);
init_clone_info(&ci, md, map, bio);
if (bio->bi_opf & REQ_PREFLUSH) {
@ -1675,18 +1684,13 @@ static blk_qc_t __split_and_process_bio(struct mapped_device *md,
* Optimized variant of __split_and_process_bio that leverages the
* fact that targets that use it do _not_ have a need to split bios.
*/
static blk_qc_t __process_bio(struct mapped_device *md,
struct dm_table *map, struct bio *bio)
static blk_qc_t __process_bio(struct mapped_device *md, struct dm_table *map,
struct bio *bio, struct dm_target *ti)
{
struct clone_info ci;
blk_qc_t ret = BLK_QC_T_NONE;
int error = 0;
if (unlikely(!map)) {
bio_io_error(bio);
return ret;
}
init_clone_info(&ci, md, map, bio);
if (bio->bi_opf & REQ_PREFLUSH) {
@ -1704,21 +1708,11 @@ static blk_qc_t __process_bio(struct mapped_device *md,
error = __send_empty_flush(&ci);
/* dec_pending submits any data associated with flush */
} else {
struct dm_target *ti = md->immutable_target;
struct dm_target_io *tio;
/*
* Defend against IO still getting in during teardown
* - as was seen for a time with nvme-fcloop
*/
if (WARN_ON_ONCE(!ti || !dm_target_is_valid(ti))) {
error = -EIO;
goto out;
}
ci.bio = bio;
ci.sector_count = bio_sectors(bio);
if (unlikely(__process_abnormal_io(&ci, ti, &error)))
if (__process_abnormal_io(&ci, ti, &error))
goto out;
tio = alloc_tio(&ci, ti, 0, GFP_NOIO);
@ -1730,11 +1724,56 @@ out:
return ret;
}
static void dm_queue_split(struct mapped_device *md, struct dm_target *ti, struct bio **bio)
{
unsigned len, sector_count;
sector_count = bio_sectors(*bio);
len = min_t(sector_t, max_io_len((*bio)->bi_iter.bi_sector, ti), sector_count);
if (sector_count > len) {
struct bio *split = bio_split(*bio, len, GFP_NOIO, &md->queue->bio_split);
bio_chain(split, *bio);
trace_block_split(md->queue, split, (*bio)->bi_iter.bi_sector);
generic_make_request(*bio);
*bio = split;
}
}
static blk_qc_t dm_process_bio(struct mapped_device *md,
struct dm_table *map, struct bio *bio)
{
blk_qc_t ret = BLK_QC_T_NONE;
struct dm_target *ti = md->immutable_target;
if (unlikely(!map)) {
bio_io_error(bio);
return ret;
}
if (!ti) {
ti = dm_table_find_target(map, bio->bi_iter.bi_sector);
if (unlikely(!ti || !dm_target_is_valid(ti))) {
bio_io_error(bio);
return ret;
}
}
/*
* If in ->make_request_fn we need to use blk_queue_split(), otherwise
* queue_limits for abnormal requests (e.g. discard, writesame, etc)
* won't be imposed.
*/
if (current->bio_list) {
if (is_abnormal_io(bio))
blk_queue_split(md->queue, &bio);
else
dm_queue_split(md, ti, &bio);
}
if (dm_get_md_type(md) == DM_TYPE_NVME_BIO_BASED)
return __process_bio(md, map, bio);
return __process_bio(md, map, bio, ti);
else
return __split_and_process_bio(md, map, bio);
}