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dm table: do not allow request-based DM to stack on partitions 

[ Upstream commit 6ba01df72b ]

Partitioned request-based devices cannot be used as underlying devices
for request-based DM because no partition offsets are added to each
incoming request.  As such, until now, stacking on partitioned devices
would _always_ result in data corruption (e.g. wiping the partition
table, writing to other partitions, etc).  Fix this by disallowing
request-based stacking on partitions.

While at it, since all .request_fn support has been removed from block
core, remove legacy dm-table code that differentiated between blk-mq and
.request_fn request-based.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
5.4-rM2-2.2.x-imx-squashed
Mike Snitzer 2019-11-05 10:43:44 -05:00 committed by Greg Kroah-Hartman
parent e645b649c4
commit d550b07e1a
1 changed files with 8 additions and 19 deletions
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27
drivers/md/dm-table.c
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@ -922,21 +922,15 @@ bool dm_table_supports_dax(struct dm_table *t,
static bool dm_table_does_not_support_partial_completion(struct dm_table *t);
struct verify_rq_based_data {
unsigned sq_count;
unsigned mq_count;
};
static int device_is_rq_based(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
static int device_is_rq_stackable(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
struct request_queue *q = bdev_get_queue(dev->bdev);
struct verify_rq_based_data *v = data;
struct block_device *bdev = dev->bdev;
struct request_queue *q = bdev_get_queue(bdev);
if (queue_is_mq(q))
v->mq_count++;
else
v->sq_count++;
/* request-based cannot stack on partitions! */
if (bdev != bdev->bd_contains)
return false;
return queue_is_mq(q);
}
@ -945,7 +939,6 @@ static int dm_table_determine_type(struct dm_table *t)
{
unsigned i;
unsigned bio_based = 0, request_based = 0, hybrid = 0;
struct verify_rq_based_data v = {.sq_count = 0, .mq_count = 0};
struct dm_target *tgt;
struct list_head *devices = dm_table_get_devices(t);
enum dm_queue_mode live_md_type = dm_get_md_type(t->md);
@ -1049,14 +1042,10 @@ verify_rq_based:
/* Non-request-stackable devices can't be used for request-based dm */
if (!tgt->type->iterate_devices ||
!tgt->type->iterate_devices(tgt, device_is_rq_based, &v)) {
!tgt->type->iterate_devices(tgt, device_is_rq_stackable, NULL)) {
DMERR("table load rejected: including non-request-stackable devices");
return -EINVAL;
}
if (v.sq_count > 0) {
DMERR("table load rejected: not all devices are blk-mq request-stackable");
return -EINVAL;
}
return 0;
}