kernel/linux.git/drivers/md/dm.h, branch v5.7.4

dm: make dm_table_find_target return NULL

2019-08-23T14:13:12+00:00

Currently, if we pass too high sector number to dm_table_find_target, it returns zeroed dm_target structure and callers test if the structure is zeroed with the macro dm_target_is_valid. However, returning NULL is common practice to indicate errors. This patch refactors the dm code, so that dm_table_find_target returns NULL and its callers test the returned value for NULL. The macro dm_target_is_valid is deleted. In alloc_targets, we no longer allocate an extra zeroed target. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm: enable synchronous dax

2019-07-05T22:19:10+00:00

This patch sets dax device 'DAXDEV_SYNC' flag if all the target devices of device mapper support synchrononous DAX. If device mapper consists of both synchronous and asynchronous dax devices, we don't set 'DAXDEV_SYNC' flag. 'dm_table_supports_dax' is refactored to pass 'iterate_devices_fn' as argument so that the callers can pass the appropriate functions. Suggested-by: Mike Snitzer Signed-off-by: Pankaj Gupta Reviewed-by: Mike Snitzer Signed-off-by: Dan Williams

dax: Arrange for dax_supported check to span multiple devices

2019-05-20T22:02:08+00:00

Pankaj reports that starting with commit ad428cdb525a "dax: Check the end of the block-device capacity with dax_direct_access()" device-mapper no longer allows dax operation. This results from the stricter checks in __bdev_dax_supported() that validate that the start and end of a block-device map to the same 'pagemap' instance. Teach the dax-core and device-mapper to validate the 'pagemap' on a per-target basis. This is accomplished by refactoring the bdev_dax_supported() internals into generic_fsdax_supported() which takes a sector range to validate. Consequently generic_fsdax_supported() is suitable to be used in a device-mapper ->iterate_devices() callback. A new ->dax_supported() operation is added to allow composite devices to split and route upper-level bdev_dax_supported() requests. Fixes: ad428cdb525a ("dax: Check the end of the block-device...") Cc: Cc: Ira Weiny Cc: Dave Jiang Cc: Keith Busch Cc: Matthew Wilcox Cc: Vishal Verma Cc: Heiko Carstens Cc: Martin Schwidefsky Reviewed-by: Jan Kara Reported-by: Pankaj Gupta Reviewed-by: Pankaj Gupta Tested-by: Pankaj Gupta Tested-by: Vaibhav Jain Reviewed-by: Mike Snitzer Signed-off-by: Dan Williams

dm: remove legacy request-based IO path

2018-10-11T15:36:09+00:00

dm supports both, and since we're killing off the legacy path in general, get rid of it in dm. Signed-off-by: Jens Axboe Signed-off-by: Mike Snitzer

dm: move dm_table_destroy() to same header as dm_table_create()

2018-01-17T14:16:06+00:00

If anyone is going to use dm_table_create(), they probably should be able to use dm_table_destroy() too. Move the dm_table_destroy() definition outside the private header, near dm_table_create() Signed-off-by: Brian Norris Signed-off-by: Mike Snitzer

dm: ensure bio-based DM's bioset and io_pool support targets' maximum IOs

2017-12-13T17:16:00+00:00

alloc_multiple_bios() assumes it can allocate the requested number of bios but until now there was no gaurantee that the mempools would be accomodating. Suggested-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm: convert dm_dev_internal.count from atomic_t to refcount_t

2017-10-24T19:09:51+00:00

atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable dm_dev_internal.count is used as pure reference counter. Convert it to refcount_t and fix up the operations. Suggested-by: Kees Cook Reviewed-by: David Windsor Reviewed-by: Hans Liljestrand Signed-off-by: Elena Reshetova Signed-off-by: Mike Snitzer

dm: introduce enum dm_queue_mode to cleanup related code

2017-04-27T21:08:44+00:00

Introduce an enumeration type for the queue mode. This patch does not change any functionality but makes the DM code easier to read. Signed-off-by: Bart Van Assche Reviewed-by: Hannes Reinecke Signed-off-by: Mike Snitzer

dm: always defer request allocation to the owner of the request_queue

2017-01-27T22:08:35+00:00

DM already calls blk_mq_alloc_request on the request_queue of the underlying device if it is a blk-mq device. But now that we allow drivers to allocate additional data and initialize it ahead of time we need to do the same for all drivers. Doing so and using the new cmd_size infrastructure in the block layer greatly simplifies the dm-rq and mpath code, and should also make arbitrary combinations of SQ and MQ devices with SQ or MQ device mapper tables easily possible as a further step. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Reviewed-by: Mike Snitzer Signed-off-by: Jens Axboe

dm: add infrastructure for DAX support

2016-07-21T03:49:49+00:00

Change mapped device to implement direct_access function, dm_blk_direct_access(), which calls a target direct_access function. 'struct target_type' is extended to have target direct_access interface. This function limits direct accessible size to the dm_target's limit with max_io_len(). Add dm_table_supports_dax() to iterate all targets and associated block devices to check for DAX support. To add DAX support to a DM target the target must only implement the direct_access function. Add a new dm type, DM_TYPE_DAX_BIO_BASED, which indicates that mapped device supports DAX and is bio based. This new type is used to assure that all target devices have DAX support and remain that way after QUEUE_FLAG_DAX is set in mapped device. At initial table load, QUEUE_FLAG_DAX is set to mapped device when setting DM_TYPE_DAX_BIO_BASED to the type. Any subsequent table load to the mapped device must have the same type, or else it fails per the check in table_load(). Signed-off-by: Toshi Kani Signed-off-by: Mike Snitzer