drivers/md/dm-mpath.c

File Facts

System

Linux kernel

Corpus path

drivers/md/dm-mpath.c

Extension

.c

Size

59998 bytes

Lines

2386

Domain

Driver Families

Bucket

drivers/md

Inferred role

Driver Families: exported/initcall integration point

Status

integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

• Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.
• Exports symbols or registers init work; inspect boot/module ordering and who consumes the exported contract.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• Allocates kernel memory; connect allocation flags and lifetime to context constraints.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/device-mapper.h
• dm-rq.h
• dm-bio-record.h
• dm-path-selector.h
• dm-uevent.h
• linux/blkdev.h
• linux/ctype.h
• linux/init.h
• linux/mempool.h
• linux/module.h
• linux/pagemap.h
• linux/slab.h
• linux/time.h
• linux/timer.h
• linux/workqueue.h
• linux/delay.h
• scsi/scsi_dh.h
• linux/atomic.h
• linux/blk-mq.h

Detected Declarations

• struct pgpath
• struct priority_group
• struct multipath
• struct dm_mpath_io
• function mpath_double_check_test_bit
• function free_pgpath
• function free_pgpaths
• function list_for_each_entry_safe
• function free_priority_group
• function alloc_multipath_stage2
• function free_multipath
• function list_for_each_entry_safe
• function multipath_per_bio_data_size
• function multipath_init_per_bio_data
• function __pg_init_all_paths
• function pg_init_all_paths
• function __switch_pg
• function list_for_each_entry
• function dm_table_device_name
• function must_push_back_rq
• function requests
• function mpath_double_check_test_bit
• function multipath_release_clone
• function bios
• function multipath_queue_bio
• function mpath_double_check_test_bit
• function __multipath_map_bio
• function multipath_map_bio
• function process_queued_io_list
• function process_queued_bios
• function queue_if_no_path
• function queue_if_no_path_timeout_work
• function enable_nopath_timeout
• function disable_nopath_timeout
• function trigger_event
• function parse_path_selector
• function setup_scsi_dh
• function parse_hw_handler
• function parse_features
• function multipath_ctr
• function multipath_wait_for_pg_init_completion
• function flush_multipath_work
• function multipath_dtr
• function fail_path
• function reinstate_path
• function action_dev
• function list_for_each_entry
• function bypass_pg

Annotated Snippet

module_init(dm_multipath_init);
module_exit(dm_multipath_exit);

module_param_named(queue_if_no_path_timeout_secs, queue_if_no_path_timeout_secs, ulong, 0644);
MODULE_PARM_DESC(queue_if_no_path_timeout_secs, "No available paths queue IO timeout in seconds");

MODULE_DESCRIPTION(DM_NAME " multipath target");
MODULE_AUTHOR("Sistina Software <dm-devel@lists.linux.dev>");
MODULE_LICENSE("GPL");

Annotation

• Immediate include surface: `linux/device-mapper.h`, `dm-rq.h`, `dm-bio-record.h`, `dm-path-selector.h`, `dm-uevent.h`, `linux/blkdev.h`, `linux/ctype.h`, `linux/init.h`.
• Detected declarations: `struct pgpath`, `struct priority_group`, `struct multipath`, `struct dm_mpath_io`, `function mpath_double_check_test_bit`, `function free_pgpath`, `function free_pgpaths`, `function list_for_each_entry_safe`, `function free_priority_group`, `function alloc_multipath_stage2`.
• Atlas domain: Driver Families / drivers/md.
• Implementation status: integration implementation candidate.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.