drivers/md/dm-bufio.c

File Facts

System

Linux kernel

Corpus path

drivers/md/dm-bufio.c

Extension

.c

Size

71439 bytes

Lines

2939

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/dm-bufio.h
• linux/device-mapper.h
• linux/dm-io.h
• linux/slab.h
• linux/sched/mm.h
• linux/jiffies.h
• linux/vmalloc.h
• linux/shrinker.h
• linux/module.h
• linux/rbtree.h
• linux/stacktrace.h
• linux/jump_label.h
• dm.h

Detected Declarations

• struct lru_entry
• struct lru_iter
• struct lru
• struct dm_buffer
• struct buffer_tree
• struct dm_buffer_cache
• struct lock_history
• struct evict_wrapper
• struct dm_bufio_client
• struct write_context
• enum evict_result
• enum data_mode
• enum it_action
• enum new_flag
• function lru_init
• function lru_destroy
• function lru_insert
• function lru_iter_begin
• function lru_iter_end
• function lru_iter_invalidate
• function list_for_each_entry
• function lru_remove
• function lru_reference
• function cache_index
• function cache_read_lock
• function cache_read_unlock
• function cache_write_lock
• function cache_write_unlock
• function lh_init
• function __lh_lock
• function __lh_unlock
• function lh_exit
• function lh_next
• function cache_init
• function cache_destroy
• function cache_count
• function cache_total
• function __cache_inc_buffer
• function __evict_pred
• function cache_mark
• function __cache_mark_many
• function cache_mark_many
• function __cache_iterate
• function cache_iterate
• function present
• function cache_insert
• function one
• function __remove_range

Annotated Snippet

module_init(dm_bufio_init)
module_exit(dm_bufio_exit)

module_param_named(max_cache_size_bytes, dm_bufio_cache_size, ulong, 0644);
MODULE_PARM_DESC(max_cache_size_bytes, "Size of metadata cache");

module_param_named(max_age_seconds, dm_bufio_max_age, uint, 0644);
MODULE_PARM_DESC(max_age_seconds, "No longer does anything");

module_param_named(retain_bytes, dm_bufio_retain_bytes, ulong, 0644);
MODULE_PARM_DESC(retain_bytes, "Try to keep at least this many bytes cached in memory");

module_param_named(peak_allocated_bytes, dm_bufio_peak_allocated, ulong, 0644);
MODULE_PARM_DESC(peak_allocated_bytes, "Tracks the maximum allocated memory");

module_param_named(allocated_kmem_cache_bytes, dm_bufio_allocated_kmem_cache, ulong, 0444);
MODULE_PARM_DESC(allocated_kmem_cache_bytes, "Memory allocated with kmem_cache_alloc");

module_param_named(allocated_kmalloc_bytes, dm_bufio_allocated_kmalloc, ulong, 0444);
MODULE_PARM_DESC(allocated_kmalloc_bytes, "Memory allocated with kmalloc_alloc");

module_param_named(allocated_get_free_pages_bytes, dm_bufio_allocated_get_free_pages, ulong, 0444);
MODULE_PARM_DESC(allocated_get_free_pages_bytes, "Memory allocated with get_free_pages");

module_param_named(allocated_vmalloc_bytes, dm_bufio_allocated_vmalloc, ulong, 0444);
MODULE_PARM_DESC(allocated_vmalloc_bytes, "Memory allocated with vmalloc");

module_param_named(current_allocated_bytes, dm_bufio_current_allocated, ulong, 0444);
MODULE_PARM_DESC(current_allocated_bytes, "Memory currently used by the cache");

MODULE_AUTHOR("Mikulas Patocka <dm-devel@lists.linux.dev>");
MODULE_DESCRIPTION(DM_NAME " buffered I/O library");
MODULE_LICENSE("GPL");

Annotation

• Immediate include surface: `linux/dm-bufio.h`, `linux/device-mapper.h`, `linux/dm-io.h`, `linux/slab.h`, `linux/sched/mm.h`, `linux/jiffies.h`, `linux/vmalloc.h`, `linux/shrinker.h`.
• Detected declarations: `struct lru_entry`, `struct lru_iter`, `struct lru`, `struct dm_buffer`, `struct buffer_tree`, `struct dm_buffer_cache`, `struct lock_history`, `struct evict_wrapper`, `struct dm_bufio_client`, `struct write_context`.
• 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.