drivers/md/dm-stats.h

File Facts

System

Linux kernel

Corpus path

drivers/md/dm-stats.h

Extension

.h

Size

1162 bytes

Lines

49

Domain

Driver Families

Bucket

drivers/md

Inferred role

Driver Families: implementation source

Status

source 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.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/types.h
• linux/mutex.h
• linux/list.h

Detected Declarations

• struct dm_stats
• struct dm_stats_aux
• struct mapped_device
• function dm_stats_used
• function dm_stats_record_start

Annotated Snippet

struct dm_stats {
	struct mutex mutex;
	struct list_head list;	/* list of struct dm_stat */
	struct dm_stats_last_position __percpu *last;
	bool precise_timestamps;
};

struct dm_stats_aux {
	bool merged;
	unsigned long long duration_ns;
};

int dm_stats_init(struct dm_stats *st);
void dm_stats_cleanup(struct dm_stats *st);

struct mapped_device;

int dm_stats_message(struct mapped_device *md, unsigned int argc, char **argv,
		     char *result, unsigned int maxlen);

void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
			 sector_t bi_sector, unsigned int bi_sectors, bool end,
			 unsigned long start_time,
			 struct dm_stats_aux *aux);

static inline bool dm_stats_used(struct dm_stats *st)
{
	return !list_empty(&st->list);
}

static inline void dm_stats_record_start(struct dm_stats *stats, struct dm_stats_aux *aux)
{
	if (unlikely(stats->precise_timestamps))
		aux->duration_ns = ktime_to_ns(ktime_get());
}

#endif

Annotation

• Immediate include surface: `linux/types.h`, `linux/mutex.h`, `linux/list.h`.
• Detected declarations: `struct dm_stats`, `struct dm_stats_aux`, `struct mapped_device`, `function dm_stats_used`, `function dm_stats_record_start`.
• Atlas domain: Driver Families / drivers/md.
• Implementation status: source implementation candidate.

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.