drivers/md/bcache/bcache_ondisk.h

Source file repositories/reference/linux-study-clean/drivers/md/bcache/bcache_ondisk.h

File Facts

System
Linux kernel
Corpus path
drivers/md/bcache/bcache_ondisk.h
Extension
.h
Size
10014 bytes
Lines
447
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.

Dependency Surface

Detected Declarations

Annotated Snippet

struct bkey {
	__u64	high;
	__u64	low;
	__u64	ptr[];
};

#define KEY_FIELD(name, field, offset, size)				\
	BITMASK(name, struct bkey, field, offset, size)

#define PTR_FIELD(name, offset, size)					\
static inline __u64 name(const struct bkey *k, unsigned int i)		\
{ return (k->ptr[i] >> offset) & ~(~0ULL << size); }			\
									\
static inline void SET_##name(struct bkey *k, unsigned int i, __u64 v)	\
{									\
	k->ptr[i] &= ~(~(~0ULL << size) << offset);			\
	k->ptr[i] |= (v & ~(~0ULL << size)) << offset;			\
}

#define KEY_SIZE_BITS		16
#define KEY_MAX_U64S		8

KEY_FIELD(KEY_PTRS,	high, 60, 3)
KEY_FIELD(__PAD0,	high, 58, 2)
KEY_FIELD(KEY_CSUM,	high, 56, 2)
KEY_FIELD(__PAD1,	high, 55, 1)
KEY_FIELD(KEY_DIRTY,	high, 36, 1)

KEY_FIELD(KEY_SIZE,	high, 20, KEY_SIZE_BITS)
KEY_FIELD(KEY_INODE,	high, 0,  20)

/* Next time I change the on disk format, KEY_OFFSET() won't be 64 bits */

static inline __u64 KEY_OFFSET(const struct bkey *k)
{
	return k->low;
}

static inline void SET_KEY_OFFSET(struct bkey *k, __u64 v)
{
	k->low = v;
}

/*
 * The high bit being set is a relic from when we used it to do binary
 * searches - it told you where a key started. It's not used anymore,
 * and can probably be safely dropped.
 */
#define KEY(inode, offset, size)					\
((struct bkey) {							\
	.high = (1ULL << 63) | ((__u64) (size) << 20) | (inode),	\
	.low = (offset)							\
})

#define ZERO_KEY			KEY(0, 0, 0)

#define MAX_KEY_INODE			(~(~0 << 20))
#define MAX_KEY_OFFSET			(~0ULL >> 1)
#define MAX_KEY				KEY(MAX_KEY_INODE, MAX_KEY_OFFSET, 0)

#define KEY_START(k)			(KEY_OFFSET(k) - KEY_SIZE(k))
#define START_KEY(k)			KEY(KEY_INODE(k), KEY_START(k), 0)

#define PTR_DEV_BITS			12

PTR_FIELD(PTR_DEV,			51, PTR_DEV_BITS)
PTR_FIELD(PTR_OFFSET,			8,  43)
PTR_FIELD(PTR_GEN,			0,  8)

#define PTR_CHECK_DEV			((1 << PTR_DEV_BITS) - 1)

#define MAKE_PTR(gen, offset, dev)					\
	((((__u64) dev) << 51) | ((__u64) offset) << 8 | gen)

/* Bkey utility code */

static inline unsigned long bkey_u64s(const struct bkey *k)
{
	return (sizeof(struct bkey) / sizeof(__u64)) + KEY_PTRS(k);
}

static inline unsigned long bkey_bytes(const struct bkey *k)
{
	return bkey_u64s(k) * sizeof(__u64);
}

#define bkey_copy(_dest, _src)	unsafe_memcpy(_dest, _src, bkey_bytes(_src), \
					/* bkey is always padded */)

static inline void bkey_copy_key(struct bkey *dest, const struct bkey *src)

Annotation

Implementation Notes