drivers/md/dm-sysfs.c

Source file repositories/reference/linux-study-clean/drivers/md/dm-sysfs.c

File Facts

System
Linux kernel
Corpus path
drivers/md/dm-sysfs.c
Extension
.c
Size
3242 bytes
Lines
146
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 dm_sysfs_attr {
	struct attribute attr;
	ssize_t (*show)(struct mapped_device *md, char *p);
	ssize_t (*store)(struct mapped_device *md, const char *p, size_t count);
};

#define DM_ATTR_RO(_name) \
struct dm_sysfs_attr dm_attr_##_name = \
	__ATTR(_name, 0444, dm_attr_##_name##_show, NULL)

static ssize_t dm_attr_show(struct kobject *kobj, struct attribute *attr,
			    char *page)
{
	struct dm_sysfs_attr *dm_attr;
	struct mapped_device *md;
	ssize_t ret;

	dm_attr = container_of(attr, struct dm_sysfs_attr, attr);
	if (!dm_attr->show)
		return -EIO;

	md = dm_get_from_kobject(kobj);
	if (!md)
		return -EINVAL;

	ret = dm_attr->show(md, page);
	dm_put(md);

	return ret;
}

#define DM_ATTR_RW(_name) \
struct dm_sysfs_attr dm_attr_##_name = \
	__ATTR(_name, 0644, dm_attr_##_name##_show, dm_attr_##_name##_store)

static ssize_t dm_attr_store(struct kobject *kobj, struct attribute *attr,
			     const char *page, size_t count)
{
	struct dm_sysfs_attr *dm_attr;
	struct mapped_device *md;
	ssize_t ret;

	dm_attr = container_of(attr, struct dm_sysfs_attr, attr);
	if (!dm_attr->store)
		return -EIO;

	md = dm_get_from_kobject(kobj);
	if (!md)
		return -EINVAL;

	ret = dm_attr->store(md, page, count);
	dm_put(md);

	return ret;
}

static ssize_t dm_attr_name_show(struct mapped_device *md, char *buf)
{
	if (dm_copy_name_and_uuid(md, buf, NULL))
		return -EIO;

	strcat(buf, "\n");
	return strlen(buf);
}

static ssize_t dm_attr_uuid_show(struct mapped_device *md, char *buf)
{
	if (dm_copy_name_and_uuid(md, NULL, buf))
		return -EIO;

	strcat(buf, "\n");
	return strlen(buf);
}

static ssize_t dm_attr_suspended_show(struct mapped_device *md, char *buf)
{
	return sysfs_emit(buf, "%d\n", dm_suspended_md(md));
}

static ssize_t dm_attr_use_blk_mq_show(struct mapped_device *md, char *buf)
{
	/* Purely for userspace compatibility */
	return sysfs_emit(buf, "%d\n", true);
}

static DM_ATTR_RO(name);
static DM_ATTR_RO(uuid);
static DM_ATTR_RO(suspended);
static DM_ATTR_RO(use_blk_mq);
static DM_ATTR_RW(rq_based_seq_io_merge_deadline);

Annotation

Implementation Notes