drivers/md/dm-unstripe.c

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

File Facts

System
Linux kernel
Corpus path
drivers/md/dm-unstripe.c
Extension
.c
Size
4610 bytes
Lines
201
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 unstripe_c {
	struct dm_dev *dev;
	sector_t physical_start;

	uint32_t stripes;

	uint32_t unstripe;
	sector_t unstripe_width;
	sector_t unstripe_offset;

	uint32_t chunk_size;
	u8 chunk_shift;
};

#define DM_MSG_PREFIX "unstriped"

static void cleanup_unstripe(struct unstripe_c *uc, struct dm_target *ti)
{
	if (uc->dev)
		dm_put_device(ti, uc->dev);
	kfree(uc);
}

/*
 * Contruct an unstriped mapping.
 * <number of stripes> <chunk size> <stripe #> <dev_path> <offset>
 */
static int unstripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
	struct unstripe_c *uc;
	sector_t tmp_len;
	unsigned long long start;
	char dummy;

	if (argc != 5) {
		ti->error = "Invalid number of arguments";
		return -EINVAL;
	}

	uc = kzalloc_obj(*uc);
	if (!uc) {
		ti->error = "Memory allocation for unstriped context failed";
		return -ENOMEM;
	}

	if (kstrtouint(argv[0], 10, &uc->stripes) || !uc->stripes) {
		ti->error = "Invalid stripe count";
		goto err;
	}

	if (kstrtouint(argv[1], 10, &uc->chunk_size) || !uc->chunk_size) {
		ti->error = "Invalid chunk_size";
		goto err;
	}

	if (kstrtouint(argv[2], 10, &uc->unstripe)) {
		ti->error = "Invalid stripe number";
		goto err;
	}

	if (uc->unstripe > uc->stripes && uc->stripes > 1) {
		ti->error = "Please provide stripe between [0, # of stripes]";
		goto err;
	}

	if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &uc->dev)) {
		ti->error = "Couldn't get striped device";
		goto err;
	}

	if (sscanf(argv[4], "%llu%c", &start, &dummy) != 1 || start != (sector_t)start) {
		ti->error = "Invalid striped device offset";
		goto err;
	}
	uc->physical_start = start;

	uc->unstripe_offset = (sector_t)uc->unstripe * uc->chunk_size;
	uc->unstripe_width = (sector_t)(uc->stripes - 1) * uc->chunk_size;
	uc->chunk_shift = is_power_of_2(uc->chunk_size) ? fls(uc->chunk_size) - 1 : 0;

	tmp_len = ti->len;
	if (sector_div(tmp_len, uc->chunk_size)) {
		ti->error = "Target length not divisible by chunk size";
		goto err;
	}

	if (dm_set_target_max_io_len(ti, uc->chunk_size)) {
		ti->error = "Failed to set max io len";
		goto err;
	}

Annotation

Implementation Notes