drivers/s390/cio/css.c

Source file repositories/reference/linux-study-clean/drivers/s390/cio/css.c

File Facts

System
Linux kernel
Corpus path
drivers/s390/cio/css.c
Extension
.c
Size
33368 bytes
Lines
1424
Domain
Driver Families
Bucket
drivers/s390
Inferred role
Driver Families: operation-table or driver-model contract
Status
pattern 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

static const struct bus_type css_bus_type;

int
for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
{
	struct subchannel_id schid;
	int ret;

	init_subchannel_id(&schid);
	do {
		do {
			ret = fn(schid, data);
			if (ret)
				break;
		} while (schid.sch_no++ < __MAX_SUBCHANNEL);
		schid.sch_no = 0;
	} while (schid.ssid++ < max_ssid);
	return ret;
}

struct cb_data {
	void *data;
	struct idset *set;
	int (*fn_known_sch)(struct subchannel *, void *);
	int (*fn_unknown_sch)(struct subchannel_id, void *);
};

static int call_fn_known_sch(struct device *dev, void *data)
{
	struct subchannel *sch = to_subchannel(dev);
	struct cb_data *cb = data;
	int rc = 0;

	if (cb->set)
		idset_sch_del(cb->set, sch->schid);
	if (cb->fn_known_sch)
		rc = cb->fn_known_sch(sch, cb->data);
	return rc;
}

static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
{
	struct cb_data *cb = data;
	int rc = 0;

	if (idset_sch_contains(cb->set, schid))
		rc = cb->fn_unknown_sch(schid, cb->data);
	return rc;
}

static int call_fn_all_sch(struct subchannel_id schid, void *data)
{
	struct cb_data *cb = data;
	struct subchannel *sch;
	int rc = 0;

	sch = get_subchannel_by_schid(schid);
	if (sch) {
		if (cb->fn_known_sch)
			rc = cb->fn_known_sch(sch, cb->data);
		put_device(&sch->dev);
	} else {
		if (cb->fn_unknown_sch)
			rc = cb->fn_unknown_sch(schid, cb->data);
	}

	return rc;
}

int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
			       int (*fn_unknown)(struct subchannel_id,
			       void *), void *data)
{
	struct cb_data cb;
	int rc;

	cb.data = data;
	cb.fn_known_sch = fn_known;
	cb.fn_unknown_sch = fn_unknown;

	if (fn_known && !fn_unknown) {
		/* Skip idset allocation in case of known-only loop. */
		cb.set = NULL;
		return bus_for_each_dev(&css_bus_type, NULL, &cb,
					call_fn_known_sch);
	}

	cb.set = idset_sch_new();
	if (!cb.set)
		/* fall back to brute force scanning in case of oom */

Annotation

Implementation Notes