[PATCH 3.18 05/33] s390/qeth: unbreak OSM and OSN support

Greg Kroah-Hartman
2017-06-05T16:17:55Z

From: Julian Wiedmann <jwi@linux.vnet.ibm.com>

[ Upstream commit 2d2ebb3ed0c6acfb014f98e427298673a5d07b82 ]

commit b4d72c08b358 ("qeth: bridgeport support - basic control")
broke the support for OSM and OSN devices as follows:

As OSM and OSN are L2 only, qeth_core_probe_device() does an early
setup by loading the l2 discipline and calling qeth_l2_probe_device().
In this context, adding the l2-specific bridgeport sysfs attributes
via qeth_l2_create_device_attributes() hits a BUG_ON in fs/sysfs/group.c,
since the basic sysfs infrastructure for the device hasn't been
established yet.

Note that OSN actually has its own unique sysfs attributes
(qeth_osn_devtype), so the additional attributes shouldn't be created
at all.
For OSM, add a new qeth_l2_devtype that contains all the common
and l2-specific sysfs attributes.
When qeth_core_probe_device() does early setup for OSM or OSN, assign
the corresponding devtype so that the ccwgroup probe code creates the
full set of sysfs attributes.
This allows us to skip qeth_l2_create_device_attributes() in case
of an early setup.

Any device that can't do early setup will initially have only the
generic sysfs attributes, and when it's probed later
qeth_l2_probe_device() adds the l2-specific attributes.

If an early-setup device is removed (by calling ccwgroup_ungroup()),
device_unregister() will - using the devtype - delete the
l2-specific attributes before qeth_l2_remove_device() is called.
So make sure to not remove them twice.

What complicates the issue is that qeth_l2_probe_device() and
qeth_l2_remove_device() is also called on a device when its
layer2 attribute changes (ie. its layer mode is switched).
For early-setup devices this wouldn't work properly - we wouldn't
remove the l2-specific attributes when switching to L3.
But switching the layer mode doesn't actually make any sense;
we already decided that the device can only operate in L2!
So just refuse to switch the layer mode on such devices. Note that
OSN doesn't have a layer2 attribute, so we only need to special-case
OSM.

Based on an initial patch by Ursula Braun.

Fixes: b4d72c08b358 ("qeth: bridgeport support - basic control")
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/s390/net/qeth_core.h | 4 ++++
drivers/s390/net/qeth_core_main.c | 17 +++++++++--------
drivers/s390/net/qeth_core_sys.c | 22 ++++++++++++++--------
drivers/s390/net/qeth_l2.h | 2 ++
drivers/s390/net/qeth_l2_main.c | 17 +++++++++++++----
drivers/s390/net/qeth_l2_sys.c | 8 ++++++++
drivers/s390/net/qeth_l3_main.c | 1 +
7 files changed, 51 insertions(+), 20 deletions(-)

--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -722,6 +722,7 @@ enum qeth_discipline_id {
};

struct qeth_discipline {
+ const struct device_type *devtype;
void (*start_poll)(struct ccw_device *, int, unsigned long);
qdio_handler_t *input_handler;
qdio_handler_t *output_handler;
@@ -887,6 +888,9 @@ extern struct qeth_discipline qeth_l2_di
extern struct qeth_discipline qeth_l3_discipline;
extern const struct attribute_group *qeth_generic_attr_groups[];
extern const struct attribute_group *qeth_osn_attr_groups[];
+extern const struct attribute_group qeth_device_attr_group;
+extern const struct attribute_group qeth_device_blkt_group;
+extern const struct device_type qeth_generic_devtype;
extern struct workqueue_struct *qeth_wq;

int qeth_card_hw_is_reachable(struct qeth_card *);
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -5304,10 +5304,12 @@ void qeth_core_free_discipline(struct qe
card->discipline = NULL;
}

-static const struct device_type qeth_generic_devtype = {
+const struct device_type qeth_generic_devtype = {
.name = "qeth_generic",
.groups = qeth_generic_attr_groups,
};
+EXPORT_SYMBOL_GPL(qeth_generic_devtype);
+
static const struct device_type qeth_osn_devtype = {
.name = "qeth_osn",
.groups = qeth_osn_attr_groups,
@@ -5433,23 +5435,22 @@ static int qeth_core_probe_device(struct
goto err_card;
}

- if (card->info.type == QETH_CARD_TYPE_OSN)
- gdev->dev.type = &qeth_osn_devtype;
- else
- gdev->dev.type = &qeth_generic_devtype;
-
switch (card->info.type) {
case QETH_CARD_TYPE_OSN:
case QETH_CARD_TYPE_OSM:
rc = qeth_core_load_discipline(card, QETH_DISCIPLINE_LAYER2);
if (rc)
goto err_card;
+
+ gdev->dev.type = (card->info.type != QETH_CARD_TYPE_OSN)
+ ? card->discipline->devtype
+ : &qeth_osn_devtype;
rc = card->discipline->setup(card->gdev);
if (rc)
goto err_disc;
- case QETH_CARD_TYPE_OSD:
- case QETH_CARD_TYPE_OSX:
+ break;
default:
+ gdev->dev.type = &qeth_generic_devtype;
break;
}

--- a/drivers/s390/net/qeth_core_sys.c
+++ b/drivers/s390/net/qeth_core_sys.c
@@ -446,12 +446,16 @@ static ssize_t qeth_dev_layer2_store(str

if (card->options.layer2 == newdis)
goto out;
- else {
- card->info.mac_bits = 0;
- if (card->discipline) {
- card->discipline->remove(card->gdev);
- qeth_core_free_discipline(card);
- }
+ if (card->info.type == QETH_CARD_TYPE_OSM) {
+ /* fixed layer, can't switch */
+ rc = -EOPNOTSUPP;
+ goto out;
+ }
+
+ card->info.mac_bits = 0;
+ if (card->discipline) {
+ card->discipline->remove(card->gdev);
+ qeth_core_free_discipline(card);
}

rc = qeth_core_load_discipline(card, newdis);
@@ -745,10 +749,11 @@ static struct attribute *qeth_blkt_devic
&dev_attr_inter_jumbo.attr,
NULL,
};
-static struct attribute_group qeth_device_blkt_group = {
+const struct attribute_group qeth_device_blkt_group = {
.name = "blkt",
.attrs = qeth_blkt_device_attrs,
};
+EXPORT_SYMBOL_GPL(qeth_device_blkt_group);

static struct attribute *qeth_device_attrs[] = {
&dev_attr_state.attr,
@@ -768,9 +773,10 @@ static struct attribute *qeth_device_att
&dev_attr_switch_attrs.attr,
NULL,
};
-static struct attribute_group qeth_device_attr_group = {
+const struct attribute_group qeth_device_attr_group = {
.attrs = qeth_device_attrs,
};
+EXPORT_SYMBOL_GPL(qeth_device_attr_group);

const struct attribute_group *qeth_generic_attr_groups[] = {
&qeth_device_attr_group,
--- a/drivers/s390/net/qeth_l2.h
+++ b/drivers/s390/net/qeth_l2.h
@@ -8,6 +8,8 @@

#include "qeth_core.h"

+extern const struct attribute_group *qeth_l2_attr_groups[];
+
int qeth_l2_create_device_attributes(struct device *);
void qeth_l2_remove_device_attributes(struct device *);
void qeth_l2_setup_bridgeport_attrs(struct qeth_card *card);
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -887,14 +887,21 @@ static int qeth_l2_stop(struct net_devic
return 0;
}

+static const struct device_type qeth_l2_devtype = {
+ .name = "qeth_layer2",
+ .groups = qeth_l2_attr_groups,
+};
+
static int qeth_l2_probe_device(struct ccwgroup_device *gdev)
{
struct qeth_card *card = dev_get_drvdata(&gdev->dev);
int rc;

- rc = qeth_l2_create_device_attributes(&gdev->dev);
- if (rc)
- return rc;
+ if (gdev->dev.type == &qeth_generic_devtype) {
+ rc = qeth_l2_create_device_attributes(&gdev->dev);
+ if (rc)
+ return rc;
+ }
INIT_LIST_HEAD(&card->vid_list);
INIT_LIST_HEAD(&card->mc_list);
card->options.layer2 = 1;
@@ -906,7 +913,8 @@ static void qeth_l2_remove_device(struct
{
struct qeth_card *card = dev_get_drvdata(&cgdev->dev);

- qeth_l2_remove_device_attributes(&cgdev->dev);
+ if (cgdev->dev.type == &qeth_generic_devtype)
+ qeth_l2_remove_device_attributes(&cgdev->dev);
qeth_set_allowed_threads(card, 0, 1);
wait_event(card->wait_q, qeth_threads_running(card, 0xffffffff) == 0);

@@ -1276,6 +1284,7 @@ static int qeth_l2_control_event(struct
}

struct qeth_discipline qeth_l2_discipline = {
+ .devtype = &qeth_l2_devtype,
.start_poll = qeth_qdio_start_poll,
.input_handler = (qdio_handler_t *) qeth_qdio_input_handler,
.output_handler = (qdio_handler_t *) qeth_qdio_output_handler,
--- a/drivers/s390/net/qeth_l2_sys.c
+++ b/drivers/s390/net/qeth_l2_sys.c
@@ -216,3 +216,11 @@ void qeth_l2_setup_bridgeport_attrs(stru
} else
qeth_bridgeport_an_set(card, 0);
}
+
+const struct attribute_group *qeth_l2_attr_groups[] = {
+ &qeth_device_attr_group,
+ &qeth_device_blkt_group,
+ /* l2 specific, see l2_{create,remove}_device_attributes(): */
+ &qeth_l2_bridgeport_attr_group,
+ NULL,
+};
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -3612,6 +3612,7 @@ static int qeth_l3_control_event(struct
}

struct qeth_discipline qeth_l3_discipline = {
+ .devtype = &qeth_generic_devtype,
.start_poll = qeth_qdio_start_poll,
.input_handler = (qdio_handler_t *) qeth_qdio_input_handler,
.output_handler = (qdio_handler_t *) qeth_qdio_output_handler,