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s390/qeth: unbreak OSM and OSN support

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commit b4d72c08b3 ("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: b4d72c08b3 ("qeth: bridgeport support - basic control")
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Julian Wiedmann
2017-05-10 19:07:52 +02:00
committed by David S. Miller
parent 9111e7880c
commit 2d2ebb3ed0
7 changed files with 51 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/s390/net/qeth_l2_main.c
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@@ -880,14 +880,21 @@ static int qeth_l2_stop(struct net_device *dev)
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);
hash_init(card->mac_htable);
card->options.layer2 = 1;
@@ -899,7 +906,8 @@ static void qeth_l2_remove_device(struct ccwgroup_device *cgdev)
{
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);
@@ -1272,6 +1280,7 @@ static int qeth_l2_control_event(struct qeth_card *card,
}
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,