[PATCH net-next 09/14] net/dibs: Create class dibs

Alexandra Winter
2025-09-05T14:54:43Z

From: Julian Ruess <julianr@linux.ibm.com>

Create '/sys/class/dibs' to represent multiple kinds of dibs devices in
sysfs. Show s390/ism devices as well as dibs_loopback devices.

Show attribute fabric_id using dibs_ops.get_fabric_id(). This can help
users understand which dibs devices are connected to the same fabric in
different systems and which dibs devices are loopback devices
(fabric_id 0xffff)

Instead of using the same name as the pci device, give the ism devices
their own readable names based on uid or fid from the HW definition.

smc_loopback was never visible in sysfs. dibs_loopback is now represented
as a virtual device.

For the SMC feature "software defined pnet-id" either the ib device name or
the PCI-ID (actually the parent device name) can be used for SMC-R entries.
Mimic this behaviour for SMC-D, and check the parent device name as well.
So device name or PCI-ID can be used for ism and device name can be used
for dibs-loopback. Note that this:
IB_DEVICE_NAME_MAX - 1 == smc_pnet_policy.[SMC_PNETID_IBNAME].len
is the length of smcd_name. Future SW-pnetid cleanup patches to could use a
meaningful define, but that would touch too much unrelated code here.

Examples:
---------
ism before:
> ls /sys/bus/pci/devices/0000:00:00.0/0000:00:00.0
uevent

ism now:
> ls /sys/bus/pci/devices/0000:00:00.0/dibs/ism30
device -> ../../../0000:00:00.0/
fabric_id
subsystem -> ../../../../../class/dibs/
uevent

dibs loopback:
> ls /sys/devices/virtual/dibs/lo/
fabric_id
subsystem -> ../../../../class/dibs/
uevent

dibs class:
> ls -l /sys/class/dibs/
ism30 -> ../../devices/pci0000:00/0000:00:00.0/dibs/ism30/
lo -> ../../devices/virtual/dibs/lo/

For comparison:
> ls -l /sys/class/net/
enc8410 -> ../../devices/qeth/0.0.8410/net/enc8410/
ens1693 -> ../../devices/pci0001:00/0001:00:00.0/net/ens1693/
lo -> ../../devices/virtual/net/lo/

Signed-off-by: Julian Ruess <julianr@linux.ibm.com>
Co-developed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
---
drivers/s390/net/ism_drv.c | 5 ++++-
net/dibs/dibs_main.c | 40 ++++++++++++++++++++++++++++++++++++++
net/smc/smc_pnet.c | 16 +++++++++++----
3 files changed, 56 insertions(+), 5 deletions(-)

diff --git a/drivers/s390/net/ism_drv.c b/drivers/s390/net/ism_drv.c
index 4096ea9faa7e..ab1d61eb3e3b 100644
--- a/drivers/s390/net/ism_drv.c
+++ b/drivers/s390/net/ism_drv.c
@@ -629,6 +629,7 @@ static void ism_dev_exit(struct ism_dev *ism)
static int ism_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
struct dibs_dev *dibs;
+ struct zpci_dev *zdev;
struct ism_dev *ism;
int ret;

@@ -672,7 +673,9 @@ static int ism_probe(struct pci_dev *pdev, const struct pci_device_id *id)
goto err_dibs;

dibs->dev.parent = &pdev->dev;
- dev_set_name(&dibs->dev, "%s", dev_name(&pdev->dev));
+
+ zdev = to_zpci(pdev);
+ dev_set_name(&dibs->dev, "ism%x", zdev->uid ? zdev->uid : zdev->fid);

ret = dibs_dev_add(dibs);
if (ret)
diff --git a/net/dibs/dibs_main.c b/net/dibs/dibs_main.c
index 610b6c452211..b3f21805aa59 100644
--- a/net/dibs/dibs_main.c
+++ b/net/dibs/dibs_main.c
@@ -20,6 +20,8 @@
MODULE_DESCRIPTION("Direct Internal Buffer Sharing class");
MODULE_LICENSE("GPL");

+static struct class *dibs_class;
+
/* use an array rather a list for fast mapping: */
static struct dibs_client *clients[MAX_DIBS_CLIENTS];
static u8 max_client;
@@ -105,12 +107,35 @@ struct dibs_dev *dibs_dev_alloc(void)
if (!dibs)
return dibs;
dibs->dev.release = dibs_dev_release;
+ dibs->dev.class = dibs_class;
device_initialize(&dibs->dev);

return dibs;
}
EXPORT_SYMBOL_GPL(dibs_dev_alloc);

+static ssize_t fabric_id_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct dibs_dev *dibs;
+ u16 fabric_id;
+
+ dibs = container_of(dev, struct dibs_dev, dev);
+ fabric_id = dibs->ops->get_fabric_id(dibs);
+
+ return sysfs_emit(buf, "0x%04x\n", fabric_id);
+}
+static DEVICE_ATTR_RO(fabric_id);
+
+static struct attribute *dibs_dev_attrs[] = {
+ &dev_attr_fabric_id.attr,
+ NULL,
+};
+
+static const struct attribute_group dibs_dev_attr_group = {
+ .attrs = dibs_dev_attrs,
+};
+
int dibs_dev_add(struct dibs_dev *dibs)
{
int i, ret;
@@ -119,6 +144,11 @@ int dibs_dev_add(struct dibs_dev *dibs)
if (ret)
return ret;

+ ret = sysfs_create_group(&dibs->dev.kobj, &dibs_dev_attr_group);
+ if (ret) {
+ dev_err(&dibs->dev, "sysfs_create_group failed for dibs_dev\n");
+ goto err_device_del;
+ }
mutex_lock(&dibs_dev_list.mutex);
mutex_lock(&clients_lock);
for (i = 0; i < max_client; ++i) {
@@ -130,6 +160,11 @@ int dibs_dev_add(struct dibs_dev *dibs)
mutex_unlock(&dibs_dev_list.mutex);

return 0;
+
+err_device_del:
+ device_del(&dibs->dev);
+ return ret;
+
}
EXPORT_SYMBOL_GPL(dibs_dev_add);

@@ -158,6 +193,10 @@ static int __init dibs_init(void)
memset(clients, 0, sizeof(clients));
max_client = 0;

+ dibs_class = class_create("dibs");
+ if (IS_ERR(&dibs_class))
+ return PTR_ERR(&dibs_class);
+
rc = dibs_loopback_init();
if (rc)
pr_err("%s fails with %d\n", __func__, rc);
@@ -168,6 +207,7 @@ static int __init dibs_init(void)
static void __exit dibs_exit(void)
{
dibs_loopback_exit();
+ class_destroy(dibs_class);
}

module_init(dibs_init);
diff --git a/net/smc/smc_pnet.c b/net/smc/smc_pnet.c
index 653d7dce908a..99246d792631 100644
--- a/net/smc/smc_pnet.c
+++ b/net/smc/smc_pnet.c
@@ -332,8 +332,11 @@ static struct smcd_dev *smc_pnet_find_smcd(char *smcd_name)

mutex_lock(&smcd_dev_list.mutex);
list_for_each_entry(smcd_dev, &smcd_dev_list.list, list) {
- if (!strncmp(dev_name(&smcd_dev->dibs->dev),
- smcd_name, IB_DEVICE_NAME_MAX - 1))
+ if (!strncmp(dev_name(&smcd_dev->dibs->dev), smcd_name,
+ IB_DEVICE_NAME_MAX - 1) ||
+ (smcd_dev->dibs->dev.parent &&
+ !strncmp(dev_name(smcd_dev->dibs->dev.parent), smcd_name,
+ IB_DEVICE_NAME_MAX - 1)))
goto out;
}
smcd_dev = NULL;
@@ -1189,7 +1192,6 @@ int smc_pnetid_by_table_ib(struct smc_ib_device *smcibdev, u8 ib_port)
*/
int smc_pnetid_by_table_smcd(struct smcd_dev *smcddev)
{
- const char *ib_name = dev_name(&smcddev->dibs->dev);
struct smc_pnettable *pnettable;
struct smc_pnetentry *tmp_pe;
struct smc_net *sn;
@@ -1202,7 +1204,13 @@ int smc_pnetid_by_table_smcd(struct smcd_dev *smcddev)
mutex_lock(&pnettable->lock);
list_for_each_entry(tmp_pe, &pnettable->pnetlist, list) {
if (tmp_pe->type == SMC_PNET_IB &&
- !strncmp(tmp_pe->ib_name, ib_name, IB_DEVICE_NAME_MAX)) {
+ (!strncmp(tmp_pe->ib_name,
+ dev_name(&smcddev->dibs->dev),
+ sizeof(tmp_pe->ib_name)) ||
+ (smcddev->dibs->dev.parent &&
+ !strncmp(tmp_pe->ib_name,
+ dev_name(smcddev->dibs->dev.parent),
+ sizeof(tmp_pe->ib_name))))) {
smc_pnet_apply_smcd(smcddev, tmp_pe->pnet_name);
rc = 0;
break;
--
2.48.1