dibs: Register ism as dibs device

Register ism devices with the dibs layer. Follow-on patches will move
functionality to the dibs layer.

As DIBS is only a shim layer without any dependencies, we can depend ISM
on DIBS without adding indirect dependencies. A follow-on patch will
remove implication of SMC by ISM.

Define struct dibs_dev. Follow-on patches will move more content into
dibs_dev.  The goal of follow-on patches is that ism_dev will only
contain fields that are special for this device driver. The same concept
will apply to other dibs device drivers.

Define dibs_dev_alloc(), dibs_dev_add() and dibs_dev_del() to be called
by dibs device drivers and call them from ism_drv.c
Use ism_dev.dibs for a pointer to dibs_dev.

Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Link: https://patch.msgid.link/20250918110500.1731261-6-wintera@linux.ibm.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/drivers/dibs/dibs_main.c b/drivers/dibs/dibs_main.c
index a5d2be9c3246..2f420e077417 100644
--- a/drivers/dibs/dibs_main.c
+++ b/drivers/dibs/dibs_main.c
@@ -11,6 +11,7 @@
 
 #include <linux/module.h>
 #include <linux/types.h>
+#include <linux/slab.h>
 #include <linux/err.h>
 #include <linux/dibs.h>
 
@@ -21,6 +22,15 @@ MODULE_LICENSE("GPL");
 static struct dibs_client *clients[MAX_DIBS_CLIENTS];
 static u8 max_client;
 static DEFINE_MUTEX(clients_lock);
+struct dibs_dev_list {
+	struct list_head list;
+	struct mutex mutex; /* protects dibs device list */
+};
+
+static struct dibs_dev_list dibs_dev_list = {
+	.list = LIST_HEAD_INIT(dibs_dev_list.list),
+	.mutex = __MUTEX_INITIALIZER(dibs_dev_list.mutex),
+};
 
 int dibs_register_client(struct dibs_client *client)
 {
@@ -56,6 +66,34 @@ int dibs_unregister_client(struct dibs_client *client)
 }
 EXPORT_SYMBOL_GPL(dibs_unregister_client);
 
+struct dibs_dev *dibs_dev_alloc(void)
+{
+	struct dibs_dev *dibs;
+
+	dibs = kzalloc(sizeof(*dibs), GFP_KERNEL);
+
+	return dibs;
+}
+EXPORT_SYMBOL_GPL(dibs_dev_alloc);
+
+int dibs_dev_add(struct dibs_dev *dibs)
+{
+	mutex_lock(&dibs_dev_list.mutex);
+	list_add(&dibs->list, &dibs_dev_list.list);
+	mutex_unlock(&dibs_dev_list.mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dibs_dev_add);
+
+void dibs_dev_del(struct dibs_dev *dibs)
+{
+	mutex_lock(&dibs_dev_list.mutex);
+	list_del_init(&dibs->list);
+	mutex_unlock(&dibs_dev_list.mutex);
+}
+EXPORT_SYMBOL_GPL(dibs_dev_del);
+
 static int __init dibs_init(void)
 {
 	memset(clients, 0, sizeof(clients));