[PATCH net-next 3/9] devlink: Add support for creating region snapshots

[Alex Vesker]

Each device address region can store multiple snapshots,
each snapshot is identified using a different numerical ID.
This ID is used when deleting a snapshot or showing an address
region specific snapshot. This patch exposes a callback to add
a new snapshot (data, data length and ID) to an address region.
The snapshot are can be deleted from devlink user tool or when
destroying a region.

Signed-off-by: Alex Vesker <va...@mellanox.com>
Signed-off-by: Jiri Pirko <j...@mellanox.com>
---
 include/net/devlink.h |  9 +++++
 net/core/devlink.c    | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 108 insertions(+)

diff --git a/include/net/devlink.h b/include/net/devlink.h
index 5697c55..83e569f 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -429,6 +429,8 @@ struct devlink_region *devlink_region_create(struct devlink 
*devlink,
                                             u64 region_size);
 void devlink_region_destroy(struct devlink_region *region);
 u32 devlink_region_shapshot_id_get(struct devlink *devlink);
+int devlink_region_snapshot_create(struct devlink_region *region, u64 data_len,
+                                  u8 *data, u32 snapshot_id);
 
 #else
 
@@ -619,6 +621,13 @@ static inline bool 
devlink_dpipe_table_counter_enabled(struct devlink *devlink,
        return 0;
 }
 
+static inline int
+devlink_region_snapshot_create(struct devlink_region *region, u64 data_len,
+                              u8 *data, u32 snapshot_id)
+{
+       return 0;
+}
+
 #endif
 
 #endif /* _NET_DEVLINK_H_ */
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 4822a08..785e87d 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -336,6 +336,14 @@ struct devlink_region {
        u64 size;
 };
 
+struct devlink_snapshot {
+       struct list_head list;
+       struct devlink_region *region;
+       u64 data_len;
+       u8 *data;
+       u32 id;
+};
+
 static struct devlink_region *
 devlink_region_get_by_name(struct devlink *devlink, const char *region_name)
 {
@@ -348,6 +356,26 @@ struct devlink_region {
        return NULL;
 }
 
+static struct devlink_snapshot *
+devlink_region_snapshot_get_by_id(struct devlink_region *region, u32 id)
+{
+       struct devlink_snapshot *snapshot;
+
+       list_for_each_entry(snapshot, &region->snapshot_list, list)
+               if (snapshot->id == id)
+                       return snapshot;
+
+       return NULL;
+}
+
+static void devlink_region_snapshot_del(struct devlink_snapshot *snapshot)
+{
+       snapshot->region->cur_snapshots--;
+       list_del(&snapshot->list);
+       kfree(snapshot->data);
+       kfree(snapshot);
+}
+
 #define DEVLINK_NL_FLAG_NEED_DEVLINK   BIT(0)
 #define DEVLINK_NL_FLAG_NEED_PORT      BIT(1)
 #define DEVLINK_NL_FLAG_NEED_SB                BIT(2)
@@ -3391,8 +3419,14 @@ struct devlink_region *devlink_region_create(struct 
devlink *devlink,
 void devlink_region_destroy(struct devlink_region *region)
 {
        struct devlink *devlink = region->devlink;
+       struct devlink_snapshot *snapshot, *ts;
 
        mutex_lock(&devlink->lock);
+
+       /* Free all snapshots of region */
+       list_for_each_entry_safe(snapshot, ts, &region->snapshot_list, list)
+               devlink_region_snapshot_del(snapshot);
+
        list_del(&region->list);
        mutex_unlock(&devlink->lock);
        kfree(region);
@@ -3420,6 +3454,71 @@ u32 devlink_region_shapshot_id_get(struct devlink 
*devlink)
 }
 EXPORT_SYMBOL_GPL(devlink_region_shapshot_id_get);
 
+/**
+ *     devlink_region_snapshot_create - create a new snapshot
+ *     This will add a new snapshot of a region. The snapshot
+ *     will be stored on the region struct and can be accessed
+ *     from devlink. This is useful for future analyses of snapshots.
+ *     Multiple snapshots can be created on a region.
+ *     The @snapshot_id should be obtained using the getter function.
+ *
+ *     @devlink_region: devlink region of the snapshot
+ *     @data_len: size of snapshot data
+ *     @data: snapshot data
+ *     @snapshot_id: snapshot id to be created
+ */
+int devlink_region_snapshot_create(struct devlink_region *region, u64 data_len,
+                                  u8 *data, u32 snapshot_id)
+{
+       struct devlink *devlink = region->devlink;
+       struct devlink_snapshot *snapshot;
+       int err;
+
+       mutex_lock(&devlink->lock);
+
+       /* check if region can hold one more snapshot */
+       if (region->cur_snapshots == region->max_snapshots) {
+               err = -ENOMEM;
+               goto unlock;
+       }
+
+       if (devlink_region_snapshot_get_by_id(region, snapshot_id)) {
+               err = -EEXIST;
+               goto unlock;
+       }
+
+       snapshot = kzalloc(sizeof(*snapshot), GFP_KERNEL);
+       if (!snapshot) {
+               err = -ENOMEM;
+               goto unlock;
+       }
+
+       snapshot->data = kzalloc(data_len, GFP_KERNEL);
+       if (!snapshot->data) {
+               err = -ENOMEM;
+               goto free_snapshot;
+       }
+
+       snapshot->id = snapshot_id;
+       snapshot->region = region;
+       snapshot->data_len = data_len;
+       memcpy(snapshot->data, data, data_len);
+
+       list_add_tail(&snapshot->list, &region->snapshot_list);
+
+       region->cur_snapshots++;
+
+       mutex_unlock(&devlink->lock);
+       return 0;
+
+free_snapshot:
+       kfree(snapshot);
+unlock:
+       mutex_unlock(&devlink->lock);
+       return err;
+}
+EXPORT_SYMBOL_GPL(devlink_region_snapshot_create);
+
 static int __init devlink_module_init(void)
 {
        return genl_register_family(&devlink_nl_family);
-- 
1.8.3.1