@@ -20,6 +20,11 @@ address regions that are otherwise inaccessible to the user.
Regions may also be used to provide an additional way to debug complex error
states, but see also :doc:`devlink-health`
+Regions may optionally support capturing a snapshot on demand via the
+``DEVLINK_CMD_REGION_NEW`` netlink message. A driver wishing to allow
+requested snapshots must implement the ``.snapshot`` callback for the region
+in its ``devlink_region_ops`` structure.
+
example usage
-------------
@@ -40,6 +45,9 @@ example usage
# Delete a snapshot using:
$ devlink region del pci/0000:00:05.0/cr-space snapshot 1
+ # Request an immediate snapshot, if supported by the region
+ $ devlink region new pci/0000:00:05.0/cr-space snapshot 5
+
# Dump a snapshot:
$ devlink region dump pci/0000:00:05.0/fw-health snapshot 1
0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30
@@ -501,10 +501,16 @@ struct devlink_info_req;
* struct devlink_region_ops - Region operations
* @name: region name
* @destructor: callback used to free snapshot memory when deleting
+ * @snapshot: callback to request an immediate snapshot. On success,
+ * the data variable must be updated to point to the snapshot data.
+ * The function will be called while the devlink instance lock is
+ * held.
*/
struct devlink_region_ops {
const char *name;
void (*destructor)(const void *data);
+ int (*snapshot)(struct devlink *devlink, struct netlink_ext_ack *extack,
+ u8 **data);
};
struct devlink_fmsg;
@@ -3845,6 +3845,33 @@ static void __devlink_snapshot_id_decrement(struct devlink *devlink, u32 id)
}
}
+/**
+ * __devlink_snapshot_id_insert - Insert a specific snapshot ID
+ * @devlink: devlink instance
+ * @id: the snapshot id
+ *
+ * Mark the given snapshot id as used by inserting a zero value into the
+ * snapshot xarray.
+ *
+ * This must be called while holding the devlink instance lock. Unlike
+ * devlink_snapshot_id_get, the initial reference count is zero, not one.
+ * It is expected that the id will immediately be used before
+ * releasing the devlink instance lock.
+ *
+ * Returns zero on success, or an error code if the snapshot id could not
+ * be inserted.
+ */
+static int __devlink_snapshot_id_insert(struct devlink *devlink, u32 id)
+{
+ lockdep_assert_held(&devlink->lock);
+
+ if (WARN_ON(xa_load(&devlink->snapshot_ids, id)))
+ return -EEXIST;
+
+ return xa_err(xa_store(&devlink->snapshot_ids, id, xa_mk_value(0),
+ GFP_KERNEL));
+}
+
/**
* __devlink_region_snapshot_id_get - get snapshot ID
* @devlink: devlink instance
@@ -4038,6 +4065,71 @@ static int devlink_nl_cmd_region_del(struct sk_buff *skb,
return 0;
}
+static int
+devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info)
+{
+ struct devlink *devlink = info->user_ptr[0];
+ struct devlink_region *region;
+ const char *region_name;
+ u32 snapshot_id;
+ u8 *data;
+ int err;
+
+ if (!info->attrs[DEVLINK_ATTR_REGION_NAME]) {
+ NL_SET_ERR_MSG_MOD(info->extack, "No region name provided");
+ return -EINVAL;
+ }
+
+ if (!info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]) {
+ NL_SET_ERR_MSG_MOD(info->extack, "No snapshot id provided");
+ return -EINVAL;
+ }
+
+ region_name = nla_data(info->attrs[DEVLINK_ATTR_REGION_NAME]);
+ region = devlink_region_get_by_name(devlink, region_name);
+ if (!region) {
+ NL_SET_ERR_MSG_MOD(info->extack, "The requested region does not exist");
+ return -EINVAL;
+ }
+
+ if (!region->ops->snapshot) {
+ NL_SET_ERR_MSG_MOD(info->extack, "The requested region does not support taking an immediate snapshot");
+ return -EOPNOTSUPP;
+ }
+
+ if (region->cur_snapshots == region->max_snapshots) {
+ NL_SET_ERR_MSG_MOD(info->extack, "The region has reached the maximum number of stored snapshots");
+ return -ENOSPC;
+ }
+
+ snapshot_id = nla_get_u32(info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]);
+
+ if (devlink_region_snapshot_get_by_id(region, snapshot_id)) {
+ NL_SET_ERR_MSG_MOD(info->extack, "The requested snapshot id is already in use");
+ return -EEXIST;
+ }
+
+ err = __devlink_snapshot_id_insert(devlink, snapshot_id);
+ if (err)
+ return err;
+
+ err = region->ops->snapshot(devlink, info->extack, &data);
+ if (err)
+ goto err_snapshot_capture;
+
+ err = __devlink_region_snapshot_create(region, data, snapshot_id);
+ if (err)
+ goto err_snapshot_create;
+
+ return 0;
+
+err_snapshot_create:
+ region->ops->destructor(data);
+err_snapshot_capture:
+ __devlink_snapshot_id_decrement(devlink, snapshot_id);
+ return err;
+}
+
static int devlink_nl_cmd_region_read_chunk_fill(struct sk_buff *msg,
struct devlink *devlink,
u8 *chunk, u32 chunk_size,
@@ -6445,6 +6537,13 @@ static const struct genl_ops devlink_nl_ops[] = {
.flags = GENL_ADMIN_PERM,
.internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK,
},
+ {
+ .cmd = DEVLINK_CMD_REGION_NEW,
+ .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+ .doit = devlink_nl_cmd_region_new,
+ .flags = GENL_ADMIN_PERM,
+ .internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK,
+ },
{
.cmd = DEVLINK_CMD_REGION_DEL,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,