Messages in this thread | | | Date | Wed, 27 Mar 2019 17:35:07 +0100 | From | Jiri Pirko <> | Subject | Re: [PATCH net-next v5 10/22] ethtool: generic handlers for GET requests |
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Mon, Mar 25, 2019 at 06:08:24PM CET, mkubecek@suse.cz wrote: >Some parts of processing GET type requests and related notifications are >independent of a command. Provide universal functions so that only four >callbacks need to be defined for each command type: > > parse_request() - parse incoming message > prepare_data() - retrieve data from driver or NIC > reply_size() - estimate reply message size > fill_reply() - compose reply message > >These callback are defined in an instance of struct get_request_ops. > >Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
[...]
>+/** >+ * struct get_request_ops - unified handling of GET requests >+ * @request_cmd: command id for request (GET) >+ * @reply_cmd: command id for reply (SET) >+ * @dev_attr: attribute type for device specification >+ * @data_size: total length of data structure >+ * @repdata_offset: offset of "reply data" part (struct common_reply_data) >+ * @allow_nodev_do: do not fail if device is not specified for non-dump request >+ * @parse_request: >+ * parse request message and fill request info; request info is zero >+ * initialized on entry except reply_data pointer (which is initialized) >+ * @prepare_data: >+ * retrieve data needed to compose a reply message; reply data are zero >+ * initialized on entry except for @dev >+ * @reply_size: >+ * return size of reply message payload without device specification; >+ * returned size may be bigger than actual reply size but it must suffice >+ * to hold the reply >+ * @fill_reply: >+ * fill reply message payload using the data prepared by @prepare_data() >+ * @cleanup >+ * (optional) called when data are no longer needed; use e.g. to free >+ * any additional data structures allocated in prepare_data() which are >+ * not part of the main structure >+ * >+ * Description of variable parts of GET request handling when using the unified >+ * infrastructure. When used, a pointer to an instance of this structure is to >+ * be added to &get_requests array, generic handlers ethnl_get_doit(), >+ * ethnl_get_dumpit(), ethnl_get_start() and ethnl_get_done() used in >+ * @ethnl_genl_ops and (optionally) ethnl_std_notify() as notification handler >+ * in ðnl_notify_handlers. >+ */ >+struct get_request_ops {
First of all, please maintain the ethnl prefix. Not only here, but also for other structs and functions (common_req_info, parse_*, etc).
But I must ask, why do we need this wrappers of ops around ops? I believe it would be much nicer to use genl ops directly and do the common work in pre_doit and and post_doit. Please see devlink.c for examples.
Wrappers are unfortunately quite common in this patchset. Most of the time, they do things much harder to follow and understand :(
>+ u8 request_cmd; >+ u8 reply_cmd; >+ u16 dev_attrtype; >+ unsigned int data_size; >+ unsigned int repdata_offset; >+ bool allow_nodev_do; >+ >+ int (*parse_request)(struct common_req_info *req_info, >+ struct sk_buff *skb, struct genl_info *info, >+ const struct nlmsghdr *nlhdr); >+ int (*prepare_data)(struct common_req_info *req_info, >+ struct genl_info *info); >+ int (*reply_size)(const struct common_req_info *req_info); >+ int (*fill_reply)(struct sk_buff *skb, >+ const struct common_req_info *req_info); >+ void (*cleanup)(struct common_req_info *req_info); >+}; >+ > #endif /* _NET_ETHTOOL_NETLINK_H */ >-- >2.21.0 >
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