net: genetlink: introduce dump info struct to be available during dumpit op

Currently the cb->data is taken by ops during non-parallel dumping.
Introduce a new structure genl_dumpit_info and store the ops there.
Distribute the info to both non-parallel and parallel dumping. Also add
a helper genl_dumpit_info() to easily get the info structure in the
dumpit callback from cb.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index 9292f1c588b7afe73c02c885301c8c706a5053a3..fb838f4b0089c538d77ac71f75ebf9df1c879da4 100644 (file)
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -127,6 +127,20 @@ enum genl_validate_flags {
        GENL_DONT_VALIDATE_DUMP_STRICT          = BIT(2),
 };
 
+/**
+ * struct genl_info - info that is available during dumpit op call
+ * @ops: generic netlink ops - for internal genl code usage
+ */
+struct genl_dumpit_info {
+       const struct genl_ops *ops;
+};
+
+static inline const struct genl_dumpit_info *
+genl_dumpit_info(struct netlink_callback *cb)
+{
+       return cb->data;
+}
+
 /**
  * struct genl_ops - generic netlink operations
  * @cmd: command identifier

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index b5fa98b1577da5f790b9bcf3cd8431ec4521b53c..c785080e94012e08d3740f6d5ada22684d27b7bc 100644 (file)
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -458,10 +458,19 @@ void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 }
 EXPORT_SYMBOL(genlmsg_put);
 
+static struct genl_dumpit_info *genl_dumpit_info_alloc(void)
+{
+       return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL);
+}
+
+static void genl_dumpit_info_free(const struct genl_dumpit_info *info)
+{
+       kfree(info);
+}
+
 static int genl_lock_start(struct netlink_callback *cb)
 {
-       /* our ops are always const - netlink API doesn't propagate that */
-       const struct genl_ops *ops = cb->data;
+       const struct genl_ops *ops = genl_dumpit_info(cb)->ops;
        int rc = 0;
 
        if (ops->start) {
@@ -474,8 +483,7 @@ static int genl_lock_start(struct netlink_callback *cb)
 
 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 {
-       /* our ops are always const - netlink API doesn't propagate that */
-       const struct genl_ops *ops = cb->data;
+       const struct genl_ops *ops = genl_dumpit_info(cb)->ops;
        int rc;
 
        genl_lock();
@@ -486,8 +494,8 @@ static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 
 static int genl_lock_done(struct netlink_callback *cb)
 {
-       /* our ops are always const - netlink API doesn't propagate that */
-       const struct genl_ops *ops = cb->data;
+       const struct genl_dumpit_info *info = genl_dumpit_info(cb);
+       const struct genl_ops *ops = info->ops;
        int rc = 0;
 
        if (ops->done) {
@@ -495,6 +503,19 @@ static int genl_lock_done(struct netlink_callback *cb)
                rc = ops->done(cb);
                genl_unlock();
        }
+       genl_dumpit_info_free(info);
+       return rc;
+}
+
+static int genl_parallel_done(struct netlink_callback *cb)
+{
+       const struct genl_dumpit_info *info = genl_dumpit_info(cb);
+       const struct genl_ops *ops = info->ops;
+       int rc = 0;
+
+       if (ops->done)
+               rc = ops->done(cb);
+       genl_dumpit_info_free(info);
        return rc;
 }
 
@@ -505,6 +526,7 @@ static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
                                      const struct genl_ops *ops,
                                      int hdrlen, struct net *net)
 {
+       struct genl_dumpit_info *info;
        int err;
 
        if (!ops->dumpit)
@@ -528,11 +550,17 @@ static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
                }
        }
 
+       /* Allocate dumpit info. It is going to be freed by done() callback. */
+       info = genl_dumpit_info_alloc();
+       if (!info)
+               return -ENOMEM;
+
+       info->ops = ops;
+
        if (!family->parallel_ops) {
                struct netlink_dump_control c = {
                        .module = family->module,
-                       /* we have const, but the netlink API doesn't */
-                       .data = (void *)ops,
+                       .data = info,
                        .start = genl_lock_start,
                        .dump = genl_lock_dumpit,
                        .done = genl_lock_done,
@@ -545,9 +573,10 @@ static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
        } else {
                struct netlink_dump_control c = {
                        .module = family->module,
+                       .data = info,
                        .start = ops->start,
                        .dump = ops->dumpit,
-                       .done = ops->done,
+                       .done = genl_parallel_done,
                };
 
                err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);