netlink: add netlink_dump_control structure for netlink_dump_start()

Davem considers that the argument list of this interface is getting
out of control. This patch tries to address this issue following
his proposal:

struct netlink_dump_control c = { .dump = dump, .done = done, ... };

netlink_dump_start(..., &c);

Suggested by David S. Miller.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

12 files changed, 87 insertions, 43 deletions

diff --git a/crypto/crypto_user.c b/crypto/crypto_user.c
index 16f8693cc147..b6ac1387770c 100644
--- a/crypto/crypto_user.c
+++ b/crypto/crypto_user.c
@@ -389,9 +389,13 @@ static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
             (nlh->nlmsg_flags & NLM_F_DUMP))) {
                 if (link->dump == NULL)
                         return -EINVAL;
-
-                return netlink_dump_start(crypto_nlsk, skb, nlh,
-                                          link->dump, link->done, 0);
+                {
+                        struct netlink_dump_control c = {
+                                .dump = link->dump,
+                                .done = link->done,
+                        };
+                        return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
+                }
         }
 
         err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
diff --git a/drivers/infiniband/core/netlink.c b/drivers/infiniband/core/netlink.c
index d1c8196d15d7..396e29370304 100644
--- a/drivers/infiniband/core/netlink.c
+++ b/drivers/infiniband/core/netlink.c
@@ -147,9 +147,13 @@ static int ibnl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                         if (op < 0 || op >= client->nops ||
                             !client->cb_table[RDMA_NL_GET_OP(op)].dump)
                                 return -EINVAL;
-                        return netlink_dump_start(nls, skb, nlh,
-                                                  client->cb_table[op].dump,
-                                                  NULL, 0);
+
+                        {
+                                struct netlink_dump_control c = {
+                                        .dump = client->cb_table[op].dump,
+                                };
+                                return netlink_dump_start(nls, skb, nlh, &c);
+                        }
                 }
         }
 
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index a390e9d54827..1f8c1a95f57c 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -248,11 +248,15 @@ __nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len, int flags)
 #define NLMSG_PUT(skb, pid, seq, type, len) \
         NLMSG_NEW(skb, pid, seq, type, len, 0)
 
+struct netlink_dump_control {
+        int (*dump)(struct sk_buff *skb, struct netlink_callback *);
+        int (*done)(struct netlink_callback*);
+        u16 min_dump_alloc;
+};
+
 extern int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
                               const struct nlmsghdr *nlh,
-                              int (*dump)(struct sk_buff *skb, struct netlink_callback*),
-                              int (*done)(struct netlink_callback*),
-                              u16 min_dump_alloc);
+                              struct netlink_dump_control *control);
 
 
 #define NL_NONROOT_RECV 0x1
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 65aebd450027..7aef62e53113 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1981,8 +1981,13 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 
                 __rtnl_unlock();
                 rtnl = net->rtnl;
-                err = netlink_dump_start(rtnl, skb, nlh, dumpit,
-                                         NULL, min_dump_alloc);
+                {
+                        struct netlink_dump_control c = {
+                                .dump           = dumpit,
+                                .min_dump_alloc = min_dump_alloc,
+                        };
+                        err = netlink_dump_start(rtnl, skb, nlh, &c);
+                }
                 rtnl_lock();
                 return err;
         }
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index fcf281819cd4..8d25a1c557eb 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -960,9 +960,12 @@ static int inet_diag_rcv_msg_compat(struct sk_buff *skb, struct nlmsghdr *nlh)
                             inet_diag_bc_audit(nla_data(attr), nla_len(attr)))
                                 return -EINVAL;
                 }
-
-                return netlink_dump_start(sock_diag_nlsk, skb, nlh,
-                                          inet_diag_dump_compat, NULL, 0);
+                {
+                        struct netlink_dump_control c = {
+                                .dump = inet_diag_dump_compat,
+                        };
+                        return netlink_dump_start(sock_diag_nlsk, skb, nlh, &c);
+                }
         }
 
         return inet_diag_get_exact_compat(skb, nlh);
@@ -985,9 +988,12 @@ static int inet_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
                             inet_diag_bc_audit(nla_data(attr), nla_len(attr)))
                                 return -EINVAL;
                 }
-
-                return netlink_dump_start(sock_diag_nlsk, skb, h,
-                                          inet_diag_dump, NULL, 0);
+                {
+                        struct netlink_dump_control c = {
+                                .dump = inet_diag_dump,
+                        };
+                        return netlink_dump_start(sock_diag_nlsk, skb, h, &c);
+                }
         }
 
         return inet_diag_get_exact(skb, h, (struct inet_diag_req_v2 *)NLMSG_DATA(h));
diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index 32dbf0fa89db..e7f90e7082b4 100644
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -1162,9 +1162,13 @@ ip_set_dump(struct sock *ctnl, struct sk_buff *skb,
         if (unlikely(protocol_failed(attr)))
                 return -IPSET_ERR_PROTOCOL;
 
-        return netlink_dump_start(ctnl, skb, nlh,
-                                  ip_set_dump_start,
-                                  ip_set_dump_done, 0);
+        {
+                struct netlink_dump_control c = {
+                        .dump = ip_set_dump_start,
+                        .done = ip_set_dump_done,
+                };
+                return netlink_dump_start(ctnl, skb, nlh, &c);
+        }
 }
 
 /* Add, del and test */
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 9307b033c0c9..61f7feb7932b 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -977,9 +977,13 @@ ctnetlink_get_conntrack(struct sock *ctnl, struct sk_buff *skb,
         u16 zone;
         int err;
 
-        if (nlh->nlmsg_flags & NLM_F_DUMP)
-                return netlink_dump_start(ctnl, skb, nlh, ctnetlink_dump_table,
-                                          ctnetlink_done, 0);
+        if (nlh->nlmsg_flags & NLM_F_DUMP) {
+                struct netlink_dump_control c = {
+                        .dump = ctnetlink_dump_table,
+                        .done = ctnetlink_done,
+                };
+                return netlink_dump_start(ctnl, skb, nlh, &c);
+        }
 
         err = ctnetlink_parse_zone(cda[CTA_ZONE], &zone);
         if (err < 0)
@@ -1850,9 +1854,11 @@ ctnetlink_get_expect(struct sock *ctnl, struct sk_buff *skb,
         int err;
 
         if (nlh->nlmsg_flags & NLM_F_DUMP) {
-                return netlink_dump_start(ctnl, skb, nlh,
-                                          ctnetlink_exp_dump_table,
-                                          ctnetlink_exp_done, 0);
+                struct netlink_dump_control c = {
+                        .dump = ctnetlink_exp_dump_table,
+                        .done = ctnetlink_exp_done,
+                };
+                return netlink_dump_start(ctnl, skb, nlh, &c);
         }
 
         err = ctnetlink_parse_zone(cda[CTA_EXPECT_ZONE], &zone);
diff --git a/net/netfilter/nfnetlink_acct.c b/net/netfilter/nfnetlink_acct.c
index 11ba013e47f6..3eb348bfc4fb 100644
--- a/net/netfilter/nfnetlink_acct.c
+++ b/net/netfilter/nfnetlink_acct.c
@@ -171,8 +171,10 @@ nfnl_acct_get(struct sock *nfnl, struct sk_buff *skb,
         char *acct_name;
 
         if (nlh->nlmsg_flags & NLM_F_DUMP) {
-                return netlink_dump_start(nfnl, skb, nlh, nfnl_acct_dump,
-                                          NULL, 0);
+                struct netlink_dump_control c = {
+                        .dump = nfnl_acct_dump,
+                };
+                return netlink_dump_start(nfnl, skb, nlh, &c);
         }
 
         if (!tb[NFACCT_NAME])
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 4d751e3d4b4b..ab74845876d2 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1736,10 +1736,7 @@ errout_skb:
 
 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
                        const struct nlmsghdr *nlh,
-                       int (*dump)(struct sk_buff *skb,
-                                   struct netlink_callback *),
-                       int (*done)(struct netlink_callback *),
-                       u16 min_dump_alloc)
+                       struct netlink_dump_control *control)
 {
         struct netlink_callback *cb;
         struct sock *sk;
@@ -1750,10 +1747,10 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
         if (cb == NULL)
                 return -ENOBUFS;
 
-        cb->dump = dump;
-        cb->done = done;
+        cb->dump = control->dump;
+        cb->done = control->done;
         cb->nlh = nlh;
-        cb->min_dump_alloc = min_dump_alloc;
+        cb->min_dump_alloc = control->min_dump_alloc;
         atomic_inc(&skb->users);
         cb->skb = skb;
 
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index a1154717219e..9f40441d7a7d 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -563,8 +563,13 @@ static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                         return -EOPNOTSUPP;
 
                 genl_unlock();
-                err = netlink_dump_start(net->genl_sock, skb, nlh,
-                                         ops->dumpit, ops->done, 0);
+                {
+                        struct netlink_dump_control c = {
+                                .dump = ops->dumpit,
+                                .done = ops->done,
+                        };
+                        err = netlink_dump_start(net->genl_sock, skb, nlh, &c);
+                }
                 genl_lock();
                 return err;
         }
diff --git a/net/unix/diag.c b/net/unix/diag.c
index 6b7697fd911b..4195555aea65 100644
--- a/net/unix/diag.c
+++ b/net/unix/diag.c
@@ -301,10 +301,12 @@ static int unix_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
         if (nlmsg_len(h) < hdrlen)
                 return -EINVAL;
 
-        if (h->nlmsg_flags & NLM_F_DUMP)
-                return netlink_dump_start(sock_diag_nlsk, skb, h,
-                                          unix_diag_dump, NULL, 0);
-        else
+        if (h->nlmsg_flags & NLM_F_DUMP) {
+                struct netlink_dump_control c = {
+                        .dump = unix_diag_dump,
+                };
+                return netlink_dump_start(sock_diag_nlsk, skb, h, &c);
+        } else
                 return unix_diag_get_exact(skb, h, (struct unix_diag_req *)NLMSG_DATA(h));
 }
 
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 66b84fbf2746..7128dde0fe1a 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -2299,8 +2299,13 @@ static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                 if (link->dump == NULL)
                         return -EINVAL;
 
-                return netlink_dump_start(net->xfrm.nlsk, skb, nlh,
-                                          link->dump, link->done, 0);
+                {
+                        struct netlink_dump_control c = {
+                                .dump = link->dump,
+                                .done = link->done,
+                        };
+                        return netlink_dump_start(net->xfrm.nlsk, skb, nlh, &c);
+                }
         }
 
         err = nlmsg_parse(nlh, xfrm_msg_min[type], attrs, XFRMA_MAX,