rhashtable: Change rhashtable_walk_start to return void

Most callers of rhashtable_walk_start don't care about a resize event
which is indicated by a return value of -EAGAIN. So calls to
rhashtable_walk_start are wrapped wih code to ignore -EAGAIN. Something
like this is common:

       ret = rhashtable_walk_start(rhiter);
       if (ret && ret != -EAGAIN)
               goto out;

Since zero and -EAGAIN are the only possible return values from the
function this check is pointless. The condition never evaluates to true.

This patch changes rhashtable_walk_start to return void. This simplifies
code for the callers that ignore -EAGAIN. For the few cases where the
caller cares about the resize event, particularly where the table can be
walked in mulitple parts for netlink or seq file dump, the function
rhashtable_walk_start_check has been added that returns -EAGAIN on a
resize event.

Signed-off-by: Tom Herbert <tom@quantonium.net>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

9 files changed, 26 insertions, 70 deletions

diff --git a/net/ipv6/ila/ila_xlat.c b/net/ipv6/ila/ila_xlat.c
index 6eb5e68f112a..44c39c5f0638 100644
--- a/net/ipv6/ila/ila_xlat.c
+++ b/net/ipv6/ila/ila_xlat.c
@@ -512,9 +512,7 @@ static int ila_nl_dump(struct sk_buff *skb, struct netlink_callback *cb)
         struct ila_map *ila;
         int ret;
 
-        ret = rhashtable_walk_start(rhiter);
-        if (ret && ret != -EAGAIN)
-                goto done;
+        rhashtable_walk_start(rhiter);
 
         for (;;) {
                 ila = rhashtable_walk_next(rhiter);
diff --git a/net/ipv6/seg6.c b/net/ipv6/seg6.c
index c81407770956..7f5621d09571 100644
--- a/net/ipv6/seg6.c
+++ b/net/ipv6/seg6.c
@@ -306,9 +306,7 @@ static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
         struct seg6_hmac_info *hinfo;
         int ret;
 
-        ret = rhashtable_walk_start(iter);
-        if (ret && ret != -EAGAIN)
-                goto done;
+        rhashtable_walk_start(iter);
 
         for (;;) {
                 hinfo = rhashtable_walk_next(iter);
diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c
index 86c8dfef56a4..a5125624a76d 100644
--- a/net/mac80211/mesh_pathtbl.c
+++ b/net/mac80211/mesh_pathtbl.c
@@ -257,9 +257,7 @@ __mesh_path_lookup_by_idx(struct mesh_table *tbl, int idx)
         if (ret)
                 return NULL;
 
-        ret = rhashtable_walk_start(&iter);
-        if (ret && ret != -EAGAIN)
-                goto err;
+        rhashtable_walk_start(&iter);
 
         while ((mpath = rhashtable_walk_next(&iter))) {
                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
@@ -269,7 +267,6 @@ __mesh_path_lookup_by_idx(struct mesh_table *tbl, int idx)
                 if (i++ == idx)
                         break;
         }
-err:
         rhashtable_walk_stop(&iter);
         rhashtable_walk_exit(&iter);
 
@@ -513,9 +510,7 @@ void mesh_plink_broken(struct sta_info *sta)
         if (ret)
                 return;
 
-        ret = rhashtable_walk_start(&iter);
-        if (ret && ret != -EAGAIN)
-                goto out;
+        rhashtable_walk_start(&iter);
 
         while ((mpath = rhashtable_walk_next(&iter))) {
                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
@@ -535,7 +530,6 @@ void mesh_plink_broken(struct sta_info *sta)
                                 WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
                 }
         }
-out:
         rhashtable_walk_stop(&iter);
         rhashtable_walk_exit(&iter);
 }
@@ -584,9 +578,7 @@ void mesh_path_flush_by_nexthop(struct sta_info *sta)
         if (ret)
                 return;
 
-        ret = rhashtable_walk_start(&iter);
-        if (ret && ret != -EAGAIN)
-                goto out;
+        rhashtable_walk_start(&iter);
 
         while ((mpath = rhashtable_walk_next(&iter))) {
                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
@@ -597,7 +589,7 @@ void mesh_path_flush_by_nexthop(struct sta_info *sta)
                 if (rcu_access_pointer(mpath->next_hop) == sta)
                         __mesh_path_del(tbl, mpath);
         }
-out:
+
         rhashtable_walk_stop(&iter);
         rhashtable_walk_exit(&iter);
 }
@@ -614,9 +606,7 @@ static void mpp_flush_by_proxy(struct ieee80211_sub_if_data *sdata,
         if (ret)
                 return;
 
-        ret = rhashtable_walk_start(&iter);
-        if (ret && ret != -EAGAIN)
-                goto out;
+        rhashtable_walk_start(&iter);
 
         while ((mpath = rhashtable_walk_next(&iter))) {
                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
@@ -627,7 +617,7 @@ static void mpp_flush_by_proxy(struct ieee80211_sub_if_data *sdata,
                 if (ether_addr_equal(mpath->mpp, proxy))
                         __mesh_path_del(tbl, mpath);
         }
-out:
+
         rhashtable_walk_stop(&iter);
         rhashtable_walk_exit(&iter);
 }
@@ -642,9 +632,7 @@ static void table_flush_by_iface(struct mesh_table *tbl)
         if (ret)
                 return;
 
-        ret = rhashtable_walk_start(&iter);
-        if (ret && ret != -EAGAIN)
-                goto out;
+        rhashtable_walk_start(&iter);
 
         while ((mpath = rhashtable_walk_next(&iter))) {
                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
@@ -653,7 +641,7 @@ static void table_flush_by_iface(struct mesh_table *tbl)
                         break;
                 __mesh_path_del(tbl, mpath);
         }
-out:
+
         rhashtable_walk_stop(&iter);
         rhashtable_walk_exit(&iter);
 }
@@ -873,9 +861,7 @@ void mesh_path_tbl_expire(struct ieee80211_sub_if_data *sdata,
         if (ret)
                 return;
 
-        ret = rhashtable_walk_start(&iter);
-        if (ret && ret != -EAGAIN)
-                goto out;
+        rhashtable_walk_start(&iter);
 
         while ((mpath = rhashtable_walk_next(&iter))) {
                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
@@ -887,7 +873,7 @@ void mesh_path_tbl_expire(struct ieee80211_sub_if_data *sdata,
                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
                         __mesh_path_del(tbl, mpath);
         }
-out:
+
         rhashtable_walk_stop(&iter);
         rhashtable_walk_exit(&iter);
 }
diff --git a/net/netfilter/nft_set_hash.c b/net/netfilter/nft_set_hash.c
index f8166c1d5430..3f1624ee056f 100644
--- a/net/netfilter/nft_set_hash.c
+++ b/net/netfilter/nft_set_hash.c
@@ -251,11 +251,7 @@ static void nft_rhash_walk(const struct nft_ctx *ctx, struct nft_set *set,
         if (err)
                 return;
 
-        err = rhashtable_walk_start(&hti);
-        if (err && err != -EAGAIN) {
-                iter->err = err;
-                goto out;
-        }
+        rhashtable_walk_start(&hti);
 
         while ((he = rhashtable_walk_next(&hti))) {
                 if (IS_ERR(he)) {
@@ -306,9 +302,7 @@ static void nft_rhash_gc(struct work_struct *work)
         if (err)
                 goto schedule;
 
-        err = rhashtable_walk_start(&hti);
-        if (err && err != -EAGAIN)
-                goto out;
+        rhashtable_walk_start(&hti);
 
         while ((he = rhashtable_walk_next(&hti))) {
                 if (IS_ERR(he)) {
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index b9e0ee4e22f5..ab325d4d6fef 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2478,8 +2478,9 @@ static int netlink_walk_start(struct nl_seq_iter *iter)
                 return err;
         }
 
-        err = rhashtable_walk_start(&iter->hti);
-        return err == -EAGAIN ? 0 : err;
+        rhashtable_walk_start(&iter->hti);
+
+        return 0;
 }
 
 static void netlink_walk_stop(struct nl_seq_iter *iter)
diff --git a/net/netlink/diag.c b/net/netlink/diag.c
index 8faa20b4d457..7dda33b9b784 100644
--- a/net/netlink/diag.c
+++ b/net/netlink/diag.c
@@ -115,11 +115,7 @@ static int __netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
         if (!s_num)
                 rhashtable_walk_enter(&tbl->hash, hti);
 
-        ret = rhashtable_walk_start(hti);
-        if (ret == -EAGAIN)
-                ret = 0;
-        if (ret)
-                goto stop;
+        rhashtable_walk_start(hti);
 
         while ((nlsk = rhashtable_walk_next(hti))) {
                 if (IS_ERR(nlsk)) {
@@ -146,8 +142,8 @@ static int __netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
                 }
         }
 
-stop:
         rhashtable_walk_stop(hti);
+
         if (ret)
                 goto done;
 
diff --git a/net/sctp/proc.c b/net/sctp/proc.c
index 26b4be6b4172..4545bc2aff84 100644
--- a/net/sctp/proc.c
+++ b/net/sctp/proc.c
@@ -288,12 +288,8 @@ struct sctp_ht_iter {
 static void *sctp_transport_seq_start(struct seq_file *seq, loff_t *pos)
 {
         struct sctp_ht_iter *iter = seq->private;
-        int err = sctp_transport_walk_start(&iter->hti);
 
-        if (err) {
-                iter->start_fail = 1;
-                return ERR_PTR(err);
-        }
+        sctp_transport_walk_start(&iter->hti);
 
         iter->start_fail = 0;
         return sctp_transport_get_idx(seq_file_net(seq), &iter->hti, *pos);
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index eb17a911aa29..3e55daa37e66 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4676,20 +4676,11 @@ int sctp_get_sctp_info(struct sock *sk, struct sctp_association *asoc,
 EXPORT_SYMBOL_GPL(sctp_get_sctp_info);
 
 /* use callback to avoid exporting the core structure */
-int sctp_transport_walk_start(struct rhashtable_iter *iter)
+void sctp_transport_walk_start(struct rhashtable_iter *iter)
 {
-        int err;
-
         rhltable_walk_enter(&sctp_transport_hashtable, iter);
 
-        err = rhashtable_walk_start(iter);
-        if (err && err != -EAGAIN) {
-                rhashtable_walk_stop(iter);
-                rhashtable_walk_exit(iter);
-                return err;
-        }
-
-        return 0;
+        rhashtable_walk_start(iter);
 }
 
 void sctp_transport_walk_stop(struct rhashtable_iter *iter)
@@ -4780,12 +4771,10 @@ int sctp_for_each_transport(int (*cb)(struct sctp_transport *, void *),
                             struct net *net, int *pos, void *p) {
         struct rhashtable_iter hti;
         struct sctp_transport *tsp;
-        int ret;
+        int ret = 0;
 
 again:
-        ret = sctp_transport_walk_start(&hti);
-        if (ret)
-                return ret;
+        sctp_transport_walk_start(&hti);
 
         tsp = sctp_transport_get_idx(net, &hti, *pos + 1);
         for (; !IS_ERR_OR_NULL(tsp); tsp = sctp_transport_get_next(net, &hti)) {
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 5d18c0caa92b..22c4fd8a9dfe 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -2640,9 +2640,7 @@ void tipc_sk_reinit(struct net *net)
         rhashtable_walk_enter(&tn->sk_rht, &iter);
 
         do {
-                tsk = ERR_PTR(rhashtable_walk_start(&iter));
-                if (IS_ERR(tsk))
-                        goto walk_stop;
+                rhashtable_walk_start(&iter);
 
                 while ((tsk = rhashtable_walk_next(&iter)) && !IS_ERR(tsk)) {
                         spin_lock_bh(&tsk->sk.sk_lock.slock);
@@ -2651,7 +2649,7 @@ void tipc_sk_reinit(struct net *net)
                         msg_set_orignode(msg, tn->own_addr);
                         spin_unlock_bh(&tsk->sk.sk_lock.slock);
                 }
-walk_stop:
+
                 rhashtable_walk_stop(&iter);
         } while (tsk == ERR_PTR(-EAGAIN));
 }