diff mbox series

[net-next,1/5] rhashtable: Don't reset walker table in rhashtable_walk_start

Message ID 20171201000305.2392-2-tom@quantonium.net
State Superseded, archived
Delegated to: David Miller
Headers show
Series rhashtable: New features in walk and bucket locks | expand

Commit Message

Tom Herbert Dec. 1, 2017, 12:03 a.m. UTC 
Remove the code that resets the walker table. The walker table should
only be initialized in the walk init function or when a future table is
encountered. If the walker table is NULL this is the indication that
the walk has completed and this information can be used to break a
multi-call walk in the table (e.g. successive calls to nelink_dump
that are dumping elements of an rhashtable).

This also allows us to change rhashtable_walk_start to return void
since the only error it was returning was -EAGAIN for a table change.
This patch changes all the callers of rhashtable_walk_start to expect
void which eliminates logic needed to check the return value for a
rare condition. Note that -EAGAIN will be returned in a call
to rhashtable_walk_next which seems to always follow the start
of the walk so there should be no behavioral change in doing this.

Signed-off-by: Tom Herbert <tom@quantonium.net>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt_tc.c       |  6 +---
 .../net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c   |  7 ++---
 fs/gfs2/glock.c                                    |  8 ++---
 include/linux/rhashtable.h                         |  2 +-
 include/net/sctp/sctp.h                            |  2 +-
 lib/rhashtable.c                                   | 18 ++----------
 lib/test_rhashtable.c                              |  6 +---
 net/ipv6/ila/ila_xlat.c                            |  4 +--
 net/ipv6/seg6.c                                    |  4 +--
 net/mac80211/mesh_pathtbl.c                        | 34 +++++++---------------
 net/netfilter/nft_set_hash.c                       | 10 ++-----
 net/netlink/af_netlink.c                           |  5 ++--
 net/netlink/diag.c                                 |  8 ++---
 net/sctp/proc.c                                    |  6 +---
 net/sctp/socket.c                                  | 19 +++---------
 net/tipc/socket.c                                  |  6 ++--
 16 files changed, 37 insertions(+), 108 deletions(-)

Comments

Herbert Xu Dec. 1, 2017, 10:18 p.m. UTC | #1 
On Thu, Nov 30, 2017 at 04:03:01PM -0800, Tom Herbert wrote:
> Remove the code that resets the walker table. The walker table should
> only be initialized in the walk init function or when a future table is
> encountered. If the walker table is NULL this is the indication that
> the walk has completed and this information can be used to break a
> multi-call walk in the table (e.g. successive calls to nelink_dump
> that are dumping elements of an rhashtable).
> 
> This also allows us to change rhashtable_walk_start to return void
> since the only error it was returning was -EAGAIN for a table change.
> This patch changes all the callers of rhashtable_walk_start to expect
> void which eliminates logic needed to check the return value for a
> rare condition. Note that -EAGAIN will be returned in a call
> to rhashtable_walk_next which seems to always follow the start
> of the walk so there should be no behavioral change in doing this.
> 
> Signed-off-by: Tom Herbert <tom@quantonium.net>

Doesn't this mean that if a walk encounters a rehash you may end up
missing half or more of the hash table?

Cheers,
Tom Herbert Dec. 1, 2017, 11:29 p.m. UTC | #2 
On Fri, Dec 1, 2017 at 2:18 PM, Herbert Xu <herbert@gondor.apana.org.au> wrote:
> On Thu, Nov 30, 2017 at 04:03:01PM -0800, Tom Herbert wrote:
>> Remove the code that resets the walker table. The walker table should
>> only be initialized in the walk init function or when a future table is
>> encountered. If the walker table is NULL this is the indication that
>> the walk has completed and this information can be used to break a
>> multi-call walk in the table (e.g. successive calls to nelink_dump
>> that are dumping elements of an rhashtable).
>>
>> This also allows us to change rhashtable_walk_start to return void
>> since the only error it was returning was -EAGAIN for a table change.
>> This patch changes all the callers of rhashtable_walk_start to expect
>> void which eliminates logic needed to check the return value for a
>> rare condition. Note that -EAGAIN will be returned in a call
>> to rhashtable_walk_next which seems to always follow the start
>> of the walk so there should be no behavioral change in doing this.
>>
>> Signed-off-by: Tom Herbert <tom@quantonium.net>
>
> Doesn't this mean that if a walk encounters a rehash you may end up
> missing half or more of the hash table?
>
Because of tbl->rehash < tbl->size conditions in walk stop? How about
we add a flag to iter that indicates table needs a reset and set it
along with setting walker.tbl to NULL? On the next walk start do the
reload when walker.tbl is NULL and flag is set. In this case walk
start would automatically set walker.tbl which is already done by
nearly all callers already in that they ignore -EAGAIN returned from
start walk.

Thanks,
Tom

> Cheers,
> --
> Email: Herbert Xu <herbert@gondor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
Tom Herbert Dec. 2, 2017, 1:07 a.m. UTC | #3 
On Fri, Dec 1, 2017 at 3:29 PM, Tom Herbert <tom@quantonium.net> wrote:
> On Fri, Dec 1, 2017 at 2:18 PM, Herbert Xu <herbert@gondor.apana.org.au> wrote:
>> On Thu, Nov 30, 2017 at 04:03:01PM -0800, Tom Herbert wrote:
>>> Remove the code that resets the walker table. The walker table should
>>> only be initialized in the walk init function or when a future table is
>>> encountered. If the walker table is NULL this is the indication that
>>> the walk has completed and this information can be used to break a
>>> multi-call walk in the table (e.g. successive calls to nelink_dump
>>> that are dumping elements of an rhashtable).
>>>
>>> This also allows us to change rhashtable_walk_start to return void
>>> since the only error it was returning was -EAGAIN for a table change.
>>> This patch changes all the callers of rhashtable_walk_start to expect
>>> void which eliminates logic needed to check the return value for a
>>> rare condition. Note that -EAGAIN will be returned in a call
>>> to rhashtable_walk_next which seems to always follow the start
>>> of the walk so there should be no behavioral change in doing this.
>>>
>>> Signed-off-by: Tom Herbert <tom@quantonium.net>
>>
>> Doesn't this mean that if a walk encounters a rehash you may end up
>> missing half or more of the hash table?
>>
> Because of tbl->rehash < tbl->size conditions in walk stop? How about
> we add a flag to iter that indicates table needs a reset and set it
> along with setting walker.tbl to NULL? On the next walk start do the
> reload when walker.tbl is NULL and flag is set. In this case walk
> start would automatically set walker.tbl which is already done by
> nearly all callers already in that they ignore -EAGAIN returned from
> start walk.
>
Herbert,

Looking at this some more, I am wondering if the walkers list is
necessary. When a rehash table is done, the new table is assigned to
ht->tbl and walker->tbl is cleared for all walkers. In walk start the
walker tbl is checked and if it's NULL ht->tbl is loaded. Assuming
that -EAGAIN isn't interesting to callers here, it seems like we could
just get iter->walker.tbl in each call to walk start and not need to
maintain the walkers list at all. Am I missing something?

Tom

> Thanks,
> Tom
>
>> Cheers,
>> --
>> Email: Herbert Xu <herbert@gondor.apana.org.au>
>> Home Page: http://gondor.apana.org.au/~herbert/
>> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
diff mbox series

Patch

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_tc.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_tc.c
index d5031f436f83..df6a57087848 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_tc.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_tc.c
@@ -1416,11 +1416,7 @@  bnxt_tc_flow_stats_batch_prep(struct bnxt *bp,
 	void *flow_node;
 	int rc, i;
 
-	rc = rhashtable_walk_start(iter);
-	if (rc && rc != -EAGAIN) {
-		i = 0;
-		goto done;
-	}
+	rhashtable_walk_start(iter);
 
 	rc = 0;
 	for (i = 0; i < BNXT_FLOW_STATS_BATCH_MAX; i++) {
diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c
index d4a548a6a55c..6d7a10d0c45e 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c
@@ -765,9 +765,7 @@  static void ch_flower_stats_handler(struct work_struct *work)
 
 	rhashtable_walk_enter(&adap->flower_tbl, &iter);
 	do {
-		flower_entry = ERR_PTR(rhashtable_walk_start(&iter));
-		if (IS_ERR(flower_entry))
-			goto walk_stop;
+		rhashtable_walk_start(&iter);
 
 		while ((flower_entry = rhashtable_walk_next(&iter)) &&
 		       !IS_ERR(flower_entry)) {
@@ -786,8 +784,9 @@  static void ch_flower_stats_handler(struct work_struct *work)
 				spin_unlock(&flower_entry->lock);
 			}
 		}
-walk_stop:
+
 		rhashtable_walk_stop(&iter);
+
 	} while (flower_entry == ERR_PTR(-EAGAIN));
 	rhashtable_walk_exit(&iter);
 	mod_timer(&adap->flower_stats_timer, jiffies + STATS_CHECK_PERIOD);
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 11066d8647d2..20d1b6e2d829 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1549,16 +1549,13 @@  static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
 	rhashtable_walk_enter(&gl_hash_table, &iter);
 
 	do {
-		gl = ERR_PTR(rhashtable_walk_start(&iter));
-		if (IS_ERR(gl))
-			goto walk_stop;
+		rhashtable_walk_start(&iter);
 
 		while ((gl = rhashtable_walk_next(&iter)) && !IS_ERR(gl))
 			if (gl->gl_name.ln_sbd == sdp &&
 			    lockref_get_not_dead(&gl->gl_lockref))
 				examiner(gl);
 
-walk_stop:
 		rhashtable_walk_stop(&iter);
 	} while (cond_resched(), gl == ERR_PTR(-EAGAIN));
 
@@ -1947,8 +1944,7 @@  static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
 	loff_t n = *pos;
 
 	rhashtable_walk_enter(&gl_hash_table, &gi->hti);
-	if (rhashtable_walk_start(&gi->hti) != 0)
-		return NULL;
+	rhashtable_walk_start(&gi->hti);
 
 	do {
 		gfs2_glock_iter_next(gi);
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index 361c08e35dbc..4c976bf320a8 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -378,7 +378,7 @@  void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
 void rhashtable_walk_enter(struct rhashtable *ht,
 			   struct rhashtable_iter *iter);
 void rhashtable_walk_exit(struct rhashtable_iter *iter);
-int rhashtable_walk_start(struct rhashtable_iter *iter) __acquires(RCU);
+void rhashtable_walk_start(struct rhashtable_iter *iter) __acquires(RCU);
 void *rhashtable_walk_next(struct rhashtable_iter *iter);
 void rhashtable_walk_stop(struct rhashtable_iter *iter) __releases(RCU);
 
diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 906a9c0efa71..6f79415f6634 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -116,7 +116,7 @@  extern struct percpu_counter sctp_sockets_allocated;
 int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
 struct sk_buff *sctp_skb_recv_datagram(struct sock *, int, int, int *);
 
-int sctp_transport_walk_start(struct rhashtable_iter *iter);
+void sctp_transport_walk_start(struct rhashtable_iter *iter);
 void sctp_transport_walk_stop(struct rhashtable_iter *iter);
 struct sctp_transport *sctp_transport_get_next(struct net *net,
 			struct rhashtable_iter *iter);
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index ddd7dde87c3c..eeddfb3199cd 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -736,16 +736,9 @@  EXPORT_SYMBOL_GPL(rhashtable_walk_exit);
  * @iter:	Hash table iterator
  *
  * Start a hash table walk at the current iterator position.  Note that we take
- * the RCU lock in all cases including when we return an error.  So you must
- * always call rhashtable_walk_stop to clean up.
- *
- * Returns zero if successful.
- *
- * Returns -EAGAIN if resize event occured.  Note that the iterator
- * will rewind back to the beginning and you may use it immediately
- * by calling rhashtable_walk_next.
+ * the RCU lock so you must always call rhashtable_walk_stop to clean up.
  */
-int rhashtable_walk_start(struct rhashtable_iter *iter)
+void rhashtable_walk_start(struct rhashtable_iter *iter)
 	__acquires(RCU)
 {
 	struct rhashtable *ht = iter->ht;
@@ -756,13 +749,6 @@  int rhashtable_walk_start(struct rhashtable_iter *iter)
 	if (iter->walker.tbl)
 		list_del(&iter->walker.list);
 	spin_unlock(&ht->lock);
-
-	if (!iter->walker.tbl) {
-		iter->walker.tbl = rht_dereference_rcu(ht->tbl, ht);
-		return -EAGAIN;
-	}
-
-	return 0;
 }
 EXPORT_SYMBOL_GPL(rhashtable_walk_start);
 
diff --git a/lib/test_rhashtable.c b/lib/test_rhashtable.c
index 8e83cbdc049c..76d3667fdea2 100644
--- a/lib/test_rhashtable.c
+++ b/lib/test_rhashtable.c
@@ -162,11 +162,7 @@  static void test_bucket_stats(struct rhashtable *ht, unsigned int entries)
 		return;
 	}
 
-	err = rhashtable_walk_start(&hti);
-	if (err && err != -EAGAIN) {
-		pr_warn("Test failed: iterator failed: %d\n", err);
-		return;
-	}
+	rhashtable_walk_start(&hti);
 
 	while ((pos = rhashtable_walk_next(&hti))) {
 		if (PTR_ERR(pos) == -EAGAIN) {
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 014847e25648..1dae4742cac4 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));
 }