rhashtable: accept GFP flags in rhashtable_walk_init

In certain cases, the 802.11 mesh pathtable code wants to
iterate over all of the entries in the forwarding table from
the receive path, which is inside an RCU read-side critical
section.  Enable walks inside atomic sections by allowing
GFP_ATOMIC allocations for the walker state.

Change all existing callsites to pass in GFP_KERNEL.

Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Bob Copeland <me@bobcopeland.com>
[also adjust gfs2/glock.c and rhashtable tests]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

8 files changed, 17 insertions, 11 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 6539131c52a2..4b73bd101bdc 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1913,7 +1913,7 @@ static int gfs2_glocks_open(struct inode *inode, struct file *file)
 		if (seq->buf)
 			seq->size = GFS2_SEQ_GOODSIZE;
 		gi->gl = NULL;
-		ret = rhashtable_walk_init(&gl_hash_table, &gi->hti);
+		ret = rhashtable_walk_init(&gl_hash_table, &gi->hti, GFP_KERNEL);
 	}
 	return ret;
 }
@@ -1941,7 +1941,7 @@ static int gfs2_glstats_open(struct inode *inode, struct file *file)
 		if (seq->buf)
 			seq->size = GFS2_SEQ_GOODSIZE;
 		gi->gl = NULL;
-		ret = rhashtable_walk_init(&gl_hash_table, &gi->hti);
+		ret = rhashtable_walk_init(&gl_hash_table, &gi->hti, GFP_KERNEL);
 	}
 	return ret;
 }
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index 63bd7601b6de..3eef0802a0cd 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -346,7 +346,8 @@ struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
 					    struct bucket_table *old_tbl);
 int rhashtable_insert_rehash(struct rhashtable *ht, struct bucket_table *tbl);
 
-int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter);
+int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter,
+			 gfp_t gfp);
 void rhashtable_walk_exit(struct rhashtable_iter *iter);
 int rhashtable_walk_start(struct rhashtable_iter *iter) __acquires(RCU);
 void *rhashtable_walk_next(struct rhashtable_iter *iter);
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index cc808707d1cf..5d845ffd7982 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -487,6 +487,7 @@ EXPORT_SYMBOL_GPL(rhashtable_insert_slow);
  * rhashtable_walk_init - Initialise an iterator
  * @ht:		Table to walk over
  * @iter:	Hash table Iterator
+ * @gfp:	GFP flags for allocations
  *
  * This function prepares a hash table walk.
  *
@@ -504,14 +505,15 @@ EXPORT_SYMBOL_GPL(rhashtable_insert_slow);
  * You must call rhashtable_walk_exit if this function returns
  * successfully.
  */
-int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter)
+int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter,
+			 gfp_t gfp)
 {
 	iter->ht = ht;
 	iter->p = NULL;
 	iter->slot = 0;
 	iter->skip = 0;
 
-	iter->walker = kmalloc(sizeof(*iter->walker), GFP_KERNEL);
+	iter->walker = kmalloc(sizeof(*iter->walker), gfp);
 	if (!iter->walker)
 		return -ENOMEM;
 
diff --git a/lib/test_rhashtable.c b/lib/test_rhashtable.c
index 270bf7289b1e..297fdb5e74bd 100644
--- a/lib/test_rhashtable.c
+++ b/lib/test_rhashtable.c
@@ -143,7 +143,7 @@ static void test_bucket_stats(struct rhashtable *ht)
 	struct rhashtable_iter hti;
 	struct rhash_head *pos;
 
-	err = rhashtable_walk_init(ht, &hti);
+	err = rhashtable_walk_init(ht, &hti, GFP_KERNEL);
 	if (err) {
 		pr_warn("Test failed: allocation error");
 		return;
diff --git a/net/ipv6/ila/ila_xlat.c b/net/ipv6/ila/ila_xlat.c
index 295ca29a23c3..0b03533453e4 100644
--- a/net/ipv6/ila/ila_xlat.c
+++ b/net/ipv6/ila/ila_xlat.c
@@ -501,7 +501,8 @@ static int ila_nl_dump_start(struct netlink_callback *cb)
 	struct ila_net *ilan = net_generic(net, ila_net_id);
 	struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args;
 
-	return rhashtable_walk_init(&ilan->rhash_table, &iter->rhiter);
+	return rhashtable_walk_init(&ilan->rhash_table, &iter->rhiter,
+				    GFP_KERNEL);
 }
 
 static int ila_nl_dump_done(struct netlink_callback *cb)
diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
index 3f9d45d3d9b7..6fa016564f90 100644
--- a/net/netfilter/nft_hash.c
+++ b/net/netfilter/nft_hash.c
@@ -192,7 +192,7 @@ static void nft_hash_walk(const struct nft_ctx *ctx, const struct nft_set *set,
 	u8 genmask = nft_genmask_cur(read_pnet(&set->pnet));
 	int err;
 
-	err = rhashtable_walk_init(&priv->ht, &hti);
+	err = rhashtable_walk_init(&priv->ht, &hti, GFP_KERNEL);
 	iter->err = err;
 	if (err)
 		return;
@@ -248,7 +248,7 @@ static void nft_hash_gc(struct work_struct *work)
 	priv = container_of(work, struct nft_hash, gc_work.work);
 	set  = nft_set_container_of(priv);
 
-	err = rhashtable_walk_init(&priv->ht, &hti);
+	err = rhashtable_walk_init(&priv->ht, &hti, GFP_KERNEL);
 	if (err)
 		goto schedule;
 
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 215fc08c02ab..0f16bf635480 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2343,7 +2343,8 @@ static int netlink_walk_start(struct nl_seq_iter *iter)
 {
 	int err;
 
-	err = rhashtable_walk_init(&nl_table[iter->link].hash, &iter->hti);
+	err = rhashtable_walk_init(&nl_table[iter->link].hash, &iter->hti,
+				   GFP_KERNEL);
 	if (err) {
 		iter->link = MAX_LINKS;
 		return err;
diff --git a/net/sctp/proc.c b/net/sctp/proc.c
index 5cfac8d5d3b3..6d45d53321e6 100644
--- a/net/sctp/proc.c
+++ b/net/sctp/proc.c
@@ -319,7 +319,8 @@ static int sctp_transport_walk_start(struct seq_file *seq)
 	struct sctp_ht_iter *iter = seq->private;
 	int err;
 
-	err = rhashtable_walk_init(&sctp_transport_hashtable, &iter->hti);
+	err = rhashtable_walk_init(&sctp_transport_hashtable, &iter->hti,
+				   GFP_KERNEL);
 	if (err)
 		return err;