[PATCH net-next 4/8] netfilter: nf_tables: all transaction allocations can now sleep

[Florian Westphal <fw@strlen.de>]

Now that nft_setelem_flush is not called with rcu read lock held or
disabled softinterrupts anymore this can now use GFP_KERNEL too.

This is the last atomic allocation of transaction elements, so remove
all gfp_t arguments and the wrapper function.

This makes attempts to delete large sets much more reliable, before
this was prone to transient memory allocation failures.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/nf_tables_api.c | 47 ++++++++++++++---------------------
 1 file changed, 19 insertions(+), 28 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 58c5425d61c2..54519b3d2868 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -151,12 +151,12 @@ static void nft_ctx_init(struct nft_ctx *ctx,
 	bitmap_zero(ctx->reg_inited, NFT_REG32_NUM);
 }
 
-static struct nft_trans *nft_trans_alloc_gfp(const struct nft_ctx *ctx,
-					     int msg_type, u32 size, gfp_t gfp)
+static struct nft_trans *nft_trans_alloc(const struct nft_ctx *ctx,
+					 int msg_type, u32 size)
 {
 	struct nft_trans *trans;
 
-	trans = kzalloc(size, gfp);
+	trans = kzalloc(size, GFP_KERNEL);
 	if (trans == NULL)
 		return NULL;
 
@@ -172,12 +172,6 @@ static struct nft_trans *nft_trans_alloc_gfp(const struct nft_ctx *ctx,
 	return trans;
 }
 
-static struct nft_trans *nft_trans_alloc(const struct nft_ctx *ctx,
-					 int msg_type, u32 size)
-{
-	return nft_trans_alloc_gfp(ctx, msg_type, size, GFP_KERNEL);
-}
-
 static struct nft_trans_binding *nft_trans_get_binding(struct nft_trans *trans)
 {
 	switch (trans->msg_type) {
@@ -442,8 +436,7 @@ static bool nft_trans_collapse_set_elem_allowed(const struct nft_trans_elem *a,
 
 static bool nft_trans_collapse_set_elem(struct nftables_pernet *nft_net,
 					struct nft_trans_elem *tail,
-					struct nft_trans_elem *trans,
-					gfp_t gfp)
+					struct nft_trans_elem *trans)
 {
 	unsigned int nelems, old_nelems = tail->nelems;
 	struct nft_trans_elem *new_trans;
@@ -466,9 +459,11 @@ static bool nft_trans_collapse_set_elem(struct nftables_pernet *nft_net,
 	/* krealloc might free tail which invalidates list pointers */
 	list_del_init(&tail->nft_trans.list);
 
-	new_trans = krealloc(tail, struct_size(tail, elems, nelems), gfp);
+	new_trans = krealloc(tail, struct_size(tail, elems, nelems),
+			     GFP_KERNEL);
 	if (!new_trans) {
-		list_add_tail(&tail->nft_trans.list, &nft_net->commit_list);
+		list_add_tail(&tail->nft_trans.list,
+			      &nft_net->commit_list);
 		return false;
 	}
 
@@ -484,7 +479,7 @@ static bool nft_trans_collapse_set_elem(struct nftables_pernet *nft_net,
 }
 
 static bool nft_trans_try_collapse(struct nftables_pernet *nft_net,
-				   struct nft_trans *trans, gfp_t gfp)
+				   struct nft_trans *trans)
 {
 	struct nft_trans *tail;
 
@@ -501,7 +496,7 @@ static bool nft_trans_try_collapse(struct nftables_pernet *nft_net,
 	case NFT_MSG_DELSETELEM:
 		return nft_trans_collapse_set_elem(nft_net,
 						   nft_trans_container_elem(tail),
-						   nft_trans_container_elem(trans), gfp);
+						   nft_trans_container_elem(trans));
 	}
 
 	return false;
@@ -537,17 +532,14 @@ static void nft_trans_commit_list_add_tail(struct net *net, struct nft_trans *tr
 	}
 }
 
-static void nft_trans_commit_list_add_elem(struct net *net, struct nft_trans *trans,
-					   gfp_t gfp)
+static void nft_trans_commit_list_add_elem(struct net *net, struct nft_trans *trans)
 {
 	struct nftables_pernet *nft_net = nft_pernet(net);
 
 	WARN_ON_ONCE(trans->msg_type != NFT_MSG_NEWSETELEM &&
 		     trans->msg_type != NFT_MSG_DELSETELEM);
 
-	might_alloc(gfp);
-
-	if (nft_trans_try_collapse(nft_net, trans, gfp)) {
+	if (nft_trans_try_collapse(nft_net, trans)) {
 		kfree(trans);
 		return;
 	}
@@ -7549,7 +7541,7 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 						}
 
 						ue->priv = elem_priv;
-						nft_trans_commit_list_add_elem(ctx->net, trans, GFP_KERNEL);
+						nft_trans_commit_list_add_elem(ctx->net, trans);
 						goto err_elem_free;
 					}
 				}
@@ -7573,7 +7565,7 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 	}
 
 	nft_trans_container_elem(trans)->elems[0].priv = elem.priv;
-	nft_trans_commit_list_add_elem(ctx->net, trans, GFP_KERNEL);
+	nft_trans_commit_list_add_elem(ctx->net, trans);
 	return 0;
 
 err_set_full:
@@ -7839,7 +7831,7 @@ static int nft_del_setelem(struct nft_ctx *ctx, struct nft_set *set,
 	nft_setelem_data_deactivate(ctx->net, set, elem.priv);
 
 	nft_trans_container_elem(trans)->elems[0].priv = elem.priv;
-	nft_trans_commit_list_add_elem(ctx->net, trans, GFP_KERNEL);
+	nft_trans_commit_list_add_elem(ctx->net, trans);
 	return 0;
 
 fail_ops:
@@ -7864,9 +7856,8 @@ static int nft_setelem_flush(const struct nft_ctx *ctx,
 	if (!nft_set_elem_active(ext, iter->genmask))
 		return 0;
 
-	trans = nft_trans_alloc_gfp(ctx, NFT_MSG_DELSETELEM,
-				    struct_size_t(struct nft_trans_elem, elems, 1),
-				    GFP_ATOMIC);
+	trans = nft_trans_alloc(ctx, NFT_MSG_DELSETELEM,
+				struct_size_t(struct nft_trans_elem, elems, 1));
 	if (!trans)
 		return -ENOMEM;
 
@@ -7877,7 +7868,7 @@ static int nft_setelem_flush(const struct nft_ctx *ctx,
 	nft_trans_elem_set(trans) = set;
 	nft_trans_container_elem(trans)->nelems = 1;
 	nft_trans_container_elem(trans)->elems[0].priv = elem_priv;
-	nft_trans_commit_list_add_elem(ctx->net, trans, GFP_ATOMIC);
+	nft_trans_commit_list_add_elem(ctx->net, trans);
 
 	return 0;
 }
@@ -7894,7 +7885,7 @@ static int __nft_set_catchall_flush(const struct nft_ctx *ctx,
 
 	nft_setelem_data_deactivate(ctx->net, set, elem_priv);
 	nft_trans_container_elem(trans)->elems[0].priv = elem_priv;
-	nft_trans_commit_list_add_elem(ctx->net, trans, GFP_KERNEL);
+	nft_trans_commit_list_add_elem(ctx->net, trans);
 
 	return 0;
 }
-- 
2.49.1