[PATCH bpf-next 08/10] bpf: Use raw_spinlock_t for LPM trie

[Hou Tao <houtao@xxxxxxxxxxxxxxx>]

From: Hou Tao <houtao1@xxxxxxxxxx>

After switching from kmalloc() to the bpf memory allocator, there will be
no blocking operation during the update of LPM trie. Therefore, change
trie->lock from spinlock_t to raw_spinlock_t to make LPM trie usable in
atomic context, even on RT kernels.

Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
---
 kernel/bpf/lpm_trie.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c
index d8995acecedf..f8ff2bfcd704 100644
--- a/kernel/bpf/lpm_trie.c
+++ b/kernel/bpf/lpm_trie.c
@@ -46,7 +46,7 @@ struct lpm_trie {
 	size_t				n_entries;
 	size_t				max_prefixlen;
 	size_t				data_size;
-	spinlock_t			lock;
+	raw_spinlock_t			lock;
 };
 
 /* This trie implements a longest prefix match algorithm that can be used to
@@ -365,7 +365,7 @@ static long trie_update_elem(struct bpf_map *map,
 	if (key->prefixlen > trie->max_prefixlen)
 		return -EINVAL;
 
-	spin_lock_irqsave(&trie->lock, irq_flags);
+	raw_spin_lock_irqsave(&trie->lock, irq_flags);
 
 	/* Allocate and fill a new node */
 	new_node = lpm_trie_node_alloc(trie, value);
@@ -478,7 +478,7 @@ static long trie_update_elem(struct bpf_map *map,
 	if (ret)
 		bpf_mem_cache_free(trie->leaf_ma, new_node);
 
-	spin_unlock_irqrestore(&trie->lock, irq_flags);
+	raw_spin_unlock_irqrestore(&trie->lock, irq_flags);
 	lpm_trie_node_free(trie, free_node, true);
 
 	return ret;
@@ -500,7 +500,7 @@ static long trie_delete_elem(struct bpf_map *map, void *_key)
 	if (key->prefixlen > trie->max_prefixlen)
 		return -EINVAL;
 
-	spin_lock_irqsave(&trie->lock, irq_flags);
+	raw_spin_lock_irqsave(&trie->lock, irq_flags);
 
 	/* Walk the tree looking for an exact key/length match and keeping
 	 * track of the path we traverse.  We will need to know the node
@@ -576,7 +576,7 @@ static long trie_delete_elem(struct bpf_map *map, void *_key)
 	free_node = node;
 
 out:
-	spin_unlock_irqrestore(&trie->lock, irq_flags);
+	raw_spin_unlock_irqrestore(&trie->lock, irq_flags);
 	lpm_trie_node_free(trie, free_parent, true);
 	lpm_trie_node_free(trie, free_node, true);
 
@@ -624,7 +624,7 @@ static struct bpf_map *trie_alloc(union bpf_attr *attr)
 			  offsetof(struct bpf_lpm_trie_key_u8, data);
 	trie->max_prefixlen = trie->data_size * 8;
 
-	spin_lock_init(&trie->lock);
+	raw_spin_lock_init(&trie->lock);
 
 	size = sizeof(struct lpm_trie_node) + trie->data_size;
 	err = bpf_mem_alloc_init(&trie->ma[LPM_TRIE_MA_IM], size, false);
-- 
2.29.2