mptcp: add mptcp_pm_addr_id_bitmap_t type

Similar to defining types such as nodemask_t, dma_cap_mask_t and
cpumask_t to simplify the use of bitmap, a new type for MPTCP
userspace pm id bitmap, mptcp_pm_addr_id_bitmap_t is defined to
easily modify dump_addr() interface of the path managers to accept
an mptcp_pm_addr_id_bitmap_t type parameter. It also allows this
parameter of dump_addr() can be modified by BPF program when
implementing this interface of a BFP path manager. Because a
dump_addr() interface that accepts an 'unsigned long *bitmap'
or 'unsigned long bitmap[]' parameter is difficult to implement
in BPF program.

In addition, this also makes it easier for us to implement similar
logic to mptcp_userspace_pm_append_new_local_addr() in BPF path
manager, because there's no way to use DECLARE_BITMAP macro in BPF
program, and it's not easy to reimplement it in BPF.

Signed-off-by: Geliang Tang <[email protected]>

Author: Geliang Tang

include/net/mptcp.h

@@ -120,6 +120,13 @@ struct mptcp_sched_ops {
 	void (*release)(struct mptcp_sock *msk);
 } ____cacheline_aligned_in_smp;
 
+/* max value of mptcp_addr_info.id */
+#define MPTCP_PM_MAX_ADDR_ID		U8_MAX
+
+typedef struct {
+	DECLARE_BITMAP(map, MPTCP_PM_MAX_ADDR_ID + 1);
+} mptcp_pm_addr_id_bitmap_t;
+
 #ifdef CONFIG_MPTCP
 void mptcp_init(void);
 

net/mptcp/pm_userspace.c

@@ -47,15 +47,15 @@ static int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
 						    struct mptcp_pm_addr_entry *entry,
 						    bool needs_id)
 {
-	DECLARE_BITMAP(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
 	struct mptcp_pm_addr_entry *match = NULL;
 	struct sock *sk = (struct sock *)msk;
+	mptcp_pm_addr_id_bitmap_t id_bitmap;
 	struct mptcp_pm_addr_entry *e;
 	bool addr_match = false;
 	bool id_match = false;
 	int ret = -EINVAL;
 
-	bitmap_zero(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
+	bitmap_zero(id_bitmap.map, MPTCP_PM_MAX_ADDR_ID + 1);
 
 	spin_lock_bh(&msk->pm.lock);
 	mptcp_for_each_userspace_pm_addr(msk, e) {
@@ -69,7 +69,7 @@ static int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
 		} else if (addr_match || id_match) {
 			break;
 		}
-		__set_bit(e->addr.id, id_bitmap);
+		__set_bit(e->addr.id, id_bitmap.map);
 	}
 
 	if (!match && !addr_match && !id_match) {
@@ -84,7 +84,7 @@ static int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
 
 		*e = *entry;
 		if (!e->addr.id && needs_id)
-			e->addr.id = find_next_zero_bit(id_bitmap,
+			e->addr.id = find_next_zero_bit(id_bitmap.map,
 							MPTCP_PM_MAX_ADDR_ID + 1,
 							1);
 		list_add_tail_rcu(&e->list, &msk->pm.userspace_pm_local_addr_list);
@@ -618,16 +618,14 @@ int mptcp_userspace_pm_dump_addr(struct sk_buff *msg,
 				 struct netlink_callback *cb,
 				 const struct genl_info *info)
 {
-	struct id_bitmap {
-		DECLARE_BITMAP(map, MPTCP_PM_MAX_ADDR_ID + 1);
-	} *bitmap;
+	mptcp_pm_addr_id_bitmap_t *bitmap;
 	struct mptcp_pm_addr_entry *entry;
 	struct mptcp_sock *msk;
 	int ret = -EINVAL;
 	struct sock *sk;
 	void *hdr;
 
-	bitmap = (struct id_bitmap *)cb->ctx;
+	bitmap = (mptcp_pm_addr_id_bitmap_t *)cb->ctx;
 
 	msk = mptcp_userspace_pm_get_sock(info);
 	if (!msk)

net/mptcp/protocol.h

@@ -208,9 +208,6 @@ enum mptcp_addr_signal_status {
 	MPTCP_RM_ADDR_SIGNAL,
 };
 
-/* max value of mptcp_addr_info.id */
-#define MPTCP_PM_MAX_ADDR_ID		U8_MAX
-
 struct mptcp_pm_data {
 	struct mptcp_addr_info local;
 	struct mptcp_addr_info remote;