xsk: Move addrs from buffer pool to umem

Replicate the addrs pointer in the buffer pool to the umem. This mapping
will be the same for all buffer pools sharing the same umem. In the
buffer pool we leave the addrs pointer for performance reasons.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Link: https://lore.kernel.org/bpf/1598603189-32145-8-git-send-email-magnus.karlsson@intel.com

include/net/xdp_sock.h

@@ -18,6 +18,7 @@ struct xsk_queue;
 struct xdp_buff;
 
 struct xdp_umem {
+	void *addrs;
 	u64 size;
 	u32 headroom;
 	u32 chunk_size;

net/xdp/xdp_umem.c

@@ -39,11 +39,27 @@ static void xdp_umem_unaccount_pages(struct xdp_umem *umem)
 	}
 }
 
+static void xdp_umem_addr_unmap(struct xdp_umem *umem)
+{
+	vunmap(umem->addrs);
+	umem->addrs = NULL;
+}
+
+static int xdp_umem_addr_map(struct xdp_umem *umem, struct page **pages,
+			     u32 nr_pages)
+{
+	umem->addrs = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
+	if (!umem->addrs)
+		return -ENOMEM;
+	return 0;
+}
+
 static void xdp_umem_release(struct xdp_umem *umem)
 {
 	umem->zc = false;
 	ida_simple_remove(&umem_ida, umem->id);
 
+	xdp_umem_addr_unmap(umem);
 	xdp_umem_unpin_pages(umem);
 
 	xdp_umem_unaccount_pages(umem);
@@ -192,8 +208,14 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
 	if (err)
 		goto out_account;
 
+	err = xdp_umem_addr_map(umem, umem->pgs, umem->npgs);
+	if (err)
+		goto out_unpin;
+
 	return 0;
 
+out_unpin:
+	xdp_umem_unpin_pages(umem);
 out_account:
 	xdp_umem_unaccount_pages(umem);
 	return err;

net/xdp/xsk_buff_pool.c

@@ -35,26 +35,11 @@ void xp_del_xsk(struct xsk_buff_pool *pool, struct xdp_sock *xs)
 	spin_unlock_irqrestore(&pool->xsk_tx_list_lock, flags);
 }
 
-static void xp_addr_unmap(struct xsk_buff_pool *pool)
-{
-	vunmap(pool->addrs);
-}
-
-static int xp_addr_map(struct xsk_buff_pool *pool,
-		       struct page **pages, u32 nr_pages)
-{
-	pool->addrs = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
-	if (!pool->addrs)
-		return -ENOMEM;
-	return 0;
-}
-
 void xp_destroy(struct xsk_buff_pool *pool)
 {
 	if (!pool)
 		return;
 
-	xp_addr_unmap(pool);
 	kvfree(pool->heads);
 	kvfree(pool);
 }
@@ -64,7 +49,6 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
 {
 	struct xsk_buff_pool *pool;
 	struct xdp_buff_xsk *xskb;
-	int err;
 	u32 i;
 
 	pool = kvzalloc(struct_size(pool, free_heads, umem->chunks),
@@ -86,6 +70,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
 	pool->frame_len = umem->chunk_size - umem->headroom -
 		XDP_PACKET_HEADROOM;
 	pool->umem = umem;
+	pool->addrs = umem->addrs;
 	INIT_LIST_HEAD(&pool->free_list);
 	INIT_LIST_HEAD(&pool->xsk_tx_list);
 	spin_lock_init(&pool->xsk_tx_list_lock);
@@ -103,9 +88,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
 		pool->free_heads[i] = xskb;
 	}
 
-	err = xp_addr_map(pool, umem->pgs, umem->npgs);
-	if (!err)
-		return pool;
+	return pool;
 
 out:
 	xp_destroy(pool);