[PATCH net-next v2 07/18] net: Register system page pool as an XDP memory model

[Alexander Lobakin <aleksander.lobakin@xxxxxxxxx>]

From: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>

To make the system page pool usable as a source for allocating XDP
frames, we need to register it with xdp_reg_mem_model(), so that page
return works correctly. This is done in preparation for using the system
page pool for the XDP live frame mode in BPF_TEST_RUN; for the same
reason, make the per-cpu variable non-static so we can access it from
the test_run code as well.

Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@xxxxxxxxx>
---
 include/linux/netdevice.h |  1 +
 net/core/dev.c            | 10 +++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 72f53e7610ec..692f21c28ea5 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3308,6 +3308,7 @@ struct softnet_data {
 };
 
 DECLARE_PER_CPU_ALIGNED(struct softnet_data, softnet_data);
+DECLARE_PER_CPU(struct page_pool *, system_page_pool);
 
 #ifndef CONFIG_PREEMPT_RT
 static inline int dev_recursion_level(void)
diff --git a/net/core/dev.c b/net/core/dev.c
index b857abb5c0e9..773388f26d4f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -460,7 +460,7 @@ EXPORT_PER_CPU_SYMBOL(softnet_data);
  * PP consumers must pay attention to run APIs in the appropriate context
  * (e.g. NAPI context).
  */
-static DEFINE_PER_CPU(struct page_pool *, system_page_pool);
+DEFINE_PER_CPU(struct page_pool *, system_page_pool);
 
 #ifdef CONFIG_LOCKDEP
 /*
@@ -12103,11 +12103,18 @@ static int net_page_pool_create(int cpuid)
 		.nid = cpu_to_mem(cpuid),
 	};
 	struct page_pool *pp_ptr;
+	int err;
 
 	pp_ptr = page_pool_create_percpu(&page_pool_params, cpuid);
 	if (IS_ERR(pp_ptr))
 		return -ENOMEM;
 
+	err = xdp_reg_page_pool(pp_ptr);
+	if (err) {
+		page_pool_destroy(pp_ptr);
+		return err;
+	}
+
 	per_cpu(system_page_pool, cpuid) = pp_ptr;
 #endif
 	return 0;
@@ -12241,6 +12248,7 @@ static int __init net_dev_init(void)
 			if (!pp_ptr)
 				continue;
 
+			xdp_unreg_page_pool(pp_ptr);
 			page_pool_destroy(pp_ptr);
 			per_cpu(system_page_pool, i) = NULL;
 		}
-- 
2.46.2