[PATCH net-next v2 1/4] net: Register system page pool as an XDP memory model

[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.

Reviewed-by: Alexander Lobakin <aleksander.lobakin@xxxxxxxxx>
Tested-by: Alexander Lobakin <aleksander.lobakin@xxxxxxxxx>
Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
---
 include/linux/netdevice.h |  1 +
 net/core/dev.c            | 13 ++++++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c541550b0e6e..e1dfdf0c4075 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3345,6 +3345,7 @@ static inline void input_queue_tail_incr_save(struct softnet_data *sd,
 }
 
 DECLARE_PER_CPU_ALIGNED(struct softnet_data, softnet_data);
+DECLARE_PER_CPU_ALIGNED(struct page_pool *, system_page_pool);
 
 static inline int dev_recursion_level(void)
 {
diff --git a/net/core/dev.c b/net/core/dev.c
index d8dd293a7a27..cdb916a647e7 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -428,7 +428,7 @@ 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_ALIGNED(struct page_pool *, system_page_pool);
+DEFINE_PER_CPU_ALIGNED(struct page_pool *, system_page_pool);
 
 #ifdef CONFIG_LOCKDEP
 /*
@@ -11739,12 +11739,20 @@ static int net_page_pool_create(int cpuid)
 		.pool_size = SYSTEM_PERCPU_PAGE_POOL_SIZE,
 		.nid = NUMA_NO_NODE,
 	};
+	struct xdp_mem_info info;
 	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_mem_model(&info, MEM_TYPE_PAGE_POOL, pp_ptr);
+	if (err) {
+		page_pool_destroy(pp_ptr);
+		return err;
+	}
+
 	per_cpu(system_page_pool, cpuid) = pp_ptr;
 #endif
 	return 0;
@@ -11834,12 +11842,15 @@ static int __init net_dev_init(void)
 out:
 	if (rc < 0) {
 		for_each_possible_cpu(i) {
+			struct xdp_mem_info mem = { .type = MEM_TYPE_PAGE_POOL };
 			struct page_pool *pp_ptr;
 
 			pp_ptr = per_cpu(system_page_pool, i);
 			if (!pp_ptr)
 				continue;
 
+			mem.id = pp_ptr->xdp_mem_id;
+			xdp_unreg_mem_model(&mem);
 			page_pool_destroy(pp_ptr);
 			per_cpu(system_page_pool, i) = NULL;
 		}
-- 
2.43.0