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

Alexander Lobakin
2024-10-15T14:54:44Z

From: Toke Høiland-Jørgensen <toke@redhat.com>

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@redhat.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
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