[PATCH v7 05/15] net: page_pool: add ->scrub mem provider callback

[David Wei <dw@davidwei.uk>]

From: Pavel Begunkov <asml.silence@gmail.com>

Some page pool memory providers like io_uring need to catch the point
when the page pool is asked to be destroyed. ->destroy is not enough
because it relies on the page pool to wait for its buffers first, but
for that to happen a provider might need to react, e.g. to collect all
buffers that are currently given to the user space.

Add a new provider's scrub callback serving the purpose and called off
the pp's generic (cold) scrubbing path, i.e. page_pool_scrub().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: David Wei <dw@davidwei.uk>
---
 include/net/page_pool/types.h | 1 +
 net/core/page_pool.c          | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
index 8a35fe474adb..fd0376ad0d26 100644
--- a/include/net/page_pool/types.h
+++ b/include/net/page_pool/types.h
@@ -157,6 +157,7 @@ struct memory_provider_ops {
 	bool (*release_netmem)(struct page_pool *pool, netmem_ref netmem);
 	int (*init)(struct page_pool *pool);
 	void (*destroy)(struct page_pool *pool);
+	void (*scrub)(struct page_pool *pool);
 };
 
 struct pp_memory_provider_params {
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index c21c5b9edc68..9a675e16e6a4 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -1038,6 +1038,9 @@ static void page_pool_empty_alloc_cache_once(struct page_pool *pool)
 
 static void page_pool_scrub(struct page_pool *pool)
 {
+	if (pool->mp_ops && pool->mp_ops->scrub)
+		pool->mp_ops->scrub(pool);
+
 	page_pool_empty_alloc_cache_once(pool);
 	pool->destroy_cnt++;
 
-- 
2.43.5