Merge branch 'page_pool-bnxt_en-unlink-old-page-pool-in-queue-api-using-helper'

David Wei says:

====================
page_pool: bnxt_en: unlink old page pool in queue api using helper

56ef27e3 unexported page_pool_unlink_napi() and renamed it to
page_pool_disable_direct_recycling(). This is because there was no
in-tree user of page_pool_unlink_napi().

Since then Rx queue API and an implementation in bnxt got merged. In the
bnxt implementation, it broadly follows the following steps: allocate
new queue memory + page pool, stop old rx queue, swap, then destroy old
queue memory + page pool.

The existing NAPI instance is re-used so when the old page pool that is
no longer used but still linked to this shared NAPI instance is
destroyed, it will trigger warnings.

In my initial patches I unlinked a page pool from a NAPI instance
directly. Instead, export page_pool_disable_direct_recycling() and call
that instead to avoid having a driver touch a core struct.
====================

Link: https://patch.msgid.link/20240627030200.3647145-1-dw@davidwei.ukSigned-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -15081,11 +15081,6 @@ static void bnxt_queue_mem_free(struct net_device *dev, void *qmem)
 	bnxt_free_one_rx_ring(bp, rxr);
 	bnxt_free_one_rx_agg_ring(bp, rxr);
 
-	/* At this point, this NAPI instance has another page pool associated
-	 * with it. Disconnect here before freeing the old page pool to avoid
-	 * warnings.
-	 */
-	rxr->page_pool->p.napi = NULL;
 	page_pool_destroy(rxr->page_pool);
 	rxr->page_pool = NULL;
 
@@ -15205,6 +15200,7 @@ static int bnxt_queue_stop(struct net_device *dev, void *qmem, int idx)
 	bnxt_hwrm_rx_ring_free(bp, rxr, false);
 	bnxt_hwrm_rx_agg_ring_free(bp, rxr, false);
 	rxr->rx_next_cons = 0;
+	page_pool_disable_direct_recycling(rxr->page_pool);
 
 	memcpy(qmem, rxr, sizeof(*rxr));
 	bnxt_init_rx_ring_struct(bp, qmem);

include/net/page_pool/types.h

@@ -229,6 +229,7 @@ struct page_pool *page_pool_create_percpu(const struct page_pool_params *params,
 struct xdp_mem_info;
 
 #ifdef CONFIG_PAGE_POOL
+void page_pool_disable_direct_recycling(struct page_pool *pool);
 void page_pool_destroy(struct page_pool *pool);
 void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *),
 			   const struct xdp_mem_info *mem);

net/core/page_pool.c

@@ -1014,7 +1014,7 @@ void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *),
 	pool->xdp_mem_id = mem->id;
 }
 
-static void page_pool_disable_direct_recycling(struct page_pool *pool)
+void page_pool_disable_direct_recycling(struct page_pool *pool)
 {
 	/* Disable direct recycling based on pool->cpuid.
 	 * Paired with READ_ONCE() in page_pool_napi_local().
@@ -1032,6 +1032,7 @@ static void page_pool_disable_direct_recycling(struct page_pool *pool)
 
 	WRITE_ONCE(pool->p.napi, NULL);
 }
+EXPORT_SYMBOL(page_pool_disable_direct_recycling);
 
 void page_pool_destroy(struct page_pool *pool)
 {