net: page_pool: simplify page recycling condition tests

pool_page_reusable() is a leftover from pre-NUMA-aware times. For now,
this function is just a redundant wrapper over page_is_pfmemalloc(),
so inline it into its sole call site.
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/core/page_pool.c

@@ -350,14 +350,6 @@ static bool page_pool_recycle_in_cache(struct page *page,
 	return true;
 }
 
-/* page is NOT reusable when:
- * 1) allocated when system is under some pressure. (page_is_pfmemalloc)
- */
-static bool pool_page_reusable(struct page_pool *pool, struct page *page)
-{
-	return !page_is_pfmemalloc(page);
-}
-
 /* If the page refcnt == 1, this will try to recycle the page.
  * if PP_FLAG_DMA_SYNC_DEV is set, we'll try to sync the DMA area for
  * the configured size min(dma_sync_size, pool->max_len).
@@ -373,9 +365,11 @@ __page_pool_put_page(struct page_pool *pool, struct page *page,
 	 * regular page allocator APIs.
 	 *
 	 * refcnt == 1 means page_pool owns page, and can recycle it.
+	 *
+	 * page is NOT reusable when allocated when system is under
+	 * some pressure. (page_is_pfmemalloc)
 	 */
-	if (likely(page_ref_count(page) == 1 &&
-		   pool_page_reusable(pool, page))) {
+	if (likely(page_ref_count(page) == 1 && !page_is_pfmemalloc(page))) {
 		/* Read barrier done in page_ref_count / READ_ONCE */
 
 		if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)