include/net/page_pool.h

1 /* SPDX-License-Identifier: GPL-2.0
12  * uses one-frame-per-page, but have fallbacks that act like the
19  * API keeps track of in-flight pages, in-order to let API user know
20  * when it is safe to dealloactor page_pool object.  Thus, API users
27  * will release the DMA mapping and in-flight state accounting.  We
35 #include <linux/dma-direction.h>
37 #define PP_FLAG_DMA_MAP		BIT(0) /* Should page_pool do the DMA
38 					* map/unmap
42 					* DMA-synced-for-device according to
45 					* Please note DMA-sync-for-CPU is still
54  * use-case.  The NAPI budget is 64 packets.  After a NAPI poll the RX
58  * Keeping room for more objects, is due to XDP_DROP use-case.  As
76 	struct device	*dev; /* device, for DMA pre-mapping purposes */
77 	enum dma_data_direction dma_dir; /* DMA mapping direction */
78 	unsigned int	max_len; /* max DMA sync memory size */
79 	unsigned int	offset;  /* DMA addr offset */
100 	 * RX-queue. As the RX-queue is already protected by
114 	 * effeciently, it a way that doesn't bounce cache-lines.
122 	/* A page_pool is strictly tied to a single RX-queue being
140 /* get the stored dma direction. A driver might decide to treat this locally and
146 	return pool->p.dma_dir;  in page_pool_get_dma_dir()
173 /* Same as above but will try to sync the entire area pool->max_len */
177 	/* When page_pool isn't compiled-in, net/core/xdp.c doesn't  in page_pool_put_full_page()
181 	page_pool_put_page(pool, page, -1, allow_direct);  in page_pool_put_full_page()
185 /* Same as above but the caller must guarantee safe context. e.g NAPI */
194 	return page->dma_addr;  in page_pool_get_dma_addr()
208 	return refcount_dec_and_test(&pool->user_cnt);  in page_pool_put()
211 /* Caller must provide appropriate safe context, e.g. NAPI. */
215 	if (unlikely(pool->p.nid != new_nid))  in page_pool_nid_changed()