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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /include/net/page_pool/helpers.h | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'include/net/page_pool/helpers.h')
-rw-r--r-- | include/net/page_pool/helpers.h | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/include/net/page_pool/helpers.h b/include/net/page_pool/helpers.h new file mode 100644 index 0000000000..8e7751464f --- /dev/null +++ b/include/net/page_pool/helpers.h @@ -0,0 +1,238 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * page_pool/helpers.h + * Author: Jesper Dangaard Brouer <netoptimizer@brouer.com> + * Copyright (C) 2016 Red Hat, Inc. + */ + +/** + * DOC: page_pool allocator + * + * The page_pool allocator is optimized for the XDP mode that + * uses one frame per-page, but it can fallback on the + * regular page allocator APIs. + * + * Basic use involves replacing alloc_pages() calls with the + * page_pool_alloc_pages() call. Drivers should use + * page_pool_dev_alloc_pages() replacing dev_alloc_pages(). + * + * The API keeps track of in-flight pages, in order to let API users know + * when it is safe to free a page_pool object. Thus, API users + * must call page_pool_put_page() to free the page, or attach + * the page to a page_pool-aware object like skbs marked with + * skb_mark_for_recycle(). + * + * API users must call page_pool_put_page() once on a page, as it + * will either recycle the page, or in case of refcnt > 1, it will + * release the DMA mapping and in-flight state accounting. + */ +#ifndef _NET_PAGE_POOL_HELPERS_H +#define _NET_PAGE_POOL_HELPERS_H + +#include <net/page_pool/types.h> + +#ifdef CONFIG_PAGE_POOL_STATS +int page_pool_ethtool_stats_get_count(void); +u8 *page_pool_ethtool_stats_get_strings(u8 *data); +u64 *page_pool_ethtool_stats_get(u64 *data, void *stats); + +/* + * Drivers that wish to harvest page pool stats and report them to users + * (perhaps via ethtool, debugfs, or another mechanism) can allocate a + * struct page_pool_stats call page_pool_get_stats to get stats for the specified pool. + */ +bool page_pool_get_stats(struct page_pool *pool, + struct page_pool_stats *stats); +#else +static inline int page_pool_ethtool_stats_get_count(void) +{ + return 0; +} + +static inline u8 *page_pool_ethtool_stats_get_strings(u8 *data) +{ + return data; +} + +static inline u64 *page_pool_ethtool_stats_get(u64 *data, void *stats) +{ + return data; +} +#endif + +/** + * page_pool_dev_alloc_pages() - allocate a page. + * @pool: pool from which to allocate + * + * Get a page from the page allocator or page_pool caches. + */ +static inline struct page *page_pool_dev_alloc_pages(struct page_pool *pool) +{ + gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN); + + return page_pool_alloc_pages(pool, gfp); +} + +static inline struct page *page_pool_dev_alloc_frag(struct page_pool *pool, + unsigned int *offset, + unsigned int size) +{ + gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN); + + return page_pool_alloc_frag(pool, offset, size, gfp); +} + +/** + * page_pool_get_dma_dir() - Retrieve the stored DMA direction. + * @pool: pool from which page was allocated + * + * Get the stored dma direction. A driver might decide to store this locally + * and avoid the extra cache line from page_pool to determine the direction. + */ +static +inline enum dma_data_direction page_pool_get_dma_dir(struct page_pool *pool) +{ + return pool->p.dma_dir; +} + +/* pp_frag_count represents the number of writers who can update the page + * either by updating skb->data or via DMA mappings for the device. + * We can't rely on the page refcnt for that as we don't know who might be + * holding page references and we can't reliably destroy or sync DMA mappings + * of the fragments. + * + * When pp_frag_count reaches 0 we can either recycle the page if the page + * refcnt is 1 or return it back to the memory allocator and destroy any + * mappings we have. + */ +static inline void page_pool_fragment_page(struct page *page, long nr) +{ + atomic_long_set(&page->pp_frag_count, nr); +} + +static inline long page_pool_defrag_page(struct page *page, long nr) +{ + long ret; + + /* If nr == pp_frag_count then we have cleared all remaining + * references to the page. No need to actually overwrite it, instead + * we can leave this to be overwritten by the calling function. + * + * The main advantage to doing this is that an atomic_read is + * generally a much cheaper operation than an atomic update, + * especially when dealing with a page that may be partitioned + * into only 2 or 3 pieces. + */ + if (atomic_long_read(&page->pp_frag_count) == nr) + return 0; + + ret = atomic_long_sub_return(nr, &page->pp_frag_count); + WARN_ON(ret < 0); + return ret; +} + +static inline bool page_pool_is_last_frag(struct page_pool *pool, + struct page *page) +{ + /* If fragments aren't enabled or count is 0 we were the last user */ + return !(pool->p.flags & PP_FLAG_PAGE_FRAG) || + (page_pool_defrag_page(page, 1) == 0); +} + +/** + * page_pool_put_page() - release a reference to a page pool page + * @pool: pool from which page was allocated + * @page: page to release a reference on + * @dma_sync_size: how much of the page may have been touched by the device + * @allow_direct: released by the consumer, allow lockless caching + * + * The outcome of this depends on the page refcnt. If the driver bumps + * the refcnt > 1 this will unmap the page. If the page refcnt is 1 + * the allocator owns the page and will try to recycle it in one of the pool + * caches. If PP_FLAG_DMA_SYNC_DEV is set, the page will be synced for_device + * using dma_sync_single_range_for_device(). + */ +static inline void page_pool_put_page(struct page_pool *pool, + struct page *page, + unsigned int dma_sync_size, + bool allow_direct) +{ + /* When page_pool isn't compiled-in, net/core/xdp.c doesn't + * allow registering MEM_TYPE_PAGE_POOL, but shield linker. + */ +#ifdef CONFIG_PAGE_POOL + if (!page_pool_is_last_frag(pool, page)) + return; + + page_pool_put_defragged_page(pool, page, dma_sync_size, allow_direct); +#endif +} + +/** + * page_pool_put_full_page() - release a reference on a page pool page + * @pool: pool from which page was allocated + * @page: page to release a reference on + * @allow_direct: released by the consumer, allow lockless caching + * + * Similar to page_pool_put_page(), but will DMA sync the entire memory area + * as configured in &page_pool_params.max_len. + */ +static inline void page_pool_put_full_page(struct page_pool *pool, + struct page *page, bool allow_direct) +{ + page_pool_put_page(pool, page, -1, allow_direct); +} + +/** + * page_pool_recycle_direct() - release a reference on a page pool page + * @pool: pool from which page was allocated + * @page: page to release a reference on + * + * Similar to page_pool_put_full_page() but caller must guarantee safe context + * (e.g NAPI), since it will recycle the page directly into the pool fast cache. + */ +static inline void page_pool_recycle_direct(struct page_pool *pool, + struct page *page) +{ + page_pool_put_full_page(pool, page, true); +} + +#define PAGE_POOL_DMA_USE_PP_FRAG_COUNT \ + (sizeof(dma_addr_t) > sizeof(unsigned long)) + +/** + * page_pool_get_dma_addr() - Retrieve the stored DMA address. + * @page: page allocated from a page pool + * + * Fetch the DMA address of the page. The page pool to which the page belongs + * must had been created with PP_FLAG_DMA_MAP. + */ +static inline dma_addr_t page_pool_get_dma_addr(struct page *page) +{ + dma_addr_t ret = page->dma_addr; + + if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT) + ret |= (dma_addr_t)page->dma_addr_upper << 16 << 16; + + return ret; +} + +static inline void page_pool_set_dma_addr(struct page *page, dma_addr_t addr) +{ + page->dma_addr = addr; + if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT) + page->dma_addr_upper = upper_32_bits(addr); +} + +static inline bool page_pool_put(struct page_pool *pool) +{ + return refcount_dec_and_test(&pool->user_cnt); +} + +static inline void page_pool_nid_changed(struct page_pool *pool, int new_nid) +{ + if (unlikely(pool->p.nid != new_nid)) + page_pool_update_nid(pool, new_nid); +} + +#endif /* _NET_PAGE_POOL_HELPERS_H */ |