Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 543 insertions, 0 deletions

diff --git a/net/core/page_pool.c b/net/core/page_pool.c
new file mode 100644
index 000000000..08fbf4049
--- /dev/null
+++ b/net/core/page_pool.c
@@ -0,0 +1,543 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * page_pool.c
+ *	Author:	Jesper Dangaard Brouer <netoptimizer@brouer.com>
+ *	Copyright (C) 2016 Red Hat, Inc.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+
+#include <net/page_pool.h>
+#include <linux/dma-direction.h>
+#include <linux/dma-mapping.h>
+#include <linux/page-flags.h>
+#include <linux/mm.h> /* for __put_page() */
+
+#include <trace/events/page_pool.h>
+
+#define DEFER_TIME (msecs_to_jiffies(1000))
+#define DEFER_WARN_INTERVAL (60 * HZ)
+
+static int page_pool_init(struct page_pool *pool,
+			  const struct page_pool_params *params)
+{
+	unsigned int ring_qsize = 1024; /* Default */
+
+	memcpy(&pool->p, params, sizeof(pool->p));
+
+	/* Validate only known flags were used */
+	if (pool->p.flags & ~(PP_FLAG_ALL))
+		return -EINVAL;
+
+	if (pool->p.pool_size)
+		ring_qsize = pool->p.pool_size;
+
+	/* Sanity limit mem that can be pinned down */
+	if (ring_qsize > 32768)
+		return -E2BIG;
+
+	/* DMA direction is either DMA_FROM_DEVICE or DMA_BIDIRECTIONAL.
+	 * DMA_BIDIRECTIONAL is for allowing page used for DMA sending,
+	 * which is the XDP_TX use-case.
+	 */
+	if (pool->p.flags & PP_FLAG_DMA_MAP) {
+		if ((pool->p.dma_dir != DMA_FROM_DEVICE) &&
+		    (pool->p.dma_dir != DMA_BIDIRECTIONAL))
+			return -EINVAL;
+	}
+
+	if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) {
+		/* In order to request DMA-sync-for-device the page
+		 * needs to be mapped
+		 */
+		if (!(pool->p.flags & PP_FLAG_DMA_MAP))
+			return -EINVAL;
+
+		if (!pool->p.max_len)
+			return -EINVAL;
+
+		/* pool->p.offset has to be set according to the address
+		 * offset used by the DMA engine to start copying rx data
+		 */
+	}
+
+	if (ptr_ring_init(&pool->ring, ring_qsize, GFP_KERNEL) < 0)
+		return -ENOMEM;
+
+	atomic_set(&pool->pages_state_release_cnt, 0);
+
+	/* Driver calling page_pool_create() also call page_pool_destroy() */
+	refcount_set(&pool->user_cnt, 1);
+
+	if (pool->p.flags & PP_FLAG_DMA_MAP)
+		get_device(pool->p.dev);
+
+	return 0;
+}
+
+struct page_pool *page_pool_create(const struct page_pool_params *params)
+{
+	struct page_pool *pool;
+	int err;
+
+	pool = kzalloc_node(sizeof(*pool), GFP_KERNEL, params->nid);
+	if (!pool)
+		return ERR_PTR(-ENOMEM);
+
+	err = page_pool_init(pool, params);
+	if (err < 0) {
+		pr_warn("%s() gave up with errno %d\n", __func__, err);
+		kfree(pool);
+		return ERR_PTR(err);
+	}
+
+	return pool;
+}
+EXPORT_SYMBOL(page_pool_create);
+
+static void page_pool_return_page(struct page_pool *pool, struct page *page);
+
+noinline
+static struct page *page_pool_refill_alloc_cache(struct page_pool *pool)
+{
+	struct ptr_ring *r = &pool->ring;
+	struct page *page;
+	int pref_nid; /* preferred NUMA node */
+
+	/* Quicker fallback, avoid locks when ring is empty */
+	if (__ptr_ring_empty(r))
+		return NULL;
+
+	/* Softirq guarantee CPU and thus NUMA node is stable. This,
+	 * assumes CPU refilling driver RX-ring will also run RX-NAPI.
+	 */
+#ifdef CONFIG_NUMA
+	pref_nid = (pool->p.nid == NUMA_NO_NODE) ? numa_mem_id() : pool->p.nid;
+#else
+	/* Ignore pool->p.nid setting if !CONFIG_NUMA, helps compiler */
+	pref_nid = numa_mem_id(); /* will be zero like page_to_nid() */
+#endif
+
+	/* Slower-path: Get pages from locked ring queue */
+	spin_lock(&r->consumer_lock);
+
+	/* Refill alloc array, but only if NUMA match */
+	do {
+		page = __ptr_ring_consume(r);
+		if (unlikely(!page))
+			break;
+
+		if (likely(page_to_nid(page) == pref_nid)) {
+			pool->alloc.cache[pool->alloc.count++] = page;
+		} else {
+			/* NUMA mismatch;
+			 * (1) release 1 page to page-allocator and
+			 * (2) break out to fallthrough to alloc_pages_node.
+			 * This limit stress on page buddy alloactor.
+			 */
+			page_pool_return_page(pool, page);
+			page = NULL;
+			break;
+		}
+	} while (pool->alloc.count < PP_ALLOC_CACHE_REFILL);
+
+	/* Return last page */
+	if (likely(pool->alloc.count > 0))
+		page = pool->alloc.cache[--pool->alloc.count];
+
+	spin_unlock(&r->consumer_lock);
+	return page;
+}
+
+/* fast path */
+static struct page *__page_pool_get_cached(struct page_pool *pool)
+{
+	struct page *page;
+
+	/* Caller MUST guarantee safe non-concurrent access, e.g. softirq */
+	if (likely(pool->alloc.count)) {
+		/* Fast-path */
+		page = pool->alloc.cache[--pool->alloc.count];
+	} else {
+		page = page_pool_refill_alloc_cache(pool);
+	}
+
+	return page;
+}
+
+static void page_pool_dma_sync_for_device(struct page_pool *pool,
+					  struct page *page,
+					  unsigned int dma_sync_size)
+{
+	dma_addr_t dma_addr = page_pool_get_dma_addr(page);
+
+	dma_sync_size = min(dma_sync_size, pool->p.max_len);
+	dma_sync_single_range_for_device(pool->p.dev, dma_addr,
+					 pool->p.offset, dma_sync_size,
+					 pool->p.dma_dir);
+}
+
+/* slow path */
+noinline
+static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool,
+						 gfp_t _gfp)
+{
+	struct page *page;
+	gfp_t gfp = _gfp;
+	dma_addr_t dma;
+
+	/* We could always set __GFP_COMP, and avoid this branch, as
+	 * prep_new_page() can handle order-0 with __GFP_COMP.
+	 */
+	if (pool->p.order)
+		gfp |= __GFP_COMP;
+
+	/* FUTURE development:
+	 *
+	 * Current slow-path essentially falls back to single page
+	 * allocations, which doesn't improve performance.  This code
+	 * need bulk allocation support from the page allocator code.
+	 */
+
+	/* Cache was empty, do real allocation */
+#ifdef CONFIG_NUMA
+	page = alloc_pages_node(pool->p.nid, gfp, pool->p.order);
+#else
+	page = alloc_pages(gfp, pool->p.order);
+#endif
+	if (!page)
+		return NULL;
+
+	if (!(pool->p.flags & PP_FLAG_DMA_MAP))
+		goto skip_dma_map;
+
+	/* Setup DMA mapping: use 'struct page' area for storing DMA-addr
+	 * since dma_addr_t can be either 32 or 64 bits and does not always fit
+	 * into page private data (i.e 32bit cpu with 64bit DMA caps)
+	 * This mapping is kept for lifetime of page, until leaving pool.
+	 */
+	dma = dma_map_page_attrs(pool->p.dev, page, 0,
+				 (PAGE_SIZE << pool->p.order),
+				 pool->p.dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
+	if (dma_mapping_error(pool->p.dev, dma)) {
+		put_page(page);
+		return NULL;
+	}
+	page_pool_set_dma_addr(page, dma);
+
+	if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
+		page_pool_dma_sync_for_device(pool, page, pool->p.max_len);
+
+skip_dma_map:
+	/* Track how many pages are held 'in-flight' */
+	pool->pages_state_hold_cnt++;
+
+	trace_page_pool_state_hold(pool, page, pool->pages_state_hold_cnt);
+
+	/* When page just alloc'ed is should/must have refcnt 1. */
+	return page;
+}
+
+/* For using page_pool replace: alloc_pages() API calls, but provide
+ * synchronization guarantee for allocation side.
+ */
+struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp)
+{
+	struct page *page;
+
+	/* Fast-path: Get a page from cache */
+	page = __page_pool_get_cached(pool);
+	if (page)
+		return page;
+
+	/* Slow-path: cache empty, do real allocation */
+	page = __page_pool_alloc_pages_slow(pool, gfp);
+	return page;
+}
+EXPORT_SYMBOL(page_pool_alloc_pages);
+
+/* Calculate distance between two u32 values, valid if distance is below 2^(31)
+ *  https://en.wikipedia.org/wiki/Serial_number_arithmetic#General_Solution
+ */
+#define _distance(a, b)	(s32)((a) - (b))
+
+static s32 page_pool_inflight(struct page_pool *pool)
+{
+	u32 release_cnt = atomic_read(&pool->pages_state_release_cnt);
+	u32 hold_cnt = READ_ONCE(pool->pages_state_hold_cnt);
+	s32 inflight;
+
+	inflight = _distance(hold_cnt, release_cnt);
+
+	trace_page_pool_release(pool, inflight, hold_cnt, release_cnt);
+	WARN(inflight < 0, "Negative(%d) inflight packet-pages", inflight);
+
+	return inflight;
+}
+
+/* Disconnects a page (from a page_pool).  API users can have a need
+ * to disconnect a page (from a page_pool), to allow it to be used as
+ * a regular page (that will eventually be returned to the normal
+ * page-allocator via put_page).
+ */
+void page_pool_release_page(struct page_pool *pool, struct page *page)
+{
+	dma_addr_t dma;
+	int count;
+
+	if (!(pool->p.flags & PP_FLAG_DMA_MAP))
+		/* Always account for inflight pages, even if we didn't
+		 * map them
+		 */
+		goto skip_dma_unmap;
+
+	dma = page_pool_get_dma_addr(page);
+
+	/* When page is unmapped, it cannot be returned to our pool */
+	dma_unmap_page_attrs(pool->p.dev, dma,
+			     PAGE_SIZE << pool->p.order, pool->p.dma_dir,
+			     DMA_ATTR_SKIP_CPU_SYNC);
+	page_pool_set_dma_addr(page, 0);
+skip_dma_unmap:
+	/* This may be the last page returned, releasing the pool, so
+	 * it is not safe to reference pool afterwards.
+	 */
+	count = atomic_inc_return(&pool->pages_state_release_cnt);
+	trace_page_pool_state_release(pool, page, count);
+}
+EXPORT_SYMBOL(page_pool_release_page);
+
+/* Return a page to the page allocator, cleaning up our state */
+static void page_pool_return_page(struct page_pool *pool, struct page *page)
+{
+	page_pool_release_page(pool, page);
+
+	put_page(page);
+	/* An optimization would be to call __free_pages(page, pool->p.order)
+	 * knowing page is not part of page-cache (thus avoiding a
+	 * __page_cache_release() call).
+	 */
+}
+
+static bool page_pool_recycle_in_ring(struct page_pool *pool, struct page *page)
+{
+	int ret;
+	/* BH protection not needed if current is serving softirq */
+	if (in_serving_softirq())
+		ret = ptr_ring_produce(&pool->ring, page);
+	else
+		ret = ptr_ring_produce_bh(&pool->ring, page);
+
+	return (ret == 0) ? true : false;
+}
+
+/* Only allow direct recycling in special circumstances, into the
+ * alloc side cache.  E.g. during RX-NAPI processing for XDP_DROP use-case.
+ *
+ * Caller must provide appropriate safe context.
+ */
+static bool page_pool_recycle_in_cache(struct page *page,
+				       struct page_pool *pool)
+{
+	if (unlikely(pool->alloc.count == PP_ALLOC_CACHE_SIZE))
+		return false;
+
+	/* Caller MUST have verified/know (page_ref_count(page) == 1) */
+	pool->alloc.cache[pool->alloc.count++] = 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).
+ * If the page refcnt != 1, then the page will be returned to memory
+ * subsystem.
+ */
+void page_pool_put_page(struct page_pool *pool, struct page *page,
+			unsigned int dma_sync_size, bool allow_direct)
+{
+	/* This allocator is optimized for the XDP mode that uses
+	 * one-frame-per-page, but have fallbacks that act like the
+	 * regular page allocator APIs.
+	 *
+	 * refcnt == 1 means page_pool owns page, and can recycle it.
+	 */
+	if (likely(page_ref_count(page) == 1 &&
+		   pool_page_reusable(pool, page))) {
+		/* Read barrier done in page_ref_count / READ_ONCE */
+
+		if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
+			page_pool_dma_sync_for_device(pool, page,
+						      dma_sync_size);
+
+		if (allow_direct && in_serving_softirq())
+			if (page_pool_recycle_in_cache(page, pool))
+				return;
+
+		if (!page_pool_recycle_in_ring(pool, page)) {
+			/* Cache full, fallback to free pages */
+			page_pool_return_page(pool, page);
+		}
+		return;
+	}
+	/* Fallback/non-XDP mode: API user have elevated refcnt.
+	 *
+	 * Many drivers split up the page into fragments, and some
+	 * want to keep doing this to save memory and do refcnt based
+	 * recycling. Support this use case too, to ease drivers
+	 * switching between XDP/non-XDP.
+	 *
+	 * In-case page_pool maintains the DMA mapping, API user must
+	 * call page_pool_put_page once.  In this elevated refcnt
+	 * case, the DMA is unmapped/released, as driver is likely
+	 * doing refcnt based recycle tricks, meaning another process
+	 * will be invoking put_page.
+	 */
+	/* Do not replace this with page_pool_return_page() */
+	page_pool_release_page(pool, page);
+	put_page(page);
+}
+EXPORT_SYMBOL(page_pool_put_page);
+
+static void page_pool_empty_ring(struct page_pool *pool)
+{
+	struct page *page;
+
+	/* Empty recycle ring */
+	while ((page = ptr_ring_consume_bh(&pool->ring))) {
+		/* Verify the refcnt invariant of cached pages */
+		if (!(page_ref_count(page) == 1))
+			pr_crit("%s() page_pool refcnt %d violation\n",
+				__func__, page_ref_count(page));
+
+		page_pool_return_page(pool, page);
+	}
+}
+
+static void page_pool_free(struct page_pool *pool)
+{
+	if (pool->disconnect)
+		pool->disconnect(pool);
+
+	ptr_ring_cleanup(&pool->ring, NULL);
+
+	if (pool->p.flags & PP_FLAG_DMA_MAP)
+		put_device(pool->p.dev);
+
+	kfree(pool);
+}
+
+static void page_pool_empty_alloc_cache_once(struct page_pool *pool)
+{
+	struct page *page;
+
+	if (pool->destroy_cnt)
+		return;
+
+	/* Empty alloc cache, assume caller made sure this is
+	 * no-longer in use, and page_pool_alloc_pages() cannot be
+	 * call concurrently.
+	 */
+	while (pool->alloc.count) {
+		page = pool->alloc.cache[--pool->alloc.count];
+		page_pool_return_page(pool, page);
+	}
+}
+
+static void page_pool_scrub(struct page_pool *pool)
+{
+	page_pool_empty_alloc_cache_once(pool);
+	pool->destroy_cnt++;
+
+	/* No more consumers should exist, but producers could still
+	 * be in-flight.
+	 */
+	page_pool_empty_ring(pool);
+}
+
+static int page_pool_release(struct page_pool *pool)
+{
+	int inflight;
+
+	page_pool_scrub(pool);
+	inflight = page_pool_inflight(pool);
+	if (!inflight)
+		page_pool_free(pool);
+
+	return inflight;
+}
+
+static void page_pool_release_retry(struct work_struct *wq)
+{
+	struct delayed_work *dwq = to_delayed_work(wq);
+	struct page_pool *pool = container_of(dwq, typeof(*pool), release_dw);
+	int inflight;
+
+	inflight = page_pool_release(pool);
+	if (!inflight)
+		return;
+
+	/* Periodic warning */
+	if (time_after_eq(jiffies, pool->defer_warn)) {
+		int sec = (s32)((u32)jiffies - (u32)pool->defer_start) / HZ;
+
+		pr_warn("%s() stalled pool shutdown %d inflight %d sec\n",
+			__func__, inflight, sec);
+		pool->defer_warn = jiffies + DEFER_WARN_INTERVAL;
+	}
+
+	/* Still not ready to be disconnected, retry later */
+	schedule_delayed_work(&pool->release_dw, DEFER_TIME);
+}
+
+void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *))
+{
+	refcount_inc(&pool->user_cnt);
+	pool->disconnect = disconnect;
+}
+
+void page_pool_destroy(struct page_pool *pool)
+{
+	if (!pool)
+		return;
+
+	if (!page_pool_put(pool))
+		return;
+
+	if (!page_pool_release(pool))
+		return;
+
+	pool->defer_start = jiffies;
+	pool->defer_warn  = jiffies + DEFER_WARN_INTERVAL;
+
+	INIT_DELAYED_WORK(&pool->release_dw, page_pool_release_retry);
+	schedule_delayed_work(&pool->release_dw, DEFER_TIME);
+}
+EXPORT_SYMBOL(page_pool_destroy);
+
+/* Caller must provide appropriate safe context, e.g. NAPI. */
+void page_pool_update_nid(struct page_pool *pool, int new_nid)
+{
+	struct page *page;
+
+	trace_page_pool_update_nid(pool, new_nid);
+	pool->p.nid = new_nid;
+
+	/* Flush pool alloc cache, as refill will check NUMA node */
+	while (pool->alloc.count) {
+		page = pool->alloc.cache[--pool->alloc.count];
+		page_pool_return_page(pool, page);
+	}
+}
+EXPORT_SYMBOL(page_pool_update_nid);