Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 904 insertions, 0 deletions

diff --git a/net/core/page_pool.c b/net/core/page_pool.c
new file mode 100644
index 000000000..193c18799
--- /dev/null
+++ b/net/core/page_pool.c
@@ -0,0 +1,904 @@
+/* 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 <net/xdp.h>
+
+#include <linux/dma-direction.h>
+#include <linux/dma-mapping.h>
+#include <linux/page-flags.h>
+#include <linux/mm.h> /* for put_page() */
+#include <linux/poison.h>
+#include <linux/ethtool.h>
+
+#include <trace/events/page_pool.h>
+
+#define DEFER_TIME (msecs_to_jiffies(1000))
+#define DEFER_WARN_INTERVAL (60 * HZ)
+
+#define BIAS_MAX	LONG_MAX
+
+#ifdef CONFIG_PAGE_POOL_STATS
+/* alloc_stat_inc is intended to be used in softirq context */
+#define alloc_stat_inc(pool, __stat)	(pool->alloc_stats.__stat++)
+/* recycle_stat_inc is safe to use when preemption is possible. */
+#define recycle_stat_inc(pool, __stat)							\
+	do {										\
+		struct page_pool_recycle_stats __percpu *s = pool->recycle_stats;	\
+		this_cpu_inc(s->__stat);						\
+	} while (0)
+
+#define recycle_stat_add(pool, __stat, val)						\
+	do {										\
+		struct page_pool_recycle_stats __percpu *s = pool->recycle_stats;	\
+		this_cpu_add(s->__stat, val);						\
+	} while (0)
+
+static const char pp_stats[][ETH_GSTRING_LEN] = {
+	"rx_pp_alloc_fast",
+	"rx_pp_alloc_slow",
+	"rx_pp_alloc_slow_ho",
+	"rx_pp_alloc_empty",
+	"rx_pp_alloc_refill",
+	"rx_pp_alloc_waive",
+	"rx_pp_recycle_cached",
+	"rx_pp_recycle_cache_full",
+	"rx_pp_recycle_ring",
+	"rx_pp_recycle_ring_full",
+	"rx_pp_recycle_released_ref",
+};
+
+bool page_pool_get_stats(struct page_pool *pool,
+			 struct page_pool_stats *stats)
+{
+	int cpu = 0;
+
+	if (!stats)
+		return false;
+
+	/* The caller is responsible to initialize stats. */
+	stats->alloc_stats.fast += pool->alloc_stats.fast;
+	stats->alloc_stats.slow += pool->alloc_stats.slow;
+	stats->alloc_stats.slow_high_order += pool->alloc_stats.slow_high_order;
+	stats->alloc_stats.empty += pool->alloc_stats.empty;
+	stats->alloc_stats.refill += pool->alloc_stats.refill;
+	stats->alloc_stats.waive += pool->alloc_stats.waive;
+
+	for_each_possible_cpu(cpu) {
+		const struct page_pool_recycle_stats *pcpu =
+			per_cpu_ptr(pool->recycle_stats, cpu);
+
+		stats->recycle_stats.cached += pcpu->cached;
+		stats->recycle_stats.cache_full += pcpu->cache_full;
+		stats->recycle_stats.ring += pcpu->ring;
+		stats->recycle_stats.ring_full += pcpu->ring_full;
+		stats->recycle_stats.released_refcnt += pcpu->released_refcnt;
+	}
+
+	return true;
+}
+EXPORT_SYMBOL(page_pool_get_stats);
+
+u8 *page_pool_ethtool_stats_get_strings(u8 *data)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(pp_stats); i++) {
+		memcpy(data, pp_stats[i], ETH_GSTRING_LEN);
+		data += ETH_GSTRING_LEN;
+	}
+
+	return data;
+}
+EXPORT_SYMBOL(page_pool_ethtool_stats_get_strings);
+
+int page_pool_ethtool_stats_get_count(void)
+{
+	return ARRAY_SIZE(pp_stats);
+}
+EXPORT_SYMBOL(page_pool_ethtool_stats_get_count);
+
+u64 *page_pool_ethtool_stats_get(u64 *data, void *stats)
+{
+	struct page_pool_stats *pool_stats = stats;
+
+	*data++ = pool_stats->alloc_stats.fast;
+	*data++ = pool_stats->alloc_stats.slow;
+	*data++ = pool_stats->alloc_stats.slow_high_order;
+	*data++ = pool_stats->alloc_stats.empty;
+	*data++ = pool_stats->alloc_stats.refill;
+	*data++ = pool_stats->alloc_stats.waive;
+	*data++ = pool_stats->recycle_stats.cached;
+	*data++ = pool_stats->recycle_stats.cache_full;
+	*data++ = pool_stats->recycle_stats.ring;
+	*data++ = pool_stats->recycle_stats.ring_full;
+	*data++ = pool_stats->recycle_stats.released_refcnt;
+
+	return data;
+}
+EXPORT_SYMBOL(page_pool_ethtool_stats_get);
+
+#else
+#define alloc_stat_inc(pool, __stat)
+#define recycle_stat_inc(pool, __stat)
+#define recycle_stat_add(pool, __stat, val)
+#endif
+
+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 (PAGE_POOL_DMA_USE_PP_FRAG_COUNT &&
+	    pool->p.flags & PP_FLAG_PAGE_FRAG)
+		return -EINVAL;
+
+#ifdef CONFIG_PAGE_POOL_STATS
+	pool->recycle_stats = alloc_percpu(struct page_pool_recycle_stats);
+	if (!pool->recycle_stats)
+		return -ENOMEM;
+#endif
+
+	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)) {
+		alloc_stat_inc(pool, empty);
+		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
+
+	/* 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);
+			alloc_stat_inc(pool, waive);
+			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];
+		alloc_stat_inc(pool, refill);
+	}
+
+	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];
+		alloc_stat_inc(pool, fast);
+	} 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);
+}
+
+static bool page_pool_dma_map(struct page_pool *pool, struct page *page)
+{
+	dma_addr_t dma;
+
+	/* 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))
+		return false;
+
+	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);
+
+	return true;
+}
+
+static void page_pool_set_pp_info(struct page_pool *pool,
+				  struct page *page)
+{
+	page->pp = pool;
+	page->pp_magic |= PP_SIGNATURE;
+	if (pool->p.init_callback)
+		pool->p.init_callback(page, pool->p.init_arg);
+}
+
+static void page_pool_clear_pp_info(struct page *page)
+{
+	page->pp_magic = 0;
+	page->pp = NULL;
+}
+
+static struct page *__page_pool_alloc_page_order(struct page_pool *pool,
+						 gfp_t gfp)
+{
+	struct page *page;
+
+	gfp |= __GFP_COMP;
+	page = alloc_pages_node(pool->p.nid, gfp, pool->p.order);
+	if (unlikely(!page))
+		return NULL;
+
+	if ((pool->p.flags & PP_FLAG_DMA_MAP) &&
+	    unlikely(!page_pool_dma_map(pool, page))) {
+		put_page(page);
+		return NULL;
+	}
+
+	alloc_stat_inc(pool, slow_high_order);
+	page_pool_set_pp_info(pool, page);
+
+	/* 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);
+	return page;
+}
+
+/* slow path */
+noinline
+static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool,
+						 gfp_t gfp)
+{
+	const int bulk = PP_ALLOC_CACHE_REFILL;
+	unsigned int pp_flags = pool->p.flags;
+	unsigned int pp_order = pool->p.order;
+	struct page *page;
+	int i, nr_pages;
+
+	/* Don't support bulk alloc for high-order pages */
+	if (unlikely(pp_order))
+		return __page_pool_alloc_page_order(pool, gfp);
+
+	/* Unnecessary as alloc cache is empty, but guarantees zero count */
+	if (unlikely(pool->alloc.count > 0))
+		return pool->alloc.cache[--pool->alloc.count];
+
+	/* Mark empty alloc.cache slots "empty" for alloc_pages_bulk_array */
+	memset(&pool->alloc.cache, 0, sizeof(void *) * bulk);
+
+	nr_pages = alloc_pages_bulk_array_node(gfp, pool->p.nid, bulk,
+					       pool->alloc.cache);
+	if (unlikely(!nr_pages))
+		return NULL;
+
+	/* Pages have been filled into alloc.cache array, but count is zero and
+	 * page element have not been (possibly) DMA mapped.
+	 */
+	for (i = 0; i < nr_pages; i++) {
+		page = pool->alloc.cache[i];
+		if ((pp_flags & PP_FLAG_DMA_MAP) &&
+		    unlikely(!page_pool_dma_map(pool, page))) {
+			put_page(page);
+			continue;
+		}
+
+		page_pool_set_pp_info(pool, page);
+		pool->alloc.cache[pool->alloc.count++] = page;
+		/* 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);
+	}
+
+	/* Return last page */
+	if (likely(pool->alloc.count > 0)) {
+		page = pool->alloc.cache[--pool->alloc.count];
+		alloc_stat_inc(pool, slow);
+	} else {
+		page = NULL;
+	}
+
+	/* 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:
+	page_pool_clear_pp_info(page);
+
+	/* This may be the last page returned, releasing the pool, so
+	 * it is not safe to reference pool afterwards.
+	 */
+	count = atomic_inc_return_relaxed(&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 softirq */
+	if (in_softirq())
+		ret = ptr_ring_produce(&pool->ring, page);
+	else
+		ret = ptr_ring_produce_bh(&pool->ring, page);
+
+	if (!ret) {
+		recycle_stat_inc(pool, ring);
+		return true;
+	}
+
+	return 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)) {
+		recycle_stat_inc(pool, cache_full);
+		return false;
+	}
+
+	/* Caller MUST have verified/know (page_ref_count(page) == 1) */
+	pool->alloc.cache[pool->alloc.count++] = page;
+	recycle_stat_inc(pool, cached);
+	return true;
+}
+
+/* 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.
+ */
+static __always_inline struct page *
+__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.
+	 *
+	 * page is NOT reusable when allocated when system is under
+	 * some pressure. (page_is_pfmemalloc)
+	 */
+	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)
+			page_pool_dma_sync_for_device(pool, page,
+						      dma_sync_size);
+
+		if (allow_direct && in_softirq() &&
+		    page_pool_recycle_in_cache(page, pool))
+			return NULL;
+
+		/* Page found as candidate for recycling */
+		return page;
+	}
+	/* 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.
+	 */
+	recycle_stat_inc(pool, released_refcnt);
+	/* Do not replace this with page_pool_return_page() */
+	page_pool_release_page(pool, page);
+	put_page(page);
+
+	return NULL;
+}
+
+void page_pool_put_defragged_page(struct page_pool *pool, struct page *page,
+				  unsigned int dma_sync_size, bool allow_direct)
+{
+	page = __page_pool_put_page(pool, page, dma_sync_size, allow_direct);
+	if (page && !page_pool_recycle_in_ring(pool, page)) {
+		/* Cache full, fallback to free pages */
+		recycle_stat_inc(pool, ring_full);
+		page_pool_return_page(pool, page);
+	}
+}
+EXPORT_SYMBOL(page_pool_put_defragged_page);
+
+/* Caller must not use data area after call, as this function overwrites it */
+void page_pool_put_page_bulk(struct page_pool *pool, void **data,
+			     int count)
+{
+	int i, bulk_len = 0;
+
+	for (i = 0; i < count; i++) {
+		struct page *page = virt_to_head_page(data[i]);
+
+		/* It is not the last user for the page frag case */
+		if (!page_pool_is_last_frag(pool, page))
+			continue;
+
+		page = __page_pool_put_page(pool, page, -1, false);
+		/* Approved for bulk recycling in ptr_ring cache */
+		if (page)
+			data[bulk_len++] = page;
+	}
+
+	if (unlikely(!bulk_len))
+		return;
+
+	/* Bulk producer into ptr_ring page_pool cache */
+	page_pool_ring_lock(pool);
+	for (i = 0; i < bulk_len; i++) {
+		if (__ptr_ring_produce(&pool->ring, data[i])) {
+			/* ring full */
+			recycle_stat_inc(pool, ring_full);
+			break;
+		}
+	}
+	recycle_stat_add(pool, ring, i);
+	page_pool_ring_unlock(pool);
+
+	/* Hopefully all pages was return into ptr_ring */
+	if (likely(i == bulk_len))
+		return;
+
+	/* ptr_ring cache full, free remaining pages outside producer lock
+	 * since put_page() with refcnt == 1 can be an expensive operation
+	 */
+	for (; i < bulk_len; i++)
+		page_pool_return_page(pool, data[i]);
+}
+EXPORT_SYMBOL(page_pool_put_page_bulk);
+
+static struct page *page_pool_drain_frag(struct page_pool *pool,
+					 struct page *page)
+{
+	long drain_count = BIAS_MAX - pool->frag_users;
+
+	/* Some user is still using the page frag */
+	if (likely(page_pool_defrag_page(page, drain_count)))
+		return NULL;
+
+	if (page_ref_count(page) == 1 && !page_is_pfmemalloc(page)) {
+		if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
+			page_pool_dma_sync_for_device(pool, page, -1);
+
+		return page;
+	}
+
+	page_pool_return_page(pool, page);
+	return NULL;
+}
+
+static void page_pool_free_frag(struct page_pool *pool)
+{
+	long drain_count = BIAS_MAX - pool->frag_users;
+	struct page *page = pool->frag_page;
+
+	pool->frag_page = NULL;
+
+	if (!page || page_pool_defrag_page(page, drain_count))
+		return;
+
+	page_pool_return_page(pool, page);
+}
+
+struct page *page_pool_alloc_frag(struct page_pool *pool,
+				  unsigned int *offset,
+				  unsigned int size, gfp_t gfp)
+{
+	unsigned int max_size = PAGE_SIZE << pool->p.order;
+	struct page *page = pool->frag_page;
+
+	if (WARN_ON(!(pool->p.flags & PP_FLAG_PAGE_FRAG) ||
+		    size > max_size))
+		return NULL;
+
+	size = ALIGN(size, dma_get_cache_alignment());
+	*offset = pool->frag_offset;
+
+	if (page && *offset + size > max_size) {
+		page = page_pool_drain_frag(pool, page);
+		if (page) {
+			alloc_stat_inc(pool, fast);
+			goto frag_reset;
+		}
+	}
+
+	if (!page) {
+		page = page_pool_alloc_pages(pool, gfp);
+		if (unlikely(!page)) {
+			pool->frag_page = NULL;
+			return NULL;
+		}
+
+		pool->frag_page = page;
+
+frag_reset:
+		pool->frag_users = 1;
+		*offset = 0;
+		pool->frag_offset = size;
+		page_pool_fragment_page(page, BIAS_MAX);
+		return page;
+	}
+
+	pool->frag_users++;
+	pool->frag_offset = *offset + size;
+	alloc_stat_inc(pool, fast);
+	return page;
+}
+EXPORT_SYMBOL(page_pool_alloc_frag);
+
+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);
+
+#ifdef CONFIG_PAGE_POOL_STATS
+	free_percpu(pool->recycle_stats);
+#endif
+	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 *),
+			   struct xdp_mem_info *mem)
+{
+	refcount_inc(&pool->user_cnt);
+	pool->disconnect = disconnect;
+	pool->xdp_mem_id = mem->id;
+}
+
+void page_pool_destroy(struct page_pool *pool)
+{
+	if (!pool)
+		return;
+
+	if (!page_pool_put(pool))
+		return;
+
+	page_pool_free_frag(pool);
+
+	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);
+
+bool page_pool_return_skb_page(struct page *page)
+{
+	struct page_pool *pp;
+
+	page = compound_head(page);
+
+	/* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation
+	 * in order to preserve any existing bits, such as bit 0 for the
+	 * head page of compound page and bit 1 for pfmemalloc page, so
+	 * mask those bits for freeing side when doing below checking,
+	 * and page_is_pfmemalloc() is checked in __page_pool_put_page()
+	 * to avoid recycling the pfmemalloc page.
+	 */
+	if (unlikely((page->pp_magic & ~0x3UL) != PP_SIGNATURE))
+		return false;
+
+	pp = page->pp;
+
+	/* Driver set this to memory recycling info. Reset it on recycle.
+	 * This will *not* work for NIC using a split-page memory model.
+	 * The page will be returned to the pool here regardless of the
+	 * 'flipped' fragment being in use or not.
+	 */
+	page_pool_put_full_page(pp, page, false);
+
+	return true;
+}
+EXPORT_SYMBOL(page_pool_return_skb_page);