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, 602 insertions, 0 deletions

diff --git a/fs/pnode.c b/fs/pnode.c
new file mode 100644
index 000000000..468e4e65a
--- /dev/null
+++ b/fs/pnode.c
@@ -0,0 +1,602 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/fs/pnode.c
+ *
+ * (C) Copyright IBM Corporation 2005.
+ *	Author : Ram Pai (linuxram@us.ibm.com)
+ */
+#include <linux/mnt_namespace.h>
+#include <linux/mount.h>
+#include <linux/fs.h>
+#include <linux/nsproxy.h>
+#include <uapi/linux/mount.h>
+#include "internal.h"
+#include "pnode.h"
+
+/* return the next shared peer mount of @p */
+static inline struct mount *next_peer(struct mount *p)
+{
+	return list_entry(p->mnt_share.next, struct mount, mnt_share);
+}
+
+static inline struct mount *first_slave(struct mount *p)
+{
+	return list_entry(p->mnt_slave_list.next, struct mount, mnt_slave);
+}
+
+static inline struct mount *last_slave(struct mount *p)
+{
+	return list_entry(p->mnt_slave_list.prev, struct mount, mnt_slave);
+}
+
+static inline struct mount *next_slave(struct mount *p)
+{
+	return list_entry(p->mnt_slave.next, struct mount, mnt_slave);
+}
+
+static struct mount *get_peer_under_root(struct mount *mnt,
+					 struct mnt_namespace *ns,
+					 const struct path *root)
+{
+	struct mount *m = mnt;
+
+	do {
+		/* Check the namespace first for optimization */
+		if (m->mnt_ns == ns && is_path_reachable(m, m->mnt.mnt_root, root))
+			return m;
+
+		m = next_peer(m);
+	} while (m != mnt);
+
+	return NULL;
+}
+
+/*
+ * Get ID of closest dominating peer group having a representative
+ * under the given root.
+ *
+ * Caller must hold namespace_sem
+ */
+int get_dominating_id(struct mount *mnt, const struct path *root)
+{
+	struct mount *m;
+
+	for (m = mnt->mnt_master; m != NULL; m = m->mnt_master) {
+		struct mount *d = get_peer_under_root(m, mnt->mnt_ns, root);
+		if (d)
+			return d->mnt_group_id;
+	}
+
+	return 0;
+}
+
+static int do_make_slave(struct mount *mnt)
+{
+	struct mount *master, *slave_mnt;
+
+	if (list_empty(&mnt->mnt_share)) {
+		if (IS_MNT_SHARED(mnt)) {
+			mnt_release_group_id(mnt);
+			CLEAR_MNT_SHARED(mnt);
+		}
+		master = mnt->mnt_master;
+		if (!master) {
+			struct list_head *p = &mnt->mnt_slave_list;
+			while (!list_empty(p)) {
+				slave_mnt = list_first_entry(p,
+						struct mount, mnt_slave);
+				list_del_init(&slave_mnt->mnt_slave);
+				slave_mnt->mnt_master = NULL;
+			}
+			return 0;
+		}
+	} else {
+		struct mount *m;
+		/*
+		 * slave 'mnt' to a peer mount that has the
+		 * same root dentry. If none is available then
+		 * slave it to anything that is available.
+		 */
+		for (m = master = next_peer(mnt); m != mnt; m = next_peer(m)) {
+			if (m->mnt.mnt_root == mnt->mnt.mnt_root) {
+				master = m;
+				break;
+			}
+		}
+		list_del_init(&mnt->mnt_share);
+		mnt->mnt_group_id = 0;
+		CLEAR_MNT_SHARED(mnt);
+	}
+	list_for_each_entry(slave_mnt, &mnt->mnt_slave_list, mnt_slave)
+		slave_mnt->mnt_master = master;
+	list_move(&mnt->mnt_slave, &master->mnt_slave_list);
+	list_splice(&mnt->mnt_slave_list, master->mnt_slave_list.prev);
+	INIT_LIST_HEAD(&mnt->mnt_slave_list);
+	mnt->mnt_master = master;
+	return 0;
+}
+
+/*
+ * vfsmount lock must be held for write
+ */
+void change_mnt_propagation(struct mount *mnt, int type)
+{
+	if (type == MS_SHARED) {
+		set_mnt_shared(mnt);
+		return;
+	}
+	do_make_slave(mnt);
+	if (type != MS_SLAVE) {
+		list_del_init(&mnt->mnt_slave);
+		mnt->mnt_master = NULL;
+		if (type == MS_UNBINDABLE)
+			mnt->mnt.mnt_flags |= MNT_UNBINDABLE;
+		else
+			mnt->mnt.mnt_flags &= ~MNT_UNBINDABLE;
+	}
+}
+
+/*
+ * get the next mount in the propagation tree.
+ * @m: the mount seen last
+ * @origin: the original mount from where the tree walk initiated
+ *
+ * Note that peer groups form contiguous segments of slave lists.
+ * We rely on that in get_source() to be able to find out if
+ * vfsmount found while iterating with propagation_next() is
+ * a peer of one we'd found earlier.
+ */
+static struct mount *propagation_next(struct mount *m,
+					 struct mount *origin)
+{
+	/* are there any slaves of this mount? */
+	if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list))
+		return first_slave(m);
+
+	while (1) {
+		struct mount *master = m->mnt_master;
+
+		if (master == origin->mnt_master) {
+			struct mount *next = next_peer(m);
+			return (next == origin) ? NULL : next;
+		} else if (m->mnt_slave.next != &master->mnt_slave_list)
+			return next_slave(m);
+
+		/* back at master */
+		m = master;
+	}
+}
+
+static struct mount *skip_propagation_subtree(struct mount *m,
+						struct mount *origin)
+{
+	/*
+	 * Advance m such that propagation_next will not return
+	 * the slaves of m.
+	 */
+	if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list))
+		m = last_slave(m);
+
+	return m;
+}
+
+static struct mount *next_group(struct mount *m, struct mount *origin)
+{
+	while (1) {
+		while (1) {
+			struct mount *next;
+			if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list))
+				return first_slave(m);
+			next = next_peer(m);
+			if (m->mnt_group_id == origin->mnt_group_id) {
+				if (next == origin)
+					return NULL;
+			} else if (m->mnt_slave.next != &next->mnt_slave)
+				break;
+			m = next;
+		}
+		/* m is the last peer */
+		while (1) {
+			struct mount *master = m->mnt_master;
+			if (m->mnt_slave.next != &master->mnt_slave_list)
+				return next_slave(m);
+			m = next_peer(master);
+			if (master->mnt_group_id == origin->mnt_group_id)
+				break;
+			if (master->mnt_slave.next == &m->mnt_slave)
+				break;
+			m = master;
+		}
+		if (m == origin)
+			return NULL;
+	}
+}
+
+/* all accesses are serialized by namespace_sem */
+static struct mount *last_dest, *first_source, *last_source, *dest_master;
+static struct mountpoint *mp;
+static struct hlist_head *list;
+
+static inline bool peers(struct mount *m1, struct mount *m2)
+{
+	return m1->mnt_group_id == m2->mnt_group_id && m1->mnt_group_id;
+}
+
+static int propagate_one(struct mount *m)
+{
+	struct mount *child;
+	int type;
+	/* skip ones added by this propagate_mnt() */
+	if (IS_MNT_NEW(m))
+		return 0;
+	/* skip if mountpoint isn't covered by it */
+	if (!is_subdir(mp->m_dentry, m->mnt.mnt_root))
+		return 0;
+	if (peers(m, last_dest)) {
+		type = CL_MAKE_SHARED;
+	} else {
+		struct mount *n, *p;
+		bool done;
+		for (n = m; ; n = p) {
+			p = n->mnt_master;
+			if (p == dest_master || IS_MNT_MARKED(p))
+				break;
+		}
+		do {
+			struct mount *parent = last_source->mnt_parent;
+			if (peers(last_source, first_source))
+				break;
+			done = parent->mnt_master == p;
+			if (done && peers(n, parent))
+				break;
+			last_source = last_source->mnt_master;
+		} while (!done);
+
+		type = CL_SLAVE;
+		/* beginning of peer group among the slaves? */
+		if (IS_MNT_SHARED(m))
+			type |= CL_MAKE_SHARED;
+	}
+		
+	child = copy_tree(last_source, last_source->mnt.mnt_root, type);
+	if (IS_ERR(child))
+		return PTR_ERR(child);
+	read_seqlock_excl(&mount_lock);
+	mnt_set_mountpoint(m, mp, child);
+	if (m->mnt_master != dest_master)
+		SET_MNT_MARK(m->mnt_master);
+	read_sequnlock_excl(&mount_lock);
+	last_dest = m;
+	last_source = child;
+	hlist_add_head(&child->mnt_hash, list);
+	return count_mounts(m->mnt_ns, child);
+}
+
+/*
+ * mount 'source_mnt' under the destination 'dest_mnt' at
+ * dentry 'dest_dentry'. And propagate that mount to
+ * all the peer and slave mounts of 'dest_mnt'.
+ * Link all the new mounts into a propagation tree headed at
+ * source_mnt. Also link all the new mounts using ->mnt_list
+ * headed at source_mnt's ->mnt_list
+ *
+ * @dest_mnt: destination mount.
+ * @dest_dentry: destination dentry.
+ * @source_mnt: source mount.
+ * @tree_list : list of heads of trees to be attached.
+ */
+int propagate_mnt(struct mount *dest_mnt, struct mountpoint *dest_mp,
+		    struct mount *source_mnt, struct hlist_head *tree_list)
+{
+	struct mount *m, *n;
+	int ret = 0;
+
+	/*
+	 * we don't want to bother passing tons of arguments to
+	 * propagate_one(); everything is serialized by namespace_sem,
+	 * so globals will do just fine.
+	 */
+	last_dest = dest_mnt;
+	first_source = source_mnt;
+	last_source = source_mnt;
+	mp = dest_mp;
+	list = tree_list;
+	dest_master = dest_mnt->mnt_master;
+
+	/* all peers of dest_mnt, except dest_mnt itself */
+	for (n = next_peer(dest_mnt); n != dest_mnt; n = next_peer(n)) {
+		ret = propagate_one(n);
+		if (ret)
+			goto out;
+	}
+
+	/* all slave groups */
+	for (m = next_group(dest_mnt, dest_mnt); m;
+			m = next_group(m, dest_mnt)) {
+		/* everything in that slave group */
+		n = m;
+		do {
+			ret = propagate_one(n);
+			if (ret)
+				goto out;
+			n = next_peer(n);
+		} while (n != m);
+	}
+out:
+	read_seqlock_excl(&mount_lock);
+	hlist_for_each_entry(n, tree_list, mnt_hash) {
+		m = n->mnt_parent;
+		if (m->mnt_master != dest_mnt->mnt_master)
+			CLEAR_MNT_MARK(m->mnt_master);
+	}
+	read_sequnlock_excl(&mount_lock);
+	return ret;
+}
+
+static struct mount *find_topper(struct mount *mnt)
+{
+	/* If there is exactly one mount covering mnt completely return it. */
+	struct mount *child;
+
+	if (!list_is_singular(&mnt->mnt_mounts))
+		return NULL;
+
+	child = list_first_entry(&mnt->mnt_mounts, struct mount, mnt_child);
+	if (child->mnt_mountpoint != mnt->mnt.mnt_root)
+		return NULL;
+
+	return child;
+}
+
+/*
+ * return true if the refcount is greater than count
+ */
+static inline int do_refcount_check(struct mount *mnt, int count)
+{
+	return mnt_get_count(mnt) > count;
+}
+
+/*
+ * check if the mount 'mnt' can be unmounted successfully.
+ * @mnt: the mount to be checked for unmount
+ * NOTE: unmounting 'mnt' would naturally propagate to all
+ * other mounts its parent propagates to.
+ * Check if any of these mounts that **do not have submounts**
+ * have more references than 'refcnt'. If so return busy.
+ *
+ * vfsmount lock must be held for write
+ */
+int propagate_mount_busy(struct mount *mnt, int refcnt)
+{
+	struct mount *m, *child, *topper;
+	struct mount *parent = mnt->mnt_parent;
+
+	if (mnt == parent)
+		return do_refcount_check(mnt, refcnt);
+
+	/*
+	 * quickly check if the current mount can be unmounted.
+	 * If not, we don't have to go checking for all other
+	 * mounts
+	 */
+	if (!list_empty(&mnt->mnt_mounts) || do_refcount_check(mnt, refcnt))
+		return 1;
+
+	for (m = propagation_next(parent, parent); m;
+	     		m = propagation_next(m, parent)) {
+		int count = 1;
+		child = __lookup_mnt(&m->mnt, mnt->mnt_mountpoint);
+		if (!child)
+			continue;
+
+		/* Is there exactly one mount on the child that covers
+		 * it completely whose reference should be ignored?
+		 */
+		topper = find_topper(child);
+		if (topper)
+			count += 1;
+		else if (!list_empty(&child->mnt_mounts))
+			continue;
+
+		if (do_refcount_check(child, count))
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * Clear MNT_LOCKED when it can be shown to be safe.
+ *
+ * mount_lock lock must be held for write
+ */
+void propagate_mount_unlock(struct mount *mnt)
+{
+	struct mount *parent = mnt->mnt_parent;
+	struct mount *m, *child;
+
+	BUG_ON(parent == mnt);
+
+	for (m = propagation_next(parent, parent); m;
+			m = propagation_next(m, parent)) {
+		child = __lookup_mnt(&m->mnt, mnt->mnt_mountpoint);
+		if (child)
+			child->mnt.mnt_flags &= ~MNT_LOCKED;
+	}
+}
+
+static void umount_one(struct mount *mnt, struct list_head *to_umount)
+{
+	CLEAR_MNT_MARK(mnt);
+	mnt->mnt.mnt_flags |= MNT_UMOUNT;
+	list_del_init(&mnt->mnt_child);
+	list_del_init(&mnt->mnt_umounting);
+	list_move_tail(&mnt->mnt_list, to_umount);
+}
+
+/*
+ * NOTE: unmounting 'mnt' naturally propagates to all other mounts its
+ * parent propagates to.
+ */
+static bool __propagate_umount(struct mount *mnt,
+			       struct list_head *to_umount,
+			       struct list_head *to_restore)
+{
+	bool progress = false;
+	struct mount *child;
+
+	/*
+	 * The state of the parent won't change if this mount is
+	 * already unmounted or marked as without children.
+	 */
+	if (mnt->mnt.mnt_flags & (MNT_UMOUNT | MNT_MARKED))
+		goto out;
+
+	/* Verify topper is the only grandchild that has not been
+	 * speculatively unmounted.
+	 */
+	list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) {
+		if (child->mnt_mountpoint == mnt->mnt.mnt_root)
+			continue;
+		if (!list_empty(&child->mnt_umounting) && IS_MNT_MARKED(child))
+			continue;
+		/* Found a mounted child */
+		goto children;
+	}
+
+	/* Mark mounts that can be unmounted if not locked */
+	SET_MNT_MARK(mnt);
+	progress = true;
+
+	/* If a mount is without children and not locked umount it. */
+	if (!IS_MNT_LOCKED(mnt)) {
+		umount_one(mnt, to_umount);
+	} else {
+children:
+		list_move_tail(&mnt->mnt_umounting, to_restore);
+	}
+out:
+	return progress;
+}
+
+static void umount_list(struct list_head *to_umount,
+			struct list_head *to_restore)
+{
+	struct mount *mnt, *child, *tmp;
+	list_for_each_entry(mnt, to_umount, mnt_list) {
+		list_for_each_entry_safe(child, tmp, &mnt->mnt_mounts, mnt_child) {
+			/* topper? */
+			if (child->mnt_mountpoint == mnt->mnt.mnt_root)
+				list_move_tail(&child->mnt_umounting, to_restore);
+			else
+				umount_one(child, to_umount);
+		}
+	}
+}
+
+static void restore_mounts(struct list_head *to_restore)
+{
+	/* Restore mounts to a clean working state */
+	while (!list_empty(to_restore)) {
+		struct mount *mnt, *parent;
+		struct mountpoint *mp;
+
+		mnt = list_first_entry(to_restore, struct mount, mnt_umounting);
+		CLEAR_MNT_MARK(mnt);
+		list_del_init(&mnt->mnt_umounting);
+
+		/* Should this mount be reparented? */
+		mp = mnt->mnt_mp;
+		parent = mnt->mnt_parent;
+		while (parent->mnt.mnt_flags & MNT_UMOUNT) {
+			mp = parent->mnt_mp;
+			parent = parent->mnt_parent;
+		}
+		if (parent != mnt->mnt_parent)
+			mnt_change_mountpoint(parent, mp, mnt);
+	}
+}
+
+static void cleanup_umount_visitations(struct list_head *visited)
+{
+	while (!list_empty(visited)) {
+		struct mount *mnt =
+			list_first_entry(visited, struct mount, mnt_umounting);
+		list_del_init(&mnt->mnt_umounting);
+	}
+}
+
+/*
+ * collect all mounts that receive propagation from the mount in @list,
+ * and return these additional mounts in the same list.
+ * @list: the list of mounts to be unmounted.
+ *
+ * vfsmount lock must be held for write
+ */
+int propagate_umount(struct list_head *list)
+{
+	struct mount *mnt;
+	LIST_HEAD(to_restore);
+	LIST_HEAD(to_umount);
+	LIST_HEAD(visited);
+
+	/* Find candidates for unmounting */
+	list_for_each_entry_reverse(mnt, list, mnt_list) {
+		struct mount *parent = mnt->mnt_parent;
+		struct mount *m;
+
+		/*
+		 * If this mount has already been visited it is known that it's
+		 * entire peer group and all of their slaves in the propagation
+		 * tree for the mountpoint has already been visited and there is
+		 * no need to visit them again.
+		 */
+		if (!list_empty(&mnt->mnt_umounting))
+			continue;
+
+		list_add_tail(&mnt->mnt_umounting, &visited);
+		for (m = propagation_next(parent, parent); m;
+		     m = propagation_next(m, parent)) {
+			struct mount *child = __lookup_mnt(&m->mnt,
+							   mnt->mnt_mountpoint);
+			if (!child)
+				continue;
+
+			if (!list_empty(&child->mnt_umounting)) {
+				/*
+				 * If the child has already been visited it is
+				 * know that it's entire peer group and all of
+				 * their slaves in the propgation tree for the
+				 * mountpoint has already been visited and there
+				 * is no need to visit this subtree again.
+				 */
+				m = skip_propagation_subtree(m, parent);
+				continue;
+			} else if (child->mnt.mnt_flags & MNT_UMOUNT) {
+				/*
+				 * We have come accross an partially unmounted
+				 * mount in list that has not been visited yet.
+				 * Remember it has been visited and continue
+				 * about our merry way.
+				 */
+				list_add_tail(&child->mnt_umounting, &visited);
+				continue;
+			}
+
+			/* Check the child and parents while progress is made */
+			while (__propagate_umount(child,
+						  &to_umount, &to_restore)) {
+				/* Is the parent a umount candidate? */
+				child = child->mnt_parent;
+				if (list_empty(&child->mnt_umounting))
+					break;
+			}
+		}
+	}
+
+	umount_list(&to_umount, &to_restore);
+	restore_mounts(&to_restore);
+	cleanup_umount_visitations(&visited);
+	list_splice_tail(&to_umount, list);
+
+	return 0;
+}