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, 717 insertions, 0 deletions

diff --git a/fs/fs_context.c b/fs/fs_context.c
new file mode 100644
index 000000000..24ce12f0d
--- /dev/null
+++ b/fs/fs_context.c
@@ -0,0 +1,717 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Provide a way to create a superblock configuration context within the kernel
+ * that allows a superblock to be set up prior to mounting.
+ *
+ * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/nsproxy.h>
+#include <linux/slab.h>
+#include <linux/magic.h>
+#include <linux/security.h>
+#include <linux/mnt_namespace.h>
+#include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
+#include <net/net_namespace.h>
+#include <asm/sections.h>
+#include "mount.h"
+#include "internal.h"
+
+enum legacy_fs_param {
+	LEGACY_FS_UNSET_PARAMS,
+	LEGACY_FS_MONOLITHIC_PARAMS,
+	LEGACY_FS_INDIVIDUAL_PARAMS,
+};
+
+struct legacy_fs_context {
+	char			*legacy_data;	/* Data page for legacy filesystems */
+	size_t			data_size;
+	enum legacy_fs_param	param_type;
+};
+
+static int legacy_init_fs_context(struct fs_context *fc);
+
+static const struct constant_table common_set_sb_flag[] = {
+	{ "dirsync",	SB_DIRSYNC },
+	{ "lazytime",	SB_LAZYTIME },
+	{ "mand",	SB_MANDLOCK },
+	{ "ro",		SB_RDONLY },
+	{ "sync",	SB_SYNCHRONOUS },
+	{ },
+};
+
+static const struct constant_table common_clear_sb_flag[] = {
+	{ "async",	SB_SYNCHRONOUS },
+	{ "nolazytime",	SB_LAZYTIME },
+	{ "nomand",	SB_MANDLOCK },
+	{ "rw",		SB_RDONLY },
+	{ },
+};
+
+/*
+ * Check for a common mount option that manipulates s_flags.
+ */
+static int vfs_parse_sb_flag(struct fs_context *fc, const char *key)
+{
+	unsigned int token;
+
+	token = lookup_constant(common_set_sb_flag, key, 0);
+	if (token) {
+		fc->sb_flags |= token;
+		fc->sb_flags_mask |= token;
+		return 0;
+	}
+
+	token = lookup_constant(common_clear_sb_flag, key, 0);
+	if (token) {
+		fc->sb_flags &= ~token;
+		fc->sb_flags_mask |= token;
+		return 0;
+	}
+
+	return -ENOPARAM;
+}
+
+/**
+ * vfs_parse_fs_param_source - Handle setting "source" via parameter
+ * @fc: The filesystem context to modify
+ * @param: The parameter
+ *
+ * This is a simple helper for filesystems to verify that the "source" they
+ * accept is sane.
+ *
+ * Returns 0 on success, -ENOPARAM if this is not  "source" parameter, and
+ * -EINVAL otherwise. In the event of failure, supplementary error information
+ *  is logged.
+ */
+int vfs_parse_fs_param_source(struct fs_context *fc, struct fs_parameter *param)
+{
+	if (strcmp(param->key, "source") != 0)
+		return -ENOPARAM;
+
+	if (param->type != fs_value_is_string)
+		return invalf(fc, "Non-string source");
+
+	if (fc->source)
+		return invalf(fc, "Multiple sources");
+
+	fc->source = param->string;
+	param->string = NULL;
+	return 0;
+}
+EXPORT_SYMBOL(vfs_parse_fs_param_source);
+
+/**
+ * vfs_parse_fs_param - Add a single parameter to a superblock config
+ * @fc: The filesystem context to modify
+ * @param: The parameter
+ *
+ * A single mount option in string form is applied to the filesystem context
+ * being set up.  Certain standard options (for example "ro") are translated
+ * into flag bits without going to the filesystem.  The active security module
+ * is allowed to observe and poach options.  Any other options are passed over
+ * to the filesystem to parse.
+ *
+ * This may be called multiple times for a context.
+ *
+ * Returns 0 on success and a negative error code on failure.  In the event of
+ * failure, supplementary error information may have been set.
+ */
+int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	int ret;
+
+	if (!param->key)
+		return invalf(fc, "Unnamed parameter\n");
+
+	ret = vfs_parse_sb_flag(fc, param->key);
+	if (ret != -ENOPARAM)
+		return ret;
+
+	ret = security_fs_context_parse_param(fc, param);
+	if (ret != -ENOPARAM)
+		/* Param belongs to the LSM or is disallowed by the LSM; so
+		 * don't pass to the FS.
+		 */
+		return ret;
+
+	if (fc->ops->parse_param) {
+		ret = fc->ops->parse_param(fc, param);
+		if (ret != -ENOPARAM)
+			return ret;
+	}
+
+	/* If the filesystem doesn't take any arguments, give it the
+	 * default handling of source.
+	 */
+	ret = vfs_parse_fs_param_source(fc, param);
+	if (ret != -ENOPARAM)
+		return ret;
+
+	return invalf(fc, "%s: Unknown parameter '%s'",
+		      fc->fs_type->name, param->key);
+}
+EXPORT_SYMBOL(vfs_parse_fs_param);
+
+/**
+ * vfs_parse_fs_string - Convenience function to just parse a string.
+ */
+int vfs_parse_fs_string(struct fs_context *fc, const char *key,
+			const char *value, size_t v_size)
+{
+	int ret;
+
+	struct fs_parameter param = {
+		.key	= key,
+		.type	= fs_value_is_flag,
+		.size	= v_size,
+	};
+
+	if (value) {
+		param.string = kmemdup_nul(value, v_size, GFP_KERNEL);
+		if (!param.string)
+			return -ENOMEM;
+		param.type = fs_value_is_string;
+	}
+
+	ret = vfs_parse_fs_param(fc, &param);
+	kfree(param.string);
+	return ret;
+}
+EXPORT_SYMBOL(vfs_parse_fs_string);
+
+/**
+ * generic_parse_monolithic - Parse key[=val][,key[=val]]* mount data
+ * @ctx: The superblock configuration to fill in.
+ * @data: The data to parse
+ *
+ * Parse a blob of data that's in key[=val][,key[=val]]* form.  This can be
+ * called from the ->monolithic_mount_data() fs_context operation.
+ *
+ * Returns 0 on success or the error returned by the ->parse_option() fs_context
+ * operation on failure.
+ */
+int generic_parse_monolithic(struct fs_context *fc, void *data)
+{
+	char *options = data, *key;
+	int ret = 0;
+
+	if (!options)
+		return 0;
+
+	ret = security_sb_eat_lsm_opts(options, &fc->security);
+	if (ret)
+		return ret;
+
+	while ((key = strsep(&options, ",")) != NULL) {
+		if (*key) {
+			size_t v_len = 0;
+			char *value = strchr(key, '=');
+
+			if (value) {
+				if (value == key)
+					continue;
+				*value++ = 0;
+				v_len = strlen(value);
+			}
+			ret = vfs_parse_fs_string(fc, key, value, v_len);
+			if (ret < 0)
+				break;
+		}
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(generic_parse_monolithic);
+
+/**
+ * alloc_fs_context - Create a filesystem context.
+ * @fs_type: The filesystem type.
+ * @reference: The dentry from which this one derives (or NULL)
+ * @sb_flags: Filesystem/superblock flags (SB_*)
+ * @sb_flags_mask: Applicable members of @sb_flags
+ * @purpose: The purpose that this configuration shall be used for.
+ *
+ * Open a filesystem and create a mount context.  The mount context is
+ * initialised with the supplied flags and, if a submount/automount from
+ * another superblock (referred to by @reference) is supplied, may have
+ * parameters such as namespaces copied across from that superblock.
+ */
+static struct fs_context *alloc_fs_context(struct file_system_type *fs_type,
+				      struct dentry *reference,
+				      unsigned int sb_flags,
+				      unsigned int sb_flags_mask,
+				      enum fs_context_purpose purpose)
+{
+	int (*init_fs_context)(struct fs_context *);
+	struct fs_context *fc;
+	int ret = -ENOMEM;
+
+	fc = kzalloc(sizeof(struct fs_context), GFP_KERNEL_ACCOUNT);
+	if (!fc)
+		return ERR_PTR(-ENOMEM);
+
+	fc->purpose	= purpose;
+	fc->sb_flags	= sb_flags;
+	fc->sb_flags_mask = sb_flags_mask;
+	fc->fs_type	= get_filesystem(fs_type);
+	fc->cred	= get_current_cred();
+	fc->net_ns	= get_net(current->nsproxy->net_ns);
+	fc->log.prefix	= fs_type->name;
+
+	mutex_init(&fc->uapi_mutex);
+
+	switch (purpose) {
+	case FS_CONTEXT_FOR_MOUNT:
+		fc->user_ns = get_user_ns(fc->cred->user_ns);
+		break;
+	case FS_CONTEXT_FOR_SUBMOUNT:
+		fc->user_ns = get_user_ns(reference->d_sb->s_user_ns);
+		break;
+	case FS_CONTEXT_FOR_RECONFIGURE:
+		atomic_inc(&reference->d_sb->s_active);
+		fc->user_ns = get_user_ns(reference->d_sb->s_user_ns);
+		fc->root = dget(reference);
+		break;
+	}
+
+	/* TODO: Make all filesystems support this unconditionally */
+	init_fs_context = fc->fs_type->init_fs_context;
+	if (!init_fs_context)
+		init_fs_context = legacy_init_fs_context;
+
+	ret = init_fs_context(fc);
+	if (ret < 0)
+		goto err_fc;
+	fc->need_free = true;
+	return fc;
+
+err_fc:
+	put_fs_context(fc);
+	return ERR_PTR(ret);
+}
+
+struct fs_context *fs_context_for_mount(struct file_system_type *fs_type,
+					unsigned int sb_flags)
+{
+	return alloc_fs_context(fs_type, NULL, sb_flags, 0,
+					FS_CONTEXT_FOR_MOUNT);
+}
+EXPORT_SYMBOL(fs_context_for_mount);
+
+struct fs_context *fs_context_for_reconfigure(struct dentry *dentry,
+					unsigned int sb_flags,
+					unsigned int sb_flags_mask)
+{
+	return alloc_fs_context(dentry->d_sb->s_type, dentry, sb_flags,
+				sb_flags_mask, FS_CONTEXT_FOR_RECONFIGURE);
+}
+EXPORT_SYMBOL(fs_context_for_reconfigure);
+
+struct fs_context *fs_context_for_submount(struct file_system_type *type,
+					   struct dentry *reference)
+{
+	return alloc_fs_context(type, reference, 0, 0, FS_CONTEXT_FOR_SUBMOUNT);
+}
+EXPORT_SYMBOL(fs_context_for_submount);
+
+void fc_drop_locked(struct fs_context *fc)
+{
+	struct super_block *sb = fc->root->d_sb;
+	dput(fc->root);
+	fc->root = NULL;
+	deactivate_locked_super(sb);
+}
+
+static void legacy_fs_context_free(struct fs_context *fc);
+
+/**
+ * vfs_dup_fc_config: Duplicate a filesystem context.
+ * @src_fc: The context to copy.
+ */
+struct fs_context *vfs_dup_fs_context(struct fs_context *src_fc)
+{
+	struct fs_context *fc;
+	int ret;
+
+	if (!src_fc->ops->dup)
+		return ERR_PTR(-EOPNOTSUPP);
+
+	fc = kmemdup(src_fc, sizeof(struct fs_context), GFP_KERNEL);
+	if (!fc)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&fc->uapi_mutex);
+
+	fc->fs_private	= NULL;
+	fc->s_fs_info	= NULL;
+	fc->source	= NULL;
+	fc->security	= NULL;
+	get_filesystem(fc->fs_type);
+	get_net(fc->net_ns);
+	get_user_ns(fc->user_ns);
+	get_cred(fc->cred);
+	if (fc->log.log)
+		refcount_inc(&fc->log.log->usage);
+
+	/* Can't call put until we've called ->dup */
+	ret = fc->ops->dup(fc, src_fc);
+	if (ret < 0)
+		goto err_fc;
+
+	ret = security_fs_context_dup(fc, src_fc);
+	if (ret < 0)
+		goto err_fc;
+	return fc;
+
+err_fc:
+	put_fs_context(fc);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(vfs_dup_fs_context);
+
+/**
+ * logfc - Log a message to a filesystem context
+ * @fc: The filesystem context to log to.
+ * @fmt: The format of the buffer.
+ */
+void logfc(struct fc_log *log, const char *prefix, char level, const char *fmt, ...)
+{
+	va_list va;
+	struct va_format vaf = {.fmt = fmt, .va = &va};
+
+	va_start(va, fmt);
+	if (!log) {
+		switch (level) {
+		case 'w':
+			printk(KERN_WARNING "%s%s%pV\n", prefix ? prefix : "",
+						prefix ? ": " : "", &vaf);
+			break;
+		case 'e':
+			printk(KERN_ERR "%s%s%pV\n", prefix ? prefix : "",
+						prefix ? ": " : "", &vaf);
+			break;
+		default:
+			printk(KERN_NOTICE "%s%s%pV\n", prefix ? prefix : "",
+						prefix ? ": " : "", &vaf);
+			break;
+		}
+	} else {
+		unsigned int logsize = ARRAY_SIZE(log->buffer);
+		u8 index;
+		char *q = kasprintf(GFP_KERNEL, "%c %s%s%pV\n", level,
+						prefix ? prefix : "",
+						prefix ? ": " : "", &vaf);
+
+		index = log->head & (logsize - 1);
+		BUILD_BUG_ON(sizeof(log->head) != sizeof(u8) ||
+			     sizeof(log->tail) != sizeof(u8));
+		if ((u8)(log->head - log->tail) == logsize) {
+			/* The buffer is full, discard the oldest message */
+			if (log->need_free & (1 << index))
+				kfree(log->buffer[index]);
+			log->tail++;
+		}
+
+		log->buffer[index] = q ? q : "OOM: Can't store error string";
+		if (q)
+			log->need_free |= 1 << index;
+		else
+			log->need_free &= ~(1 << index);
+		log->head++;
+	}
+	va_end(va);
+}
+EXPORT_SYMBOL(logfc);
+
+/*
+ * Free a logging structure.
+ */
+static void put_fc_log(struct fs_context *fc)
+{
+	struct fc_log *log = fc->log.log;
+	int i;
+
+	if (log) {
+		if (refcount_dec_and_test(&log->usage)) {
+			fc->log.log = NULL;
+			for (i = 0; i <= 7; i++)
+				if (log->need_free & (1 << i))
+					kfree(log->buffer[i]);
+			kfree(log);
+		}
+	}
+}
+
+/**
+ * put_fs_context - Dispose of a superblock configuration context.
+ * @fc: The context to dispose of.
+ */
+void put_fs_context(struct fs_context *fc)
+{
+	struct super_block *sb;
+
+	if (fc->root) {
+		sb = fc->root->d_sb;
+		dput(fc->root);
+		fc->root = NULL;
+		deactivate_super(sb);
+	}
+
+	if (fc->need_free && fc->ops && fc->ops->free)
+		fc->ops->free(fc);
+
+	security_free_mnt_opts(&fc->security);
+	put_net(fc->net_ns);
+	put_user_ns(fc->user_ns);
+	put_cred(fc->cred);
+	put_fc_log(fc);
+	put_filesystem(fc->fs_type);
+	kfree(fc->source);
+	kfree(fc);
+}
+EXPORT_SYMBOL(put_fs_context);
+
+/*
+ * Free the config for a filesystem that doesn't support fs_context.
+ */
+static void legacy_fs_context_free(struct fs_context *fc)
+{
+	struct legacy_fs_context *ctx = fc->fs_private;
+
+	if (ctx) {
+		if (ctx->param_type == LEGACY_FS_INDIVIDUAL_PARAMS)
+			kfree(ctx->legacy_data);
+		kfree(ctx);
+	}
+}
+
+/*
+ * Duplicate a legacy config.
+ */
+static int legacy_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc)
+{
+	struct legacy_fs_context *ctx;
+	struct legacy_fs_context *src_ctx = src_fc->fs_private;
+
+	ctx = kmemdup(src_ctx, sizeof(*src_ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	if (ctx->param_type == LEGACY_FS_INDIVIDUAL_PARAMS) {
+		ctx->legacy_data = kmemdup(src_ctx->legacy_data,
+					   src_ctx->data_size, GFP_KERNEL);
+		if (!ctx->legacy_data) {
+			kfree(ctx);
+			return -ENOMEM;
+		}
+	}
+
+	fc->fs_private = ctx;
+	return 0;
+}
+
+/*
+ * Add a parameter to a legacy config.  We build up a comma-separated list of
+ * options.
+ */
+static int legacy_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct legacy_fs_context *ctx = fc->fs_private;
+	unsigned int size = ctx->data_size;
+	size_t len = 0;
+	int ret;
+
+	ret = vfs_parse_fs_param_source(fc, param);
+	if (ret != -ENOPARAM)
+		return ret;
+
+	if (ctx->param_type == LEGACY_FS_MONOLITHIC_PARAMS)
+		return invalf(fc, "VFS: Legacy: Can't mix monolithic and individual options");
+
+	switch (param->type) {
+	case fs_value_is_string:
+		len = 1 + param->size;
+		fallthrough;
+	case fs_value_is_flag:
+		len += strlen(param->key);
+		break;
+	default:
+		return invalf(fc, "VFS: Legacy: Parameter type for '%s' not supported",
+			      param->key);
+	}
+
+	if (size + len + 2 > PAGE_SIZE)
+		return invalf(fc, "VFS: Legacy: Cumulative options too large");
+	if (strchr(param->key, ',') ||
+	    (param->type == fs_value_is_string &&
+	     memchr(param->string, ',', param->size)))
+		return invalf(fc, "VFS: Legacy: Option '%s' contained comma",
+			      param->key);
+	if (!ctx->legacy_data) {
+		ctx->legacy_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
+		if (!ctx->legacy_data)
+			return -ENOMEM;
+	}
+
+	ctx->legacy_data[size++] = ',';
+	len = strlen(param->key);
+	memcpy(ctx->legacy_data + size, param->key, len);
+	size += len;
+	if (param->type == fs_value_is_string) {
+		ctx->legacy_data[size++] = '=';
+		memcpy(ctx->legacy_data + size, param->string, param->size);
+		size += param->size;
+	}
+	ctx->legacy_data[size] = '\0';
+	ctx->data_size = size;
+	ctx->param_type = LEGACY_FS_INDIVIDUAL_PARAMS;
+	return 0;
+}
+
+/*
+ * Add monolithic mount data.
+ */
+static int legacy_parse_monolithic(struct fs_context *fc, void *data)
+{
+	struct legacy_fs_context *ctx = fc->fs_private;
+
+	if (ctx->param_type != LEGACY_FS_UNSET_PARAMS) {
+		pr_warn("VFS: Can't mix monolithic and individual options\n");
+		return -EINVAL;
+	}
+
+	ctx->legacy_data = data;
+	ctx->param_type = LEGACY_FS_MONOLITHIC_PARAMS;
+	if (!ctx->legacy_data)
+		return 0;
+
+	if (fc->fs_type->fs_flags & FS_BINARY_MOUNTDATA)
+		return 0;
+	return security_sb_eat_lsm_opts(ctx->legacy_data, &fc->security);
+}
+
+/*
+ * Get a mountable root with the legacy mount command.
+ */
+static int legacy_get_tree(struct fs_context *fc)
+{
+	struct legacy_fs_context *ctx = fc->fs_private;
+	struct super_block *sb;
+	struct dentry *root;
+
+	root = fc->fs_type->mount(fc->fs_type, fc->sb_flags,
+				      fc->source, ctx->legacy_data);
+	if (IS_ERR(root))
+		return PTR_ERR(root);
+
+	sb = root->d_sb;
+	BUG_ON(!sb);
+
+	fc->root = root;
+	return 0;
+}
+
+/*
+ * Handle remount.
+ */
+static int legacy_reconfigure(struct fs_context *fc)
+{
+	struct legacy_fs_context *ctx = fc->fs_private;
+	struct super_block *sb = fc->root->d_sb;
+
+	if (!sb->s_op->remount_fs)
+		return 0;
+
+	return sb->s_op->remount_fs(sb, &fc->sb_flags,
+				    ctx ? ctx->legacy_data : NULL);
+}
+
+const struct fs_context_operations legacy_fs_context_ops = {
+	.free			= legacy_fs_context_free,
+	.dup			= legacy_fs_context_dup,
+	.parse_param		= legacy_parse_param,
+	.parse_monolithic	= legacy_parse_monolithic,
+	.get_tree		= legacy_get_tree,
+	.reconfigure		= legacy_reconfigure,
+};
+
+/*
+ * Initialise a legacy context for a filesystem that doesn't support
+ * fs_context.
+ */
+static int legacy_init_fs_context(struct fs_context *fc)
+{
+	fc->fs_private = kzalloc(sizeof(struct legacy_fs_context), GFP_KERNEL_ACCOUNT);
+	if (!fc->fs_private)
+		return -ENOMEM;
+	fc->ops = &legacy_fs_context_ops;
+	return 0;
+}
+
+int parse_monolithic_mount_data(struct fs_context *fc, void *data)
+{
+	int (*monolithic_mount_data)(struct fs_context *, void *);
+
+	monolithic_mount_data = fc->ops->parse_monolithic;
+	if (!monolithic_mount_data)
+		monolithic_mount_data = generic_parse_monolithic;
+
+	return monolithic_mount_data(fc, data);
+}
+
+/*
+ * Clean up a context after performing an action on it and put it into a state
+ * from where it can be used to reconfigure a superblock.
+ *
+ * Note that here we do only the parts that can't fail; the rest is in
+ * finish_clean_context() below and in between those fs_context is marked
+ * FS_CONTEXT_AWAITING_RECONF.  The reason for splitup is that after
+ * successful mount or remount we need to report success to userland.
+ * Trying to do full reinit (for the sake of possible subsequent remount)
+ * and failing to allocate memory would've put us into a nasty situation.
+ * So here we only discard the old state and reinitialization is left
+ * until we actually try to reconfigure.
+ */
+void vfs_clean_context(struct fs_context *fc)
+{
+	if (fc->need_free && fc->ops && fc->ops->free)
+		fc->ops->free(fc);
+	fc->need_free = false;
+	fc->fs_private = NULL;
+	fc->s_fs_info = NULL;
+	fc->sb_flags = 0;
+	security_free_mnt_opts(&fc->security);
+	kfree(fc->source);
+	fc->source = NULL;
+
+	fc->purpose = FS_CONTEXT_FOR_RECONFIGURE;
+	fc->phase = FS_CONTEXT_AWAITING_RECONF;
+}
+
+int finish_clean_context(struct fs_context *fc)
+{
+	int error;
+
+	if (fc->phase != FS_CONTEXT_AWAITING_RECONF)
+		return 0;
+
+	if (fc->fs_type->init_fs_context)
+		error = fc->fs_type->init_fs_context(fc);
+	else
+		error = legacy_init_fs_context(fc);
+	if (unlikely(error)) {
+		fc->phase = FS_CONTEXT_FAILED;
+		return error;
+	}
+	fc->need_free = true;
+	fc->phase = FS_CONTEXT_RECONF_PARAMS;
+	return 0;
+}