selftests/bpf: Add a test for objects stuck in free_by_rcu_ttracegrafted

Delete all elements of BPF_F_NO_PREALLOC hash map in one batch. The first
free_bulk() starts RCU tasks trace GP and the rest of the elements are
freed while it's in flight. Wait for call_rcu_ttrace_in_progress to clear
in bpf_mem_cache of every cpu and check that free_by_rcu_ttrace and
waiting_for_gp_ttrace lists are empty.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20260930095920.601738-4-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 786 insertions, 0 deletions

diff --git a/fs/afs/proc.c b/fs/afs/proc.c
new file mode 100644
index 000000000..a9cc5cdb4
--- /dev/null
+++ b/fs/afs/proc.c
@@ -0,0 +1,786 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* /proc interface for AFS
+ *
+ * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/sched.h>
+#include <linux/uaccess.h>
+#include "internal.h"
+
+struct afs_vl_seq_net_private {
+	struct seq_net_private		seq;	/* Must be first */
+	struct afs_vlserver_list	*vllist;
+};
+
+static inline struct afs_net *afs_seq2net(struct seq_file *m)
+{
+	return afs_net(seq_file_net(m));
+}
+
+static inline struct afs_net *afs_seq2net_single(struct seq_file *m)
+{
+	return afs_net(seq_file_single_net(m));
+}
+
+/*
+ * Display the list of cells known to the namespace.
+ */
+static int afs_proc_cells_show(struct seq_file *m, void *v)
+{
+	struct afs_vlserver_list *vllist;
+	struct afs_cell *cell;
+
+	if (v == SEQ_START_TOKEN) {
+		/* display header on line 1 */
+		seq_puts(m, "USE ACT    TTL SV ST NAME\n");
+		return 0;
+	}
+
+	cell = list_entry(v, struct afs_cell, proc_link);
+	vllist = rcu_dereference(cell->vl_servers);
+
+	/* display one cell per line on subsequent lines */
+	seq_printf(m, "%3u %3u %6lld %2u %2u %s\n",
+		   refcount_read(&cell->ref),
+		   atomic_read(&cell->active),
+		   cell->dns_expiry - ktime_get_real_seconds(),
+		   vllist ? vllist->nr_servers : 0,
+		   cell->state,
+		   cell->name);
+	return 0;
+}
+
+static void *afs_proc_cells_start(struct seq_file *m, loff_t *_pos)
+	__acquires(rcu)
+{
+	rcu_read_lock();
+	return seq_hlist_start_head_rcu(&afs_seq2net(m)->proc_cells, *_pos);
+}
+
+static void *afs_proc_cells_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	return seq_hlist_next_rcu(v, &afs_seq2net(m)->proc_cells, pos);
+}
+
+static void afs_proc_cells_stop(struct seq_file *m, void *v)
+	__releases(rcu)
+{
+	rcu_read_unlock();
+}
+
+static const struct seq_operations afs_proc_cells_ops = {
+	.start	= afs_proc_cells_start,
+	.next	= afs_proc_cells_next,
+	.stop	= afs_proc_cells_stop,
+	.show	= afs_proc_cells_show,
+};
+
+/*
+ * handle writes to /proc/fs/afs/cells
+ * - to add cells: echo "add <cellname> <IP>[:<IP>][:<IP>]"
+ */
+static int afs_proc_cells_write(struct file *file, char *buf, size_t size)
+{
+	struct seq_file *m = file->private_data;
+	struct afs_net *net = afs_seq2net(m);
+	char *name, *args;
+	int ret;
+
+	/* trim to first NL */
+	name = memchr(buf, '\n', size);
+	if (name)
+		*name = 0;
+
+	/* split into command, name and argslist */
+	name = strchr(buf, ' ');
+	if (!name)
+		goto inval;
+	do {
+		*name++ = 0;
+	} while(*name == ' ');
+	if (!*name)
+		goto inval;
+
+	args = strchr(name, ' ');
+	if (args) {
+		do {
+			*args++ = 0;
+		} while(*args == ' ');
+		if (!*args)
+			goto inval;
+	}
+
+	/* determine command to perform */
+	_debug("cmd=%s name=%s args=%s", buf, name, args);
+
+	if (strcmp(buf, "add") == 0) {
+		struct afs_cell *cell;
+
+		cell = afs_lookup_cell(net, name, strlen(name), args,
+				       AFS_LOOKUP_CELL_PRELOAD,
+				       afs_cell_trace_use_lookup_add);
+		if (IS_ERR(cell)) {
+			ret = PTR_ERR(cell);
+			goto done;
+		}
+
+		if (test_and_set_bit(AFS_CELL_FL_NO_GC, &cell->flags))
+			afs_unuse_cell(cell, afs_cell_trace_unuse_no_pin);
+	} else {
+		goto inval;
+	}
+
+	ret = 0;
+
+done:
+	_leave(" = %d", ret);
+	return ret;
+
+inval:
+	ret = -EINVAL;
+	printk("kAFS: Invalid Command on /proc/fs/afs/cells file\n");
+	goto done;
+}
+
+/*
+ * Display the list of addr_prefs known to the namespace.
+ */
+static int afs_proc_addr_prefs_show(struct seq_file *m, void *v)
+{
+	struct afs_addr_preference_list *preflist;
+	struct afs_addr_preference *pref;
+	struct afs_net *net = afs_seq2net_single(m);
+	union {
+		struct sockaddr_in sin;
+		struct sockaddr_in6 sin6;
+	} addr;
+	unsigned int i;
+	char buf[44]; /* Maximum ipv6 + max subnet is 43 */
+
+	rcu_read_lock();
+	preflist = rcu_dereference(net->address_prefs);
+
+	if (!preflist) {
+		seq_puts(m, "NO PREFS\n");
+		goto out;
+	}
+
+	seq_printf(m, "PROT SUBNET                                      PRIOR (v=%u n=%u/%u/%u)\n",
+		   preflist->version, preflist->ipv6_off, preflist->nr, preflist->max_prefs);
+
+	memset(&addr, 0, sizeof(addr));
+
+	for (i = 0; i < preflist->nr; i++) {
+		pref = &preflist->prefs[i];
+
+		addr.sin.sin_family = pref->family;
+		if (pref->family == AF_INET) {
+			memcpy(&addr.sin.sin_addr, &pref->ipv4_addr,
+			       sizeof(addr.sin.sin_addr));
+			snprintf(buf, sizeof(buf), "%pISc/%u", &addr.sin, pref->subnet_mask);
+			seq_printf(m, "UDP  %-43.43s %5u\n", buf, pref->prio);
+		} else {
+			memcpy(&addr.sin6.sin6_addr, &pref->ipv6_addr,
+			       sizeof(addr.sin6.sin6_addr));
+			snprintf(buf, sizeof(buf), "%pISc/%u", &addr.sin6, pref->subnet_mask);
+			seq_printf(m, "UDP  %-43.43s %5u\n", buf, pref->prio);
+		}
+	}
+
+out:
+	rcu_read_unlock();
+	return 0;
+}
+
+/*
+ * Display the name of the current workstation cell.
+ */
+static int afs_proc_rootcell_show(struct seq_file *m, void *v)
+{
+	struct afs_cell *cell;
+	struct afs_net *net;
+
+	net = afs_seq2net_single(m);
+	down_read(&net->cells_lock);
+	cell = rcu_dereference_protected(net->ws_cell, lockdep_is_held(&net->cells_lock));
+	if (cell)
+		seq_printf(m, "%s\n", cell->name);
+	up_read(&net->cells_lock);
+	return 0;
+}
+
+/*
+ * Set the current workstation cell and optionally supply its list of volume
+ * location servers.
+ *
+ *	echo "cell.name:192.168.231.14" >/proc/fs/afs/rootcell
+ */
+static int afs_proc_rootcell_write(struct file *file, char *buf, size_t size)
+{
+	struct seq_file *m = file->private_data;
+	struct afs_net *net = afs_seq2net_single(m);
+	char *s;
+	int ret;
+
+	ret = -EINVAL;
+	if (buf[0] == '.')
+		goto out;
+	if (memchr(buf, '/', size))
+		goto out;
+
+	/* trim to first NL */
+	s = memchr(buf, '\n', size);
+	if (s)
+		*s = 0;
+
+	/* determine command to perform */
+	_debug("rootcell=%s", buf);
+
+	ret = -EEXIST;
+	inode_lock(file_inode(file));
+	if (!rcu_access_pointer(net->ws_cell))
+		ret = afs_cell_init(net, buf);
+	else
+		printk("busy\n");
+	inode_unlock(file_inode(file));
+
+out:
+	_leave(" = %d", ret);
+	return ret;
+}
+
+static const char afs_vol_types[3][3] = {
+	[AFSVL_RWVOL]	= "RW",
+	[AFSVL_ROVOL]	= "RO",
+	[AFSVL_BACKVOL]	= "BK",
+};
+
+/*
+ * Display the list of volumes known to a cell.
+ */
+static int afs_proc_cell_volumes_show(struct seq_file *m, void *v)
+{
+	struct afs_volume *vol = hlist_entry(v, struct afs_volume, proc_link);
+
+	/* Display header on line 1 */
+	if (v == SEQ_START_TOKEN) {
+		seq_puts(m, "USE VID      TY NAME\n");
+		return 0;
+	}
+
+	seq_printf(m, "%3d %08llx %s %s\n",
+		   refcount_read(&vol->ref), vol->vid,
+		   afs_vol_types[vol->type],
+		   vol->name);
+
+	return 0;
+}
+
+static void *afs_proc_cell_volumes_start(struct seq_file *m, loff_t *_pos)
+	__acquires(cell->proc_lock)
+{
+	struct afs_cell *cell = pde_data(file_inode(m->file));
+
+	rcu_read_lock();
+	return seq_hlist_start_head_rcu(&cell->proc_volumes, *_pos);
+}
+
+static void *afs_proc_cell_volumes_next(struct seq_file *m, void *v,
+					loff_t *_pos)
+{
+	struct afs_cell *cell = pde_data(file_inode(m->file));
+
+	return seq_hlist_next_rcu(v, &cell->proc_volumes, _pos);
+}
+
+static void afs_proc_cell_volumes_stop(struct seq_file *m, void *v)
+	__releases(cell->proc_lock)
+{
+	rcu_read_unlock();
+}
+
+static const struct seq_operations afs_proc_cell_volumes_ops = {
+	.start	= afs_proc_cell_volumes_start,
+	.next	= afs_proc_cell_volumes_next,
+	.stop	= afs_proc_cell_volumes_stop,
+	.show	= afs_proc_cell_volumes_show,
+};
+
+static const char *const dns_record_sources[NR__dns_record_source + 1] = {
+	[DNS_RECORD_UNAVAILABLE]	= "unav",
+	[DNS_RECORD_FROM_CONFIG]	= "cfg",
+	[DNS_RECORD_FROM_DNS_A]		= "A",
+	[DNS_RECORD_FROM_DNS_AFSDB]	= "AFSDB",
+	[DNS_RECORD_FROM_DNS_SRV]	= "SRV",
+	[DNS_RECORD_FROM_NSS]		= "nss",
+	[NR__dns_record_source]		= "[weird]"
+};
+
+static const char *const dns_lookup_statuses[NR__dns_lookup_status + 1] = {
+	[DNS_LOOKUP_NOT_DONE]		= "no-lookup",
+	[DNS_LOOKUP_GOOD]		= "good",
+	[DNS_LOOKUP_GOOD_WITH_BAD]	= "good/bad",
+	[DNS_LOOKUP_BAD]		= "bad",
+	[DNS_LOOKUP_GOT_NOT_FOUND]	= "not-found",
+	[DNS_LOOKUP_GOT_LOCAL_FAILURE]	= "local-failure",
+	[DNS_LOOKUP_GOT_TEMP_FAILURE]	= "temp-failure",
+	[DNS_LOOKUP_GOT_NS_FAILURE]	= "ns-failure",
+	[NR__dns_lookup_status]		= "[weird]"
+};
+
+/*
+ * Display the list of Volume Location servers we're using for a cell.
+ */
+static int afs_proc_cell_vlservers_show(struct seq_file *m, void *v)
+{
+	const struct afs_vl_seq_net_private *priv = m->private;
+	const struct afs_vlserver_list *vllist = priv->vllist;
+	const struct afs_vlserver_entry *entry;
+	const struct afs_vlserver *vlserver;
+	const struct afs_addr_list *alist;
+	int i;
+
+	if (v == SEQ_START_TOKEN) {
+		seq_printf(m, "# source %s, status %s\n",
+			   dns_record_sources[vllist ? vllist->source : 0],
+			   dns_lookup_statuses[vllist ? vllist->status : 0]);
+		return 0;
+	}
+
+	entry = v;
+	vlserver = entry->server;
+	alist = rcu_dereference(vlserver->addresses);
+
+	seq_printf(m, "%s [p=%hu w=%hu s=%s,%s]:\n",
+		   vlserver->name, entry->priority, entry->weight,
+		   dns_record_sources[alist ? alist->source : entry->source],
+		   dns_lookup_statuses[alist ? alist->status : entry->status]);
+	if (alist) {
+		for (i = 0; i < alist->nr_addrs; i++)
+			seq_printf(m, " %c %pISpc\n",
+				   alist->preferred == i ? '>' : '-',
+				   rxrpc_kernel_remote_addr(alist->addrs[i].peer));
+	}
+	seq_printf(m, " info: fl=%lx rtt=%d\n", vlserver->flags, vlserver->rtt);
+	seq_printf(m, " probe: fl=%x e=%d ac=%d out=%d\n",
+		   vlserver->probe.flags, vlserver->probe.error,
+		   vlserver->probe.abort_code,
+		   atomic_read(&vlserver->probe_outstanding));
+	return 0;
+}
+
+static void *afs_proc_cell_vlservers_start(struct seq_file *m, loff_t *_pos)
+	__acquires(rcu)
+{
+	struct afs_vl_seq_net_private *priv = m->private;
+	struct afs_vlserver_list *vllist;
+	struct afs_cell *cell = pde_data(file_inode(m->file));
+	loff_t pos = *_pos;
+
+	rcu_read_lock();
+
+	vllist = rcu_dereference(cell->vl_servers);
+	priv->vllist = vllist;
+
+	if (pos < 0)
+		*_pos = pos = 0;
+	if (pos == 0)
+		return SEQ_START_TOKEN;
+
+	if (pos - 1 >= vllist->nr_servers)
+		return NULL;
+
+	return &vllist->servers[pos - 1];
+}
+
+static void *afs_proc_cell_vlservers_next(struct seq_file *m, void *v,
+					  loff_t *_pos)
+{
+	struct afs_vl_seq_net_private *priv = m->private;
+	struct afs_vlserver_list *vllist = priv->vllist;
+	loff_t pos;
+
+	pos = *_pos;
+	pos++;
+	*_pos = pos;
+	if (!vllist || pos - 1 >= vllist->nr_servers)
+		return NULL;
+
+	return &vllist->servers[pos - 1];
+}
+
+static void afs_proc_cell_vlservers_stop(struct seq_file *m, void *v)
+	__releases(rcu)
+{
+	rcu_read_unlock();
+}
+
+static const struct seq_operations afs_proc_cell_vlservers_ops = {
+	.start	= afs_proc_cell_vlservers_start,
+	.next	= afs_proc_cell_vlservers_next,
+	.stop	= afs_proc_cell_vlservers_stop,
+	.show	= afs_proc_cell_vlservers_show,
+};
+
+/*
+ * Display the list of fileservers we're using within a namespace.
+ */
+static int afs_proc_servers_show(struct seq_file *m, void *v)
+{
+	struct afs_endpoint_state *estate;
+	struct afs_addr_list *alist;
+	struct afs_server *server;
+	unsigned long failed;
+	int i;
+
+	if (v == SEQ_START_TOKEN) {
+		seq_puts(m, "UUID                                 REF ACT CELL\n");
+		return 0;
+	}
+
+	server = list_entry(v, struct afs_server, proc_link);
+	seq_printf(m, "%pU %3d %3d %s\n",
+		   &server->uuid,
+		   refcount_read(&server->ref),
+		   atomic_read(&server->active),
+		   server->cell->name);
+	seq_printf(m, "  - info: fl=%lx rtt=%u\n",
+		   server->flags, server->rtt);
+	seq_printf(m, "  - probe: last=%d\n",
+		   (int)(jiffies - server->probed_at) / HZ);
+
+	estate = rcu_dereference(server->endpoint_state);
+	if (!estate)
+		goto out;
+	failed = estate->failed_set;
+	seq_printf(m, "  - ESTATE pq=%x np=%u rsp=%lx f=%lx\n",
+		   estate->probe_seq, atomic_read(&estate->nr_probing),
+		   estate->responsive_set, estate->failed_set);
+
+	alist = estate->addresses;
+	seq_printf(m, "  - ALIST v=%u ap=%u\n",
+		   alist->version, alist->addr_pref_version);
+	for (i = 0; i < alist->nr_addrs; i++) {
+		const struct afs_address *addr = &alist->addrs[i];
+
+		seq_printf(m, "    [%x] %pISpc%s rtt=%d err=%d p=%u\n",
+			   i, rxrpc_kernel_remote_addr(addr->peer),
+			   alist->preferred == i ? "*" :
+			   test_bit(i, &failed) ? "!" : "",
+			   rxrpc_kernel_get_srtt(addr->peer),
+			   addr->last_error, addr->prio);
+	}
+
+out:
+	return 0;
+}
+
+static void *afs_proc_servers_start(struct seq_file *m, loff_t *_pos)
+	__acquires(rcu)
+{
+	rcu_read_lock();
+	return seq_hlist_start_head_rcu(&afs_seq2net(m)->fs_proc, *_pos);
+}
+
+static void *afs_proc_servers_next(struct seq_file *m, void *v, loff_t *_pos)
+{
+	return seq_hlist_next_rcu(v, &afs_seq2net(m)->fs_proc, _pos);
+}
+
+static void afs_proc_servers_stop(struct seq_file *m, void *v)
+	__releases(rcu)
+{
+	rcu_read_unlock();
+}
+
+static const struct seq_operations afs_proc_servers_ops = {
+	.start	= afs_proc_servers_start,
+	.next	= afs_proc_servers_next,
+	.stop	= afs_proc_servers_stop,
+	.show	= afs_proc_servers_show,
+};
+
+/*
+ * Display the list of strings that may be substituted for the @sys pathname
+ * macro.
+ */
+static int afs_proc_sysname_show(struct seq_file *m, void *v)
+{
+	struct afs_net *net = afs_seq2net(m);
+	struct afs_sysnames *sysnames = net->sysnames;
+	unsigned int i = (unsigned long)v - 1;
+
+	if (i < sysnames->nr)
+		seq_printf(m, "%s\n", sysnames->subs[i]);
+	return 0;
+}
+
+static void *afs_proc_sysname_start(struct seq_file *m, loff_t *pos)
+	__acquires(&net->sysnames_lock)
+{
+	struct afs_net *net = afs_seq2net(m);
+	struct afs_sysnames *names;
+
+	read_lock(&net->sysnames_lock);
+
+	names = net->sysnames;
+	if (*pos >= names->nr)
+		return NULL;
+	return (void *)(unsigned long)(*pos + 1);
+}
+
+static void *afs_proc_sysname_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct afs_net *net = afs_seq2net(m);
+	struct afs_sysnames *names = net->sysnames;
+
+	*pos += 1;
+	if (*pos >= names->nr)
+		return NULL;
+	return (void *)(unsigned long)(*pos + 1);
+}
+
+static void afs_proc_sysname_stop(struct seq_file *m, void *v)
+	__releases(&net->sysnames_lock)
+{
+	struct afs_net *net = afs_seq2net(m);
+
+	read_unlock(&net->sysnames_lock);
+}
+
+static const struct seq_operations afs_proc_sysname_ops = {
+	.start	= afs_proc_sysname_start,
+	.next	= afs_proc_sysname_next,
+	.stop	= afs_proc_sysname_stop,
+	.show	= afs_proc_sysname_show,
+};
+
+/*
+ * Allow the @sys substitution to be configured.
+ */
+static int afs_proc_sysname_write(struct file *file, char *buf, size_t size)
+{
+	struct afs_sysnames *sysnames, *kill;
+	struct seq_file *m = file->private_data;
+	struct afs_net *net = afs_seq2net(m);
+	char *s, *p, *sub;
+	int ret, len;
+
+	sysnames = kzalloc_obj(*sysnames);
+	if (!sysnames)
+		return -ENOMEM;
+	refcount_set(&sysnames->usage, 1);
+	kill = sysnames;
+
+	p = buf;
+	while ((s = strsep(&p, " \t\n"))) {
+		len = strlen(s);
+		if (len == 0)
+			continue;
+		ret = -ENAMETOOLONG;
+		if (len >= AFSNAMEMAX)
+			goto error;
+
+		if (len >= 4 &&
+		    s[len - 4] == '@' &&
+		    s[len - 3] == 's' &&
+		    s[len - 2] == 'y' &&
+		    s[len - 1] == 's')
+			/* Protect against recursion */
+			goto invalid;
+
+		if (s[0] == '.' &&
+		    (len < 2 || (len == 2 && s[1] == '.')))
+			goto invalid;
+
+		if (memchr(s, '/', len))
+			goto invalid;
+
+		ret = -EFBIG;
+		if (sysnames->nr >= AFS_NR_SYSNAME)
+			goto out;
+
+		if (strcmp(s, afs_init_sysname) == 0) {
+			sub = (char *)afs_init_sysname;
+		} else {
+			ret = -ENOMEM;
+			sub = kmemdup(s, len + 1, GFP_KERNEL);
+			if (!sub)
+				goto out;
+		}
+
+		sysnames->subs[sysnames->nr] = sub;
+		sysnames->nr++;
+	}
+
+	if (sysnames->nr == 0) {
+		sysnames->subs[0] = sysnames->blank;
+		sysnames->nr++;
+	}
+
+	write_lock(&net->sysnames_lock);
+	kill = net->sysnames;
+	net->sysnames = sysnames;
+	write_unlock(&net->sysnames_lock);
+	ret = 0;
+out:
+	afs_put_sysnames(kill);
+	return ret;
+
+invalid:
+	ret = -EINVAL;
+error:
+	goto out;
+}
+
+void afs_put_sysnames(struct afs_sysnames *sysnames)
+{
+	int i;
+
+	if (sysnames && refcount_dec_and_test(&sysnames->usage)) {
+		for (i = 0; i < sysnames->nr; i++)
+			if (sysnames->subs[i] != afs_init_sysname &&
+			    sysnames->subs[i] != sysnames->blank)
+				kfree(sysnames->subs[i]);
+		kfree(sysnames);
+	}
+}
+
+/*
+ * Display general per-net namespace statistics
+ */
+static int afs_proc_stats_show(struct seq_file *m, void *v)
+{
+	struct afs_net *net = afs_seq2net_single(m);
+
+	seq_puts(m, "kAFS statistics\n");
+
+	seq_printf(m, "dir-mgmt: look=%u reval=%u inval=%u relpg=%u\n",
+		   atomic_read(&net->n_lookup),
+		   atomic_read(&net->n_reval),
+		   atomic_read(&net->n_inval),
+		   atomic_read(&net->n_relpg));
+
+	seq_printf(m, "dir-data: rdpg=%u\n",
+		   atomic_read(&net->n_read_dir));
+
+	seq_printf(m, "dir-edit: cr=%u rm=%u\n",
+		   atomic_read(&net->n_dir_cr),
+		   atomic_read(&net->n_dir_rm));
+
+	seq_printf(m, "file-rd : n=%u nb=%lu\n",
+		   atomic_read(&net->n_fetches),
+		   atomic_long_read(&net->n_fetch_bytes));
+	seq_printf(m, "file-wr : n=%u nb=%lu\n",
+		   atomic_read(&net->n_stores),
+		   atomic_long_read(&net->n_store_bytes));
+	return 0;
+}
+
+/*
+ * initialise /proc/fs/afs/<cell>/
+ */
+int afs_proc_cell_setup(struct afs_cell *cell)
+{
+	struct proc_dir_entry *dir;
+	struct afs_net *net = cell->net;
+
+	_enter("%p{%s},%p", cell, cell->name, net->proc_afs);
+
+	dir = proc_net_mkdir(net->net, cell->name, net->proc_afs);
+	if (!dir)
+		goto error_dir;
+
+	if (!proc_create_net_data("vlservers", 0444, dir,
+				  &afs_proc_cell_vlservers_ops,
+				  sizeof(struct afs_vl_seq_net_private),
+				  cell) ||
+	    !proc_create_net_data("volumes", 0444, dir,
+				  &afs_proc_cell_volumes_ops,
+				  sizeof(struct seq_net_private),
+				  cell))
+		goto error_tree;
+
+	_leave(" = 0");
+	return 0;
+
+error_tree:
+	remove_proc_subtree(cell->name, net->proc_afs);
+error_dir:
+	_leave(" = -ENOMEM");
+	return -ENOMEM;
+}
+
+/*
+ * remove /proc/fs/afs/<cell>/
+ */
+void afs_proc_cell_remove(struct afs_cell *cell)
+{
+	struct afs_net *net = cell->net;
+
+	_enter("");
+	remove_proc_subtree(cell->name, net->proc_afs);
+	_leave("");
+}
+
+/*
+ * initialise the /proc/fs/afs/ directory
+ */
+int afs_proc_init(struct afs_net *net)
+{
+	struct proc_dir_entry *p;
+
+	_enter("");
+
+	p = proc_net_mkdir(net->net, "afs", net->net->proc_net);
+	if (!p)
+		goto error_dir;
+
+	if (!proc_create_net_data_write("cells", 0644, p,
+					&afs_proc_cells_ops,
+					afs_proc_cells_write,
+					sizeof(struct seq_net_private),
+					NULL) ||
+	    !proc_create_net_single_write("rootcell", 0644, p,
+					  afs_proc_rootcell_show,
+					  afs_proc_rootcell_write,
+					  NULL) ||
+	    !proc_create_net("servers", 0444, p, &afs_proc_servers_ops,
+			     sizeof(struct seq_net_private)) ||
+	    !proc_create_net_single("stats", 0444, p, afs_proc_stats_show, NULL) ||
+	    !proc_create_net_data_write("sysname", 0644, p,
+					&afs_proc_sysname_ops,
+					afs_proc_sysname_write,
+					sizeof(struct seq_net_private),
+					NULL) ||
+	    !proc_create_net_single_write("addr_prefs", 0644, p,
+					  afs_proc_addr_prefs_show,
+					  afs_proc_addr_prefs_write,
+					  NULL))
+		goto error_tree;
+
+	net->proc_afs = p;
+	_leave(" = 0");
+	return 0;
+
+error_tree:
+	proc_remove(p);
+error_dir:
+	_leave(" = -ENOMEM");
+	return -ENOMEM;
+}
+
+/*
+ * clean up the /proc/fs/afs/ directory
+ */
+void afs_proc_cleanup(struct afs_net *net)
+{
+	proc_remove(net->proc_afs);
+	net->proc_afs = NULL;
+}