STATIC int
xfs_reclaim_inode_grab(
struct xfs_inode *ip,
int flags)
{
ASSERT(rcu_read_lock_held());
if (!ip->i_ino)
return 1;
if ((flags & SYNC_TRYLOCK) &&
__xfs_iflags_test(ip, XFS_IFLOCK | XFS_IRECLAIM))
return 1;
spin_lock(&ip->i_flags_lock);
if (!__xfs_iflags_test(ip, XFS_IRECLAIMABLE) ||
__xfs_iflags_test(ip, XFS_IRECLAIM)) {
spin_unlock(&ip->i_flags_lock);
return 1;
}
__xfs_iflags_set(ip, XFS_IRECLAIM);
spin_unlock(&ip->i_flags_lock);
return 0;
}
static void mesh_sync_offset_adjust_tsf(struct ieee80211_sub_if_data *sdata,
struct beacon_data *beacon)
{
struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
WARN_ON(ifmsh->mesh_sp_id != IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET);
WARN_ON(!rcu_read_lock_held());
spin_lock_bh(&ifmsh->sync_offset_lock);
if (ifmsh->sync_offset_clockdrift_max > TOFFSET_MINIMUM_ADJUSTMENT) {
/* Since ajusting the tsf here would
* require a possibly blocking call
* to the driver tsf setter, we punt
* the tsf adjustment to the mesh tasklet
*/
msync_dbg(sdata,
"TSF : kicking off TSF adjustment with clockdrift_max=%lld\n",
ifmsh->sync_offset_clockdrift_max);
set_bit(MESH_WORK_DRIFT_ADJUST, &ifmsh->wrkq_flags);
} else {
msync_dbg(sdata,
"TSF : max clockdrift=%lld; too small to adjust\n",
(long long)ifmsh->sync_offset_clockdrift_max);
ifmsh->sync_offset_clockdrift_max = 0;
}
spin_unlock_bh(&ifmsh->sync_offset_lock);
}
static int stack_map_get_next_key(struct bpf_map *map, void *key,
void *next_key)
{
struct bpf_stack_map *smap = container_of(map,
struct bpf_stack_map, map);
u32 id;
WARN_ON_ONCE(!rcu_read_lock_held());
if (!key) {
id = 0;
} else {
id = *(u32 *)key;
if (id >= smap->n_buckets || !smap->buckets[id])
id = 0;
else
id++;
}
while (id < smap->n_buckets && !smap->buckets[id])
id++;
if (id >= smap->n_buckets)
return -ENOENT;
*(u32 *)next_key = id;
return 0;
}
/* assumes rcu_read_lock() held at entry */
struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
{
struct page_map *page_map;
WARN_ON_ONCE(!rcu_read_lock_held());
page_map = radix_tree_lookup(&pgmap_radix, phys >> PA_SECTION_SHIFT);
return page_map ? &page_map->pgmap : NULL;
}
static u64 bpf_map_delete_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
void *key = (void *) (unsigned long) r2;
WARN_ON_ONCE(!rcu_read_lock_held());
return map->ops->map_delete_elem(map, key);
}
/**
* skb_dst_set_noref - sets skb dst, without a reference
* @skb: buffer
* @dst: dst entry
*
* Sets skb dst, assuming a reference was not taken on dst
* skb_dst_drop() should not dst_release() this dst
*/
void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
{
WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
/* If dst not in cache, we must take a reference, because
* dst_release() will destroy dst as soon as its refcount becomes zero
*/
if (unlikely(dst->flags & DST_NOCACHE)) {
dst_hold(dst);
skb_dst_set(skb, dst);
} else {
skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
}
}
STATIC int
xfs_inode_ag_walk_grab(
struct xfs_inode *ip)
{
struct inode *inode = VFS_I(ip);
ASSERT(rcu_read_lock_held());
/*
* check for stale RCU freed inode
*
* If the inode has been reallocated, it doesn't matter if it's not in
* the AG we are walking - we are walking for writeback, so if it
* passes all the "valid inode" checks and is dirty, then we'll write
* it back anyway. If it has been reallocated and still being
* initialised, the XFS_INEW check below will catch it.
*/
spin_lock(&ip->i_flags_lock);
if (!ip->i_ino)
goto out_unlock_noent;
/* avoid new or reclaimable inodes. Leave for reclaim code to flush */
if (__xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM))
goto out_unlock_noent;
spin_unlock(&ip->i_flags_lock);
/* nothing to sync during shutdown */
if (XFS_FORCED_SHUTDOWN(ip->i_mount))
return EFSCORRUPTED;
/* If we can't grab the inode, it must on it's way to reclaim. */
if (!igrab(inode))
return ENOENT;
if (is_bad_inode(inode)) {
IRELE(ip);
return ENOENT;
}
/* inode is valid */
return 0;
out_unlock_noent:
spin_unlock(&ip->i_flags_lock);
return ENOENT;
}
/* Must be called with rcu_read_lock. */
static
struct plum_replicator_elem *replicator_lookup_port(const struct plum *plum,
u32 replicator_id,
u32 port_id)
{
struct hlist_head *head;
struct plum_replicator_elem *elem;
WARN_ON_ONCE(!rcu_read_lock_held());
head = replicator_hash_bucket(plum, replicator_id);
hlist_for_each_entry_rcu(elem, head, hash_node) {
if (elem->replicator_id == replicator_id &&
elem->port_id == port_id)
return elem;
}
return NULL;
}
/* If kernel subsystem is allowing eBPF programs to call this function,
* inside its own verifier_ops->get_func_proto() callback it should return
* bpf_map_lookup_elem_proto, so that verifier can properly check the arguments
*
* Different map implementations will rely on rcu in map methods
* lookup/update/delete, therefore eBPF programs must run under rcu lock
* if program is allowed to access maps, so check rcu_read_lock_held in
* all three functions.
*/
static u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
/* verifier checked that R1 contains a valid pointer to bpf_map
* and R2 points to a program stack and map->key_size bytes were
* initialized
*/
struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
void *key = (void *) (unsigned long) r2;
void *value;
WARN_ON_ONCE(!rcu_read_lock_held());
value = map->ops->map_lookup_elem(map, key);
/* lookup() returns either pointer to element value or NULL
* which is the meaning of PTR_TO_MAP_VALUE_OR_NULL type
*/
return (unsigned long) value;
}
/*
* Grab the inode for reclaim exclusively.
* Return 0 if we grabbed it, non-zero otherwise.
*/
STATIC int
xfs_reclaim_inode_grab(
struct xfs_inode *ip,
int flags)
{
ASSERT(rcu_read_lock_held());
/* quick check for stale RCU freed inode */
if (!ip->i_ino)
return 1;
/*
* do some unlocked checks first to avoid unnecessary lock traffic.
* The first is a flush lock check, the second is a already in reclaim
* check. Only do these checks if we are not going to block on locks.
*/
if ((flags & SYNC_TRYLOCK) &&
(!ip->i_flush.done || __xfs_iflags_test(ip, XFS_IRECLAIM))) {
return 1;
}
/*
* The radix tree lock here protects a thread in xfs_iget from racing
* with us starting reclaim on the inode. Once we have the
* XFS_IRECLAIM flag set it will not touch us.
*
* Due to RCU lookup, we may find inodes that have been freed and only
* have XFS_IRECLAIM set. Indeed, we may see reallocated inodes that
* aren't candidates for reclaim at all, so we must check the
* XFS_IRECLAIMABLE is set first before proceeding to reclaim.
*/
spin_lock(&ip->i_flags_lock);
if (!__xfs_iflags_test(ip, XFS_IRECLAIMABLE) ||
__xfs_iflags_test(ip, XFS_IRECLAIM)) {
/* not a reclaim candidate. */
spin_unlock(&ip->i_flags_lock);
return 1;
}
__xfs_iflags_set(ip, XFS_IRECLAIM);
spin_unlock(&ip->i_flags_lock);
return 0;
}
/*
* Grab the inode for reclaim exclusively.
* Return 0 if we grabbed it, non-zero otherwise.
*/
STATIC int
xfs_reclaim_inode_grab(
struct xfs_inode *ip,
int flags)
{
ASSERT(rcu_read_lock_held());
/* quick check for stale RCU freed inode */
if (!ip->i_ino)
return 1;
/*
* If we are asked for non-blocking operation, do unlocked checks to
* see if the inode already is being flushed or in reclaim to avoid
* lock traffic.
*/
if ((flags & SYNC_TRYLOCK) &&
__xfs_iflags_test(ip, XFS_IFLOCK | XFS_IRECLAIM))
return 1;
/*
* The radix tree lock here protects a thread in xfs_iget from racing
* with us starting reclaim on the inode. Once we have the
* XFS_IRECLAIM flag set it will not touch us.
*
* Due to RCU lookup, we may find inodes that have been freed and only
* have XFS_IRECLAIM set. Indeed, we may see reallocated inodes that
* aren't candidates for reclaim at all, so we must check the
* XFS_IRECLAIMABLE is set first before proceeding to reclaim.
*/
spin_lock(&ip->i_flags_lock);
if (!__xfs_iflags_test(ip, XFS_IRECLAIMABLE) ||
__xfs_iflags_test(ip, XFS_IRECLAIM)) {
/* not a reclaim candidate. */
spin_unlock(&ip->i_flags_lock);
return 1;
}
__xfs_iflags_set(ip, XFS_IRECLAIM);
spin_unlock(&ip->i_flags_lock);
return 0;
}
STATIC int
xfs_inode_ag_walk_grab(
struct xfs_inode *ip)
{
struct inode *inode = VFS_I(ip);
ASSERT(rcu_read_lock_held());
spin_lock(&ip->i_flags_lock);
if (!ip->i_ino)
goto out_unlock_noent;
if (__xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM))
goto out_unlock_noent;
spin_unlock(&ip->i_flags_lock);
if (XFS_FORCED_SHUTDOWN(ip->i_mount))
return EFSCORRUPTED;
if (!igrab(inode))
return ENOENT;
if (is_bad_inode(inode)) {
IRELE(ip);
return ENOENT;
}
return 0;
out_unlock_noent:
spin_unlock(&ip->i_flags_lock);
return ENOENT;
}
BPF_CALL_2(bpf_map_delete_elem, struct bpf_map *, map, void *, key)
{
WARN_ON_ONCE(!rcu_read_lock_held());
return map->ops->map_delete_elem(map, key);
}
BPF_CALL_4(bpf_map_update_elem, struct bpf_map *, map, void *, key,
void *, value, u64, flags)
{
WARN_ON_ONCE(!rcu_read_lock_held());
return map->ops->map_update_elem(map, key, value, flags);
}
/* If kernel subsystem is allowing eBPF programs to call this function,
* inside its own verifier_ops->get_func_proto() callback it should return
* bpf_map_lookup_elem_proto, so that verifier can properly check the arguments
*
* Different map implementations will rely on rcu in map methods
* lookup/update/delete, therefore eBPF programs must run under rcu lock
* if program is allowed to access maps, so check rcu_read_lock_held in
* all three functions.
*/
BPF_CALL_2(bpf_map_lookup_elem, struct bpf_map *, map, void *, key)
{
WARN_ON_ONCE(!rcu_read_lock_held());
return (unsigned long) map->ops->map_lookup_elem(map, key);
}
/**
* xprt_iter_xprt - Returns the rpc_xprt pointed to by the cursor
* @xpi: pointer to rpc_xprt_iter
*
* Returns a pointer to the struct rpc_xprt that is currently
* pointed to by the cursor.
* Caller must be holding rcu_read_lock().
*/
struct rpc_xprt *xprt_iter_xprt(struct rpc_xprt_iter *xpi)
{
WARN_ON_ONCE(!rcu_read_lock_held());
return xprt_iter_ops(xpi)->xpi_xprt(xpi);
}