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![Jiri Pirko](/assets/img/avatar_default.png)
In case the qdisc_match_from_root function() is called from non-rcu path with rtnl mutex held, a suspiciout rcu usage warning appears: [ 241.504354] ============================= [ 241.504358] WARNING: suspicious RCU usage [ 241.504366] 5.8.0-rc4-custom-01521-g72a7c7d549c3 #32 Not tainted [ 241.504370] ----------------------------- [ 241.504378] net/sched/sch_api.c:270 RCU-list traversed in non-reader section!! [ 241.504382] other info that might help us debug this: [ 241.504388] rcu_scheduler_active = 2, debug_locks = 1 [ 241.504394] 1 lock held by tc/1391: [ 241.504398] #0: ffffffff85a27850 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x49a/0xbd0 [ 241.504431] stack backtrace: [ 241.504440] CPU: 0 PID: 1391 Comm: tc Not tainted 5.8.0-rc4-custom-01521-g72a7c7d549c3 #32 [ 241.504446] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-2.fc32 04/01/2014 [ 241.504453] Call Trace: [ 241.504465] dump_stack+0x100/0x184 [ 241.504482] lockdep_rcu_suspicious+0x153/0x15d [ 241.504499] qdisc_match_from_root+0x293/0x350 Fix this by passing the rtnl held lockdep condition down to hlist_for_each_entry_rcu() Reported-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
209 lines
6.7 KiB
C
209 lines
6.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Statically sized hash table implementation
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* (C) 2012 Sasha Levin <levinsasha928@gmail.com>
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*/
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#ifndef _LINUX_HASHTABLE_H
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#define _LINUX_HASHTABLE_H
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#include <linux/list.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/hash.h>
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#include <linux/rculist.h>
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#define DEFINE_HASHTABLE(name, bits) \
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struct hlist_head name[1 << (bits)] = \
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{ [0 ... ((1 << (bits)) - 1)] = HLIST_HEAD_INIT }
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#define DEFINE_READ_MOSTLY_HASHTABLE(name, bits) \
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struct hlist_head name[1 << (bits)] __read_mostly = \
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{ [0 ... ((1 << (bits)) - 1)] = HLIST_HEAD_INIT }
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#define DECLARE_HASHTABLE(name, bits) \
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struct hlist_head name[1 << (bits)]
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#define HASH_SIZE(name) (ARRAY_SIZE(name))
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#define HASH_BITS(name) ilog2(HASH_SIZE(name))
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/* Use hash_32 when possible to allow for fast 32bit hashing in 64bit kernels. */
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#define hash_min(val, bits) \
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(sizeof(val) <= 4 ? hash_32(val, bits) : hash_long(val, bits))
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static inline void __hash_init(struct hlist_head *ht, unsigned int sz)
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{
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unsigned int i;
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for (i = 0; i < sz; i++)
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INIT_HLIST_HEAD(&ht[i]);
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}
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/**
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* hash_init - initialize a hash table
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* @hashtable: hashtable to be initialized
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*
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* Calculates the size of the hashtable from the given parameter, otherwise
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* same as hash_init_size.
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*
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* This has to be a macro since HASH_BITS() will not work on pointers since
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* it calculates the size during preprocessing.
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*/
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#define hash_init(hashtable) __hash_init(hashtable, HASH_SIZE(hashtable))
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/**
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* hash_add - add an object to a hashtable
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* @hashtable: hashtable to add to
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* @node: the &struct hlist_node of the object to be added
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* @key: the key of the object to be added
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*/
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#define hash_add(hashtable, node, key) \
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hlist_add_head(node, &hashtable[hash_min(key, HASH_BITS(hashtable))])
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/**
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* hash_add_rcu - add an object to a rcu enabled hashtable
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* @hashtable: hashtable to add to
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* @node: the &struct hlist_node of the object to be added
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* @key: the key of the object to be added
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*/
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#define hash_add_rcu(hashtable, node, key) \
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hlist_add_head_rcu(node, &hashtable[hash_min(key, HASH_BITS(hashtable))])
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/**
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* hash_hashed - check whether an object is in any hashtable
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* @node: the &struct hlist_node of the object to be checked
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*/
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static inline bool hash_hashed(struct hlist_node *node)
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{
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return !hlist_unhashed(node);
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}
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static inline bool __hash_empty(struct hlist_head *ht, unsigned int sz)
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{
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unsigned int i;
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for (i = 0; i < sz; i++)
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if (!hlist_empty(&ht[i]))
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return false;
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return true;
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}
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/**
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* hash_empty - check whether a hashtable is empty
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* @hashtable: hashtable to check
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*
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* This has to be a macro since HASH_BITS() will not work on pointers since
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* it calculates the size during preprocessing.
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*/
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#define hash_empty(hashtable) __hash_empty(hashtable, HASH_SIZE(hashtable))
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/**
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* hash_del - remove an object from a hashtable
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* @node: &struct hlist_node of the object to remove
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*/
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static inline void hash_del(struct hlist_node *node)
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{
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hlist_del_init(node);
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}
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/**
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* hash_del_rcu - remove an object from a rcu enabled hashtable
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* @node: &struct hlist_node of the object to remove
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*/
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static inline void hash_del_rcu(struct hlist_node *node)
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{
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hlist_del_init_rcu(node);
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}
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/**
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* hash_for_each - iterate over a hashtable
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* @name: hashtable to iterate
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* @bkt: integer to use as bucket loop cursor
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* @obj: the type * to use as a loop cursor for each entry
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* @member: the name of the hlist_node within the struct
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*/
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#define hash_for_each(name, bkt, obj, member) \
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for ((bkt) = 0, obj = NULL; obj == NULL && (bkt) < HASH_SIZE(name);\
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(bkt)++)\
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hlist_for_each_entry(obj, &name[bkt], member)
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/**
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* hash_for_each_rcu - iterate over a rcu enabled hashtable
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* @name: hashtable to iterate
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* @bkt: integer to use as bucket loop cursor
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* @obj: the type * to use as a loop cursor for each entry
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* @member: the name of the hlist_node within the struct
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*/
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#define hash_for_each_rcu(name, bkt, obj, member) \
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for ((bkt) = 0, obj = NULL; obj == NULL && (bkt) < HASH_SIZE(name);\
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(bkt)++)\
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hlist_for_each_entry_rcu(obj, &name[bkt], member)
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/**
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* hash_for_each_safe - iterate over a hashtable safe against removal of
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* hash entry
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* @name: hashtable to iterate
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* @bkt: integer to use as bucket loop cursor
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* @tmp: a &struct hlist_node used for temporary storage
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* @obj: the type * to use as a loop cursor for each entry
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* @member: the name of the hlist_node within the struct
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*/
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#define hash_for_each_safe(name, bkt, tmp, obj, member) \
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for ((bkt) = 0, obj = NULL; obj == NULL && (bkt) < HASH_SIZE(name);\
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(bkt)++)\
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hlist_for_each_entry_safe(obj, tmp, &name[bkt], member)
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/**
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* hash_for_each_possible - iterate over all possible objects hashing to the
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* same bucket
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* @name: hashtable to iterate
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* @obj: the type * to use as a loop cursor for each entry
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* @member: the name of the hlist_node within the struct
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* @key: the key of the objects to iterate over
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*/
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#define hash_for_each_possible(name, obj, member, key) \
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hlist_for_each_entry(obj, &name[hash_min(key, HASH_BITS(name))], member)
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/**
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* hash_for_each_possible_rcu - iterate over all possible objects hashing to the
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* same bucket in an rcu enabled hashtable
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* @name: hashtable to iterate
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* @obj: the type * to use as a loop cursor for each entry
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* @member: the name of the hlist_node within the struct
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* @key: the key of the objects to iterate over
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*/
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#define hash_for_each_possible_rcu(name, obj, member, key, cond...) \
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hlist_for_each_entry_rcu(obj, &name[hash_min(key, HASH_BITS(name))],\
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member, ## cond)
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/**
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* hash_for_each_possible_rcu_notrace - iterate over all possible objects hashing
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* to the same bucket in an rcu enabled hashtable in a rcu enabled hashtable
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* @name: hashtable to iterate
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* @obj: the type * to use as a loop cursor for each entry
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* @member: the name of the hlist_node within the struct
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* @key: the key of the objects to iterate over
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*
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* This is the same as hash_for_each_possible_rcu() except that it does
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* not do any RCU debugging or tracing.
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*/
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#define hash_for_each_possible_rcu_notrace(name, obj, member, key) \
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hlist_for_each_entry_rcu_notrace(obj, \
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&name[hash_min(key, HASH_BITS(name))], member)
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/**
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* hash_for_each_possible_safe - iterate over all possible objects hashing to the
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* same bucket safe against removals
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* @name: hashtable to iterate
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* @obj: the type * to use as a loop cursor for each entry
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* @tmp: a &struct hlist_node used for temporary storage
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* @member: the name of the hlist_node within the struct
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* @key: the key of the objects to iterate over
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*/
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#define hash_for_each_possible_safe(name, obj, tmp, member, key) \
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hlist_for_each_entry_safe(obj, tmp,\
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&name[hash_min(key, HASH_BITS(name))], member)
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#endif
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