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rcu: List-debug variants of rcu list routines.

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* Make __list_add_rcu check the next->prev and prev->next pointers
  just like __list_add does.
* Make list_del_rcu use __list_del_entry, which does the same checking
  at deletion time.

Has been running for a week here without anything being tripped up,
but it seems worth adding for completeness just in case something
ever does corrupt those lists.

Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Dave Jones 2012-03-14 22:17:39 -04:00 committed by Paul E. McKenney
parent 66f75a5d02
commit 559f9badd1
2 changed files with 28 additions and 1 deletions
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7
include/linux/rculist.h
View File

@ -30,6 +30,7 @@
* This is only for internal list manipulation where we know * This is only for internal list manipulation where we know
* the prev/next entries already! * the prev/next entries already!
*/ */
#ifndef CONFIG_DEBUG_LIST
static inline void __list_add_rcu(struct list_head *new, static inline void __list_add_rcu(struct list_head *new,
struct list_head *prev, struct list_head *next) struct list_head *prev, struct list_head *next)
{ {
@ -38,6 +39,10 @@ static inline void __list_add_rcu(struct list_head *new,
rcu_assign_pointer(list_next_rcu(prev), new); rcu_assign_pointer(list_next_rcu(prev), new);
next->prev = new; next->prev = new;
} }
#else
extern void __list_add_rcu(struct list_head *new,
struct list_head *prev, struct list_head *next);
#endif
/** /**
* list_add_rcu - add a new entry to rcu-protected list * list_add_rcu - add a new entry to rcu-protected list
@ -108,7 +113,7 @@ static inline void list_add_tail_rcu(struct list_head *new,
*/ */
static inline void list_del_rcu(struct list_head *entry) static inline void list_del_rcu(struct list_head *entry)
{ {
__list_del(entry->prev, entry->next); __list_del_entry(entry);
entry->prev = LIST_POISON2; entry->prev = LIST_POISON2;
} }

22
lib/list_debug.c
View File

@ -10,6 +10,7 @@
#include <linux/list.h> #include <linux/list.h>
#include <linux/bug.h> #include <linux/bug.h>
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/rculist.h>
/* /*
* Insert a new entry between two known consecutive entries. * Insert a new entry between two known consecutive entries.
@ -75,3 +76,24 @@ void list_del(struct list_head *entry)
entry->prev = LIST_POISON2; entry->prev = LIST_POISON2;
} }
EXPORT_SYMBOL(list_del); EXPORT_SYMBOL(list_del);
/*
* RCU variants.
*/
void __list_add_rcu(struct list_head *new,
struct list_head *prev, struct list_head *next)
{
WARN(next->prev != prev,
"list_add_rcu corruption. next->prev should be "
"prev (%p), but was %p. (next=%p).\n",
prev, next->prev, next);
WARN(prev->next != next,
"list_add_rcu corruption. prev->next should be "
"next (%p), but was %p. (prev=%p).\n",
next, prev->next, prev);
new->next = next;
new->prev = prev;
rcu_assign_pointer(list_next_rcu(prev), new);
next->prev = new;
}
EXPORT_SYMBOL(__list_add_rcu);