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locks: encapsulate the fl_link list handling

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Move the fl_link list handling routines into a separate set of helpers.
Also ensure that locks and requests are always put on global lists
last (after fully initializing them) and are taken off before unintializing
them.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Jeff Layton 2013-06-21 08:58:14 -04:00 committed by Al Viro
parent b9746ef80f
commit 8897469171
1 changed files with 36 additions and 9 deletions
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45
fs/locks.c
View file

@ -153,13 +153,15 @@ int lease_break_time = 45;
#define for_each_lock(inode, lockp) \
for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next)
/* The global file_lock_list is only used for displaying /proc/locks. */
static LIST_HEAD(file_lock_list);
/* The blocked_list is used to find POSIX lock loops for deadlock detection. */
static LIST_HEAD(blocked_list);
/* Protects the two list heads above, plus the inode->i_flock list */
static DEFINE_SPINLOCK(file_lock_lock);
/*
* Protects the two list heads above, plus the inode->i_flock list
*/
void lock_flocks(void)
{
spin_lock(&file_lock_lock);
@ -484,13 +486,37 @@ static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
return fl1->fl_owner == fl2->fl_owner;
}
static inline void
locks_insert_global_locks(struct file_lock *fl)
{
list_add_tail(&fl->fl_link, &file_lock_list);
}
static inline void
locks_delete_global_locks(struct file_lock *fl)
{
list_del_init(&fl->fl_link);
}
static inline void
locks_insert_global_blocked(struct file_lock *waiter)
{
list_add(&waiter->fl_link, &blocked_list);
}
static inline void
locks_delete_global_blocked(struct file_lock *waiter)
{
list_del_init(&waiter->fl_link);
}
/* Remove waiter from blocker's block list.
* When blocker ends up pointing to itself then the list is empty.
*/
static void __locks_delete_block(struct file_lock *waiter)
{
locks_delete_global_blocked(waiter);
list_del_init(&waiter->fl_block);
list_del_init(&waiter->fl_link);
waiter->fl_next = NULL;
}
@ -512,10 +538,10 @@ static void locks_insert_block(struct file_lock *blocker,
struct file_lock *waiter)
{
BUG_ON(!list_empty(&waiter->fl_block));
list_add_tail(&waiter->fl_block, &blocker->fl_block);
waiter->fl_next = blocker;
list_add_tail(&waiter->fl_block, &blocker->fl_block);
if (IS_POSIX(blocker))
list_add(&waiter->fl_link, &blocked_list);
locks_insert_global_blocked(request);
}
/*
@ -543,13 +569,13 @@ static void locks_wake_up_blocks(struct file_lock *blocker)
*/
static void locks_insert_lock(struct file_lock **pos, struct file_lock *fl)
{
list_add(&fl->fl_link, &file_lock_list);
fl->fl_nspid = get_pid(task_tgid(current));
/* insert into file's list */
fl->fl_next = *pos;
*pos = fl;
locks_insert_global_locks(fl);
}
/*
@ -562,9 +588,10 @@ static void locks_delete_lock(struct file_lock **thisfl_p)
{
struct file_lock *fl = *thisfl_p;
locks_delete_global_locks(fl);
*thisfl_p = fl->fl_next;
fl->fl_next = NULL;
list_del_init(&fl->fl_link);
if (fl->fl_nspid) {
put_pid(fl->fl_nspid);