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Merge branch 'sched-wait-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull wait_var_event updates from Ingo Molnar:
 "This introduces the new wait_var_event() API, which is a more flexible
  waiting primitive than wait_on_atomic_t().

  All wait_on_atomic_t() users are migrated over to the new API and
  wait_on_atomic_t() is removed. The migration fixes one bug and should
  result in no functional changes for the other usecases"

* 'sched-wait-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/wait: Improve __var_waitqueue() code generation
  sched/wait: Remove the wait_on_atomic_t() API
  sched/wait, arch/mips: Fix and convert wait_on_atomic_t() usage to the new wait_var_event() API
  sched/wait, fs/ocfs2: Convert wait_on_atomic_t() usage to the new wait_var_event() API
  sched/wait, fs/nfs: Convert wait_on_atomic_t() usage to the new wait_var_event() API
  sched/wait, fs/fscache: Convert wait_on_atomic_t() usage to the new wait_var_event() API
  sched/wait, fs/btrfs: Convert wait_on_atomic_t() usage to the new wait_var_event() API
  sched/wait, fs/afs: Convert wait_on_atomic_t() usage to the new wait_var_event() API
  sched/wait, drivers/media: Convert wait_on_atomic_t() usage to the new wait_var_event() API
  sched/wait, drivers/drm: Convert wait_on_atomic_t() usage to the new wait_var_event() API
  sched/wait: Introduce wait_var_event()
This commit is contained in:
Linus Torvalds
2018-04-02 16:50:39 -07:00
parent a5532439eb b3fc5c9bb3
commit ce6eba3dba
19 changed files with 147 additions and 170 deletions
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110
kernel/sched/wait_bit.c
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@@ -149,106 +149,48 @@ void wake_up_bit(void *word, int bit)
}
EXPORT_SYMBOL(wake_up_bit);
/*
* Manipulate the atomic_t address to produce a better bit waitqueue table hash
* index (we're keying off bit -1, but that would produce a horrible hash
* value).
*/
static inline wait_queue_head_t *atomic_t_waitqueue(atomic_t *p)
wait_queue_head_t *__var_waitqueue(void *p)
{
if (BITS_PER_LONG == 64) {
unsigned long q = (unsigned long)p;
return bit_waitqueue((void *)(q & ~1), q & 1);
}
return bit_waitqueue(p, 0);
return bit_wait_table + hash_ptr(p, WAIT_TABLE_BITS);
}
EXPORT_SYMBOL(__var_waitqueue);
static int wake_atomic_t_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync,
void *arg)
static int
var_wake_function(struct wait_queue_entry *wq_entry, unsigned int mode,
int sync, void *arg)
{
struct wait_bit_key *key = arg;
struct wait_bit_queue_entry *wait_bit = container_of(wq_entry, struct wait_bit_queue_entry, wq_entry);
atomic_t *val = key->flags;
struct wait_bit_queue_entry *wbq_entry =
container_of(wq_entry, struct wait_bit_queue_entry, wq_entry);
if (wait_bit->key.flags != key->flags ||
wait_bit->key.bit_nr != key->bit_nr ||
atomic_read(val) != 0)
if (wbq_entry->key.flags != key->flags ||
wbq_entry->key.bit_nr != key->bit_nr)
return 0;
return autoremove_wake_function(wq_entry, mode, sync, key);
}
/*
* To allow interruptible waiting and asynchronous (i.e. nonblocking) waiting,
* the actions of __wait_on_atomic_t() are permitted return codes. Nonzero
* return codes halt waiting and return.
*/
static __sched
int __wait_on_atomic_t(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry,
wait_atomic_t_action_f action, unsigned int mode)
void init_wait_var_entry(struct wait_bit_queue_entry *wbq_entry, void *var, int flags)
{
atomic_t *val;
int ret = 0;
do {
prepare_to_wait(wq_head, &wbq_entry->wq_entry, mode);
val = wbq_entry->key.flags;
if (atomic_read(val) == 0)
break;
ret = (*action)(val, mode);
} while (!ret && atomic_read(val) != 0);
finish_wait(wq_head, &wbq_entry->wq_entry);
return ret;
*wbq_entry = (struct wait_bit_queue_entry){
.key = {
.flags = (var),
.bit_nr = -1,
},
.wq_entry = {
.private = current,
.func = var_wake_function,
.entry = LIST_HEAD_INIT(wbq_entry->wq_entry.entry),
},
};
}
EXPORT_SYMBOL(init_wait_var_entry);
#define DEFINE_WAIT_ATOMIC_T(name, p) \
struct wait_bit_queue_entry name = { \
.key = __WAIT_ATOMIC_T_KEY_INITIALIZER(p), \
.wq_entry = { \
.private = current, \
.func = wake_atomic_t_function, \
.entry = \
LIST_HEAD_INIT((name).wq_entry.entry), \
}, \
}
__sched int out_of_line_wait_on_atomic_t(atomic_t *p,
wait_atomic_t_action_f action,
unsigned int mode)
void wake_up_var(void *var)
{
struct wait_queue_head *wq_head = atomic_t_waitqueue(p);
DEFINE_WAIT_ATOMIC_T(wq_entry, p);
return __wait_on_atomic_t(wq_head, &wq_entry, action, mode);
__wake_up_bit(__var_waitqueue(var), var, -1);
}
EXPORT_SYMBOL(out_of_line_wait_on_atomic_t);
__sched int atomic_t_wait(atomic_t *counter, unsigned int mode)
{
schedule();
if (signal_pending_state(mode, current))
return -EINTR;
return 0;
}
EXPORT_SYMBOL(atomic_t_wait);
/**
* wake_up_atomic_t - Wake up a waiter on a atomic_t
* @p: The atomic_t being waited on, a kernel virtual address
*
* Wake up anyone waiting for the atomic_t to go to zero.
*
* Abuse the bit-waker function and its waitqueue hash table set (the atomic_t
* check is done by the waiter's wake function, not the by the waker itself).
*/
void wake_up_atomic_t(atomic_t *p)
{
__wake_up_bit(atomic_t_waitqueue(p), p, WAIT_ATOMIC_T_BIT_NR);
}
EXPORT_SYMBOL(wake_up_atomic_t);
EXPORT_SYMBOL(wake_up_var);
__sched int bit_wait(struct wait_bit_key *word, int mode)
{