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sched/wait: Split out the wait_bit*() APIs from <linux/wait.h> into <linux/wait_bit.h>

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The wait_bit*() types and APIs are mixed into wait.h, but they
are a pretty orthogonal extension of wait-queues.

Furthermore, only about 50 kernel files use these APIs, while
over 1000 use the regular wait-queue functionality.

So clean up the main wait.h by moving the wait-bit functionality
out of it, into a separate .h and .c file:

  include/linux/wait_bit.h  for types and APIs
  kernel/sched/wait_bit.c   for the implementation

Update all header dependencies.

This reduces the size of wait.h rather significantly, by about 30%.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar
2017-06-20 12:19:09 +02:00
parent 4b1c480bfa
commit 5dd43ce2f6
11 changed files with 530 additions and 511 deletions
Download Patch File Download Diff File Expand all files Collapse all files

250
include/linux/wait.h
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@@ -29,18 +29,6 @@ struct wait_queue_entry {
struct list_head task_list;
};
struct wait_bit_key {
void *flags;
int bit_nr;
#define WAIT_ATOMIC_T_BIT_NR -1
unsigned long timeout;
};
struct wait_bit_queue_entry {
struct wait_bit_key key;
struct wait_queue_entry wq_entry;
};
struct wait_queue_head {
spinlock_t lock;
struct list_head task_list;
@@ -68,12 +56,6 @@ struct task_struct;
#define DECLARE_WAIT_QUEUE_HEAD(name) \
struct wait_queue_head name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
#define __WAIT_BIT_KEY_INITIALIZER(word, bit) \
{ .flags = word, .bit_nr = bit, }
#define __WAIT_ATOMIC_T_KEY_INITIALIZER(p) \
{ .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, }
extern void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *);
#define init_waitqueue_head(wq_head) \
@@ -200,22 +182,11 @@ __remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq
list_del(&wq_entry->task_list);
}
typedef int wait_bit_action_f(struct wait_bit_key *key, int mode);
void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr);
void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode, int nr);
void __wake_up_bit(struct wait_queue_head *wq_head, void *word, int bit);
int __wait_on_bit(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry, wait_bit_action_f *action, unsigned int mode);
int __wait_on_bit_lock(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry, wait_bit_action_f *action, unsigned int mode);
void wake_up_bit(void *word, int bit);
void wake_up_atomic_t(atomic_t *p);
int out_of_line_wait_on_bit(void *word, int, wait_bit_action_f *action, unsigned int mode);
int out_of_line_wait_on_bit_timeout(void *word, int, wait_bit_action_f *action, unsigned int mode, unsigned long timeout);
int out_of_line_wait_on_bit_lock(void *word, int, wait_bit_action_f *action, unsigned int mode);
int out_of_line_wait_on_atomic_t(atomic_t *p, int (*)(atomic_t *), unsigned int mode);
struct wait_queue_head *bit_waitqueue(void *word, int bit);
#define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL)
#define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL)
@@ -976,7 +947,6 @@ void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_en
long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout);
int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key);
#define DEFINE_WAIT_FUNC(name, function) \
struct wait_queue_entry name = { \
@@ -987,17 +957,6 @@ int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync
#define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
#define DEFINE_WAIT_BIT(name, word, bit) \
struct wait_bit_queue_entry name = { \
.key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \
.wq_entry = { \
.private = current, \
.func = wake_bit_function, \
.task_list = \
LIST_HEAD_INIT((name).wq_entry.task_list), \
}, \
}
#define init_wait(wait) \
do { \
(wait)->private = current; \
@@ -1006,213 +965,4 @@ int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync
(wait)->flags = 0; \
} while (0)
extern int bit_wait(struct wait_bit_key *key, int bit);
extern int bit_wait_io(struct wait_bit_key *key, int bit);
extern int bit_wait_timeout(struct wait_bit_key *key, int bit);
extern int bit_wait_io_timeout(struct wait_bit_key *key, int bit);
/**
* wait_on_bit - wait for a bit to be cleared
* @word: the word being waited on, a kernel virtual address
* @bit: the bit of the word being waited on
* @mode: the task state to sleep in
*
* There is a standard hashed waitqueue table for generic use. This
* is the part of the hashtable's accessor API that waits on a bit.
* For instance, if one were to have waiters on a bitflag, one would
* call wait_on_bit() in threads waiting for the bit to clear.
* One uses wait_on_bit() where one is waiting for the bit to clear,
* but has no intention of setting it.
* Returned value will be zero if the bit was cleared, or non-zero
* if the process received a signal and the mode permitted wakeup
* on that signal.
*/
static inline int
wait_on_bit(unsigned long *word, int bit, unsigned mode)
{
might_sleep();
if (!test_bit(bit, word))
return 0;
return out_of_line_wait_on_bit(word, bit,
bit_wait,
mode);
}
/**
* wait_on_bit_io - wait for a bit to be cleared
* @word: the word being waited on, a kernel virtual address
* @bit: the bit of the word being waited on
* @mode: the task state to sleep in
*
* Use the standard hashed waitqueue table to wait for a bit
* to be cleared. This is similar to wait_on_bit(), but calls
* io_schedule() instead of schedule() for the actual waiting.
*
* Returned value will be zero if the bit was cleared, or non-zero
* if the process received a signal and the mode permitted wakeup
* on that signal.
*/
static inline int
wait_on_bit_io(unsigned long *word, int bit, unsigned mode)
{
might_sleep();
if (!test_bit(bit, word))
return 0;
return out_of_line_wait_on_bit(word, bit,
bit_wait_io,
mode);
}
/**
* wait_on_bit_timeout - wait for a bit to be cleared or a timeout elapses
* @word: the word being waited on, a kernel virtual address
* @bit: the bit of the word being waited on
* @mode: the task state to sleep in
* @timeout: timeout, in jiffies
*
* Use the standard hashed waitqueue table to wait for a bit
* to be cleared. This is similar to wait_on_bit(), except also takes a
* timeout parameter.
*
* Returned value will be zero if the bit was cleared before the
* @timeout elapsed, or non-zero if the @timeout elapsed or process
* received a signal and the mode permitted wakeup on that signal.
*/
static inline int
wait_on_bit_timeout(unsigned long *word, int bit, unsigned mode,
unsigned long timeout)
{
might_sleep();
if (!test_bit(bit, word))
return 0;
return out_of_line_wait_on_bit_timeout(word, bit,
bit_wait_timeout,
mode, timeout);
}
/**
* wait_on_bit_action - wait for a bit to be cleared
* @word: the word being waited on, a kernel virtual address
* @bit: the bit of the word being waited on
* @action: the function used to sleep, which may take special actions
* @mode: the task state to sleep in
*
* Use the standard hashed waitqueue table to wait for a bit
* to be cleared, and allow the waiting action to be specified.
* This is like wait_on_bit() but allows fine control of how the waiting
* is done.
*
* Returned value will be zero if the bit was cleared, or non-zero
* if the process received a signal and the mode permitted wakeup
* on that signal.
*/
static inline int
wait_on_bit_action(unsigned long *word, int bit, wait_bit_action_f *action,
unsigned mode)
{
might_sleep();
if (!test_bit(bit, word))
return 0;
return out_of_line_wait_on_bit(word, bit, action, mode);
}
/**
* wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
* @word: the word being waited on, a kernel virtual address
* @bit: the bit of the word being waited on
* @mode: the task state to sleep in
*
* There is a standard hashed waitqueue table for generic use. This
* is the part of the hashtable's accessor API that waits on a bit
* when one intends to set it, for instance, trying to lock bitflags.
* For instance, if one were to have waiters trying to set bitflag
* and waiting for it to clear before setting it, one would call
* wait_on_bit() in threads waiting to be able to set the bit.
* One uses wait_on_bit_lock() where one is waiting for the bit to
* clear with the intention of setting it, and when done, clearing it.
*
* Returns zero if the bit was (eventually) found to be clear and was
* set. Returns non-zero if a signal was delivered to the process and
* the @mode allows that signal to wake the process.
*/
static inline int
wait_on_bit_lock(unsigned long *word, int bit, unsigned mode)
{
might_sleep();
if (!test_and_set_bit(bit, word))
return 0;
return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
}
/**
* wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it
* @word: the word being waited on, a kernel virtual address
* @bit: the bit of the word being waited on
* @mode: the task state to sleep in
*
* Use the standard hashed waitqueue table to wait for a bit
* to be cleared and then to atomically set it. This is similar
* to wait_on_bit(), but calls io_schedule() instead of schedule()
* for the actual waiting.
*
* Returns zero if the bit was (eventually) found to be clear and was
* set. Returns non-zero if a signal was delivered to the process and
* the @mode allows that signal to wake the process.
*/
static inline int
wait_on_bit_lock_io(unsigned long *word, int bit, unsigned mode)
{
might_sleep();
if (!test_and_set_bit(bit, word))
return 0;
return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
}
/**
* wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it
* @word: the word being waited on, a kernel virtual address
* @bit: the bit of the word being waited on
* @action: the function used to sleep, which may take special actions
* @mode: the task state to sleep in
*
* Use the standard hashed waitqueue table to wait for a bit
* to be cleared and then to set it, and allow the waiting action
* to be specified.
* This is like wait_on_bit() but allows fine control of how the waiting
* is done.
*
* Returns zero if the bit was (eventually) found to be clear and was
* set. Returns non-zero if a signal was delivered to the process and
* the @mode allows that signal to wake the process.
*/
static inline int
wait_on_bit_lock_action(unsigned long *word, int bit, wait_bit_action_f *action,
unsigned mode)
{
might_sleep();
if (!test_and_set_bit(bit, word))
return 0;
return out_of_line_wait_on_bit_lock(word, bit, action, mode);
}
/**
* wait_on_atomic_t - Wait for an atomic_t to become 0
* @val: The atomic value being waited on, a kernel virtual address
* @action: the function used to sleep, which may take special actions
* @mode: the task state to sleep in
*
* Wait for an atomic_t to become 0. We abuse the bit-wait waitqueue table for
* the purpose of getting a waitqueue, but we set the key to a bit number
* outside of the target 'word'.
*/
static inline
int wait_on_atomic_t(atomic_t *val, int (*action)(atomic_t *), unsigned mode)
{
might_sleep();
if (atomic_read(val) == 0)
return 0;
return out_of_line_wait_on_atomic_t(val, action, mode);
}
#endif /* _LINUX_WAIT_H */