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

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>

1 files changed, 0 insertions, 250 deletions

diff --git a/include/linux/wait.h b/include/linux/wait.h
index 0805098f3589..629489746f8a 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -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 */