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sched: change wake_up_bit() and related function to expect unsigned long *

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wake_up_bit() currently allows a "void *".  While this isn't strictly a
problem as the address is never dereferenced, it is inconsistent with
the corresponding wait_on_bit() which requires "unsigned long *" and
does dereference the pointer.

Any code that needs to wait for a change in something other than an
unsigned long would be better served by wake_up_var()/wait_var_event().

This patch changes all related "void *" to "unsigned long *".

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240925053405.3960701-2-neilb@suse.de
This commit is contained in:
NeilBrown 2024-09-25 15:31:38 +10:00 committed by Peter Zijlstra
parent 8cf0b93919
commit 2382d68d7d
2 changed files with 14 additions and 14 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

16
include/linux/wait_bit.h
View file

@ -8,7 +8,7 @@
#include <linux/wait.h> #include <linux/wait.h>
struct wait_bit_key { struct wait_bit_key {
void *flags; unsigned long *flags;
int bit_nr; int bit_nr;
unsigned long timeout; unsigned long timeout;
}; };
@ -23,14 +23,14 @@ struct wait_bit_queue_entry {
typedef int wait_bit_action_f(struct wait_bit_key *key, int mode); typedef int wait_bit_action_f(struct wait_bit_key *key, int mode);
void __wake_up_bit(struct wait_queue_head *wq_head, void *word, int bit); void __wake_up_bit(struct wait_queue_head *wq_head, unsigned long *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(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); 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_bit(unsigned long *word, int bit);
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(unsigned long *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_timeout(unsigned long *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_bit_lock(unsigned long *word, int, wait_bit_action_f *action, unsigned int mode);
struct wait_queue_head *bit_waitqueue(void *word, int bit); struct wait_queue_head *bit_waitqueue(unsigned long *word, int bit);
extern void __init wait_bit_init(void); extern void __init wait_bit_init(void);
int wake_bit_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);
@ -327,7 +327,7 @@ do { \
* You can use this helper if bitflags are manipulated atomically rather than * You can use this helper if bitflags are manipulated atomically rather than
* non-atomically under a lock. * non-atomically under a lock.
*/ */
static inline void clear_and_wake_up_bit(int bit, void *word) static inline void clear_and_wake_up_bit(int bit, unsigned long *word)
{ {
clear_bit_unlock(bit, word); clear_bit_unlock(bit, word);
/* See wake_up_bit() for which memory barrier you need to use. */ /* See wake_up_bit() for which memory barrier you need to use. */

12
kernel/sched/wait_bit.c
View file

@ -9,7 +9,7 @@
static wait_queue_head_t bit_wait_table[WAIT_TABLE_SIZE] __cacheline_aligned; static wait_queue_head_t bit_wait_table[WAIT_TABLE_SIZE] __cacheline_aligned;
wait_queue_head_t *bit_waitqueue(void *word, int bit) wait_queue_head_t *bit_waitqueue(unsigned long *word, int bit)
{ {
const int shift = BITS_PER_LONG == 32 ? 5 : 6; const int shift = BITS_PER_LONG == 32 ? 5 : 6;
unsigned long val = (unsigned long)word << shift | bit; unsigned long val = (unsigned long)word << shift | bit;
@ -55,7 +55,7 @@ __wait_on_bit(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_
} }
EXPORT_SYMBOL(__wait_on_bit); EXPORT_SYMBOL(__wait_on_bit);
int __sched out_of_line_wait_on_bit(void *word, int bit, int __sched out_of_line_wait_on_bit(unsigned long *word, int bit,
wait_bit_action_f *action, unsigned mode) wait_bit_action_f *action, unsigned mode)
{ {
struct wait_queue_head *wq_head = bit_waitqueue(word, bit); struct wait_queue_head *wq_head = bit_waitqueue(word, bit);
@ -66,7 +66,7 @@ int __sched out_of_line_wait_on_bit(void *word, int bit,
EXPORT_SYMBOL(out_of_line_wait_on_bit); EXPORT_SYMBOL(out_of_line_wait_on_bit);
int __sched out_of_line_wait_on_bit_timeout( int __sched out_of_line_wait_on_bit_timeout(
void *word, int bit, wait_bit_action_f *action, unsigned long *word, int bit, wait_bit_action_f *action,
unsigned mode, unsigned long timeout) unsigned mode, unsigned long timeout)
{ {
struct wait_queue_head *wq_head = bit_waitqueue(word, bit); struct wait_queue_head *wq_head = bit_waitqueue(word, bit);
@ -108,7 +108,7 @@ __wait_on_bit_lock(struct wait_queue_head *wq_head, struct wait_bit_queue_entry
} }
EXPORT_SYMBOL(__wait_on_bit_lock); EXPORT_SYMBOL(__wait_on_bit_lock);
int __sched out_of_line_wait_on_bit_lock(void *word, int bit, int __sched out_of_line_wait_on_bit_lock(unsigned long *word, int bit,
wait_bit_action_f *action, unsigned mode) wait_bit_action_f *action, unsigned mode)
{ {
struct wait_queue_head *wq_head = bit_waitqueue(word, bit); struct wait_queue_head *wq_head = bit_waitqueue(word, bit);
@ -118,7 +118,7 @@ int __sched out_of_line_wait_on_bit_lock(void *word, int bit,
} }
EXPORT_SYMBOL(out_of_line_wait_on_bit_lock); EXPORT_SYMBOL(out_of_line_wait_on_bit_lock);
void __wake_up_bit(struct wait_queue_head *wq_head, void *word, int bit) void __wake_up_bit(struct wait_queue_head *wq_head, unsigned long *word, int bit)
{ {
struct wait_bit_key key = __WAIT_BIT_KEY_INITIALIZER(word, bit); struct wait_bit_key key = __WAIT_BIT_KEY_INITIALIZER(word, bit);
@ -144,7 +144,7 @@ EXPORT_SYMBOL(__wake_up_bit);
* may need to use a less regular barrier, such fs/inode.c's smp_mb(), * may need to use a less regular barrier, such fs/inode.c's smp_mb(),
* because spin_unlock() does not guarantee a memory barrier. * because spin_unlock() does not guarantee a memory barrier.
*/ */
void wake_up_bit(void *word, int bit) void wake_up_bit(unsigned long *word, int bit)
{ {
__wake_up_bit(bit_waitqueue(word, bit), word, bit); __wake_up_bit(bit_waitqueue(word, bit), word, bit);
} }