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Message-ID: <20240925053118.3956520-3-neilb@suse.de>
Date: Wed, 25 Sep 2024 15:24:05 +1000
From: NeilBrown <neilb@...e.de>
To: Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH 2/8] sched: change wake_up_bit() and related function to expect unsigned long *
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@...ux-foundation.org>
Signed-off-by: NeilBrown <neilb@...e.de>
---
include/linux/wait_bit.h | 16 ++++++++--------
kernel/sched/wait_bit.c | 12 ++++++------
2 files changed, 14 insertions(+), 14 deletions(-)
diff --git a/include/linux/wait_bit.h b/include/linux/wait_bit.h
index 7725b7579b78..48e123839892 100644
--- a/include/linux/wait_bit.h
+++ b/include/linux/wait_bit.h
@@ -8,7 +8,7 @@
#include <linux/wait.h>
struct wait_bit_key {
- void *flags;
+ unsigned long *flags;
int bit_nr;
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);
-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_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);
-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);
-struct wait_queue_head *bit_waitqueue(void *word, int bit);
+void wake_up_bit(unsigned long *word, int bit);
+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(unsigned long *word, int, wait_bit_action_f *action, unsigned int mode, unsigned long timeout);
+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(unsigned long *word, int bit);
extern void __init wait_bit_init(void);
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
* 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);
/* See wake_up_bit() for which memory barrier you need to use. */
diff --git a/kernel/sched/wait_bit.c b/kernel/sched/wait_bit.c
index 134d7112ef71..058b0e18727e 100644
--- a/kernel/sched/wait_bit.c
+++ b/kernel/sched/wait_bit.c
@@ -9,7 +9,7 @@
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;
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);
-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)
{
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);
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)
{
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);
-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)
{
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);
-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);
@@ -144,7 +144,7 @@ EXPORT_SYMBOL(__wake_up_bit);
* may need to use a less regular barrier, such fs/inode.c's smp_mb(),
* 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);
}
--
2.46.0
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