Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar:
"Misc fixes: lockstat fix, futex fix on !MMU systems, big endian fix
for qrwlocks and a race fix for pvqspinlocks"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/pvqspinlock: Fix a bug in qstat_read()
locking/pvqspinlock: Fix double hash race
locking/qrwlock: Fix write unlock bug on big endian systems
futex: Assume all mappings are private on !MMU systems
+48
-5
+25
-2
include/asm-generic/qrwlock.h
+25
-2
include/asm-generic/qrwlock.h
···
25
25
#include <asm-generic/qrwlock_types.h>
26
26
27
27
/*
28
-
* Writer states & reader shift and bias
28
+
* Writer states & reader shift and bias.
29
+
*
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+
* | +0 | +1 | +2 | +3 |
31
+
* ----+----+----+----+----+
32
+
* LE | 78 | 56 | 34 | 12 | 0x12345678
33
+
* ----+----+----+----+----+
34
+
* | wr | rd |
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+
* +----+----+----+----+
36
+
*
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+
* ----+----+----+----+----+
38
+
* BE | 12 | 34 | 56 | 78 | 0x12345678
39
+
* ----+----+----+----+----+
40
+
* | rd | wr |
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+
* +----+----+----+----+
29
42
*/
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43
#define _QW_WAITING 1 /* A writer is waiting */
31
44
#define _QW_LOCKED 0xff /* A writer holds the lock */
···
147
134
}
148
135
149
136
/**
137
+
* __qrwlock_write_byte - retrieve the write byte address of a queue rwlock
138
+
* @lock : Pointer to queue rwlock structure
139
+
* Return: the write byte address of a queue rwlock
140
+
*/
141
+
static inline u8 *__qrwlock_write_byte(struct qrwlock *lock)
142
+
{
143
+
return (u8 *)lock + 3 * IS_BUILTIN(CONFIG_CPU_BIG_ENDIAN);
144
+
}
145
+
146
+
/**
150
147
* queued_write_unlock - release write lock of a queue rwlock
151
148
* @lock : Pointer to queue rwlock structure
152
149
*/
153
150
static inline void queued_write_unlock(struct qrwlock *lock)
154
151
{
155
-
smp_store_release((u8 *)&lock->cnts, 0);
152
+
smp_store_release(__qrwlock_write_byte(lock), 0);
156
153
}
157
154
158
155
/*
+22
-1
kernel/futex.c
+22
-1
kernel/futex.c
···
179
179
* Futex flags used to encode options to functions and preserve them across
180
180
* restarts.
181
181
*/
182
-
#define FLAGS_SHARED 0x01
182
+
#ifdef CONFIG_MMU
183
+
# define FLAGS_SHARED 0x01
184
+
#else
185
+
/*
186
+
* NOMMU does not have per process address space. Let the compiler optimize
187
+
* code away.
188
+
*/
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+
# define FLAGS_SHARED 0x00
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+
#endif
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#define FLAGS_CLOCKRT 0x02
184
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#define FLAGS_HAS_TIMEOUT 0x04
185
193
···
413
405
if (!key->both.ptr)
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406
return;
415
407
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+
/*
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+
* On MMU less systems futexes are always "private" as there is no per
410
+
* process address space. We need the smp wmb nevertheless - yes,
411
+
* arch/blackfin has MMU less SMP ...
412
+
*/
413
+
if (!IS_ENABLED(CONFIG_MMU)) {
414
+
smp_mb(); /* explicit smp_mb(); (B) */
415
+
return;
416
+
}
417
+
416
418
switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) {
417
419
case FUT_OFF_INODE:
418
420
ihold(key->shared.inode); /* implies smp_mb(); (B) */
···
453
435
WARN_ON_ONCE(1);
454
436
return;
455
437
}
438
+
439
+
if (!IS_ENABLED(CONFIG_MMU))
440
+
return;
456
441
457
442
switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) {
458
443
case FUT_OFF_INODE:
+1
-1
kernel/locking/qspinlock_paravirt.h
+1
-1
kernel/locking/qspinlock_paravirt.h