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once: rename _SLOW to _SLEEPABLE
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The _SLOW designation wasn't really descriptive of anything. This is
meant to be called from process context when it's possible to sleep. So
name this more aptly _SLEEPABLE, which better fits its intended use.

Fixes: 62c0798 ("once: add DO_ONCE_SLOW() for sleepable contexts")
Cc: Christophe Leroy <[email protected]>
Signed-off-by: Jason A. Donenfeld <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
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zx2c4 authored and kuba-moo committed Oct 4, 2022
1 parent 3318348 commit 2a4187f
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Showing 3 changed files with 26 additions and 26 deletions.
38 changes: 19 additions & 19 deletions include/linux/once.h
Original file line number Diff line number Diff line change
Expand Up @@ -13,9 +13,9 @@ void __do_once_done(bool *done, struct static_key_true *once_key,
unsigned long *flags, struct module *mod);

/* Variant for process contexts only. */
bool __do_once_slow_start(bool *done);
void __do_once_slow_done(bool *done, struct static_key_true *once_key,
struct module *mod);
bool __do_once_sleepable_start(bool *done);
void __do_once_sleepable_done(bool *done, struct static_key_true *once_key,
struct module *mod);

/* Call a function exactly once. The idea of DO_ONCE() is to perform
* a function call such as initialization of random seeds, etc, only
Expand Down Expand Up @@ -61,26 +61,26 @@ void __do_once_slow_done(bool *done, struct static_key_true *once_key,
})

/* Variant of DO_ONCE() for process/sleepable contexts. */
#define DO_ONCE_SLOW(func, ...) \
({ \
bool ___ret = false; \
static bool __section(".data.once") ___done = false; \
static DEFINE_STATIC_KEY_TRUE(___once_key); \
if (static_branch_unlikely(&___once_key)) { \
___ret = __do_once_slow_start(&___done); \
if (unlikely(___ret)) { \
func(__VA_ARGS__); \
__do_once_slow_done(&___done, &___once_key, \
THIS_MODULE); \
} \
} \
___ret; \
#define DO_ONCE_SLEEPABLE(func, ...) \
({ \
bool ___ret = false; \
static bool __section(".data.once") ___done = false; \
static DEFINE_STATIC_KEY_TRUE(___once_key); \
if (static_branch_unlikely(&___once_key)) { \
___ret = __do_once_sleepable_start(&___done); \
if (unlikely(___ret)) { \
func(__VA_ARGS__); \
__do_once_sleepable_done(&___done, &___once_key,\
THIS_MODULE); \
} \
} \
___ret; \
})

#define get_random_once(buf, nbytes) \
DO_ONCE(get_random_bytes, (buf), (nbytes))

#define get_random_slow_once(buf, nbytes) \
DO_ONCE_SLOW(get_random_bytes, (buf), (nbytes))
#define get_random_sleepable_once(buf, nbytes) \
DO_ONCE_SLEEPABLE(get_random_bytes, (buf), (nbytes))

#endif /* _LINUX_ONCE_H */
10 changes: 5 additions & 5 deletions lib/once.c
Original file line number Diff line number Diff line change
Expand Up @@ -69,30 +69,30 @@ EXPORT_SYMBOL(__do_once_done);

static DEFINE_MUTEX(once_mutex);

bool __do_once_slow_start(bool *done)
bool __do_once_sleepable_start(bool *done)
__acquires(once_mutex)
{
mutex_lock(&once_mutex);
if (*done) {
mutex_unlock(&once_mutex);
/* Keep sparse happy by restoring an even lock count on
* this mutex. In case we return here, we don't call into
* __do_once_done but return early in the DO_ONCE_SLOW() macro.
* __do_once_done but return early in the DO_ONCE_SLEEPABLE() macro.
*/
__acquire(once_mutex);
return false;
}

return true;
}
EXPORT_SYMBOL(__do_once_slow_start);
EXPORT_SYMBOL(__do_once_sleepable_start);

void __do_once_slow_done(bool *done, struct static_key_true *once_key,
void __do_once_sleepable_done(bool *done, struct static_key_true *once_key,
struct module *mod)
__releases(once_mutex)
{
*done = true;
mutex_unlock(&once_mutex);
once_disable_jump(once_key, mod);
}
EXPORT_SYMBOL(__do_once_slow_done);
EXPORT_SYMBOL(__do_once_sleepable_done);
4 changes: 2 additions & 2 deletions net/ipv4/inet_hashtables.c
Original file line number Diff line number Diff line change
Expand Up @@ -958,8 +958,8 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
if (likely(remaining > 1))
remaining &= ~1U;

get_random_slow_once(table_perturb,
INET_TABLE_PERTURB_SIZE * sizeof(*table_perturb));
get_random_sleepable_once(table_perturb,
INET_TABLE_PERTURB_SIZE * sizeof(*table_perturb));
index = port_offset & (INET_TABLE_PERTURB_SIZE - 1);

offset = READ_ONCE(table_perturb[index]) + (port_offset >> 32);
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