2022-10-03 18:51:21

by Jason A. Donenfeld

[permalink] [raw]
Subject: [PATCH] once: rename _SLOW to _SLEEPABLE

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: 62c07983bef9 ("once: add DO_ONCE_SLOW() for sleepable contexts")
Cc: Jakub Kicinski <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Christophe Leroy <[email protected]>
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
include/linux/once.h | 38 +++++++++++++++++++-------------------
lib/once.c | 10 +++++-----
net/ipv4/inet_hashtables.c | 4 ++--
3 files changed, 26 insertions(+), 26 deletions(-)

diff --git a/include/linux/once.h b/include/linux/once.h
index 176ab75b42df..bc714d414448 100644
--- a/include/linux/once.h
+++ b/include/linux/once.h
@@ -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
@@ -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 */
diff --git a/lib/once.c b/lib/once.c
index 351f66aad310..2c306f0e891e 100644
--- a/lib/once.c
+++ b/lib/once.c
@@ -69,7 +69,7 @@ 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);
@@ -77,7 +77,7 @@ bool __do_once_slow_start(bool *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;
@@ -85,9 +85,9 @@ bool __do_once_slow_start(bool *done)

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)
{
@@ -95,4 +95,4 @@ void __do_once_slow_done(bool *done, struct static_key_true *once_key,
mutex_unlock(&once_mutex);
once_disable_jump(once_key, mod);
}
-EXPORT_SYMBOL(__do_once_slow_done);
+EXPORT_SYMBOL(__do_once_sleepable_done);
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index dc1c5629cd0d..a0ad34e4f044 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -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);
--
2.37.3


2022-10-03 23:18:33

by Eric Dumazet

[permalink] [raw]
Subject: Re: [PATCH] once: rename _SLOW to _SLEEPABLE

On Mon, Oct 3, 2022 at 11:14 AM Jason A. Donenfeld <[email protected]> wrote:
>
> 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: 62c07983bef9 ("once: add DO_ONCE_SLOW() for sleepable contexts")

Yes, this works for me, thank you.

Reviewed-by: Eric Dumazet <[email protected]>