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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2024-06-20 15:21:52 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-06-24 16:41:22 -0700 |
| commit | c5bcab7558220bbad8bd4863576afd1b340ce29f (patch) | |
| tree | e0306e6f6a81fe02bd9b6567ee1901be33fa35f9 /include/linux/lockdep.h | |
| parent | 07e4fd4c0592ad57fe4c5033393d30362dbfaa5d (diff) | |
| download | lwn-c5bcab7558220bbad8bd4863576afd1b340ce29f.tar.gz lwn-c5bcab7558220bbad8bd4863576afd1b340ce29f.zip | |
locking/local_lock: Add local nested BH locking infrastructure.
Add local_lock_nested_bh() locking. It is based on local_lock_t and the
naming follows the preempt_disable_nested() example.
For !PREEMPT_RT + !LOCKDEP it is a per-CPU annotation for locking
assumptions based on local_bh_disable(). The macro is optimized away
during compilation.
For !PREEMPT_RT + LOCKDEP the local_lock_nested_bh() is reduced to
the usual lock-acquire plus lockdep_assert_in_softirq() - ensuring that
BH is disabled.
For PREEMPT_RT local_lock_nested_bh() acquires the specified per-CPU
lock. It does not disable CPU migration because it relies on
local_bh_disable() disabling CPU migration.
With LOCKDEP it performans the usual lockdep checks as with !PREEMPT_RT.
Due to include hell the softirq check has been moved spinlock.c.
The intention is to use this locking in places where locking of a per-CPU
variable relies on BH being disabled. Instead of treating disabled
bottom halves as a big per-CPU lock, PREEMPT_RT can use this to reduce
the locking scope to what actually needs protecting.
A side effect is that it also documents the protection scope of the
per-CPU variables.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20240620132727.660738-3-bigeasy@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include/linux/lockdep.h')
| -rw-r--r-- | include/linux/lockdep.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 08b0d1d9d78b..3f5a551579cc 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -600,6 +600,8 @@ do { \ (!in_softirq() || in_irq() || in_nmi())); \ } while (0) +extern void lockdep_assert_in_softirq_func(void); + #else # define might_lock(lock) do { } while (0) # define might_lock_read(lock) do { } while (0) @@ -613,6 +615,7 @@ do { \ # define lockdep_assert_preemption_enabled() do { } while (0) # define lockdep_assert_preemption_disabled() do { } while (0) # define lockdep_assert_in_softirq() do { } while (0) +# define lockdep_assert_in_softirq_func() do { } while (0) #endif #ifdef CONFIG_PROVE_RAW_LOCK_NESTING |