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| author |   Paul E. McKenney <paulmck@kernel.org> | 2022-08-02 11:59:49 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2022-08-31 05:10:15 -0700 |
| commit | de3f2671ae563d24c679dcca36c9e0ebd9564ebd (patch) | |
| tree | 0cd0a5fa7b7668a31f26df0a1d2a0fcfff642a49 | |
| parent | srcu: Add GP and maximum requested GP to Tiny SRCU rcutorture output (diff) | |
| download | linux-dev-de3f2671ae563d24c679dcca36c9e0ebd9564ebd.tar.xz linux-dev-de3f2671ae563d24c679dcca36c9e0ebd9564ebd.zip | |
srcu: Make Tiny SRCU poll_state_synchronize_srcu() more precise
This commit applies the more-precise grace-period-state check used by
rcu_seq_done_exact() to poll_state_synchronize_srcu(). This is important
because Tiny SRCU uses a 16-bit counter, which can wrap quite quickly.
If counter wrap continues to be a problem, then expanding ->srcu_idx
and ->srcu_idx_max to 32 bits might be warranted.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
| -rw-r--r-- | kernel/rcu/srcutiny.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c index 92c002d65482..a2af24f21467 100644 --- a/kernel/rcu/srcutiny.c +++ b/kernel/rcu/srcutiny.c @@ -240,10 +240,10 @@ EXPORT_SYMBOL_GPL(start_poll_synchronize_srcu); */ bool poll_state_synchronize_srcu(struct srcu_struct *ssp, unsigned long cookie) { - bool ret = USHORT_CMP_GE(READ_ONCE(ssp->srcu_idx), cookie); + unsigned short cur_s = READ_ONCE(ssp->srcu_idx); barrier(); - return ret; + return USHORT_CMP_GE(cur_s, cookie) || USHORT_CMP_LT(cur_s, cookie - 3); } EXPORT_SYMBOL_GPL(poll_state_synchronize_srcu); |