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| author | Ildar Ismagilov <devix84@gmail.com> | 2018-01-31 22:39:53 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-02-20 16:21:11 -0800 |
| commit | a35d13ec3686612b17771bf1abcad75d2ebd42ef (patch) | |
| tree | 4a01547083b852f276e2601a2ce23ac76808ede4 /kernel/rcu/srcutree.c | |
| parent | cb4081cd4e0c9fd88d186553edcc78e1bbb96ce6 (diff) | |
| download | linux-next-a35d13ec3686612b17771bf1abcad75d2ebd42ef.tar.gz | |
srcu: Prevent sdp->srcu_gp_seq_needed_exp counter wrap
SRCU checks each srcu_data structure's grace-period number for counter
wrap four times per cycle by default. This frequency guarantees that
normal comparisons will detect potential wrap. However, the expedited
grace-period number is not checked. The consquences are not too horrible
(a failure to expedite a grace period when requested), but it would be
good to avoid such things. This commit therefore adds this check to
the expedited grace-period number.
Signed-off-by: Ildar Ismagilov <devix84@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu/srcutree.c')
| -rw-r--r-- | kernel/rcu/srcutree.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index 01f4a8bf0e03..bb9607baad9b 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -579,6 +579,9 @@ static void srcu_gp_end(struct srcu_struct *sp) if (ULONG_CMP_GE(gpseq, sdp->srcu_gp_seq_needed + 100)) sdp->srcu_gp_seq_needed = gpseq; + if (ULONG_CMP_GE(gpseq, + sdp->srcu_gp_seq_needed_exp + 100)) + sdp->srcu_gp_seq_needed_exp = gpseq; spin_unlock_irqrestore_rcu_node(sdp, flags); } } |