path: root/virt
diff options
authorAhmed S. Darwish <>2020-07-20 17:55:29 +0200
committerPeter Zijlstra <>2020-07-29 16:14:29 +0200
commit5c73b9a2b1b4ecc809a914aa64970157b3d8c936 (patch)
treef9f5b5ecce4d530e1da06a6a2ce2ef84c7855cc6 /virt
parent2ca97ac8bdcc31fdc868f40c73c017f0a648dc07 (diff)
kvm/eventfd: Use sequence counter with associated spinlock
A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_spinlock_t data type, which allows to associate a spinlock with the sequence counter. This enables lockdep to verify that the spinlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. Signed-off-by: Ahmed S. Darwish <> Signed-off-by: Peter Zijlstra (Intel) <> Acked-by: Paolo Bonzini <> Link:
Diffstat (limited to 'virt')
1 files changed, 1 insertions, 1 deletions
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index ef7ed916ad4a..d6408bb497dc 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -303,7 +303,7 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
INIT_WORK(&irqfd->inject, irqfd_inject);
INIT_WORK(&irqfd->shutdown, irqfd_shutdown);
- seqcount_init(&irqfd->irq_entry_sc);
+ seqcount_spinlock_init(&irqfd->irq_entry_sc, &kvm->irqfds.lock);
f = fdget(args->fd);
if (!f.file) {