linux-kernel - [PATCH] kvm/eventfd:do wildcard calculation before list_for_each_entry

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Date:   Fri, 11 Sep 2020 13:56:52 +0800
From:   Yi Li <yili@...hong.com>
To:     pbonzini@...hat.com
Cc:     yilikernel@...il.com, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, Yi Li <yili@...hong.com>
Subject: [PATCH] kvm/eventfd:do wildcard calculation before list_for_each_entry_safe

There is no need to calculate wildcard in each loop
since wildcard is not changed.

Signed-off-by: Yi Li <yili@...hong.com>
---
 virt/kvm/eventfd.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index d6408bb497dc..c2323c27a28b 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -853,15 +853,17 @@ kvm_deassign_ioeventfd_idx(struct kvm *kvm, enum kvm_bus bus_idx,
 	struct eventfd_ctx       *eventfd;
 	struct kvm_io_bus	 *bus;
 	int                       ret = -ENOENT;
+	bool                      wildcard;
 
 	eventfd = eventfd_ctx_fdget(args->fd);
 	if (IS_ERR(eventfd))
 		return PTR_ERR(eventfd);
 
+	wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);
+
 	mutex_lock(&kvm->slots_lock);
 
 	list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) {
-		bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);
 
 		if (p->bus_idx != bus_idx ||
 		    p->eventfd != eventfd  ||
-- 
2.25.3