kvm/eventfd: use list_for_each_entry when deassign ioeventfd

Simpify kvm_deassign_ioeventfd_idx to use list_for_each_entry as the
loop just ends at the entry that's found and deleted.

Note, coalesced_mmio_ops and ioeventfd_ops are the only instances of
kvm_io_device_ops that implement a destructor, all other callers of
kvm_io_bus_unregister_dev() are unaffected by this change.

Suggested-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230207123713.3905-3-wei.w.wang@intel.com
[sean: call out that only select users implement a destructor]
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 4d47fff..89912a1 100644 (file)
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -901,7 +901,7 @@ static int
 kvm_deassign_ioeventfd_idx(struct kvm *kvm, enum kvm_bus bus_idx,
                           struct kvm_ioeventfd *args)
 {
-       struct _ioeventfd        *p, *tmp;
+       struct _ioeventfd        *p;
        struct eventfd_ctx       *eventfd;
        struct kvm_io_bus        *bus;
        int                       ret = -ENOENT;
@@ -915,8 +915,7 @@ kvm_deassign_ioeventfd_idx(struct kvm *kvm, enum kvm_bus bus_idx,
 
        mutex_lock(&kvm->slots_lock);
 
-       list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) {
-
+       list_for_each_entry(p, &kvm->ioeventfds, list) {
                if (p->bus_idx != bus_idx ||
                    p->eventfd != eventfd  ||
                    p->addr != args->addr  ||