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| author | Peter Xu <peterx@redhat.com> | 2021-06-25 11:32:07 -0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-08-02 11:01:46 -0400 |
| commit | 605c713023e3925d0444f495a42c903cb6ce875f (patch) | |
| tree | 2096d96ce98862bac429840fcb3b79b979ad1072 /virt | |
| parent | 1694caef426247bb406c2b04672336ef77b5fb87 (diff) | |
| download | linux-stable-605c713023e3925d0444f495a42c903cb6ce875f.tar.gz linux-stable-605c713023e3925d0444f495a42c903cb6ce875f.tar.bz2 linux-stable-605c713023e3925d0444f495a42c903cb6ce875f.zip | |
KVM: Introduce kvm_get_kvm_safe()
Introduce this safe version of kvm_get_kvm() so that it can be called even
during vm destruction. Use it in kvm_debugfs_open() and remove the verbose
comment. Prepare to be used elsewhere.
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20210625153214.43106-3-peterx@redhat.com>
[Preserve the comment in kvm_debugfs_open. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/kvm_main.c | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 965c51ab0fe3..5cc79373827f 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1120,6 +1120,16 @@ void kvm_get_kvm(struct kvm *kvm) } EXPORT_SYMBOL_GPL(kvm_get_kvm); +/* + * Make sure the vm is not during destruction, which is a safe version of + * kvm_get_kvm(). Return true if kvm referenced successfully, false otherwise. + */ +bool kvm_get_kvm_safe(struct kvm *kvm) +{ + return refcount_inc_not_zero(&kvm->users_count); +} +EXPORT_SYMBOL_GPL(kvm_get_kvm_safe); + void kvm_put_kvm(struct kvm *kvm) { if (refcount_dec_and_test(&kvm->users_count)) @@ -4969,12 +4979,12 @@ static int kvm_debugfs_open(struct inode *inode, struct file *file, struct kvm_stat_data *stat_data = (struct kvm_stat_data *) inode->i_private; - /* The debugfs files are a reference to the kvm struct which - * is still valid when kvm_destroy_vm is called. - * To avoid the race between open and the removal of the debugfs - * directory we test against the users count. + /* + * The debugfs files are a reference to the kvm struct which + * is still valid when kvm_destroy_vm is called. kvm_get_kvm_safe + * avoids the race between open and the removal of the debugfs directory. */ - if (!refcount_inc_not_zero(&stat_data->kvm->users_count)) + if (!kvm_get_kvm_safe(stat_data->kvm)) return -ENOENT; if (simple_attr_open(inode, file, get, |