Re: [PATCH v3 6/6] KVM: Hoist debugfs_dentry init to kvm_create_vm_debugfs() (again)

[Sean Christopherson <seanjc@google.com>]

On Wed, Jul 20, 2022, Oliver Upton wrote:
> From: Oliver Upton <oupton@google.com>
> 
> Since KVM now sanely handles debugfs init/destroy w.r.t. the VM, it is
> safe to hoist kvm_create_vm_debugfs() back into kvm_create_vm(). The
> author of this commit remains bitter for having been burned by the old
> wreck in commit a44a4cc1c969 ("KVM: Don't create VM debugfs files
> outside of the VM directory").
> 
> Signed-off-by: Oliver Upton <oupton@google.com>
> Reviewed-by: Sean Christopherson <seanjc@google.com>

Heh, so this amusingly has my review, but I'd rather omit this patch and leave
the initialization with the pile of other code that initializes fields for which
zero-initialization is insufficient/incorrect.

Any objections to dropping this?

> ---
>  virt/kvm/kvm_main.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 609f49a133f8..7ac60f75cfa1 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -1032,6 +1032,12 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, const char *fdname)
>  	int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc +
>  				      kvm_vcpu_stats_header.num_desc;
>  
> +	/*
> +	 * Force subsequent debugfs file creations to fail if the VM directory
> +	 * is not created.
> +	 */
> +	kvm->debugfs_dentry = ERR_PTR(-ENOENT);
> +
>  	if (!debugfs_initialized())
>  		return 0;
>  
> @@ -1154,12 +1160,6 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
>  
>  	BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX);
>  
> -	/*
> -	 * Force subsequent debugfs file creations to fail if the VM directory
> -	 * is not created (by kvm_create_vm_debugfs()).
> -	 */
> -	kvm->debugfs_dentry = ERR_PTR(-ENOENT);
> -
>  	snprintf(kvm->stats_id, sizeof(kvm->stats_id), "kvm-%d",
>  		 task_pid_nr(current));
>  
> -- 
> 2.37.0.170.g444d1eabd0-goog
>