[PATCH linux-next v2] KVM: SVM: Remove the unneeded result variable

[PATCH linux-next v2] KVM: SVM: Remove the unneeded result variable

[cgel.zte]

From: ye xingchen <ye.xingchen@zte.com.cn>

Return the value from sev_guest_activate(&activate, error) and
sev_issue_cmd_external_user(f.file, id, data, error) directly
instead of storing it in another redundant variable.And also change
the position of handle and asid to simplify the code.

Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
---
v1 -> v2
Suggested-by: SeanChristopherson <seanjc@google.com>

Change the position of handle and asid.
Change the explain about this patch.
Dropping the comment about asid + handle.
 arch/x86/kvm/svm/sev.c | 19 ++++++-------------
 1 file changed, 6 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 28064060413a..4448f2e512b9 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -276,31 +276,24 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
 
 static int sev_bind_asid(struct kvm *kvm, unsigned int handle, int *error)
 {
-	struct sev_data_activate activate;
-	int asid = sev_get_asid(kvm);
-	int ret;
-
-	/* activate ASID on the given handle */
-	activate.handle = handle;
-	activate.asid   = asid;
-	ret = sev_guest_activate(&activate, error);
+	struct sev_data_activate activate = {
+		.handle = handle,
+		.asid = sev_get_asid(kvm),
+	};
 
-	return ret;
+	return sev_guest_activate(&activate, error);
 }
 
 static int __sev_issue_cmd(int fd, int id, void *data, int *error)
 {
 	struct fd f;
-	int ret;
 
 	f = fdget(fd);
 	if (!f.file)
 		return -EBADF;
 
-	ret = sev_issue_cmd_external_user(f.file, id, data, error);
-
 	fdput(f);
-	return ret;
+	return sev_issue_cmd_external_user(f.file, id, data, error);
 }
 
 static int sev_issue_cmd(struct kvm *kvm, int id, void *data, int *error)
-- 
2.25.1

Re: [PATCH linux-next v2] KVM: SVM: Remove the unneeded result variable

[Sean Christopherson]

On Mon, Aug 22, 2022, cgel.zte@gmail.com wrote:
> From: ye xingchen <ye.xingchen@zte.com.cn>
> 
> Return the value from sev_guest_activate(&activate, error) and
> sev_issue_cmd_external_user(f.file, id, data, error) directly
> instead of storing it in another redundant variable.And also change
> the position of handle and asid to simplify the code.
> 
> Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
> ---
> v1 -> v2
> Suggested-by: SeanChristopherson <seanjc@google.com>
> 
> Change the position of handle and asid.
> Change the explain about this patch.
> Dropping the comment about asid + handle.
>  arch/x86/kvm/svm/sev.c | 19 ++++++-------------
>  1 file changed, 6 insertions(+), 13 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 28064060413a..4448f2e512b9 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -276,31 +276,24 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
>  
>  static int sev_bind_asid(struct kvm *kvm, unsigned int handle, int *error)
>  {
> -	struct sev_data_activate activate;
> -	int asid = sev_get_asid(kvm);
> -	int ret;
> -
> -	/* activate ASID on the given handle */
> -	activate.handle = handle;
> -	activate.asid   = asid;
> -	ret = sev_guest_activate(&activate, error);
> +	struct sev_data_activate activate = {
> +		.handle = handle,
> +		.asid = sev_get_asid(kvm),
> +	};
>  
> -	return ret;
> +	return sev_guest_activate(&activate, error);
>  }
>  
>  static int __sev_issue_cmd(int fd, int id, void *data, int *error)
>  {
>  	struct fd f;
> -	int ret;
>  
>  	f = fdget(fd);
>  	if (!f.file)
>  		return -EBADF;
>  
> -	ret = sev_issue_cmd_external_user(f.file, id, data, error);
> -
>  	fdput(f);
> -	return ret;
> +	return sev_issue_cmd_external_user(f.file, id, data, error);

Again, this is broken, the fdput() needs to stay after f.file is consumed, i.e.
eliminating "ret" is wrong.

>  }
>  
>  static int sev_issue_cmd(struct kvm *kvm, int id, void *data, int *error)
> -- 
> 2.25.1