[PATCH 0/3] cleanup of redundant statements

[PATCH 0/3] cleanup of redundant statements

[Christian Borntraeger]

Paolo,

I was playing with some static code checkers. Here is some "fallout"
from the kvm common code. Only minor things that are not real error,
just redundant statements.

One could argue here and there that these statement make the code easier
to understand. So, please have a look and either drop or apply the patches.

Christian Borntraeger (3):
  KVM: remove redundant check of in_spin_loop
  KVM: remove redundant assigment of return value in kvm_dev_ioctl
  KVM: remove redundant assignments in __kvm_set_memory_region

 virt/kvm/kvm_main.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

-- 
1.8.4.2

[PATCH 1/3] KVM: remove redundant check of in_spin_loop

[Christian Borntraeger]

The expression `vcpu->spin_loop.in_spin_loop' is always true,
because it is evaluated only when the condition
`!vcpu->spin_loop.in_spin_loop' is false.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 virt/kvm/kvm_main.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 7176929..0a824a0 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1768,10 +1768,9 @@ static bool kvm_vcpu_eligible_for_directed_yield(struct kvm_vcpu *vcpu)
 #ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
 	bool eligible;
 
 	eligible = !vcpu->spin_loop.in_spin_loop ||
-			(vcpu->spin_loop.in_spin_loop &&
-			 vcpu->spin_loop.dy_eligible);
+		    vcpu->spin_loop.dy_eligible;
 
 	if (vcpu->spin_loop.in_spin_loop)
 		kvm_vcpu_set_dy_eligible(vcpu, !vcpu->spin_loop.dy_eligible);
 
-- 
1.8.4.2

[PATCH 2/3] KVM: remove redundant assigment of return value in kvm_dev_ioctl

[Christian Borntraeger]

The first statement of kvm_dev_ioctl is
        long r = -EINVAL;

No need to reassign the same value.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 virt/kvm/kvm_main.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 0a824a0..5ea65d2 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2610,9 +2610,8 @@ static long kvm_dev_ioctl(struct file *filp,
 	long r = -EINVAL;
 
 	switch (ioctl) {
 	case KVM_GET_API_VERSION:
-		r = -EINVAL;
 		if (arg)
 			goto out;
 		r = KVM_API_VERSION;
 		break;
@@ -2622,9 +2621,8 @@ static long kvm_dev_ioctl(struct file *filp,
 	case KVM_CHECK_EXTENSION:
 		r = kvm_vm_ioctl_check_extension_generic(NULL, arg);
 		break;
 	case KVM_GET_VCPU_MMAP_SIZE:
-		r = -EINVAL;
 		if (arg)
 			goto out;
 		r = PAGE_SIZE;     /* struct kvm_run */
 #ifdef CONFIG_X86
-- 
1.8.4.2

[PATCH 3/3] KVM: remove redundant assignments in __kvm_set_memory_region

[Christian Borntraeger]

__kvm_set_memory_region sets r to EINVAL very early.
Doing it again is not necessary. The same is true later on, where
r is assigned -ENOMEM twice.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 virt/kvm/kvm_main.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 5ea65d2..2d868ad 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -776,9 +776,8 @@ int __kvm_set_memory_region(struct kvm *kvm,
 	slot = id_to_memslot(kvm->memslots, mem->slot);
 	base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;
 	npages = mem->memory_size >> PAGE_SHIFT;
 
-	r = -EINVAL;
 	if (npages > KVM_MEM_MAX_NR_PAGES)
 		goto out;
 
 	if (!npages)
@@ -790,9 +789,8 @@ int __kvm_set_memory_region(struct kvm *kvm,
 	new.base_gfn = base_gfn;
 	new.npages = npages;
 	new.flags = mem->flags;
 
-	r = -EINVAL;
 	if (npages) {
 		if (!old.npages)
 			change = KVM_MR_CREATE;
 		else { /* Modify an existing slot. */
@@ -846,9 +844,8 @@ int __kvm_set_memory_region(struct kvm *kvm,
 			goto out_free;
 	}
 
 	if ((change == KVM_MR_DELETE) || (change == KVM_MR_MOVE)) {
-		r = -ENOMEM;
 		slots = kmemdup(kvm->memslots, sizeof(struct kvm_memslots),
 				GFP_KERNEL);
 		if (!slots)
 			goto out_free;
-- 
1.8.4.2

Re: [PATCH 0/3] cleanup of redundant statements

[Paolo Bonzini]

Il 04/09/2014 21:13, Christian Borntraeger ha scritto:
> Paolo,
> 
> I was playing with some static code checkers. Here is some "fallout"
> from the kvm common code. Only minor things that are not real error,
> just redundant statements.
> 
> One could argue here and there that these statement make the code easier
> to understand. So, please have a look and either drop or apply the patches.

I think all the patches are an improvement.  Thanks!

Paolo