Skip to contentSkip to conversation

kvm: remove invalid check for debugfs_create_dir()

PATCH In review Greg Kroah-Hartman 2 participants 4 messages Jun 12, 2019 KVM

lore
Share & tools
lore
#0 lore raw

PATCH 1/1 kvm: remove invalid check for debugfs_create_dir()

debugfs_create_dir() can never return NULL, so no need to check for an impossible thing.

It's also not needed to ever check the return value of this function, so just remove the check entirely, and indent the previous line to a sane formatting :)

---
 virt/kvm/kvm_main.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
virt/kvm/kvm_main.c +1 -3
index ca54b09adf5b..4b4ef642d8fa 100644
@@ -2605,9 +2605,7 @@ static int kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
 
 	snprintf(dir_name, sizeof(dir_name), "vcpu%d", vcpu->vcpu_id);
 	vcpu->debugfs_dentry = debugfs_create_dir(dir_name,
-								vcpu->kvm->debugfs_dentry);
-	if (!vcpu->debugfs_dentry)
-		return -ENOMEM;
+						  vcpu->kvm->debugfs_dentry);
 
 	ret = kvm_arch_create_vcpu_debugfs(vcpu);
 	if (ret < 0) {
Signature · 1 line
2.22.0
#1 lore raw
Quoted 32 lines · Greg Kroah-Hartman

debugfs_create_dir() can never return NULL, so no need to check for an impossible thing.

It's also not needed to ever check the return value of this function, so just remove the check entirely, and indent the previous line to a sane formatting :)

---
 virt/kvm/kvm_main.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
virt/kvm/kvm_main.c +1 -3
index ca54b09adf5b..4b4ef642d8fa 100644
@@ -2605,9 +2605,7 @@ static int kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
 
 	snprintf(dir_name, sizeof(dir_name), "vcpu%d", vcpu->vcpu_id);
 	vcpu->debugfs_dentry = debugfs_create_dir(dir_name,
-								vcpu->kvm->debugfs_dentry);
-	if (!vcpu->debugfs_dentry)
-		return -ENOMEM;
+						  vcpu->kvm->debugfs_dentry);
 
 	ret = kvm_arch_create_vcpu_debugfs(vcpu);
 	if (ret < 0) {
Signature · 1 line
2.22.0

Any objection to me pulling this into a series to clean up similar issues in arch/x86/kvm/debugfs.c -> kvm_arch_create_vcpu_debugfs(), and to change kvm_create_vcpu_debugfs() to not return success/failure? It'd be nice to fix everything in a single shot.

#2 lore raw
Quoted 29 lines · Sean Christopherson
Quoted 28 lines · Greg Kroah-Hartman

debugfs_create_dir() can never return NULL, so no need to check for an impossible thing.

It's also not needed to ever check the return value of this function, so just remove the check entirely, and indent the previous line to a sane formatting :)

---
 virt/kvm/kvm_main.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
virt/kvm/kvm_main.c +1 -3
index ca54b09adf5b..4b4ef642d8fa 100644
@@ -2605,9 +2605,7 @@ static int kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
 
 	snprintf(dir_name, sizeof(dir_name), "vcpu%d", vcpu->vcpu_id);
 	vcpu->debugfs_dentry = debugfs_create_dir(dir_name,
-								vcpu->kvm->debugfs_dentry);
-	if (!vcpu->debugfs_dentry)
-		return -ENOMEM;
+						  vcpu->kvm->debugfs_dentry);
 
Quoted 9 lines
Quoted 4 lines
virt/kvm/kvm_main.c +0 -0
 	ret = kvm_arch_create_vcpu_debugfs(vcpu);
 	if (ret < 0) {
Signature · 1 line
2.22.0

Any objection to me pulling this into a series to clean up similar issues in arch/x86/kvm/debugfs.c -> kvm_arch_create_vcpu_debugfs(), and to change kvm_create_vcpu_debugfs() to not return success/failure? It'd be nice to fix everything in a single shot.

It was on my todo list to do the cleanup of the x86 kvm stuff. I figured this arch-neutral fix was independent, but if you want me to do it all at once, I'll be glad to do so later this week.

thanks,

greg k-h

#3 lore raw
Quoted 40 lines · Greg Kroah-Hartman
Quoted 29 lines · Sean Christopherson
Quoted 28 lines · Greg Kroah-Hartman

debugfs_create_dir() can never return NULL, so no need to check for an impossible thing.

It's also not needed to ever check the return value of this function, so just remove the check entirely, and indent the previous line to a sane formatting :)

---
 virt/kvm/kvm_main.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
virt/kvm/kvm_main.c +1 -3
index ca54b09adf5b..4b4ef642d8fa 100644
@@ -2605,9 +2605,7 @@ static int kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
 
 	snprintf(dir_name, sizeof(dir_name), "vcpu%d", vcpu->vcpu_id);
 	vcpu->debugfs_dentry = debugfs_create_dir(dir_name,
-								vcpu->kvm->debugfs_dentry);
-	if (!vcpu->debugfs_dentry)
-		return -ENOMEM;
+						  vcpu->kvm->debugfs_dentry);
 
Quoted 9 lines
Quoted 4 lines
virt/kvm/kvm_main.c +0 -0
 	ret = kvm_arch_create_vcpu_debugfs(vcpu);
 	if (ret < 0) {
Signature · 1 line
2.22.0

Any objection to me pulling this into a series to clean up similar issues in arch/x86/kvm/debugfs.c -> kvm_arch_create_vcpu_debugfs(), and to change kvm_create_vcpu_debugfs() to not return success/failure? It'd be nice to fix everything in a single shot.

Quoted 3 lines

It was on my todo list to do the cleanup of the x86 kvm stuff. I figured this arch-neutral fix was independent, but if you want me to do it all at once, I'll be glad to do so later this week.

My preference would be to get it done all at once, having a discrepancy between kvm_main and x86 leads to a bit of head scratching.

The x86 change would be independent, the piece that's not is converting kvm_create_vcpu_debugfs() to handle failure internally and not return errors, which would depend on this patch's removal of "return -ENOMEM". At a minimum I think that change should be paired with this fix.