[PATCH] kvm: no need to check return value of debugfs_create functions

[Greg Kroah-Hartman]

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

This cleans up the error handling a lot, as this code will never get
hit.

Cc: Paul Mackerras <paulus at ozlabs.org>
Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: Christoffer Dall <christoffer.dall at arm.com>
Cc: Marc Zyngier <marc.zyngier at arm.com>
Cc: Paolo Bonzini <pbonzini at redhat.com>
Cc: "Radim Krčmář" <rkrcmar at redhat.com>
Cc: Arvind Yadav <arvind.yadav.cs at gmail.com>
Cc: Eric Auger <eric.auger at redhat.com>
Cc: Andre Przywara <andre.przywara at arm.com>
Cc: kvm-ppc at vger.kernel.org
Cc: linuxppc-dev at lists.ozlabs.org
Cc: linux-kernel at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: kvmarm at lists.cs.columbia.edu
Cc: kvm at vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
 arch/powerpc/kvm/book3s_hv.c   |  3 +--
 virt/kvm/arm/vgic/vgic-debug.c | 17 ++++-----------
 virt/kvm/arm/vgic/vgic.h       |  4 ++--
 virt/kvm/kvm_main.c            | 40 +++++++---------------------------
 4 files changed, 15 insertions(+), 49 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 4d07fca5121c..67d7de1470cc 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -3950,8 +3950,7 @@ static int kvmppc_core_init_vm_hv(struct kvm *kvm)
 	 */
 	snprintf(buf, sizeof(buf), "vm%d", current->pid);
 	kvm->arch.debugfs_dir = debugfs_create_dir(buf, kvm_debugfs_dir);
-	if (!IS_ERR_OR_NULL(kvm->arch.debugfs_dir))
-		kvmppc_mmu_debugfs_init(kvm);
+	kvmppc_mmu_debugfs_init(kvm);
 
 	return 0;
 }
diff --git a/virt/kvm/arm/vgic/vgic-debug.c b/virt/kvm/arm/vgic/vgic-debug.c
index 10b38178cff2..0140b29079b6 100644
--- a/virt/kvm/arm/vgic/vgic-debug.c
+++ b/virt/kvm/arm/vgic/vgic-debug.c
@@ -263,21 +263,12 @@ static const struct file_operations vgic_debug_fops = {
 	.release = seq_release
 };
 
-int vgic_debug_init(struct kvm *kvm)
+void vgic_debug_init(struct kvm *kvm)
 {
-	if (!kvm->debugfs_dentry)
-		return -ENOENT;
-
-	if (!debugfs_create_file("vgic-state", 0444,
-				 kvm->debugfs_dentry,
-				 kvm,
-				 &vgic_debug_fops))
-		return -ENOMEM;
-
-	return 0;
+	debugfs_create_file("vgic-state", 0444, kvm->debugfs_dentry, kvm,
+			    &vgic_debug_fops);
 }
 
-int vgic_debug_destroy(struct kvm *kvm)
+void vgic_debug_destroy(struct kvm *kvm)
 {
-	return 0;
 }
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index 830e815748a0..3c38c5349953 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -229,8 +229,8 @@ void vgic_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
 int vgic_lazy_init(struct kvm *kvm);
 int vgic_init(struct kvm *kvm);
 
-int vgic_debug_init(struct kvm *kvm);
-int vgic_debug_destroy(struct kvm *kvm);
+void vgic_debug_init(struct kvm *kvm);
+void vgic_debug_destroy(struct kvm *kvm);
 
 bool lock_all_vcpus(struct kvm *kvm);
 void unlock_all_vcpus(struct kvm *kvm);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c7b2e927f699..0ad400f353fc 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -572,10 +572,7 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, int fd)
 		return 0;
 
 	snprintf(dir_name, sizeof(dir_name), "%d-%d", task_pid_nr(current), fd);
-	kvm->debugfs_dentry = debugfs_create_dir(dir_name,
-						 kvm_debugfs_dir);
-	if (!kvm->debugfs_dentry)
-		return -ENOMEM;
+	kvm->debugfs_dentry = debugfs_create_dir(dir_name, kvm_debugfs_dir);
 
 	kvm->debugfs_stat_data = kcalloc(kvm_debugfs_num_entries,
 					 sizeof(*kvm->debugfs_stat_data),
@@ -591,11 +588,8 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, int fd)
 		stat_data->kvm = kvm;
 		stat_data->offset = p->offset;
 		kvm->debugfs_stat_data[p - debugfs_entries] = stat_data;
-		if (!debugfs_create_file(p->name, 0644,
-					 kvm->debugfs_dentry,
-					 stat_data,
-					 stat_fops_per_vm[p->kind]))
-			return -ENOMEM;
+		debugfs_create_file(p->name, 0644, kvm->debugfs_dentry,
+				    stat_data, stat_fops_per_vm[p->kind]);
 	}
 	return 0;
 }
@@ -3896,29 +3890,18 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
 	kfree(env);
 }
 
-static int kvm_init_debug(void)
+static void kvm_init_debug(void)
 {
-	int r = -EEXIST;
 	struct kvm_stats_debugfs_item *p;
 
 	kvm_debugfs_dir = debugfs_create_dir("kvm", NULL);
-	if (kvm_debugfs_dir == NULL)
-		goto out;
 
 	kvm_debugfs_num_entries = 0;
 	for (p = debugfs_entries; p->name; ++p, kvm_debugfs_num_entries++) {
-		if (!debugfs_create_file(p->name, 0644, kvm_debugfs_dir,
-					 (void *)(long)p->offset,
-					 stat_fops[p->kind]))
-			goto out_dir;
+		debugfs_create_file(p->name, 0644, kvm_debugfs_dir,
+				    (void *)(long)p->offset,
+				    stat_fops[p->kind]);
 	}
-
-	return 0;
-
-out_dir:
-	debugfs_remove_recursive(kvm_debugfs_dir);
-out:
-	return r;
 }
 
 static int kvm_suspend(void)
@@ -4046,20 +4029,13 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
 	kvm_preempt_ops.sched_in = kvm_sched_in;
 	kvm_preempt_ops.sched_out = kvm_sched_out;
 
-	r = kvm_init_debug();
-	if (r) {
-		pr_err("kvm: create debugfs files failed\n");
-		goto out_undebugfs;
-	}
+	kvm_init_debug();
 
 	r = kvm_vfio_ops_init();
 	WARN_ON(r);
 
 	return 0;
 
-out_undebugfs:
-	unregister_syscore_ops(&kvm_syscore_ops);
-	misc_deregister(&kvm_dev);
 out_unreg:
 	kvm_async_pf_deinit();
 out_free:
-- 
2.17.0