powerpc/kvm: no need to check return value of debugfs_create functions

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.

Because of this cleanup, we get to remove a few fields in struct
kvm_arch that are now unused.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[mpe: Fix build error in kvm/timing.c, adapt kvmppc_remove_cpu_debugfs()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200209105901.1620958-2-gregkh@linuxfoundation.org

arch/powerpc/include/asm/kvm_host.h

@@ -308,8 +308,6 @@ struct kvm_arch {
 	pgd_t *pgtable;
 	u64 process_table;
 	struct dentry *debugfs_dir;
-	struct dentry *htab_dentry;
-	struct dentry *radix_dentry;
 	struct kvm_resize_hpt *resize_hpt; /* protected by kvm->lock */
 #endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
 #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
@@ -830,7 +828,6 @@ struct kvm_vcpu_arch {
 	struct kvmhv_tb_accumulator cede_time;	/* time napping inside guest */
 
 	struct dentry *debugfs_dir;
-	struct dentry *debugfs_timings;
 #endif /* CONFIG_KVM_BOOK3S_HV_EXIT_TIMING */
 };
 

arch/powerpc/kvm/book3s_64_mmu_hv.c

@@ -2138,8 +2138,7 @@ static const struct file_operations debugfs_htab_fops = {
 
 void kvmppc_mmu_debugfs_init(struct kvm *kvm)
 {
-	kvm->arch.htab_dentry = debugfs_create_file("htab", 0400,
-						    kvm->arch.debugfs_dir, kvm,
+	debugfs_create_file("htab", 0400, kvm->arch.debugfs_dir, kvm,
 			    &debugfs_htab_fops);
 }
 

arch/powerpc/kvm/book3s_64_mmu_radix.c

@@ -1376,8 +1376,7 @@ static const struct file_operations debugfs_radix_fops = {
 
 void kvmhv_radix_debugfs_init(struct kvm *kvm)
 {
-	kvm->arch.radix_dentry = debugfs_create_file("radix", 0400,
-						     kvm->arch.debugfs_dir, kvm,
+	debugfs_create_file("radix", 0400, kvm->arch.debugfs_dir, kvm,
 			    &debugfs_radix_fops);
 }
 

arch/powerpc/kvm/book3s_hv.c

@@ -2258,14 +2258,9 @@ static void debugfs_vcpu_init(struct kvm_vcpu *vcpu, unsigned int id)
 	struct kvm *kvm = vcpu->kvm;
 
 	snprintf(buf, sizeof(buf), "vcpu%u", id);
-	if (IS_ERR_OR_NULL(kvm->arch.debugfs_dir))
-		return;
 	vcpu->arch.debugfs_dir = debugfs_create_dir(buf, kvm->arch.debugfs_dir);
-	if (IS_ERR_OR_NULL(vcpu->arch.debugfs_dir))
-		return;
-	vcpu->arch.debugfs_timings =
-		debugfs_create_file("timings", 0444, vcpu->arch.debugfs_dir,
-				    vcpu, &debugfs_timings_ops);
+	debugfs_create_file("timings", 0444, vcpu->arch.debugfs_dir, vcpu,
+			    &debugfs_timings_ops);
 }
 
 #else /* CONFIG_KVM_BOOK3S_HV_EXIT_TIMING */

arch/powerpc/kvm/timing.c

@@ -211,23 +211,14 @@ void kvmppc_create_vcpu_debugfs(struct kvm_vcpu *vcpu, unsigned int id)
 
 	snprintf(dbg_fname, sizeof(dbg_fname), "vm%u_vcpu%u_timing",
 		 current->pid, id);
-	debugfs_file = debugfs_create_file(dbg_fname, 0666,
-					kvm_debugfs_dir, vcpu,
-					&kvmppc_exit_timing_fops);
-
-	if (!debugfs_file) {
-		printk(KERN_ERR"%s: error creating debugfs file %s\n",
-			__func__, dbg_fname);
-		return;
-	}
+	debugfs_file = debugfs_create_file(dbg_fname, 0666, kvm_debugfs_dir,
+						vcpu, &kvmppc_exit_timing_fops);
 
 	vcpu->arch.debugfs_exit_timing = debugfs_file;
 }
 
 void kvmppc_remove_vcpu_debugfs(struct kvm_vcpu *vcpu)
 {
-	if (vcpu->arch.debugfs_exit_timing) {
 	debugfs_remove(vcpu->arch.debugfs_exit_timing);
 	vcpu->arch.debugfs_exit_timing = NULL;
-	}
 }