[Bionic,01/18] kvm: no need to check return value of debugfs_create functions
diff mbox series

Message ID 20181031150931.16284-2-joserz@linux.ibm.com
State New
Headers show
Series
  • NVIDIA GPU passthrough - part I
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Commit Message

Jose Ricardo Ziviani Oct. 31, 2018, 3:09 p.m. UTC
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

BugLink: https://bugs.launchpad.net/qemu-kvm/+bug/1800649

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@ozlabs.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim KrÄmář" <rkrcmar@redhat.com>
Cc: Arvind Yadav <arvind.yadav.cs@gmail.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: kvm-ppc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: kvmarm@lists.cs.columbia.edu
Cc: kvm@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 929f45e32499171ce3e5a15db972256eac513ad7)
Signed-off-by: Jose Ricardo Ziviani <joserz@linux.ibm.com>
---
 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(-)

Patch
diff mbox series

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index dc9eb6b495ce..9f4da904ebee 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -3954,8 +3954,7 @@  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 4ffc0b5e6105..c589d4c2b478 100644
--- a/virt/kvm/arm/vgic/vgic-debug.c
+++ b/virt/kvm/arm/vgic/vgic-debug.c
@@ -264,21 +264,12 @@  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 3742fa670c9c..661155686c81 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -218,8 +218,8 @@  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 234d03abcb75..a25ae49d3e1c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -577,10 +577,7 @@  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),
@@ -596,11 +593,8 @@  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;
 }
@@ -3919,29 +3913,18 @@  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)
@@ -4065,20 +4048,13 @@  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: