linux-kernel - Re: [PATCH] kvm: no need to check return value of debugfs

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Message-ID: <20190122172907.GF28513@linux.intel.com>
Date:   Tue, 22 Jan 2019 09:29:07 -0800
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        kvm@...r.kernel.org
Subject: Re: [PATCH] kvm: no need to check return value of debugfs_create
 functions

On Tue, Jan 22, 2019 at 09:21:02AM -0800, Sean Christopherson wrote:
> On Tue, Jan 22, 2019 at 04:21:50PM +0100, Greg Kroah-Hartman wrote:
> > 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.
> 
> What about wanting to make the debugfs all-or-nothing?  That seems like
> a legitimate usage of checking the return value.
> 
> E.g. KVM removes the debugfs if kvm_arch_create_vcpu_debugfs() fails, and
> the arch/x86/kvm/debugfs.c implementation of kvm_arch_create_vcpu_debugfs()
> returns an error if any of its debugfs_create_file() calls fail.
> 
> If you're adamant about removing all debugfs create return value checks,
> the aforementioned debugfs_create_file() calls should also be removed.
> And at that point kvm_create_vcpu_debugfs() should have a 'void' return
> value.

Belatedly saw the other series.  It'll require a bit more coordination,
but folding this into the x86 series would allow for converting the KVM
call stack to have 'void' returns.