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From:   Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Date:   Thu, 18 Oct 2018 00:34:08 +0900
To:     Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        rostedt <rostedt@goodmis.org>,
        Peter Zijlstra <peterz@infradead.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-api <linux-api@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Andy Lutomirski <luto@amacapital.net>,
        Dave Watson <davejwatson@fb.com>, Paul Turner <pjt@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Russell King <linux@arm.linux.org.uk>,
        Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Andi Kleen <andi@firstfloor.org>,
        Chris Lameter <cl@linux.com>, Ben Maurer <bmaurer@fb.com>,
        Josh Triplett <josh@joshtriplett.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Joel Fernandes <joelaf@google.com>
Subject: Re: [RFC PATCH for 4.21 04/16] mm: Introduce vm_map_user_ram,
 vm_unmap_user_ram
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On (10/17/18 11:04), Mathieu Desnoyers wrote:
> >> 
> >>> 	if (WARN_ON(x))
> >>> 		return;
> >> 
> >> Given that this somewhat MM-related, I'd may be say VM_WARN_ON().
> 
> I notice that VM_WARN_ON() casts the result of WARN_ON() to (void), so it
> cannot be used in a if () statement.
> 
> VM_WARN_ON() will only warn if CONFIG_DEBUG_VM is set.
> 
> Is it really what we want ?

Oh, indeed... Sorry, I forgot that they cast WANR_ON() return to void.
Let's do what Steven suggested.

	-ss