Re: [PATCH] mm: use in_atomic() in print_vma_addr()

From: Bart Van Assche <Bart.VanAssche@wdc.com>
To: "yang.s@alibaba-inc.com" <yang.s@alibaba-inc.com>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>
Cc: "joe@perches.com" <joe@perches.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"mhocko@kernel.org" <mhocko@kernel.org>,
	"mingo@redhat.com" <mingo@redhat.com>
Subject: Re: [PATCH] mm: use in_atomic() in print_vma_addr()
Date: Fri, 3 Nov 2017 20:09:49 +0000	[thread overview]
Message-ID: <1509739786.2473.33.camel@wdc.com> (raw)
In-Reply-To: <20171103110245.7049460a05cc18c7e8a9feb2@linux-foundation.org>

On Fri, 2017-11-03 at 11:02 -0700, Andrew Morton wrote:
> Also, checkpatch says
> 
> WARNING: use of in_atomic() is incorrect outside core kernel code
> #43: FILE: mm/memory.c:4491:
> +       if (in_atomic())
> 
> I don't recall why we did that, but perhaps this should be revisited?

Is the comment above in_atomic() still up-to-date? From <linux/preempt.h>:

/*
 * Are we running in atomic context?  WARNING: this macro cannot
 * always detect atomic context; in particular, it cannot know about
 * held spinlocks in non-preemptible kernels.  Thus it should not be
 * used in the general case to determine whether sleeping is possible.
 * Do not use in_atomic() in driver code.
 */
#define in_atomic()	(preempt_count() != 0)

Bart.