linux-kernel - Re: [022/119] highmem: Fix debug_kmap_atomic() to also handle KM_IRQ_PTE, KM_NMI, and KM_NMI

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Message-ID: <Pine.LNX.4.64.0912070105370.2642@sister.anvils>
Date:	Mon, 7 Dec 2009 01:11:55 +0000 (GMT)
From:	Hugh Dickins <hugh.dickins@...cali.co.uk>
To:	Greg KH <gregkh@...e.de>
cc:	linux-kernel@...r.kernel.org, stable@...nel.org,
	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Soeren Sandmann Pedersen <sandmann@...hat.com>,
	a.p.zijlstra@...llo.nl, Ingo Molnar <mingo@...e.hu>
Subject: Re: [022/119] highmem: Fix debug_kmap_atomic() to also handle
 KM_IRQ_PTE, KM_NMI, and KM_NMI_PTE

On Sun, 6 Dec 2009, Greg KH wrote:

> 2.6.31-stable review patch.  If anyone has any objections, please let us know.
> 
> ------------------
> From: Soeren Sandmann <sandmann@...mi.au.dk>
> 
> commit d4515646699b6ad7b1a98ceb871296b957f3ef47 upstream.
> 
> Previously calling debug_kmap_atomic() with these types would
> cause spurious warnings.
> 
> (triggered by SysProf using perf events)
> 
> Signed-off-by: Soeren Sandmann Pedersen <sandmann@...hat.com>
> Cc: Linus Torvalds <torvalds@...ux-foundation.org>
> Cc: a.p.zijlstra@...llo.nl
> LKML-Reference: <ye8vdhz8krw.fsf@...el23.daimi.au.dk>
> Signed-off-by: Ingo Molnar <mingo@...e.hu>
> Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

IIRC, this patch caused build failures in a number of architectures,
those which didn't already define KM_NMI, KM_NMI_PTE or KM_IRQ_PTE
e.g. compare the 2.6.32 arch/arm/include/asm/kmap_types.h against
its 2.6.31 version.

Should be fixable if you include the extras necessary, but I'm
ashamed to say I've left that as an exercise for the reader ;)

Hugh

> 
> ---
>  mm/highmem.c |   13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
> 
> --- a/mm/highmem.c
> +++ b/mm/highmem.c
> @@ -432,10 +432,15 @@ void debug_kmap_atomic(enum km_type type
>  		return;
>  
>  	if (unlikely(in_interrupt())) {
> -		if (in_irq()) {
> +		if (in_nmi()) {
> +			if (type != KM_NMI && type != KM_NMI_PTE) {
> +				WARN_ON(1);
> +				warn_count--;
> +			}
> +		} else if (in_irq()) {
>  			if (type != KM_IRQ0 && type != KM_IRQ1 &&
>  			    type != KM_BIO_SRC_IRQ && type != KM_BIO_DST_IRQ &&
> -			    type != KM_BOUNCE_READ) {
> +			    type != KM_BOUNCE_READ && type != KM_IRQ_PTE) {
>  				WARN_ON(1);
>  				warn_count--;
>  			}
> @@ -452,7 +457,9 @@ void debug_kmap_atomic(enum km_type type
>  	}
>  
>  	if (type == KM_IRQ0 || type == KM_IRQ1 || type == KM_BOUNCE_READ ||
> -			type == KM_BIO_SRC_IRQ || type == KM_BIO_DST_IRQ) {
> +			type == KM_BIO_SRC_IRQ || type == KM_BIO_DST_IRQ ||
> +			type == KM_IRQ_PTE || type == KM_NMI ||
> +			type == KM_NMI_PTE ) {
>  		if (!irqs_disabled()) {
>  			WARN_ON(1);
>  			warn_count--;
> 
> 
> --
--
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