Re: [022/119] highmem: Fix debug_kmap_atomic() to also handleKM_IRQ_PTE, KM_NMI, and KM_NMI_PTE

[Hugh Dickins]

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@xxxxxxxxxxx>
> 
> 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@xxxxxxxxxx>
> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Cc: a.p.zijlstra@xxxxxxxxx
> LKML-Reference: <ye8vdhz8krw.fsf@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

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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