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Commit f4112de6 authored by Akinobu Mita's avatar Akinobu Mita Committed by Linus Torvalds
Browse files

mm: introduce debug_kmap_atomic 



x86 has debug_kmap_atomic_prot() which is error checking function for
kmap_atomic.  It is usefull for the other architectures, although it needs
CONFIG_TRACE_IRQFLAGS_SUPPORT.

This patch exposes it to the other architectures.

Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 851a039c

arch/x86/mm/highmem_32.c

+1 −44
Original line number Original line Diff line number Diff line
@@ -19,49 +19,6 @@ void kunmap(struct page *page) 
	kunmap_high(page);

	kunmap_high(page);

}

}





static void debug_kmap_atomic_prot(enum km_type type)

{

#ifdef CONFIG_DEBUG_HIGHMEM

	static unsigned warn_count = 10;



	if (unlikely(warn_count == 0))

		return;



	if (unlikely(in_interrupt())) {

		if (in_irq()) {

			if (type != KM_IRQ0 && type != KM_IRQ1 &&

			    type != KM_BIO_SRC_IRQ && type != KM_BIO_DST_IRQ &&

			    type != KM_BOUNCE_READ) {

				WARN_ON(1);

				warn_count--;

			}

		} else if (!irqs_disabled()) {	/* softirq */

			if (type != KM_IRQ0 && type != KM_IRQ1 &&

			    type != KM_SOFTIRQ0 && type != KM_SOFTIRQ1 &&

			    type != KM_SKB_SUNRPC_DATA &&

			    type != KM_SKB_DATA_SOFTIRQ &&

			    type != KM_BOUNCE_READ) {

				WARN_ON(1);

				warn_count--;

			}

		}

	}



	if (type == KM_IRQ0 || type == KM_IRQ1 || type == KM_BOUNCE_READ ||

			type == KM_BIO_SRC_IRQ || type == KM_BIO_DST_IRQ) {

		if (!irqs_disabled()) {

			WARN_ON(1);

			warn_count--;

		}

	} else if (type == KM_SOFTIRQ0 || type == KM_SOFTIRQ1) {

		if (irq_count() == 0 && !irqs_disabled()) {

			WARN_ON(1);

			warn_count--;

		}

	}

#endif

}



/*

/*

 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because

 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because

 * no global lock is needed and because the kmap code must perform a global TLB

 * no global lock is needed and because the kmap code must perform a global TLB
@@ -81,7 +38,7 @@ void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot) 
	if (!PageHighMem(page))

	if (!PageHighMem(page))

		return page_address(page);

		return page_address(page);





	debug_kmap_atomic_prot(type);

	debug_kmap_atomic(type);





	idx = type + KM_TYPE_NR*smp_processor_id();

	idx = type + KM_TYPE_NR*smp_processor_id();

	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);

	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);

include/linux/highmem.h

+12 −0
Original line number Original line Diff line number Diff line
@@ -187,4 +187,16 @@ static inline void copy_highpage(struct page *to, struct page *from) 
	kunmap_atomic(vto, KM_USER1);

	kunmap_atomic(vto, KM_USER1);

}

}





#if defined(CONFIG_DEBUG_HIGHMEM) && defined(CONFIG_TRACE_IRQFLAGS_SUPPORT)



void debug_kmap_atomic(enum km_type type);



#else



static inline void debug_kmap_atomic(enum km_type type)

{

}



#endif



#endif /* _LINUX_HIGHMEM_H */
 
#endif /* _LINUX_HIGHMEM_H */

mm/highmem.c

+45 −0
Original line number Original line Diff line number Diff line
@@ -422,3 +422,48 @@ void __init page_address_init(void) 
}

}





#endif	/* defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL) */

#endif	/* defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL) */



#if defined(CONFIG_DEBUG_HIGHMEM) && defined(CONFIG_TRACE_IRQFLAGS_SUPPORT)



void debug_kmap_atomic(enum km_type type)

{

	static unsigned warn_count = 10;



	if (unlikely(warn_count == 0))

		return;



	if (unlikely(in_interrupt())) {

		if (in_irq()) {

			if (type != KM_IRQ0 && type != KM_IRQ1 &&

			    type != KM_BIO_SRC_IRQ && type != KM_BIO_DST_IRQ &&

			    type != KM_BOUNCE_READ) {

				WARN_ON(1);

				warn_count--;

			}

		} else if (!irqs_disabled()) {	/* softirq */

			if (type != KM_IRQ0 && type != KM_IRQ1 &&

			    type != KM_SOFTIRQ0 && type != KM_SOFTIRQ1 &&

			    type != KM_SKB_SUNRPC_DATA &&

			    type != KM_SKB_DATA_SOFTIRQ &&

			    type != KM_BOUNCE_READ) {

				WARN_ON(1);

				warn_count--;

			}

		}

	}



	if (type == KM_IRQ0 || type == KM_IRQ1 || type == KM_BOUNCE_READ ||

			type == KM_BIO_SRC_IRQ || type == KM_BIO_DST_IRQ) {

		if (!irqs_disabled()) {

			WARN_ON(1);

			warn_count--;

		}

	} else if (type == KM_SOFTIRQ0 || type == KM_SOFTIRQ1) {

		if (irq_count() == 0 && !irqs_disabled()) {

			WARN_ON(1);

			warn_count--;

		}

	}

}



#endif