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2cb7c9cb42
The existing code relies on pagefault_disable() implicitly disabling preemption, so that no schedule will happen between kmap_atomic() and kunmap_atomic(). Let's make this explicit, to prepare for pagefault_disable() not touching preemption anymore. Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-5-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
91 lines
2 KiB
C
91 lines
2 KiB
C
/* highmem.c: arch-specific highmem stuff
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*
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* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/highmem.h>
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#include <linux/module.h>
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void *kmap(struct page *page)
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{
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might_sleep();
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if (!PageHighMem(page))
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return page_address(page);
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return kmap_high(page);
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}
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EXPORT_SYMBOL(kmap);
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void kunmap(struct page *page)
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{
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if (in_interrupt())
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BUG();
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if (!PageHighMem(page))
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return;
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kunmap_high(page);
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}
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EXPORT_SYMBOL(kunmap);
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struct page *kmap_atomic_to_page(void *ptr)
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{
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return virt_to_page(ptr);
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}
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void *kmap_atomic(struct page *page)
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{
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unsigned long paddr;
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int type;
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preempt_disable();
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pagefault_disable();
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type = kmap_atomic_idx_push();
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paddr = page_to_phys(page);
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switch (type) {
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/*
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* The first 4 primary maps are reserved for architecture code
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*/
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case 0: return __kmap_atomic_primary(0, paddr, 6);
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case 1: return __kmap_atomic_primary(0, paddr, 7);
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case 2: return __kmap_atomic_primary(0, paddr, 8);
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case 3: return __kmap_atomic_primary(0, paddr, 9);
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case 4: return __kmap_atomic_primary(0, paddr, 10);
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case 5 ... 5 + NR_TLB_LINES - 1:
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return __kmap_atomic_secondary(type - 5, paddr);
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default:
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BUG();
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return NULL;
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}
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}
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EXPORT_SYMBOL(kmap_atomic);
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void __kunmap_atomic(void *kvaddr)
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{
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int type = kmap_atomic_idx();
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switch (type) {
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case 0: __kunmap_atomic_primary(0, 6); break;
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case 1: __kunmap_atomic_primary(0, 7); break;
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case 2: __kunmap_atomic_primary(0, 8); break;
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case 3: __kunmap_atomic_primary(0, 9); break;
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case 4: __kunmap_atomic_primary(0, 10); break;
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case 5 ... 5 + NR_TLB_LINES - 1:
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__kunmap_atomic_secondary(type - 5, kvaddr);
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break;
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default:
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BUG();
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}
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kmap_atomic_idx_pop();
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pagefault_enable();
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preempt_enable();
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}
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EXPORT_SYMBOL(__kunmap_atomic);
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