linux-stable/include/linux/highmem.h
Randy Dunlap 3ecabd3134 include/linux/highmem.h: fix duplicated words in a comment
Change the doubled word "is" in a comment to "it is".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/ad605959-0083-4794-8d31-6b073300dd6f@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:57 -07:00

348 lines
8.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_HIGHMEM_H
#define _LINUX_HIGHMEM_H
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/bug.h>
#include <linux/mm.h>
#include <linux/uaccess.h>
#include <linux/hardirq.h>
#include <asm/cacheflush.h>
#ifndef ARCH_HAS_FLUSH_ANON_PAGE
static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
{
}
#endif
#ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
static inline void flush_kernel_dcache_page(struct page *page)
{
}
static inline void flush_kernel_vmap_range(void *vaddr, int size)
{
}
static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
{
}
#endif
#include <asm/kmap_types.h>
#ifdef CONFIG_HIGHMEM
extern void *kmap_atomic_high_prot(struct page *page, pgprot_t prot);
extern void kunmap_atomic_high(void *kvaddr);
#include <asm/highmem.h>
#ifndef ARCH_HAS_KMAP_FLUSH_TLB
static inline void kmap_flush_tlb(unsigned long addr) { }
#endif
#ifndef kmap_prot
#define kmap_prot PAGE_KERNEL
#endif
void *kmap_high(struct page *page);
static inline void *kmap(struct page *page)
{
void *addr;
might_sleep();
if (!PageHighMem(page))
addr = page_address(page);
else
addr = kmap_high(page);
kmap_flush_tlb((unsigned long)addr);
return addr;
}
void kunmap_high(struct page *page);
static inline void kunmap(struct page *page)
{
might_sleep();
if (!PageHighMem(page))
return;
kunmap_high(page);
}
/*
* 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
* invalidation when the kmap pool wraps.
*
* However when holding an atomic kmap it is not legal to sleep, so atomic
* kmaps are appropriate for short, tight code paths only.
*
* The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
* gives a more generic (and caching) interface. But kmap_atomic can
* be used in IRQ contexts, so in some (very limited) cases we need
* it.
*/
static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
{
preempt_disable();
pagefault_disable();
if (!PageHighMem(page))
return page_address(page);
return kmap_atomic_high_prot(page, prot);
}
#define kmap_atomic(page) kmap_atomic_prot(page, kmap_prot)
/* declarations for linux/mm/highmem.c */
unsigned int nr_free_highpages(void);
extern atomic_long_t _totalhigh_pages;
static inline unsigned long totalhigh_pages(void)
{
return (unsigned long)atomic_long_read(&_totalhigh_pages);
}
static inline void totalhigh_pages_inc(void)
{
atomic_long_inc(&_totalhigh_pages);
}
static inline void totalhigh_pages_dec(void)
{
atomic_long_dec(&_totalhigh_pages);
}
static inline void totalhigh_pages_add(long count)
{
atomic_long_add(count, &_totalhigh_pages);
}
static inline void totalhigh_pages_set(long val)
{
atomic_long_set(&_totalhigh_pages, val);
}
void kmap_flush_unused(void);
struct page *kmap_to_page(void *addr);
#else /* CONFIG_HIGHMEM */
static inline unsigned int nr_free_highpages(void) { return 0; }
static inline struct page *kmap_to_page(void *addr)
{
return virt_to_page(addr);
}
static inline unsigned long totalhigh_pages(void) { return 0UL; }
static inline void *kmap(struct page *page)
{
might_sleep();
return page_address(page);
}
static inline void kunmap_high(struct page *page)
{
}
static inline void kunmap(struct page *page)
{
#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
kunmap_flush_on_unmap(page_address(page));
#endif
}
static inline void *kmap_atomic(struct page *page)
{
preempt_disable();
pagefault_disable();
return page_address(page);
}
#define kmap_atomic_prot(page, prot) kmap_atomic(page)
static inline void kunmap_atomic_high(void *addr)
{
/*
* Mostly nothing to do in the CONFIG_HIGHMEM=n case as kunmap_atomic()
* handles re-enabling faults + preemption
*/
#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
kunmap_flush_on_unmap(addr);
#endif
}
#define kmap_atomic_pfn(pfn) kmap_atomic(pfn_to_page(pfn))
#define kmap_flush_unused() do {} while(0)
#endif /* CONFIG_HIGHMEM */
#if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
DECLARE_PER_CPU(int, __kmap_atomic_idx);
static inline int kmap_atomic_idx_push(void)
{
int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
#ifdef CONFIG_DEBUG_HIGHMEM
WARN_ON_ONCE(in_irq() && !irqs_disabled());
BUG_ON(idx >= KM_TYPE_NR);
#endif
return idx;
}
static inline int kmap_atomic_idx(void)
{
return __this_cpu_read(__kmap_atomic_idx) - 1;
}
static inline void kmap_atomic_idx_pop(void)
{
#ifdef CONFIG_DEBUG_HIGHMEM
int idx = __this_cpu_dec_return(__kmap_atomic_idx);
BUG_ON(idx < 0);
#else
__this_cpu_dec(__kmap_atomic_idx);
#endif
}
#endif
/*
* Prevent people trying to call kunmap_atomic() as if it were kunmap()
* kunmap_atomic() should get the return value of kmap_atomic, not the page.
*/
#define kunmap_atomic(addr) \
do { \
BUILD_BUG_ON(__same_type((addr), struct page *)); \
kunmap_atomic_high(addr); \
pagefault_enable(); \
preempt_enable(); \
} while (0)
/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
#ifndef clear_user_highpage
static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
{
void *addr = kmap_atomic(page);
clear_user_page(addr, vaddr, page);
kunmap_atomic(addr);
}
#endif
#ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
/**
* __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
* @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
* @vma: The VMA the page is to be allocated for
* @vaddr: The virtual address the page will be inserted into
*
* This function will allocate a page for a VMA but the caller is expected
* to specify via movableflags whether the page will be movable in the
* future or not
*
* An architecture may override this function by defining
* __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
* implementation.
*/
static inline struct page *
__alloc_zeroed_user_highpage(gfp_t movableflags,
struct vm_area_struct *vma,
unsigned long vaddr)
{
struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
vma, vaddr);
if (page)
clear_user_highpage(page, vaddr);
return page;
}
#endif
/**
* alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
* @vma: The VMA the page is to be allocated for
* @vaddr: The virtual address the page will be inserted into
*
* This function will allocate a page for a VMA that the caller knows will
* be able to migrate in the future using move_pages() or reclaimed
*/
static inline struct page *
alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
unsigned long vaddr)
{
return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
}
static inline void clear_highpage(struct page *page)
{
void *kaddr = kmap_atomic(page);
clear_page(kaddr);
kunmap_atomic(kaddr);
}
static inline void zero_user_segments(struct page *page,
unsigned start1, unsigned end1,
unsigned start2, unsigned end2)
{
void *kaddr = kmap_atomic(page);
BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
if (end1 > start1)
memset(kaddr + start1, 0, end1 - start1);
if (end2 > start2)
memset(kaddr + start2, 0, end2 - start2);
kunmap_atomic(kaddr);
flush_dcache_page(page);
}
static inline void zero_user_segment(struct page *page,
unsigned start, unsigned end)
{
zero_user_segments(page, start, end, 0, 0);
}
static inline void zero_user(struct page *page,
unsigned start, unsigned size)
{
zero_user_segments(page, start, start + size, 0, 0);
}
#ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
static inline void copy_user_highpage(struct page *to, struct page *from,
unsigned long vaddr, struct vm_area_struct *vma)
{
char *vfrom, *vto;
vfrom = kmap_atomic(from);
vto = kmap_atomic(to);
copy_user_page(vto, vfrom, vaddr, to);
kunmap_atomic(vto);
kunmap_atomic(vfrom);
}
#endif
#ifndef __HAVE_ARCH_COPY_HIGHPAGE
static inline void copy_highpage(struct page *to, struct page *from)
{
char *vfrom, *vto;
vfrom = kmap_atomic(from);
vto = kmap_atomic(to);
copy_page(vto, vfrom);
kunmap_atomic(vto);
kunmap_atomic(vfrom);
}
#endif
#endif /* _LINUX_HIGHMEM_H */