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ARM: 7755/1: handle user space mapped pages in flush_kernel_dcache_page

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Commit f8b63c1 made flush_kernel_dcache_page a no-op assuming that
the pages it needs to handle are kernel mapped only.  However, for
example when doing direct I/O, pages with user space mappings may
occur.

Thus, continue to do lazy flushing if there are no user space
mappings.  Otherwise, flush the kernel cache lines directly.

Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org> # 3.2+
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Simon Baatz 2013-06-10 21:10:12 +01:00 committed by Russell King
parent 049be07053
commit 1bc39742aa
2 changed files with 34 additions and 3 deletions
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4
arch/arm/include/asm/cacheflush.h
View File

@ -320,9 +320,7 @@ static inline void flush_anon_page(struct vm_area_struct *vma,
}
#define ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
static inline void flush_kernel_dcache_page(struct page *page)
{
}
extern void flush_kernel_dcache_page(struct page *);
#define flush_dcache_mmap_lock(mapping) \
spin_lock_irq(&(mapping)->tree_lock)

33
arch/arm/mm/flush.c
View File

@ -300,6 +300,39 @@ void flush_dcache_page(struct page *page)
}
EXPORT_SYMBOL(flush_dcache_page);
/*
* Ensure cache coherency for the kernel mapping of this page. We can
* assume that the page is pinned via kmap.
*
* If the page only exists in the page cache and there are no user
* space mappings, this is a no-op since the page was already marked
* dirty at creation. Otherwise, we need to flush the dirty kernel
* cache lines directly.
*/
void flush_kernel_dcache_page(struct page *page)
{
if (cache_is_vivt() || cache_is_vipt_aliasing()) {
struct address_space *mapping;
mapping = page_mapping(page);
if (!mapping || mapping_mapped(mapping)) {
void *addr;
addr = page_address(page);
/*
* kmap_atomic() doesn't set the page virtual
* address for highmem pages, and
* kunmap_atomic() takes care of cache
* flushing already.
*/
if (!IS_ENABLED(CONFIG_HIGHMEM) || addr)
__cpuc_flush_dcache_area(addr, PAGE_SIZE);
}
}
}
EXPORT_SYMBOL(flush_kernel_dcache_page);
/*
* Flush an anonymous page so that users of get_user_pages()
* can safely access the data. The expected sequence is: