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authorMel Gorman <mgorman@suse.de>2012-07-31 16:45:02 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-31 18:42:47 -0700
commit5a178119b0fbe37f7dfb602b37df9cc4b1dc9d71 (patch)
tree22ddd286aac202ccb8c063f02792fc9c90a0b8da /include/linux/highmem.h
parenta509bc1a9e487d952d9404318f7f990166ab57a7 (diff)
downloadop-kernel-dev-5a178119b0fbe37f7dfb602b37df9cc4b1dc9d71.zip
op-kernel-dev-5a178119b0fbe37f7dfb602b37df9cc4b1dc9d71.tar.gz
mm: add support for direct_IO to highmem pages
The patch "mm: add support for a filesystem to activate swap files and use direct_IO for writing swap pages" added support for using direct_IO to write swap pages but it is insufficient for highmem pages. To support highmem pages, this patch kmaps() the page before calling the direct_IO() handler. As direct_IO deals with virtual addresses an additional helper is necessary for get_kernel_pages() to lookup the struct page for a kmap virtual address. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: David S. Miller <davem@davemloft.net> Cc: Eric B Munson <emunson@mgebm.net> Cc: Eric Paris <eparis@redhat.com> Cc: James Morris <jmorris@namei.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Neil Brown <neilb@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Xiaotian Feng <dfeng@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/highmem.h')
-rw-r--r--include/linux/highmem.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 774fa47..ef788b5b 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -39,10 +39,17 @@ extern unsigned long totalhigh_pages;
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);
+}
+
#define totalhigh_pages 0UL
#ifndef ARCH_HAS_KMAP
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