We may now have to zero and flush higher order pages. Implement
clear_mapping_page and flush_mapping_page to do that job. Replace
the flushing and clearing at some key locations for the pagecache.

Signed-off-by: Christoph Lameter <[EMAIL PROTECTED]>

---
 fs/libfs.c              |    4 ++--
 include/linux/highmem.h |   31 +++++++++++++++++++++++++++++--
 include/linux/pagemap.h |    1 +
 mm/filemap.c            |    8 ++++----
 mm/filemap_xip.c        |    4 ++--
 5 files changed, 38 insertions(+), 10 deletions(-)

Index: linux-2.6.22-rc4-mm2/fs/libfs.c
===================================================================
--- linux-2.6.22-rc4-mm2.orig/fs/libfs.c        2007-06-19 20:10:05.000000000 
-0700
+++ linux-2.6.22-rc4-mm2/fs/libfs.c     2007-06-19 20:10:45.000000000 -0700
@@ -330,8 +330,8 @@ int simple_rename(struct inode *old_dir,
 
 int simple_readpage(struct file *file, struct page *page)
 {
-       clear_highpage(page);
-       flush_dcache_page(page);
+       clear_mapping_page(page);
+       flush_mapping_page(page);
        SetPageUptodate(page);
        unlock_page(page);
        return 0;
Index: linux-2.6.22-rc4-mm2/include/linux/highmem.h
===================================================================
--- linux-2.6.22-rc4-mm2.orig/include/linux/highmem.h   2007-06-19 
20:06:06.000000000 -0700
+++ linux-2.6.22-rc4-mm2/include/linux/highmem.h        2007-06-19 
20:30:06.000000000 -0700
@@ -124,14 +124,41 @@ static inline void clear_highpage(struct
        kunmap_atomic(kaddr, KM_USER0);
 }
 
+/*
+ * Clear a higher order page
+ */
+static inline void clear_mapping_page(struct page *page)
+{
+       int nr_pages = compound_pages(page);
+       int i;
+
+       for (i = 0; i < nr_pages; i++)
+               clear_highpage(page + i);
+}
+
+/*
+ * Primitive support for flushing higher order pages.
+ *
+ * A bit stupid: On many platforms flushing the first page
+ * will flush any TLB starting there
+ */
+static inline void flush_mapping_page(struct page *page)
+{
+       int nr_pages = compound_pages(page);
+       int i;
+
+       for (i = 0; i < nr_pages; i++)
+               flush_dcache_page(page + i);
+}
+
 static inline void zero_user_segments(struct page *page,
        unsigned start1, unsigned end1,
        unsigned start2, unsigned end2)
 {
        void *kaddr = kmap_atomic(page, KM_USER0);
 
-       BUG_ON(end1 > PAGE_SIZE ||
-               end2 > PAGE_SIZE);
+       BUG_ON(end1 > compound_size(page) ||
+               end2 > compound_size(page));
 
        if (end1 > start1)
                memset(kaddr + start1, 0, end1 - start1);
Index: linux-2.6.22-rc4-mm2/mm/filemap.c
===================================================================
--- linux-2.6.22-rc4-mm2.orig/mm/filemap.c      2007-06-19 20:10:52.000000000 
-0700
+++ linux-2.6.22-rc4-mm2/mm/filemap.c   2007-06-19 20:11:44.000000000 -0700
@@ -946,7 +946,7 @@ page_ok:
                 * before reading the page on the kernel side.
                 */
                if (mapping_writably_mapped(mapping))
-                       flush_dcache_page(page);
+                       flush_mapping_page(page);
 
                /*
                 * When a sequential read accesses a page several times,
@@ -2004,7 +2004,7 @@ int pagecache_write_end(struct file *fil
                unsigned offset = page_cache_offset(mapping, pos);
                struct inode *inode = mapping->host;
 
-               flush_dcache_page(page);
+               flush_mapping_page(page);
                ret = aops->commit_write(file, page, offset, offset+len);
                unlock_page(page);
                page_cache_release(page);
@@ -2216,7 +2216,7 @@ static ssize_t generic_perform_write_2co
                        kunmap_atomic(src, KM_USER0);
                        copied = bytes;
                }
-               flush_dcache_page(page);
+               flush_mapping_page(page);
 
                status = a_ops->commit_write(file, page, offset, offset+bytes);
                if (unlikely(status < 0 || status == AOP_TRUNCATED_PAGE))
@@ -2314,7 +2314,7 @@ again:
                pagefault_disable();
                copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes);
                pagefault_enable();
-               flush_dcache_page(page);
+               flush_mapping_page(page);
 
                status = a_ops->write_end(file, mapping, pos, bytes, copied,
                                                page, fsdata);
Index: linux-2.6.22-rc4-mm2/mm/filemap_xip.c
===================================================================
--- linux-2.6.22-rc4-mm2.orig/mm/filemap_xip.c  2007-06-19 20:12:10.000000000 
-0700
+++ linux-2.6.22-rc4-mm2/mm/filemap_xip.c       2007-06-19 20:12:46.000000000 
-0700
@@ -103,7 +103,7 @@ do_xip_mapping_read(struct address_space
                 * before reading the page on the kernel side.
                 */
                if (mapping_writably_mapped(mapping))
-                       flush_dcache_page(page);
+                       flush_mapping_page(page);
 
                /*
                 * Ok, we have the page, so now we can copy it to user space...
@@ -347,7 +347,7 @@ __xip_file_write(struct file *filp, cons
                copied = bytes -
                        __copy_from_user_inatomic_nocache(kaddr, buf, bytes);
                kunmap_atomic(kaddr, KM_USER0);
-               flush_dcache_page(page);
+               flush_mapping_page(page);
 
                if (likely(copied > 0)) {
                        status = copied;

-- 
-
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