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 <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Eric B Munson <[email protected]>
Cc: Eric Paris <[email protected]>
Cc: James Morris <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Mike Christie <[email protected]>
Cc: Neil Brown <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: Trond Myklebust <[email protected]>
Cc: Xiaotian Feng <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Mel Gorman 2012-07-31 16:45:02 -07:00 • committed by Linus Torvalds
commit 5a178119b0
4 changed files with 22 additions and 3 deletions

View file

@ -94,6 +94,18 @@ static DECLARE_WAIT_QUEUE_HEAD(pkmap_map_wait);
do { spin_unlock(&kmap_lock); (void)(flags); } while (0)
#endif
struct page *kmap_to_page(void *vaddr)
{
unsigned long addr = (unsigned long)vaddr;
if (addr >= PKMAP_ADDR(0) && addr <= PKMAP_ADDR(LAST_PKMAP)) {
int i = (addr - PKMAP_ADDR(0)) >> PAGE_SHIFT;
return pte_page(pkmap_page_table[i]);
}
return virt_to_page(addr);
}
static void flush_all_zero_pkmaps(void)
{
int i;