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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 /mm
parenta509bc1a9e487d952d9404318f7f990166ab57a7 (diff)
downloadlinux-linaro-stable-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 'mm')
-rw-r--r--mm/highmem.c12
-rw-r--r--mm/page_io.c3
-rw-r--r--mm/swap.c3
3 files changed, 15 insertions, 3 deletions
diff --git a/mm/highmem.c b/mm/highmem.c
index 57d82c6250c3..d517cd16a6eb 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -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;
diff --git a/mm/page_io.c b/mm/page_io.c
index 4a379629e31f..78eee32ee486 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -205,7 +205,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
struct file *swap_file = sis->swap_file;
struct address_space *mapping = swap_file->f_mapping;
struct iovec iov = {
- .iov_base = page_address(page),
+ .iov_base = kmap(page),
.iov_len = PAGE_SIZE,
};
@@ -218,6 +218,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
ret = mapping->a_ops->direct_IO(KERNEL_WRITE,
&kiocb, &iov,
kiocb.ki_pos, 1);
+ kunmap(page);
if (ret == PAGE_SIZE) {
count_vm_event(PSWPOUT);
ret = 0;
diff --git a/mm/swap.c b/mm/swap.c
index 7d7f80c8044a..77825883298f 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -258,8 +258,7 @@ int get_kernel_pages(const struct kvec *kiov, int nr_segs, int write,
if (WARN_ON(kiov[seg].iov_len != PAGE_SIZE))
return seg;
- /* virt_to_page sanity checks the PFN */
- pages[seg] = virt_to_page(kiov[seg].iov_base);
+ pages[seg] = kmap_to_page(kiov[seg].iov_base);
page_cache_get(pages[seg]);
}