The patch titled
Subject: mm: add support for direct_IO to highmem pages
has been removed from the -mm tree. Its filename was
mm-add-support-for-direct_io-to-highmem-pages.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxx>
Subject: 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@xxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Eric B Munson <emunson@xxxxxxxxx>
Cc: Eric Paris <eparis@xxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Mike Christie <michaelc@xxxxxxxxxxx>
Cc: Neil Brown <neilb@xxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Sebastian Andrzej Siewior <sebastian@xxxxxxxxxxxxx>
Cc: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Cc: Xiaotian Feng <dfeng@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/highmem.h | 7 +++++++
mm/highmem.c | 12 ++++++++++++
mm/page_io.c | 3 ++-
mm/swap.c | 3 +--
4 files changed, 22 insertions(+), 3 deletions(-)
diff -puN include/linux/highmem.h~mm-add-support-for-direct_io-to-highmem-pages include/linux/highmem.h
--- a/include/linux/highmem.h~mm-add-support-for-direct_io-to-highmem-pages
+++ a/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
diff -puN mm/highmem.c~mm-add-support-for-direct_io-to-highmem-pages mm/highmem.c
--- a/mm/highmem.c~mm-add-support-for-direct_io-to-highmem-pages
+++ a/mm/highmem.c
@@ -94,6 +94,18 @@ static DECLARE_WAIT_QUEUE_HEAD(pkmap_map
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 -puN mm/page_io.c~mm-add-support-for-direct_io-to-highmem-pages mm/page_io.c
--- a/mm/page_io.c~mm-add-support-for-direct_io-to-highmem-pages
+++ a/mm/page_io.c
@@ -205,7 +205,7 @@ int swap_writepage(struct page *page, st
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, st
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 -puN mm/swap.c~mm-add-support-for-direct_io-to-highmem-pages mm/swap.c
--- a/mm/swap.c~mm-add-support-for-direct_io-to-highmem-pages
+++ a/mm/swap.c
@@ -258,8 +258,7 @@ int get_kernel_pages(const struct kvec *
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]);
}
_
Patches currently in -mm which might be from mgorman@xxxxxxx are
origin.patch
linux-next.patch
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