diff options
| author | Mel Gorman <mgorman@suse.de> | 2012-07-31 16:45:02 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-07-31 18:42:47 -0700 |
| commit | 5a178119b0fbe37f7dfb602b37df9cc4b1dc9d71 (patch) | |
| tree | 22ddd286aac202ccb8c063f02792fc9c90a0b8da | |
| parent | a509bc1a9e487d952d9404318f7f990166ab57a7 (diff) | |
| download | lwn-5a178119b0fbe37f7dfb602b37df9cc4b1dc9d71.tar.gz lwn-5a178119b0fbe37f7dfb602b37df9cc4b1dc9d71.zip | |
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>
| -rw-r--r-- | include/linux/highmem.h | 7 | ||||
| -rw-r--r-- | mm/highmem.c | 12 | ||||
| -rw-r--r-- | mm/page_io.c | 3 | ||||
| -rw-r--r-- | mm/swap.c | 3 |
4 files changed, 22 insertions, 3 deletions
diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 774fa47b3b5b..ef788b5b4a35 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 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]); } |