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authorOmar Sandoval <osandov@fb.com>2018-10-26 15:10:51 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-10-26 16:38:15 -0700
commitbc4ae27d817a4e92071ef67cb6368120cfabe7ec (patch)
treeaaa6b5b87cad72a3839ed10f9b06ea21030759dc
parent91cbacc34512e37c9bb89125ca4b224ca6459245 (diff)
mm: split SWP_FILE into SWP_ACTIVATED and SWP_FS
The SWP_FILE flag serves two purposes: to make swap_{read,write}page() go through the filesystem, and to make swapoff() call ->swap_deactivate(). For Btrfs, we want the latter but not the former, so split this flag into two. This makes us always call ->swap_deactivate() if ->swap_activate() succeeded, not just if it didn't add any swap extents itself. This also resolves the issue of the very misleading name of SWP_FILE, which is only used for swap files over NFS. Link: http://lkml.kernel.org/r/6d63d8668c4287a4f6d203d65696e96f80abdfc7.1536704650.git.osandov@fb.com Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: David Sterba <dsterba@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/swap.h13
-rw-r--r--mm/page_io.c6
-rw-r--r--mm/swapfile.c13
3 files changed, 18 insertions, 14 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h
index b93740d72e78..38195f5c96b1 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -167,13 +167,14 @@ enum {
SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
SWP_BLKDEV = (1 << 6), /* its a block device */
- SWP_FILE = (1 << 7), /* set after swap_activate success */
- SWP_AREA_DISCARD = (1 << 8), /* single-time swap area discards */
- SWP_PAGE_DISCARD = (1 << 9), /* freed swap page-cluster discards */
- SWP_STABLE_WRITES = (1 << 10), /* no overwrite PG_writeback pages */
- SWP_SYNCHRONOUS_IO = (1 << 11), /* synchronous IO is efficient */
+ SWP_ACTIVATED = (1 << 7), /* set after swap_activate success */
+ SWP_FS = (1 << 8), /* swap file goes through fs */
+ SWP_AREA_DISCARD = (1 << 9), /* single-time swap area discards */
+ SWP_PAGE_DISCARD = (1 << 10), /* freed swap page-cluster discards */
+ SWP_STABLE_WRITES = (1 << 11), /* no overwrite PG_writeback pages */
+ SWP_SYNCHRONOUS_IO = (1 << 12), /* synchronous IO is efficient */
/* add others here before... */
- SWP_SCANNING = (1 << 12), /* refcount in scan_swap_map */
+ SWP_SCANNING = (1 << 13), /* refcount in scan_swap_map */
};
#define SWAP_CLUSTER_MAX 32UL
diff --git a/mm/page_io.c b/mm/page_io.c
index 573d3663d846..a451ffa9491c 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -283,7 +283,7 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc,
struct swap_info_struct *sis = page_swap_info(page);
VM_BUG_ON_PAGE(!PageSwapCache(page), page);
- if (sis->flags & SWP_FILE) {
+ if (sis->flags & SWP_FS) {
struct kiocb kiocb;
struct file *swap_file = sis->swap_file;
struct address_space *mapping = swap_file->f_mapping;
@@ -365,7 +365,7 @@ int swap_readpage(struct page *page, bool synchronous)
goto out;
}
- if (sis->flags & SWP_FILE) {
+ if (sis->flags & SWP_FS) {
struct file *swap_file = sis->swap_file;
struct address_space *mapping = swap_file->f_mapping;
@@ -423,7 +423,7 @@ int swap_set_page_dirty(struct page *page)
{
struct swap_info_struct *sis = page_swap_info(page);
- if (sis->flags & SWP_FILE) {
+ if (sis->flags & SWP_FS) {
struct address_space *mapping = sis->swap_file->f_mapping;
VM_BUG_ON_PAGE(!PageSwapCache(page), page);
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 2681e50592c5..f0c7e4c11bab 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1003,7 +1003,7 @@ start_over:
goto nextsi;
}
if (size == SWAPFILE_CLUSTER) {
- if (!(si->flags & SWP_FILE))
+ if (!(si->flags & SWP_FS))
n_ret = swap_alloc_cluster(si, swp_entries);
} else
n_ret = scan_swap_map_slots(si, SWAP_HAS_CACHE,
@@ -2299,12 +2299,13 @@ static void destroy_swap_extents(struct swap_info_struct *sis)
kfree(se);
}
- if (sis->flags & SWP_FILE) {
+ if (sis->flags & SWP_ACTIVATED) {
struct file *swap_file = sis->swap_file;
struct address_space *mapping = swap_file->f_mapping;
- sis->flags &= ~SWP_FILE;
- mapping->a_ops->swap_deactivate(swap_file);
+ sis->flags &= ~SWP_ACTIVATED;
+ if (mapping->a_ops->swap_deactivate)
+ mapping->a_ops->swap_deactivate(swap_file);
}
}
@@ -2400,8 +2401,10 @@ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span)
if (mapping->a_ops->swap_activate) {
ret = mapping->a_ops->swap_activate(sis, swap_file, span);
+ if (ret >= 0)
+ sis->flags |= SWP_ACTIVATED;
if (!ret) {
- sis->flags |= SWP_FILE;
+ sis->flags |= SWP_FS;
ret = add_swap_extent(sis, 0, sis->max, 0);
*span = sis->pages;
}