+ swap-rename-swp_fs-to-swap_fs_ops-to-avoid-ambiguity.patch added to -mm tree

+ swap-rename-swp_fs-to-swap_fs_ops-to-avoid-ambiguity.patch added to -mm tree

[akpm]

The patch titled
     Subject: swap: rename SWP_FS to SWAP_FS_OPS to avoid ambiguity
has been added to the -mm tree.  Its filename is
     swap-rename-swp_fs-to-swap_fs_ops-to-avoid-ambiguity.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/swap-rename-swp_fs-to-swap_fs_ops-to-avoid-ambiguity.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/swap-rename-swp_fs-to-swap_fs_ops-to-avoid-ambiguity.patch

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------------------------------------------------------
From: Gao Xiang <hsiangkao@redhat.com>
Subject: swap: rename SWP_FS to SWAP_FS_OPS to avoid ambiguity

SWP_FS is used to make swap_{read,write}page() go through the filesystem,
and it's only used for swap files over NFS for now.  Otherwise it will
directly submit IO to blockdev according to swapfile extents reported by
filesystems in advance.

As Matthew pointed out [1], SWP_FS naming is somewhat confusing, so let's
rename to SWP_FS_OPS.

[1] https://lore.kernel.org/r/20200820113448.GM17456@casper.infradead.org

Link: https://lkml.kernel.org/r/20200822113019.11319-1-hsiangkao@redhat.com
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/swap.h |    2 +-
 mm/page_io.c         |    6 +++---
 mm/swap_state.c      |    2 +-
 mm/swapfile.c        |    2 +-
 4 files changed, 6 insertions(+), 6 deletions(-)

--- a/include/linux/swap.h~swap-rename-swp_fs-to-swap_fs_ops-to-avoid-ambiguity
+++ a/include/linux/swap.h
@@ -170,7 +170,7 @@ enum {
 	SWP_CONTINUED	= (1 << 5),	/* swap_map has count continuation */
 	SWP_BLKDEV	= (1 << 6),	/* its a block device */
 	SWP_ACTIVATED	= (1 << 7),	/* set after swap_activate success */
-	SWP_FS		= (1 << 8),	/* swap file goes through fs */
+	SWP_FS_OPS	= (1 << 8),	/* swapfile operations go 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 */
--- a/mm/page_io.c~swap-rename-swp_fs-to-swap_fs_ops-to-avoid-ambiguity
+++ a/mm/page_io.c
@@ -302,7 +302,7 @@ int __swap_writepage(struct page *page,
 	struct swap_info_struct *sis = page_swap_info(page);
 
 	VM_BUG_ON_PAGE(!PageSwapCache(page), page);
-	if (data_race(sis->flags & SWP_FS)) {
+	if (data_race(sis->flags & SWP_FS_OPS)) {
 		struct kiocb kiocb;
 		struct file *swap_file = sis->swap_file;
 		struct address_space *mapping = swap_file->f_mapping;
@@ -393,7 +393,7 @@ int swap_readpage(struct page *page, boo
 		goto out;
 	}
 
-	if (data_race(sis->flags & SWP_FS)) {
+	if (data_race(sis->flags & SWP_FS_OPS)) {
 		struct file *swap_file = sis->swap_file;
 		struct address_space *mapping = swap_file->f_mapping;
 
@@ -455,7 +455,7 @@ int swap_set_page_dirty(struct page *pag
 {
 	struct swap_info_struct *sis = page_swap_info(page);
 
-	if (data_race(sis->flags & SWP_FS)) {
+	if (data_race(sis->flags & SWP_FS_OPS)) {
 		struct address_space *mapping = sis->swap_file->f_mapping;
 
 		VM_BUG_ON_PAGE(!PageSwapCache(page), page);
--- a/mm/swapfile.c~swap-rename-swp_fs-to-swap_fs_ops-to-avoid-ambiguity
+++ a/mm/swapfile.c
@@ -2433,7 +2433,7 @@ static int setup_swap_extents(struct swa
 		if (ret >= 0)
 			sis->flags |= SWP_ACTIVATED;
 		if (!ret) {
-			sis->flags |= SWP_FS;
+			sis->flags |= SWP_FS_OPS;
 			ret = add_swap_extent(sis, 0, sis->max, 0);
 			*span = sis->pages;
 		}
--- a/mm/swap_state.c~swap-rename-swp_fs-to-swap_fs_ops-to-avoid-ambiguity
+++ a/mm/swap_state.c
@@ -631,7 +631,7 @@ struct page *swap_cluster_readahead(swp_
 		goto skip;
 
 	/* Test swap type to make sure the dereference is safe */
-	if (likely(si->flags & (SWP_BLKDEV | SWP_FS))) {
+	if (likely(si->flags & (SWP_BLKDEV | SWP_FS_OPS))) {
 		struct inode *inode = si->swap_file->f_mapping->host;
 		if (inode_read_congested(inode))
 			goto skip;
_

Patches currently in -mm which might be from hsiangkao@redhat.com are

mm-thp-swap-fix-allocating-cluster-for-swapfile-by-mistake.patch
swap-rename-swp_fs-to-swap_fs_ops-to-avoid-ambiguity.patch