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

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

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 23c6e43..7bd5b4a 100644 (file)
--- a/include/linux/swap.h
+++ b/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 */

diff --git a/mm/page_io.c b/mm/page_io.c
index f9e9267..2ffe4c4 100644 (file)
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -312,7 +312,7 @@ 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 (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;
@@ -403,7 +403,7 @@ int swap_readpage(struct page *page, bool synchronous)
                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;
 
@@ -467,7 +467,7 @@ int swap_set_page_dirty(struct page *page)
 {
        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);

diff --git a/mm/swap_state.c b/mm/swap_state.c
index f24f2ce..aa40e70 100644 (file)
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -665,7 +665,7 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask,
                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;

diff --git a/mm/swapfile.c b/mm/swapfile.c
index ced4635..183b87b 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2437,7 +2437,7 @@ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span)
                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;
                }