[PATCH v2] fs: clean up usage of noop_dirty_folio

From: Xueshi Hu
Date: Mon Aug 28 2023 - 03:59:30 EST


In folio_mark_dirty(), it can automatically fallback to
noop_dirty_folio() if a_ops->dirty_folio is not registered.

As anon_aops, dev_dax_aops and fb_deferred_io_aops becames empty, remove
them too.

Signed-off-by: Xueshi Hu <xueshi.hu@xxxxxxxxxx>
---
Changes in v2:
- make noop_dirty_folio() inline as suggested by Matthew
- v1: https://lore.kernel.org/linux-mm/ZOxAfrz9etoVUfLQ@xxxxxxxxxxxxx/T/#m073d45909b1df03ff09f382557dc4e84d0607c49

drivers/dax/device.c | 5 -----
drivers/video/fbdev/core/fb_defio.c | 5 -----
fs/aio.c | 1 -
fs/ext2/inode.c | 1 -
fs/ext4/inode.c | 1 -
fs/fuse/dax.c | 1 -
fs/hugetlbfs/inode.c | 1 -
fs/libfs.c | 5 -----
fs/xfs/xfs_aops.c | 1 -
include/linux/pagemap.h | 1 -
mm/page-writeback.c | 18 +++++-------------
mm/secretmem.c | 1 -
mm/shmem.c | 1 -
mm/swap_state.c | 1 -
14 files changed, 5 insertions(+), 38 deletions(-)

diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 30665a3ff6ea..018aa9f88ec7 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -345,10 +345,6 @@ static unsigned long dax_get_unmapped_area(struct file *filp,
return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
}

-static const struct address_space_operations dev_dax_aops = {
- .dirty_folio = noop_dirty_folio,
-};
-
static int dax_open(struct inode *inode, struct file *filp)
{
struct dax_device *dax_dev = inode_dax(inode);
@@ -358,7 +354,6 @@ static int dax_open(struct inode *inode, struct file *filp)
dev_dbg(&dev_dax->dev, "trace\n");
inode->i_mapping = __dax_inode->i_mapping;
inode->i_mapping->host = __dax_inode;
- inode->i_mapping->a_ops = &dev_dax_aops;
filp->f_mapping = inode->i_mapping;
filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
filp->f_sb_err = file_sample_sb_err(filp);
diff --git a/drivers/video/fbdev/core/fb_defio.c b/drivers/video/fbdev/core/fb_defio.c
index 274f5d0fa247..08be3592281f 100644
--- a/drivers/video/fbdev/core/fb_defio.c
+++ b/drivers/video/fbdev/core/fb_defio.c
@@ -221,10 +221,6 @@ static const struct vm_operations_struct fb_deferred_io_vm_ops = {
.page_mkwrite = fb_deferred_io_mkwrite,
};

-static const struct address_space_operations fb_deferred_io_aops = {
- .dirty_folio = noop_dirty_folio,
-};
-
int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
vma->vm_ops = &fb_deferred_io_vm_ops;
@@ -307,7 +303,6 @@ void fb_deferred_io_open(struct fb_info *info,
{
struct fb_deferred_io *fbdefio = info->fbdefio;

- file->f_mapping->a_ops = &fb_deferred_io_aops;
fbdefio->open_count++;
}
EXPORT_SYMBOL_GPL(fb_deferred_io_open);
diff --git a/fs/aio.c b/fs/aio.c
index 77e33619de40..4cf386f9cb1c 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -484,7 +484,6 @@ static int aio_migrate_folio(struct address_space *mapping, struct folio *dst,
#endif

static const struct address_space_operations aio_ctx_aops = {
- .dirty_folio = noop_dirty_folio,
.migrate_folio = aio_migrate_folio,
};

diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 75983215c7a1..ce191bdf1c78 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -971,7 +971,6 @@ const struct address_space_operations ext2_aops = {
static const struct address_space_operations ext2_dax_aops = {
.writepages = ext2_dax_writepages,
.direct_IO = noop_direct_IO,
- .dirty_folio = noop_dirty_folio,
};

/*
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 43775a6ca505..67c1710c01b0 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3561,7 +3561,6 @@ static const struct address_space_operations ext4_da_aops = {
static const struct address_space_operations ext4_dax_aops = {
.writepages = ext4_dax_writepages,
.direct_IO = noop_direct_IO,
- .dirty_folio = noop_dirty_folio,
.bmap = ext4_bmap,
.swap_activate = ext4_iomap_swap_activate,
};
diff --git a/fs/fuse/dax.c b/fs/fuse/dax.c
index 8e74f278a3f6..50ca767cbd5e 100644
--- a/fs/fuse/dax.c
+++ b/fs/fuse/dax.c
@@ -1326,7 +1326,6 @@ bool fuse_dax_inode_alloc(struct super_block *sb, struct fuse_inode *fi)
static const struct address_space_operations fuse_dax_file_aops = {
.writepages = fuse_dax_writepages,
.direct_IO = noop_direct_IO,
- .dirty_folio = noop_dirty_folio,
};

static bool fuse_should_enable_dax(struct inode *inode, unsigned int flags)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 7b17ccfa039d..5404286f0c13 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -1266,7 +1266,6 @@ static void hugetlbfs_destroy_inode(struct inode *inode)
static const struct address_space_operations hugetlbfs_aops = {
.write_begin = hugetlbfs_write_begin,
.write_end = hugetlbfs_write_end,
- .dirty_folio = noop_dirty_folio,
.migrate_folio = hugetlbfs_migrate_folio,
.error_remove_page = hugetlbfs_error_remove_page,
};
diff --git a/fs/libfs.c b/fs/libfs.c
index 5b851315eeed..982f220a9ee3 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -627,7 +627,6 @@ const struct address_space_operations ram_aops = {
.read_folio = simple_read_folio,
.write_begin = simple_write_begin,
.write_end = simple_write_end,
- .dirty_folio = noop_dirty_folio,
};
EXPORT_SYMBOL(ram_aops);

@@ -1231,16 +1230,12 @@ EXPORT_SYMBOL(kfree_link);

struct inode *alloc_anon_inode(struct super_block *s)
{
- static const struct address_space_operations anon_aops = {
- .dirty_folio = noop_dirty_folio,
- };
struct inode *inode = new_inode_pseudo(s);

if (!inode)
return ERR_PTR(-ENOMEM);

inode->i_ino = get_next_ino();
- inode->i_mapping->a_ops = &anon_aops;

/*
* Mark the inode dirty from the very beginning,
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 451942fb38ec..300acea9ee63 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -590,6 +590,5 @@ const struct address_space_operations xfs_address_space_operations = {

const struct address_space_operations xfs_dax_aops = {
.writepages = xfs_dax_writepages,
- .dirty_folio = noop_dirty_folio,
.swap_activate = xfs_iomap_swapfile_activate,
};
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 716953ee1ebd..9de3be51dee2 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -1074,7 +1074,6 @@ bool folio_clear_dirty_for_io(struct folio *folio);
bool clear_page_dirty_for_io(struct page *page);
void folio_invalidate(struct folio *folio, size_t offset, size_t length);
int __set_page_dirty_nobuffers(struct page *page);
-bool noop_dirty_folio(struct address_space *mapping, struct folio *folio);

#ifdef CONFIG_MIGRATION
int filemap_migrate_folio(struct address_space *mapping, struct folio *dst,
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index d3f42009bb70..d2d739109bfe 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2585,17 +2585,6 @@ int do_writepages(struct address_space *mapping, struct writeback_control *wbc)
return ret;
}

-/*
- * For address_spaces which do not use buffers nor write back.
- */
-bool noop_dirty_folio(struct address_space *mapping, struct folio *folio)
-{
- if (!folio_test_dirty(folio))
- return !folio_test_set_dirty(folio);
- return false;
-}
-EXPORT_SYMBOL(noop_dirty_folio);
-
/*
* Helper function for set_page_dirty family.
*
@@ -2799,10 +2788,13 @@ bool folio_mark_dirty(struct folio *folio)
*/
if (folio_test_reclaim(folio))
folio_clear_reclaim(folio);
- return mapping->a_ops->dirty_folio(mapping, folio);
+ if (mapping->a_ops->dirty_folio)
+ return mapping->a_ops->dirty_folio(mapping, folio);
}

- return noop_dirty_folio(mapping, folio);
+ if (!folio_test_dirty(folio))
+ return !folio_test_set_dirty(folio);
+ return false;
}
EXPORT_SYMBOL(folio_mark_dirty);

diff --git a/mm/secretmem.c b/mm/secretmem.c
index 86442a15d12f..3fe1c35f9c8d 100644
--- a/mm/secretmem.c
+++ b/mm/secretmem.c
@@ -157,7 +157,6 @@ static void secretmem_free_folio(struct folio *folio)
}

const struct address_space_operations secretmem_aops = {
- .dirty_folio = noop_dirty_folio,
.free_folio = secretmem_free_folio,
.migrate_folio = secretmem_migrate_folio,
};
diff --git a/mm/shmem.c b/mm/shmem.c
index d963c747dabc..9bdef68a088a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -4090,7 +4090,6 @@ static int shmem_error_remove_page(struct address_space *mapping,

const struct address_space_operations shmem_aops = {
.writepage = shmem_writepage,
- .dirty_folio = noop_dirty_folio,
#ifdef CONFIG_TMPFS
.write_begin = shmem_write_begin,
.write_end = shmem_write_end,
diff --git a/mm/swap_state.c b/mm/swap_state.c
index f8ea7015bad4..3666439487db 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -30,7 +30,6 @@
*/
static const struct address_space_operations swap_aops = {
.writepage = swap_writepage,
- .dirty_folio = noop_dirty_folio,
#ifdef CONFIG_MIGRATION
.migrate_folio = migrate_folio,
#endif
--
2.40.1