stop passing a writeback_control to swap/shmem writeout

stop passing a writeback_control to swap/shmem writeout

[Christoph Hellwig]

Hi all,

this series was intended to remove the last remaining users of
AOP_WRITEPAGE_ACTIVATE after my other pending patches removed the
rest, but spectacularly failed at that.

But instead it nicely improves the code, and removes two pointers
and a flag from struct writeback_control.

Note that the last patch needs this f2fs series to compile, so
it should probably be delayed until after -rc1:

https://lore.kernel.org/lkml/20250508051520.4169795-1-hch@lst.de/

Diffstat:
 drivers/gpu/drm/i915/gem/i915_gem_shmem.c |    3 -
 drivers/gpu/drm/ttm/ttm_backup.c          |    9 ---
 fs/fuse/file.c                            |   11 ---
 fs/nfs/write.c                            |    2 
 fs/nilfs2/mdt.c                           |    2 
 fs/nilfs2/segment.c                       |   16 -----
 fs/nilfs2/segment.h                       |    1 
 include/linux/shmem_fs.h                  |    5 +
 include/linux/writeback.h                 |   11 ---
 include/trace/events/btrfs.h              |    7 --
 include/trace/events/writeback.h          |    8 --
 mm/page_io.c                              |   71 +++++++++++--------------
 mm/shmem.c                                |   17 ++----
 mm/swap.h                                 |    6 +-
 mm/vmscan.c                               |   84 +++++++++++++-----------------
 mm/zswap.c                                |    5 -
 16 files changed, 94 insertions(+), 164 deletions(-)

[PATCH 1/7] mm: split out a writeout helper from pageout

[Christoph Hellwig]

Move the code to write back swap / shmem folios into a self-contained
helper to keep prepare for refactoring it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 mm/vmscan.c | 94 +++++++++++++++++++++++++++--------------------------
 1 file changed, 48 insertions(+), 46 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index c9f22abf0d38..42302d2b8739 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -652,14 +652,55 @@ typedef enum {
 	PAGE_CLEAN,
 } pageout_t;
 
+static pageout_t writeout(struct folio *folio, struct address_space *mapping,
+		struct swap_iocb **plug, struct list_head *folio_list)
+{
+	struct writeback_control wbc = {
+		.sync_mode = WB_SYNC_NONE,
+		.nr_to_write = SWAP_CLUSTER_MAX,
+		.range_start = 0,
+		.range_end = LLONG_MAX,
+		.for_reclaim = 1,
+		.swap_plug = plug,
+	};
+	int res;
+
+	folio_set_reclaim(folio);
+
+	/*
+	 * The large shmem folio can be split if CONFIG_THP_SWAP is not enabled
+	 * or we failed to allocate contiguous swap entries.
+	 */
+	if (shmem_mapping(mapping)) {
+		if (folio_test_large(folio))
+			wbc.list = folio_list;
+		res = shmem_writeout(folio, &wbc);
+	} else {
+		res = swap_writeout(folio, &wbc);
+	}
+
+	if (res < 0)
+		handle_write_error(mapping, folio, res);
+	if (res == AOP_WRITEPAGE_ACTIVATE) {
+		folio_clear_reclaim(folio);
+		return PAGE_ACTIVATE;
+	}
+
+	/* synchronous write? */
+	if (!folio_test_writeback(folio))
+		folio_clear_reclaim(folio);
+
+	trace_mm_vmscan_write_folio(folio);
+	node_stat_add_folio(folio, NR_VMSCAN_WRITE);
+	return PAGE_SUCCESS;
+}
+
 /*
  * pageout is called by shrink_folio_list() for each dirty folio.
  */
 static pageout_t pageout(struct folio *folio, struct address_space *mapping,
 			 struct swap_iocb **plug, struct list_head *folio_list)
 {
-	int (*writeout)(struct folio *, struct writeback_control *);
-
 	/*
 	 * We no longer attempt to writeback filesystem folios here, other
 	 * than tmpfs/shmem.  That's taken care of in page-writeback.
@@ -690,51 +731,12 @@ static pageout_t pageout(struct folio *folio, struct address_space *mapping,
 		}
 		return PAGE_KEEP;
 	}
-	if (shmem_mapping(mapping))
-		writeout = shmem_writeout;
-	else if (folio_test_anon(folio))
-		writeout = swap_writeout;
-	else
-		return PAGE_ACTIVATE;
-
-	if (folio_clear_dirty_for_io(folio)) {
-		int res;
-		struct writeback_control wbc = {
-			.sync_mode = WB_SYNC_NONE,
-			.nr_to_write = SWAP_CLUSTER_MAX,
-			.range_start = 0,
-			.range_end = LLONG_MAX,
-			.for_reclaim = 1,
-			.swap_plug = plug,
-		};
 
-		/*
-		 * The large shmem folio can be split if CONFIG_THP_SWAP is
-		 * not enabled or contiguous swap entries are failed to
-		 * allocate.
-		 */
-		if (shmem_mapping(mapping) && folio_test_large(folio))
-			wbc.list = folio_list;
-
-		folio_set_reclaim(folio);
-		res = writeout(folio, &wbc);
-		if (res < 0)
-			handle_write_error(mapping, folio, res);
-		if (res == AOP_WRITEPAGE_ACTIVATE) {
-			folio_clear_reclaim(folio);
-			return PAGE_ACTIVATE;
-		}
-
-		if (!folio_test_writeback(folio)) {
-			/* synchronous write? */
-			folio_clear_reclaim(folio);
-		}
-		trace_mm_vmscan_write_folio(folio);
-		node_stat_add_folio(folio, NR_VMSCAN_WRITE);
-		return PAGE_SUCCESS;
-	}
-
-	return PAGE_CLEAN;
+	if (!shmem_mapping(mapping) && !folio_test_anon(folio))
+		return PAGE_ACTIVATE;
+	if (!folio_clear_dirty_for_io(folio))
+		return PAGE_CLEAN;
+	return writeout(folio, mapping, plug, folio_list);
 }
 
 /*
-- 
2.47.2

[PATCH 2/7] mm: stop passing a writeback_control structure to shmem_writeout

[Christoph Hellwig]

shmem_writeout only needs the swap_iocb cookie and the split folio
list.  Pass those explicitly and remove the now unused list member
from struct writeback_control.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/gpu/drm/i915/gem/i915_gem_shmem.c |  2 +-
 drivers/gpu/drm/ttm/ttm_backup.c          |  9 +-------
 include/linux/shmem_fs.h                  |  5 ++++-
 include/linux/writeback.h                 |  3 ---
 mm/shmem.c                                | 25 ++++++++++++++---------
 mm/vmscan.c                               | 12 +++++------
 6 files changed, 26 insertions(+), 30 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
index 5e784db9f315..dbb7a78ceea7 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
@@ -318,7 +318,7 @@ void __shmem_writeback(size_t size, struct address_space *mapping)
 		if (folio_mapped(folio))
 			folio_redirty_for_writepage(&wbc, folio);
 		else
-			error = shmem_writeout(folio, &wbc);
+			error = shmem_writeout(folio, NULL, NULL);
 	}
 }
 
diff --git a/drivers/gpu/drm/ttm/ttm_backup.c b/drivers/gpu/drm/ttm/ttm_backup.c
index ffaab68bd5dd..6f2e58be4f3e 100644
--- a/drivers/gpu/drm/ttm/ttm_backup.c
+++ b/drivers/gpu/drm/ttm/ttm_backup.c
@@ -112,15 +112,8 @@ ttm_backup_backup_page(struct file *backup, struct page *page,
 
 	if (writeback && !folio_mapped(to_folio) &&
 	    folio_clear_dirty_for_io(to_folio)) {
-		struct writeback_control wbc = {
-			.sync_mode = WB_SYNC_NONE,
-			.nr_to_write = SWAP_CLUSTER_MAX,
-			.range_start = 0,
-			.range_end = LLONG_MAX,
-			.for_reclaim = 1,
-		};
 		folio_set_reclaim(to_folio);
-		ret = shmem_writeout(to_folio, &wbc);
+		ret = shmem_writeout(to_folio, NULL, NULL);
 		if (!folio_test_writeback(to_folio))
 			folio_clear_reclaim(to_folio);
 		/*
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index 5f03a39a26f7..6d0f9c599ff7 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -11,6 +11,8 @@
 #include <linux/fs_parser.h>
 #include <linux/userfaultfd_k.h>
 
+struct swap_iocb;
+
 /* inode in-kernel data */
 
 #ifdef CONFIG_TMPFS_QUOTA
@@ -107,7 +109,8 @@ static inline bool shmem_mapping(struct address_space *mapping)
 void shmem_unlock_mapping(struct address_space *mapping);
 struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
 					pgoff_t index, gfp_t gfp_mask);
-int shmem_writeout(struct folio *folio, struct writeback_control *wbc);
+int shmem_writeout(struct folio *folio, struct swap_iocb **plug,
+		struct list_head *folio_list);
 void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
 int shmem_unuse(unsigned int type);
 
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index eda4b62511f7..82f217970092 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -79,9 +79,6 @@ struct writeback_control {
 	 */
 	struct swap_iocb **swap_plug;
 
-	/* Target list for splitting a large folio */
-	struct list_head *list;
-
 	/* internal fields used by the ->writepages implementation: */
 	struct folio_batch fbatch;
 	pgoff_t index;
diff --git a/mm/shmem.c b/mm/shmem.c
index 858cee02ca49..941b9b29e78a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1540,10 +1540,13 @@ int shmem_unuse(unsigned int type)
  * shmem_writeout - Write the folio to swap
  * @folio: The folio to write
  * @wbc: How writeback is to be done
+ * @plug: swap plug
+ * @folio_list: list to put back folios on split
  *
  * Move the folio from the page cache to the swap cache.
  */
-int shmem_writeout(struct folio *folio, struct writeback_control *wbc)
+int shmem_writeout(struct folio *folio, struct swap_iocb **plug,
+		struct list_head *folio_list)
 {
 	struct address_space *mapping = folio->mapping;
 	struct inode *inode = mapping->host;
@@ -1553,9 +1556,6 @@ int shmem_writeout(struct folio *folio, struct writeback_control *wbc)
 	int nr_pages;
 	bool split = false;
 
-	if (WARN_ON_ONCE(!wbc->for_reclaim))
-		goto redirty;
-
 	if ((info->flags & VM_LOCKED) || sbinfo->noswap)
 		goto redirty;
 
@@ -1582,7 +1582,7 @@ int shmem_writeout(struct folio *folio, struct writeback_control *wbc)
 try_split:
 		/* Ensure the subpages are still dirty */
 		folio_test_set_dirty(folio);
-		if (split_folio_to_list(folio, wbc->list))
+		if (split_folio_to_list(folio, folio_list))
 			goto redirty;
 		folio_clear_dirty(folio);
 	}
@@ -1635,13 +1635,21 @@ int shmem_writeout(struct folio *folio, struct writeback_control *wbc)
 		list_add(&info->swaplist, &shmem_swaplist);
 
 	if (!folio_alloc_swap(folio, __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN)) {
+		struct writeback_control wbc = {
+			.sync_mode	= WB_SYNC_NONE,
+			.nr_to_write	= SWAP_CLUSTER_MAX,
+			.range_start	= 0,
+			.range_end	= LLONG_MAX,
+			.for_reclaim	= 1,
+			.swap_plug	= plug,
+		};
 		shmem_recalc_inode(inode, 0, nr_pages);
 		swap_shmem_alloc(folio->swap, nr_pages);
 		shmem_delete_from_page_cache(folio, swp_to_radix_entry(folio->swap));
 
 		mutex_unlock(&shmem_swaplist_mutex);
 		BUG_ON(folio_mapped(folio));
-		return swap_writeout(folio, wbc);
+		return swap_writeout(folio, &wbc);
 	}
 
 	list_del_init(&info->swaplist);
@@ -1650,10 +1658,7 @@ int shmem_writeout(struct folio *folio, struct writeback_control *wbc)
 		goto try_split;
 redirty:
 	folio_mark_dirty(folio);
-	if (wbc->for_reclaim)
-		return AOP_WRITEPAGE_ACTIVATE;	/* Return with folio locked */
-	folio_unlock(folio);
-	return 0;
+	return AOP_WRITEPAGE_ACTIVATE;	/* Return with folio locked */
 }
 EXPORT_SYMBOL_GPL(shmem_writeout);
 
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 42302d2b8739..fea78f01d04e 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -669,15 +669,13 @@ static pageout_t writeout(struct folio *folio, struct address_space *mapping,
 
 	/*
 	 * The large shmem folio can be split if CONFIG_THP_SWAP is not enabled
-	 * or we failed to allocate contiguous swap entries.
+	 * or we failed to allocate contiguous swap entries, in which case
+	 * the split out folios get added back to folio_list.
 	 */
-	if (shmem_mapping(mapping)) {
-		if (folio_test_large(folio))
-			wbc.list = folio_list;
-		res = shmem_writeout(folio, &wbc);
-	} else {
+	if (shmem_mapping(mapping))
+		res = shmem_writeout(folio, plug, folio_list);
+	else
 		res = swap_writeout(folio, &wbc);
-	}
 
 	if (res < 0)
 		handle_write_error(mapping, folio, res);
-- 
2.47.2

Re: [PATCH 2/7] mm: stop passing a writeback_control structure to shmem_writeout

[kernel test robot]

Hi Christoph,

kernel test robot noticed the following build warnings:

[auto build test WARNING on next-20250507]
[cannot apply to akpm-mm/mm-everything konis-nilfs2/upstream linus/master v6.15-rc5 v6.15-rc4 v6.15-rc3 v6.15-rc5]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Christoph-Hellwig/mm-stop-passing-a-writeback_control-structure-to-shmem_writeout/20250508-144804
base:   next-20250507
patch link:    https://lore.kernel.org/r/20250508054938.15894-3-hch%40lst.de
patch subject: [PATCH 2/7] mm: stop passing a writeback_control structure to shmem_writeout
config: arm-allnoconfig (https://download.01.org/0day-ci/archive/20250508/202505082050.us12v40j-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project f819f46284f2a79790038e1f6649172789734ae8)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250508/202505082050.us12v40j-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202505082050.us12v40j-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> Warning: mm/shmem.c:1549 Excess function parameter 'wbc' description in 'shmem_writeout'

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 2/7] mm: stop passing a writeback_control structure to shmem_writeout

[Matthew Wilcox]

On Thu, May 08, 2025 at 07:47:44AM +0200, Christoph Hellwig wrote:
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> @@ -318,7 +318,7 @@ void __shmem_writeback(size_t size, struct address_space *mapping)
>  		if (folio_mapped(folio))
>  			folio_redirty_for_writepage(&wbc, folio);
>  		else
> -			error = shmem_writeout(folio, &wbc);
> +			error = shmem_writeout(folio, NULL, NULL);
>  	}
>  }

This got me to look at why we need to keep wbc in __shmem_writeback().
We only have it because folio_redirty_for_writepage() needs it.  And
folio_redirty_for_writepage() only needs it because it updates
pages_skipped.

I'm not quite sure if we can simply call filemap_dirty_folio() here
or whether mapping_can_writeback() is true for shmem and we need to
do all the other things -- in which case we could just change that one
line to

	if (wbc)
		wbc->pages_skipped += nr;

and then pass NULL to folio_redirty_for_writepage() and delete the
wbc on the stack.

Re: [PATCH 2/7] mm: stop passing a writeback_control structure to shmem_writeout

[Christoph Hellwig]

On Thu, May 08, 2025 at 02:25:00PM +0100, Matthew Wilcox wrote:
> This got me to look at why we need to keep wbc in __shmem_writeback().
> We only have it because folio_redirty_for_writepage() needs it.  And
> folio_redirty_for_writepage() only needs it because it updates
> pages_skipped.

in linux-next you also changed it to use writeback_iter, which needs
the wbc as well.  That probably as an improvement compared to the
previous version, but overall it still feels odd.

> I'm not quite sure if we can simply call filemap_dirty_folio() here
> or whether mapping_can_writeback() is true for shmem and we need to
> do all the other things -- in which case we could just change that one
> line to

shmem doesn't set up a bdi, so it should not be true.

[PATCH 3/7] mm: tidy up swap_writeout

[Christoph Hellwig]

Use a goto label to consolidate the unlock folio and return pattern
and don't bother with an else after a return / goto.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 mm/page_io.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index f7716b6569fa..c420b0aa0f22 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -239,12 +239,11 @@ static void swap_zeromap_folio_clear(struct folio *folio)
  */
 int swap_writeout(struct folio *folio, struct writeback_control *wbc)
 {
-	int ret;
+	int ret = 0;
+
+	if (folio_free_swap(folio))
+		goto out_unlock;
 
-	if (folio_free_swap(folio)) {
-		folio_unlock(folio);
-		return 0;
-	}
 	/*
 	 * Arch code may have to preserve more data than just the page
 	 * contents, e.g. memory tags.
@@ -252,8 +251,7 @@ int swap_writeout(struct folio *folio, struct writeback_control *wbc)
 	ret = arch_prepare_to_swap(folio);
 	if (ret) {
 		folio_mark_dirty(folio);
-		folio_unlock(folio);
-		return ret;
+		goto out_unlock;
 	}
 
 	/*
@@ -264,20 +262,19 @@ int swap_writeout(struct folio *folio, struct writeback_control *wbc)
 	 */
 	if (is_folio_zero_filled(folio)) {
 		swap_zeromap_folio_set(folio);
-		folio_unlock(folio);
-		return 0;
-	} else {
-		/*
-		 * Clear bits this folio occupies in the zeromap to prevent
-		 * zero data being read in from any previous zero writes that
-		 * occupied the same swap entries.
-		 */
-		swap_zeromap_folio_clear(folio);
+		goto out_unlock;
 	}
+
+	/*
+	 * Clear bits this folio occupies in the zeromap to prevent zero data
+	 * being read in from any previous zero writes that occupied the same
+	 * swap entries.
+	 */
+	swap_zeromap_folio_clear(folio);
+
 	if (zswap_store(folio)) {
 		count_mthp_stat(folio_order(folio), MTHP_STAT_ZSWPOUT);
-		folio_unlock(folio);
-		return 0;
+		goto out_unlock;
 	}
 	if (!mem_cgroup_zswap_writeback_enabled(folio_memcg(folio))) {
 		folio_mark_dirty(folio);
@@ -286,6 +283,9 @@ int swap_writeout(struct folio *folio, struct writeback_control *wbc)
 
 	__swap_writepage(folio, wbc);
 	return 0;
+out_unlock:
+	folio_unlock(folio);
+	return ret;
 }
 
 static inline void count_swpout_vm_event(struct folio *folio)
-- 
2.47.2

[PATCH 4/7] mm: stop passing a writeback_control structure to __swap_writepage

[Christoph Hellwig]

__swap_writepage only needs the swap_iocb cookie from the
writeback_control structure, so pass it explicitly and remove the
now unused swap_iocb member from struct writeback_control.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 mm/page_io.c | 33 ++++++++++++++-------------------
 mm/swap.h    |  2 +-
 mm/zswap.c   |  5 +----
 3 files changed, 16 insertions(+), 24 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index c420b0aa0f22..fb52bedcc966 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -281,7 +281,7 @@ int swap_writeout(struct folio *folio, struct writeback_control *wbc)
 		return AOP_WRITEPAGE_ACTIVATE;
 	}
 
-	__swap_writepage(folio, wbc);
+	__swap_writepage(folio, wbc->swap_plug);
 	return 0;
 out_unlock:
 	folio_unlock(folio);
@@ -371,9 +371,9 @@ static void sio_write_complete(struct kiocb *iocb, long ret)
 	mempool_free(sio, sio_pool);
 }
 
-static void swap_writepage_fs(struct folio *folio, struct writeback_control *wbc)
+static void swap_writepage_fs(struct folio *folio, struct swap_iocb **swap_plug)
 {
-	struct swap_iocb *sio = NULL;
+	struct swap_iocb *sio = swap_plug ? *swap_plug : NULL;
 	struct swap_info_struct *sis = swp_swap_info(folio->swap);
 	struct file *swap_file = sis->swap_file;
 	loff_t pos = swap_dev_pos(folio->swap);
@@ -381,8 +381,6 @@ static void swap_writepage_fs(struct folio *folio, struct writeback_control *wbc
 	count_swpout_vm_event(folio);
 	folio_start_writeback(folio);
 	folio_unlock(folio);
-	if (wbc->swap_plug)
-		sio = *wbc->swap_plug;
 	if (sio) {
 		if (sio->iocb.ki_filp != swap_file ||
 		    sio->iocb.ki_pos + sio->len != pos) {
@@ -401,22 +399,21 @@ static void swap_writepage_fs(struct folio *folio, struct writeback_control *wbc
 	bvec_set_folio(&sio->bvec[sio->pages], folio, folio_size(folio), 0);
 	sio->len += folio_size(folio);
 	sio->pages += 1;
-	if (sio->pages == ARRAY_SIZE(sio->bvec) || !wbc->swap_plug) {
+	if (sio->pages == ARRAY_SIZE(sio->bvec) || !swap_plug) {
 		swap_write_unplug(sio);
 		sio = NULL;
 	}
-	if (wbc->swap_plug)
-		*wbc->swap_plug = sio;
+	if (swap_plug)
+		*swap_plug = sio;
 }
 
 static void swap_writepage_bdev_sync(struct folio *folio,
-		struct writeback_control *wbc, struct swap_info_struct *sis)
+		struct swap_info_struct *sis)
 {
 	struct bio_vec bv;
 	struct bio bio;
 
-	bio_init(&bio, sis->bdev, &bv, 1,
-		 REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc));
+	bio_init(&bio, sis->bdev, &bv, 1, REQ_OP_WRITE | REQ_SWAP);
 	bio.bi_iter.bi_sector = swap_folio_sector(folio);
 	bio_add_folio_nofail(&bio, folio, folio_size(folio), 0);
 
@@ -431,13 +428,11 @@ static void swap_writepage_bdev_sync(struct folio *folio,
 }
 
 static void swap_writepage_bdev_async(struct folio *folio,
-		struct writeback_control *wbc, struct swap_info_struct *sis)
+		struct swap_info_struct *sis)
 {
 	struct bio *bio;
 
-	bio = bio_alloc(sis->bdev, 1,
-			REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc),
-			GFP_NOIO);
+	bio = bio_alloc(sis->bdev, 1, REQ_OP_WRITE | REQ_SWAP, GFP_NOIO);
 	bio->bi_iter.bi_sector = swap_folio_sector(folio);
 	bio->bi_end_io = end_swap_bio_write;
 	bio_add_folio_nofail(bio, folio, folio_size(folio), 0);
@@ -449,7 +444,7 @@ static void swap_writepage_bdev_async(struct folio *folio,
 	submit_bio(bio);
 }
 
-void __swap_writepage(struct folio *folio, struct writeback_control *wbc)
+void __swap_writepage(struct folio *folio, struct swap_iocb **swap_plug)
 {
 	struct swap_info_struct *sis = swp_swap_info(folio->swap);
 
@@ -460,16 +455,16 @@ void __swap_writepage(struct folio *folio, struct writeback_control *wbc)
 	 * is safe.
 	 */
 	if (data_race(sis->flags & SWP_FS_OPS))
-		swap_writepage_fs(folio, wbc);
+		swap_writepage_fs(folio, swap_plug);
 	/*
 	 * ->flags can be updated non-atomicially (scan_swap_map_slots),
 	 * but that will never affect SWP_SYNCHRONOUS_IO, so the data_race
 	 * is safe.
 	 */
 	else if (data_race(sis->flags & SWP_SYNCHRONOUS_IO))
-		swap_writepage_bdev_sync(folio, wbc, sis);
+		swap_writepage_bdev_sync(folio, sis);
 	else
-		swap_writepage_bdev_async(folio, wbc, sis);
+		swap_writepage_bdev_async(folio, sis);
 }
 
 void swap_write_unplug(struct swap_iocb *sio)
diff --git a/mm/swap.h b/mm/swap.h
index aa62463976d5..bd642078544a 100644
--- a/mm/swap.h
+++ b/mm/swap.h
@@ -21,7 +21,7 @@ static inline void swap_read_unplug(struct swap_iocb *plug)
 }
 void swap_write_unplug(struct swap_iocb *sio);
 int swap_writeout(struct folio *folio, struct writeback_control *wbc);
-void __swap_writepage(struct folio *folio, struct writeback_control *wbc);
+void __swap_writepage(struct folio *folio, struct swap_iocb **swap_plug);
 
 /* linux/mm/swap_state.c */
 /* One swap address space for each 64M swap space */
diff --git a/mm/zswap.c b/mm/zswap.c
index 455e9425c5f5..3c0fd8a13718 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1070,9 +1070,6 @@ static int zswap_writeback_entry(struct zswap_entry *entry,
 	struct mempolicy *mpol;
 	bool folio_was_allocated;
 	struct swap_info_struct *si;
-	struct writeback_control wbc = {
-		.sync_mode = WB_SYNC_NONE,
-	};
 	int ret = 0;
 
 	/* try to allocate swap cache folio */
@@ -1134,7 +1131,7 @@ static int zswap_writeback_entry(struct zswap_entry *entry,
 	folio_set_reclaim(folio);
 
 	/* start writeback */
-	__swap_writepage(folio, &wbc);
+	__swap_writepage(folio, NULL);
 
 out:
 	if (ret && ret != -EEXIST) {
-- 
2.47.2

[PATCH 5/7] mm: stop passing a writeback_control structure to swap_writeout

[Christoph Hellwig]

swap_writeout only needs the swap_iocb cookie from the writeback_control
structure, so pass it explicitly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/writeback.h |  7 -------
 mm/page_io.c              |  4 ++--
 mm/shmem.c                | 10 +---------
 mm/swap.h                 |  4 +++-
 mm/vmscan.c               | 10 +---------
 5 files changed, 7 insertions(+), 28 deletions(-)

diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 82f217970092..9e960f2faf79 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -72,13 +72,6 @@ struct writeback_control {
 	 */
 	unsigned no_cgroup_owner:1;
 
-	/* To enable batching of swap writes to non-block-device backends,
-	 * "plug" can be set point to a 'struct swap_iocb *'.  When all swap
-	 * writes have been submitted, if with swap_iocb is not NULL,
-	 * swap_write_unplug() should be called.
-	 */
-	struct swap_iocb **swap_plug;
-
 	/* internal fields used by the ->writepages implementation: */
 	struct folio_batch fbatch;
 	pgoff_t index;
diff --git a/mm/page_io.c b/mm/page_io.c
index fb52bedcc966..a2056a5ecb13 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -237,7 +237,7 @@ static void swap_zeromap_folio_clear(struct folio *folio)
  * We may have stale swap cache pages in memory: notice
  * them here and get rid of the unnecessary final write.
  */
-int swap_writeout(struct folio *folio, struct writeback_control *wbc)
+int swap_writeout(struct folio *folio, struct swap_iocb **swap_plug)
 {
 	int ret = 0;
 
@@ -281,7 +281,7 @@ int swap_writeout(struct folio *folio, struct writeback_control *wbc)
 		return AOP_WRITEPAGE_ACTIVATE;
 	}
 
-	__swap_writepage(folio, wbc->swap_plug);
+	__swap_writepage(folio, swap_plug);
 	return 0;
 out_unlock:
 	folio_unlock(folio);
diff --git a/mm/shmem.c b/mm/shmem.c
index 941b9b29e78a..2033d2e3d35d 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1635,21 +1635,13 @@ int shmem_writeout(struct folio *folio, struct swap_iocb **plug,
 		list_add(&info->swaplist, &shmem_swaplist);
 
 	if (!folio_alloc_swap(folio, __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN)) {
-		struct writeback_control wbc = {
-			.sync_mode	= WB_SYNC_NONE,
-			.nr_to_write	= SWAP_CLUSTER_MAX,
-			.range_start	= 0,
-			.range_end	= LLONG_MAX,
-			.for_reclaim	= 1,
-			.swap_plug	= plug,
-		};
 		shmem_recalc_inode(inode, 0, nr_pages);
 		swap_shmem_alloc(folio->swap, nr_pages);
 		shmem_delete_from_page_cache(folio, swp_to_radix_entry(folio->swap));
 
 		mutex_unlock(&shmem_swaplist_mutex);
 		BUG_ON(folio_mapped(folio));
-		return swap_writeout(folio, &wbc);
+		return swap_writeout(folio, plug);
 	}
 
 	list_del_init(&info->swaplist);
diff --git a/mm/swap.h b/mm/swap.h
index bd642078544a..c6d661fa9db7 100644
--- a/mm/swap.h
+++ b/mm/swap.h
@@ -3,6 +3,8 @@
 #define _MM_SWAP_H
 
 struct mempolicy;
+struct swap_iocb;
+
 extern int page_cluster;
 
 #ifdef CONFIG_SWAP
@@ -20,7 +22,7 @@ static inline void swap_read_unplug(struct swap_iocb *plug)
 		__swap_read_unplug(plug);
 }
 void swap_write_unplug(struct swap_iocb *sio);
-int swap_writeout(struct folio *folio, struct writeback_control *wbc);
+int swap_writeout(struct folio *folio, struct swap_iocb **swap_plug);
 void __swap_writepage(struct folio *folio, struct swap_iocb **swap_plug);
 
 /* linux/mm/swap_state.c */
diff --git a/mm/vmscan.c b/mm/vmscan.c
index fea78f01d04e..ad89b36eba01 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -655,14 +655,6 @@ typedef enum {
 static pageout_t writeout(struct folio *folio, struct address_space *mapping,
 		struct swap_iocb **plug, struct list_head *folio_list)
 {
-	struct writeback_control wbc = {
-		.sync_mode = WB_SYNC_NONE,
-		.nr_to_write = SWAP_CLUSTER_MAX,
-		.range_start = 0,
-		.range_end = LLONG_MAX,
-		.for_reclaim = 1,
-		.swap_plug = plug,
-	};
 	int res;
 
 	folio_set_reclaim(folio);
@@ -675,7 +667,7 @@ static pageout_t writeout(struct folio *folio, struct address_space *mapping,
 	if (shmem_mapping(mapping))
 		res = shmem_writeout(folio, plug, folio_list);
 	else
-		res = swap_writeout(folio, &wbc);
+		res = swap_writeout(folio, plug);
 
 	if (res < 0)
 		handle_write_error(mapping, folio, res);
-- 
2.47.2

Re: [PATCH 5/7] mm: stop passing a writeback_control structure to swap_writeout

[kernel test robot]

Hi Christoph,

kernel test robot noticed the following build errors:

[auto build test ERROR on next-20250507]
[cannot apply to akpm-mm/mm-everything konis-nilfs2/upstream linus/master v6.15-rc5 v6.15-rc4 v6.15-rc3 v6.15-rc5]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Christoph-Hellwig/mm-stop-passing-a-writeback_control-structure-to-shmem_writeout/20250508-144804
base:   next-20250507
patch link:    https://lore.kernel.org/r/20250508054938.15894-6-hch%40lst.de
patch subject: [PATCH 5/7] mm: stop passing a writeback_control structure to swap_writeout
config: openrisc-allnoconfig (https://download.01.org/0day-ci/archive/20250508/202505081941.kyY28sRZ-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250508/202505081941.kyY28sRZ-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202505081941.kyY28sRZ-lkp@intel.com/

All errors (new ones prefixed by >>):

   mm/vmscan.c: In function 'writeout':
>> mm/vmscan.c:670:44: error: passing argument 2 of 'swap_writeout' from incompatible pointer type [-Wincompatible-pointer-types]
     670 |                 res = swap_writeout(folio, plug);
         |                                            ^~~~
         |                                            |
         |                                            struct swap_iocb **
   In file included from mm/vmscan.c:69:
   mm/swap.h:146:76: note: expected 'struct writeback_control *' but argument is of type 'struct swap_iocb **'
     146 | static inline int swap_writeout(struct folio *f, struct writeback_control *wbc)
         |                                                  ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
--
   mm/shmem.c: In function 'shmem_writeout':
>> mm/shmem.c:1644:45: error: passing argument 2 of 'swap_writeout' from incompatible pointer type [-Wincompatible-pointer-types]
    1644 |                 return swap_writeout(folio, plug);
         |                                             ^~~~
         |                                             |
         |                                             struct swap_iocb **
   In file included from mm/shmem.c:44:
   mm/swap.h:146:76: note: expected 'struct writeback_control *' but argument is of type 'struct swap_iocb **'
     146 | static inline int swap_writeout(struct folio *f, struct writeback_control *wbc)
         |                                                  ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~


vim +/swap_writeout +670 mm/vmscan.c

   654	
   655	static pageout_t writeout(struct folio *folio, struct address_space *mapping,
   656			struct swap_iocb **plug, struct list_head *folio_list)
   657	{
   658		int res;
   659	
   660		folio_set_reclaim(folio);
   661	
   662		/*
   663		 * The large shmem folio can be split if CONFIG_THP_SWAP is not enabled
   664		 * or we failed to allocate contiguous swap entries, in which case
   665		 * the split out folios get added back to folio_list.
   666		 */
   667		if (shmem_mapping(mapping))
   668			res = shmem_writeout(folio, plug, folio_list);
   669		else
 > 670			res = swap_writeout(folio, plug);
   671	
   672		if (res < 0)
   673			handle_write_error(mapping, folio, res);
   674		if (res == AOP_WRITEPAGE_ACTIVATE) {
   675			folio_clear_reclaim(folio);
   676			return PAGE_ACTIVATE;
   677		}
   678	
   679		/* synchronous write? */
   680		if (!folio_test_writeback(folio))
   681			folio_clear_reclaim(folio);
   682	
   683		trace_mm_vmscan_write_folio(folio);
   684		node_stat_add_folio(folio, NR_VMSCAN_WRITE);
   685		return PAGE_SUCCESS;
   686	}
   687	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH 6/7] nilfs2: remove wbc->for_reclaim handling

[Christoph Hellwig]

Since commit 013a07052a1a ("nilfs2: convert metadata aops from writepage
to writepages"), nilfs_mdt_write_folio can't be called from reclaim
context any more.  Remove the code keyed of the wbc->for_rename flag,
which is now only set for writing out swap or shmem pages inside the
swap code, but never passed to file systems.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/nilfs2/mdt.c     |  2 --
 fs/nilfs2/segment.c | 16 ----------------
 fs/nilfs2/segment.h |  1 -
 3 files changed, 19 deletions(-)

diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index 2f850a18d6e7..946b0d3534a5 100644
--- a/fs/nilfs2/mdt.c
+++ b/fs/nilfs2/mdt.c
@@ -422,8 +422,6 @@ static int nilfs_mdt_write_folio(struct folio *folio,
 
 	if (wbc->sync_mode == WB_SYNC_ALL)
 		err = nilfs_construct_segment(sb);
-	else if (wbc->for_reclaim)
-		nilfs_flush_segment(sb, inode->i_ino);
 
 	return err;
 }
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 83970d97840b..61a4141f8d6b 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2221,22 +2221,6 @@ static void nilfs_segctor_do_flush(struct nilfs_sc_info *sci, int bn)
 	spin_unlock(&sci->sc_state_lock);
 }
 
-/**
- * nilfs_flush_segment - trigger a segment construction for resource control
- * @sb: super block
- * @ino: inode number of the file to be flushed out.
- */
-void nilfs_flush_segment(struct super_block *sb, ino_t ino)
-{
-	struct the_nilfs *nilfs = sb->s_fs_info;
-	struct nilfs_sc_info *sci = nilfs->ns_writer;
-
-	if (!sci || nilfs_doing_construction())
-		return;
-	nilfs_segctor_do_flush(sci, NILFS_MDT_INODE(sb, ino) ? ino : 0);
-					/* assign bit 0 to data files */
-}
-
 struct nilfs_segctor_wait_request {
 	wait_queue_entry_t	wq;
 	__u32		seq;
diff --git a/fs/nilfs2/segment.h b/fs/nilfs2/segment.h
index f723f47ddc4e..4b39ed43ae72 100644
--- a/fs/nilfs2/segment.h
+++ b/fs/nilfs2/segment.h
@@ -226,7 +226,6 @@ extern void nilfs_relax_pressure_in_lock(struct super_block *);
 extern int nilfs_construct_segment(struct super_block *);
 extern int nilfs_construct_dsync_segment(struct super_block *, struct inode *,
 					 loff_t, loff_t);
-extern void nilfs_flush_segment(struct super_block *, ino_t);
 extern int nilfs_clean_segments(struct super_block *, struct nilfs_argv *,
 				void **);
 
-- 
2.47.2

Re: [PATCH 6/7] nilfs2: remove wbc->for_reclaim handling

[Ryusuke Konishi]

On Thu, May 8, 2025 at 2:50 PM Christoph Hellwig wrote:
>
> Since commit 013a07052a1a ("nilfs2: convert metadata aops from writepage
> to writepages"), nilfs_mdt_write_folio can't be called from reclaim
> context any more.  Remove the code keyed of the wbc->for_rename flag,
> which is now only set for writing out swap or shmem pages inside the
> swap code, but never passed to file systems.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Yes, the parts removed in this patch look like dead code now.

So far, no issues have been detected with the previous conversion, but
even if it turns out that something has changed in that conversion and
needs to be fixed, I have no objection to this cleanup.  Feel free to
add:

Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>

Thanks,
Ryusuke Konishi

> ---
>  fs/nilfs2/mdt.c     |  2 --
>  fs/nilfs2/segment.c | 16 ----------------
>  fs/nilfs2/segment.h |  1 -
>  3 files changed, 19 deletions(-)
>
> diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
> index 2f850a18d6e7..946b0d3534a5 100644
> --- a/fs/nilfs2/mdt.c
> +++ b/fs/nilfs2/mdt.c
> @@ -422,8 +422,6 @@ static int nilfs_mdt_write_folio(struct folio *folio,
>
>         if (wbc->sync_mode == WB_SYNC_ALL)
>                 err = nilfs_construct_segment(sb);
> -       else if (wbc->for_reclaim)
> -               nilfs_flush_segment(sb, inode->i_ino);
>
>         return err;
>  }
> diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
> index 83970d97840b..61a4141f8d6b 100644
> --- a/fs/nilfs2/segment.c
> +++ b/fs/nilfs2/segment.c
> @@ -2221,22 +2221,6 @@ static void nilfs_segctor_do_flush(struct nilfs_sc_info *sci, int bn)
>         spin_unlock(&sci->sc_state_lock);
>  }
>
> -/**
> - * nilfs_flush_segment - trigger a segment construction for resource control
> - * @sb: super block
> - * @ino: inode number of the file to be flushed out.
> - */
> -void nilfs_flush_segment(struct super_block *sb, ino_t ino)
> -{
> -       struct the_nilfs *nilfs = sb->s_fs_info;
> -       struct nilfs_sc_info *sci = nilfs->ns_writer;
> -
> -       if (!sci || nilfs_doing_construction())
> -               return;
> -       nilfs_segctor_do_flush(sci, NILFS_MDT_INODE(sb, ino) ? ino : 0);
> -                                       /* assign bit 0 to data files */
> -}
> -
>  struct nilfs_segctor_wait_request {
>         wait_queue_entry_t      wq;
>         __u32           seq;
> diff --git a/fs/nilfs2/segment.h b/fs/nilfs2/segment.h
> index f723f47ddc4e..4b39ed43ae72 100644
> --- a/fs/nilfs2/segment.h
> +++ b/fs/nilfs2/segment.h
> @@ -226,7 +226,6 @@ extern void nilfs_relax_pressure_in_lock(struct super_block *);
>  extern int nilfs_construct_segment(struct super_block *);
>  extern int nilfs_construct_dsync_segment(struct super_block *, struct inode *,
>                                          loff_t, loff_t);
> -extern void nilfs_flush_segment(struct super_block *, ino_t);
>  extern int nilfs_clean_segments(struct super_block *, struct nilfs_argv *,
>                                 void **);
>
> --
> 2.47.2
>

Re: [PATCH 6/7] nilfs2: remove wbc->for_reclaim handling

[Christoph Hellwig]

On Fri, May 09, 2025 at 01:16:36AM +0900, Ryusuke Konishi wrote:
> > Since commit 013a07052a1a ("nilfs2: convert metadata aops from writepage
> > to writepages"), nilfs_mdt_write_folio can't be called from reclaim
> > context any more.  Remove the code keyed of the wbc->for_rename flag,
> > which is now only set for writing out swap or shmem pages inside the
> > swap code, but never passed to file systems.
> >
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> 
> Yes, the parts removed in this patch look like dead code now.
> 
> So far, no issues have been detected with the previous conversion, but
> even if it turns out that something has changed in that conversion and
> needs to be fixed, I have no objection to this cleanup.  Feel free to
> add:

Can you queue this up in the nilfs2 tree as it's independent of the
previous patches in the series, and the last one can't go in until
all dependencies have been merged anyway?

Re: [PATCH 6/7] nilfs2: remove wbc->for_reclaim handling

[Ryusuke Konishi]

On Fri, May 16, 2025 at 1:55 PM Christoph Hellwig wrote:
>
> On Fri, May 09, 2025 at 01:16:36AM +0900, Ryusuke Konishi wrote:
> > > Since commit 013a07052a1a ("nilfs2: convert metadata aops from writepage
> > > to writepages"), nilfs_mdt_write_folio can't be called from reclaim
> > > context any more.  Remove the code keyed of the wbc->for_rename flag,
> > > which is now only set for writing out swap or shmem pages inside the
> > > swap code, but never passed to file systems.
> > >
> > > Signed-off-by: Christoph Hellwig <hch@lst.de>
> >
> > Yes, the parts removed in this patch look like dead code now.
> >
> > So far, no issues have been detected with the previous conversion, but
> > even if it turns out that something has changed in that conversion and
> > needs to be fixed, I have no objection to this cleanup.  Feel free to
> > add:
>
> Can you queue this up in the nilfs2 tree as it's independent of the
> previous patches in the series, and the last one can't go in until
> all dependencies have been merged anyway?

All right, I'll handle this patch so it can go into the next merge
window separately (though it will go through the -mm tree anyway).

Regards,
Ryusuke Konishi

[PATCH 7/7] mm: remove the for_reclaim field from struct writeback_control

[Christoph Hellwig]

This field is now only set to one in the i915 gem code that only
calls writeback_iter on it, which ignores the flag.  All other
checks are thuse dead code and the field can be removed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/gpu/drm/i915/gem/i915_gem_shmem.c |  1 -
 fs/fuse/file.c                            | 11 -----------
 fs/nfs/write.c                            |  2 +-
 include/linux/writeback.h                 |  1 -
 include/trace/events/btrfs.h              |  7 ++-----
 include/trace/events/writeback.h          |  8 ++------
 6 files changed, 5 insertions(+), 25 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
index dbb7a78ceea7..7dac121d35a4 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
@@ -303,7 +303,6 @@ void __shmem_writeback(size_t size, struct address_space *mapping)
 		.nr_to_write = SWAP_CLUSTER_MAX,
 		.range_start = 0,
 		.range_end = LLONG_MAX,
-		.for_reclaim = 1,
 	};
 	struct folio *folio = NULL;
 	int error = 0;
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index e203dd4fcc0f..c950317bd3dd 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1902,17 +1902,6 @@ int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
 	struct fuse_file *ff;
 	int err;
 
-	/*
-	 * Inode is always written before the last reference is dropped and
-	 * hence this should not be reached from reclaim.
-	 *
-	 * Writing back the inode from reclaim can deadlock if the request
-	 * processing itself needs an allocation.  Allocations triggering
-	 * reclaim while serving a request can't be prevented, because it can
-	 * involve any number of unrelated userspace processes.
-	 */
-	WARN_ON(wbc->for_reclaim);
-
 	ff = __fuse_write_file_get(fi);
 	err = fuse_flush_times(inode, ff);
 	if (ff)
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 374fc6b34c79..cf1d720b8251 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -720,7 +720,7 @@ int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 	nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 
 	if (!(mntflags & NFS_MOUNT_WRITE_EAGER) || wbc->for_kupdate ||
-	    wbc->for_background || wbc->for_sync || wbc->for_reclaim) {
+	    wbc->for_background || wbc->for_sync) {
 		ioc = nfs_io_completion_alloc(GFP_KERNEL);
 		if (ioc)
 			nfs_io_completion_init(ioc, nfs_io_completion_commit,
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 9e960f2faf79..a2848d731a46 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -59,7 +59,6 @@ struct writeback_control {
 	unsigned for_kupdate:1;		/* A kupdate writeback */
 	unsigned for_background:1;	/* A background writeback */
 	unsigned tagged_writepages:1;	/* tag-and-write to avoid livelock */
-	unsigned for_reclaim:1;		/* Invoked from the page allocator */
 	unsigned range_cyclic:1;	/* range_start is cyclic */
 	unsigned for_sync:1;		/* sync(2) WB_SYNC_ALL writeback */
 	unsigned unpinned_netfs_wb:1;	/* Cleared I_PINNING_NETFS_WB */
diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index bebc252db865..0adc40f5e72b 100644
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -686,7 +686,6 @@ DECLARE_EVENT_CLASS(btrfs__writepage,
 		__field(	loff_t, range_start		)
 		__field(	loff_t, range_end		)
 		__field(	char,   for_kupdate		)
-		__field(	char,   for_reclaim		)
 		__field(	char,   range_cyclic		)
 		__field(	unsigned long,  writeback_index	)
 		__field(	u64,    root_objectid		)
@@ -700,7 +699,6 @@ DECLARE_EVENT_CLASS(btrfs__writepage,
 		__entry->range_start	= wbc->range_start;
 		__entry->range_end	= wbc->range_end;
 		__entry->for_kupdate	= wbc->for_kupdate;
-		__entry->for_reclaim	= wbc->for_reclaim;
 		__entry->range_cyclic	= wbc->range_cyclic;
 		__entry->writeback_index = inode->i_mapping->writeback_index;
 		__entry->root_objectid	= btrfs_root_id(BTRFS_I(inode)->root);
@@ -709,13 +707,12 @@ DECLARE_EVENT_CLASS(btrfs__writepage,
 	TP_printk_btrfs("root=%llu(%s) ino=%llu page_index=%lu "
 		  "nr_to_write=%ld pages_skipped=%ld range_start=%llu "
 		  "range_end=%llu for_kupdate=%d "
-		  "for_reclaim=%d range_cyclic=%d writeback_index=%lu",
+		  "range_cyclic=%d writeback_index=%lu",
 		  show_root_type(__entry->root_objectid),
 		  __entry->ino, __entry->index,
 		  __entry->nr_to_write, __entry->pages_skipped,
 		  __entry->range_start, __entry->range_end,
-		  __entry->for_kupdate,
-		  __entry->for_reclaim, __entry->range_cyclic,
+		  __entry->for_kupdate, __entry->range_cyclic,
 		  __entry->writeback_index)
 );
 
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index 0ff388131fc9..1e23919c0da9 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -459,7 +459,6 @@ DECLARE_EVENT_CLASS(wbc_class,
 		__field(int, sync_mode)
 		__field(int, for_kupdate)
 		__field(int, for_background)
-		__field(int, for_reclaim)
 		__field(int, range_cyclic)
 		__field(long, range_start)
 		__field(long, range_end)
@@ -473,23 +472,20 @@ DECLARE_EVENT_CLASS(wbc_class,
 		__entry->sync_mode	= wbc->sync_mode;
 		__entry->for_kupdate	= wbc->for_kupdate;
 		__entry->for_background	= wbc->for_background;
-		__entry->for_reclaim	= wbc->for_reclaim;
 		__entry->range_cyclic	= wbc->range_cyclic;
 		__entry->range_start	= (long)wbc->range_start;
 		__entry->range_end	= (long)wbc->range_end;
 		__entry->cgroup_ino	= __trace_wbc_assign_cgroup(wbc);
 	),
 
-	TP_printk("bdi %s: towrt=%ld skip=%ld mode=%d kupd=%d "
-		"bgrd=%d reclm=%d cyclic=%d "
-		"start=0x%lx end=0x%lx cgroup_ino=%lu",
+	TP_printk("bdi %s: towrt=%ld skip=%ld mode=%d kupd=%d bgrd=%d "
+		"cyclic=%d start=0x%lx end=0x%lx cgroup_ino=%lu",
 		__entry->name,
 		__entry->nr_to_write,
 		__entry->pages_skipped,
 		__entry->sync_mode,
 		__entry->for_kupdate,
 		__entry->for_background,
-		__entry->for_reclaim,
 		__entry->range_cyclic,
 		__entry->range_start,
 		__entry->range_end,
-- 
2.47.2