diff mbox series

[Concept,04/23] linux: Add writeback.h with writeback operation stubs

Message ID 20260119061529.3383191-5-sjg@u-boot.org
State New
Headers
Series Reduce ext4_uboot.h by moving definitions to linux headers |

Commit Message

Simon Glass Jan. 19, 2026, 6:15 a.m. UTC 
  From: Simon Glass <simon.glass@canonical.com>

Create linux/writeback.h with wbc_to_tag() function,
WB_REASON_* constants, and try_to_writeback_inodes_sb() stub
for filesystem writeback control.

Update ext4_uboot.h to use linux/writeback.h instead of
duplicating these definitions.

Co-developed-by: Claude Opus 4.5 <noreply@anthropic.com>
Signed-off-by: Simon Glass <simon.glass@canonical.com>
---

 fs/ext4l/ext4_uboot.h     | 14 +++--------
 include/linux/writeback.h | 49 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 11 deletions(-)
 create mode 100644 include/linux/writeback.h
diff mbox series

Patch

diff --git a/fs/ext4l/ext4_uboot.h b/fs/ext4l/ext4_uboot.h
index bfeb31f465c..873f02cf508 100644
--- a/fs/ext4l/ext4_uboot.h
+++ b/fs/ext4l/ext4_uboot.h
@@ -863,19 +863,11 @@  static inline unsigned long memweight(const void *ptr, size_t bytes)
 #include <linux/pagemap.h>
 #include <linux/xarray.h>
 
-/* wbc_to_tag - convert writeback control to pagecache tag */
-static inline xa_mark_t wbc_to_tag(struct writeback_control *wbc)
-{
-	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
-		return PAGECACHE_TAG_TOWRITE;
-	return PAGECACHE_TAG_DIRTY;
-}
+/* wbc_to_tag, WB_REASON_* - use linux/writeback.h */
+#include <linux/writeback.h>
 
 /* blk_plug is now in linux/blkdev.h */
 
-/* Writeback reasons */
-#define WB_REASON_FS_FREE_SPACE	0
-
 /* address_space_operations is in linux/fs.h */
 /* buffer_migrate_folio, buffer_migrate_folio_norefs, noop_dirty_folio are in linux/buffer_head.h */
 /* readahead_control, FGP_*, kmap/kunmap, folio stubs are in linux/pagemap.h */
@@ -952,7 +944,7 @@  void mapping_clear_folio_cache(struct address_space *mapping);
 /* percpu_counter_sub is in linux/percpu_counter.h */
 
 /* Filemap operations are in linux/pagemap.h */
-#define try_to_writeback_inodes_sb(sb, r)	do { } while (0)
+/* try_to_writeback_inodes_sb is in linux/writeback.h */
 
 /* Buffer operations - additional */
 #define getblk_unmovable(bdev, block, size)	sb_getblk(bdev->bd_super, block)
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
new file mode 100644
index 00000000000..e408e3ddebb
--- /dev/null
+++ b/include/linux/writeback.h
@@ -0,0 +1,49 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Writeback definitions for U-Boot
+ *
+ * Based on Linux writeback.h - writeback control and operations.
+ * U-Boot stub - writeback operations are no-ops.
+ */
+#ifndef WRITEBACK_H
+#define WRITEBACK_H
+
+#include <linux/pagemap.h>
+#include <linux/xarray.h>
+
+/* Forward declarations */
+struct super_block;
+struct writeback_control;
+
+/* Writeback reasons */
+#define WB_REASON_FS_FREE_SPACE		0
+#define WB_REASON_SYNC			1
+#define WB_REASON_PERIODIC		2
+#define WB_REASON_LAPTOP_TIMER		3
+#define WB_REASON_VMSCAN		4
+#define WB_REASON_FORKER_THREAD		5
+
+/**
+ * wbc_to_tag() - convert writeback control to pagecache tag
+ * @wbc: writeback control structure
+ *
+ * Return: PAGECACHE_TAG_TOWRITE for sync writes, PAGECACHE_TAG_DIRTY otherwise
+ */
+static inline xa_mark_t wbc_to_tag(struct writeback_control *wbc)
+{
+	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
+		return PAGECACHE_TAG_TOWRITE;
+	return PAGECACHE_TAG_DIRTY;
+}
+
+/**
+ * try_to_writeback_inodes_sb() - try to start writeback on superblock
+ * @sb: superblock to writeback
+ * @reason: reason for writeback
+ *
+ * U-Boot stub - no-op since writeback is synchronous.
+ */
+#define try_to_writeback_inodes_sb(sb, reason) \
+	do { (void)(sb); (void)(reason); } while (0)
+
+#endif /* WRITEBACK_H */