mm/filemap: add filemap_fdatawrite_range_kick() helper
Works like filemap_fdatawrite_range(), except it's a non-integrity data
writeback and hence only starts writeback on the specified range. Will
help facilitate generically starting uncached writeback from
generic_write_sync(), as header dependencies preclude doing this inline
from fs.h.
Link: https://lkml.kernel.org/r/20241220154831.1086649-11-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Chris Mason <clm@meta.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6a838b54..653b5ef 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2878,6 +2878,8 @@ extern int __must_check file_fdatawait_range(struct file *file, loff_t lstart,
extern int __must_check file_check_and_advance_wb_err(struct file *file);
extern int __must_check file_write_and_wait_range(struct file *file,
loff_t start, loff_t end);
+int filemap_fdatawrite_range_kick(struct address_space *mapping, loff_t start,
+ loff_t end);
static inline int file_write_and_wait(struct file *file)
{
diff --git a/mm/filemap.c b/mm/filemap.c
index fb17b57..0aa3861 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -441,6 +441,24 @@ int filemap_fdatawrite_range(struct address_space *mapping, loff_t start,
EXPORT_SYMBOL(filemap_fdatawrite_range);
/**
+ * filemap_fdatawrite_range_kick - start writeback on a range
+ * @mapping: target address_space
+ * @start: index to start writeback on
+ * @end: last (non-inclusive) index for writeback
+ *
+ * This is a non-integrity writeback helper, to start writing back folios
+ * for the indicated range.
+ *
+ * Return: %0 on success, negative error code otherwise.
+ */
+int filemap_fdatawrite_range_kick(struct address_space *mapping, loff_t start,
+ loff_t end)
+{
+ return __filemap_fdatawrite_range(mapping, start, end, WB_SYNC_NONE);
+}
+EXPORT_SYMBOL_GPL(filemap_fdatawrite_range_kick);
+
+/**
* filemap_flush - mostly a non-blocking flush
* @mapping: target address_space
*
