[PATCH 2/3] mm: use filemap_range_needs_writeback() for O_DIRECT IO
From: Jens Axboe <axboe@kernel.dk>
Date: 2021-02-08 22:19:38
Also in:
linux-fsdevel
Subsystem:
memory management, page cache, the rest · Maintainers:
Andrew Morton, Matthew Wilcox, Linus Torvalds
For the generic page cache read/write helpers, use the better variant of checking for the need to call filemap_write_and_wait_range() when doing O_DIRECT reads or writes. This avoids falling back to the slow path for IOCB_NOWAIT, if there are no pages to wait for (or write out). Signed-off-by: Jens Axboe <axboe@kernel.dk> --- mm/filemap.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index 1ed7acac8a1b..3bc76f99ddc3 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c@@ -2646,8 +2646,8 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) size = i_size_read(inode); if (iocb->ki_flags & IOCB_NOWAIT) { - if (filemap_range_has_page(mapping, iocb->ki_pos, - iocb->ki_pos + count - 1)) + if (filemap_range_needs_writeback(mapping, iocb->ki_pos, + iocb->ki_pos + count - 1)) return -EAGAIN; } else { retval = filemap_write_and_wait_range(mapping,
@@ -3326,7 +3326,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from) if (iocb->ki_flags & IOCB_NOWAIT) { /* If there are pages to writeback, return */ - if (filemap_range_has_page(file->f_mapping, pos, + if (filemap_range_needs_writeback(file->f_mapping, pos, pos + write_len - 1)) return -EAGAIN; } else {
--
2.30.0