[PATCH 09/12] xfs: refactor the ioend merging code

Christoph Hellwig
2019-06-24T05:53:44Z

Introduce two nicely abstracted helper, which can be moved to the
iomap code later. Also use list_pop and list_first_entry_or_null
to simplify the code a bit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/xfs_aops.c | 66 ++++++++++++++++++++++++++---------------------
1 file changed, 36 insertions(+), 30 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index acbd73976067..5d302ebe2a33 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -121,6 +121,19 @@ xfs_destroy_ioend(
}
}

+static void
+xfs_destroy_ioends(
+ struct xfs_ioend *ioend,
+ int error)
+{
+ struct list_head tmp;
+
+ list_replace_init(&ioend->io_list, &tmp);
+ xfs_destroy_ioend(ioend, error);
+ while ((ioend = list_pop(&tmp, struct xfs_ioend, io_list)))
+ xfs_destroy_ioend(ioend, error);
+}
+
/*
* Fast and loose check if this write could update the on-disk inode size.
*/
@@ -173,7 +186,6 @@ xfs_end_ioend(
struct xfs_ioend *ioend)
{
unsigned int nofs_flag = memalloc_nofs_save();
- struct list_head ioend_list;
struct xfs_inode *ip = XFS_I(ioend->io_inode);
xfs_off_t offset = ioend->io_offset;
size_t size = ioend->io_size;
@@ -207,16 +219,7 @@ xfs_end_ioend(
if (!error && xfs_ioend_is_append(ioend))
error = xfs_setfilesize(ip, offset, size);
done:
- list_replace_init(&ioend->io_list, &ioend_list);
- xfs_destroy_ioend(ioend, error);
-
- while (!list_empty(&ioend_list)) {
- ioend = list_first_entry(&ioend_list, struct xfs_ioend,
- io_list);
- list_del_init(&ioend->io_list);
- xfs_destroy_ioend(ioend, error);
- }
-
+ xfs_destroy_ioends(ioend, error);
memalloc_nofs_restore(nofs_flag);
}

@@ -246,15 +249,16 @@ xfs_ioend_try_merge(
struct xfs_ioend *ioend,
struct list_head *more_ioends)
{
- struct xfs_ioend *next_ioend;
+ struct xfs_ioend *next;

- while (!list_empty(more_ioends)) {
- next_ioend = list_first_entry(more_ioends, struct xfs_ioend,
- io_list);
- if (!xfs_ioend_can_merge(ioend, next_ioend))
+ INIT_LIST_HEAD(&ioend->io_list);
+
+ while ((next = list_first_entry_or_null(more_ioends, struct xfs_ioend,
+ io_list))) {
+ if (!xfs_ioend_can_merge(ioend, next))
break;
- list_move_tail(&next_ioend->io_list, &ioend->io_list);
- ioend->io_size += next_ioend->io_size;
+ list_move_tail(&next->io_list, &ioend->io_list);
+ ioend->io_size += next->io_size;
}
}

@@ -277,29 +281,31 @@ xfs_ioend_compare(
return 0;
}

+static void
+xfs_sort_ioends(
+ struct list_head *ioend_list)
+{
+ list_sort(NULL, ioend_list, xfs_ioend_compare);
+}
+
/* Finish all pending io completions. */
void
xfs_end_io(
struct work_struct *work)
{
- struct xfs_inode *ip;
+ struct xfs_inode *ip =
+ container_of(work, struct xfs_inode, i_ioend_work);
struct xfs_ioend *ioend;
- struct list_head completion_list;
+ struct list_head tmp;
unsigned long flags;

- ip = container_of(work, struct xfs_inode, i_ioend_work);
-
spin_lock_irqsave(&ip->i_ioend_lock, flags);
- list_replace_init(&ip->i_ioend_list, &completion_list);
+ list_replace_init(&ip->i_ioend_list, &tmp);
spin_unlock_irqrestore(&ip->i_ioend_lock, flags);

- list_sort(NULL, &completion_list, xfs_ioend_compare);
-
- while (!list_empty(&completion_list)) {
- ioend = list_first_entry(&completion_list, struct xfs_ioend,
- io_list);
- list_del_init(&ioend->io_list);
- xfs_ioend_try_merge(ioend, &completion_list);
+ xfs_sort_ioends(&tmp);
+ while ((ioend = list_pop(&tmp, struct xfs_ioend, io_list))) {
+ xfs_ioend_try_merge(ioend, &tmp);
xfs_end_ioend(ioend);
}
}
--
2.20.1