[PATCH 03/16] xfs: add a xfs_group_next_range helper

Darrick J. Wong
2024-10-11T00:44:58Z

From: Christoph Hellwig <hch@lst.de>

Add a helper to iterate over iterate over all groups, which can be used
as a simple while loop:

struct xfs_group *xg = NULL;

while ((xg = xfs_group_next_range(mp, xg, 0, MAX_GROUP))) {
...
}

This will be wrapped by the realtime group code first, and eventually
replace the for_each_rtgroup_from and for_each_rtgroup_range helpers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/libxfs/xfs_group.c | 26 ++++++++++++++++++++++++++
fs/xfs/libxfs/xfs_group.h | 3 +++
2 files changed, 29 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_group.c b/fs/xfs/libxfs/xfs_group.c
index 5b81221c3e9665..9b2fb5285c7eaa 100644
--- a/fs/xfs/libxfs/xfs_group.c
+++ b/fs/xfs/libxfs/xfs_group.c
@@ -87,6 +87,32 @@ xfs_group_grab(
return xg;
}

+/*
+ * Iterate to the next group. To start the iteration at @start_index, a %NULL
+ * @xg is passed, else the previous group returned from this function. The
+ * caller should break out of the loop when this returns %NULL. If the caller
+ * wants to break out of a loop that did not finish it needs to release the
+ * active reference to @xg using xfs_group_rele() itself.
+ */
+struct xfs_group *
+xfs_group_next_range(
+ struct xfs_mount *mp,
+ struct xfs_group *xg,
+ uint32_t start_index,
+ uint32_t end_index,
+ enum xfs_group_type type)
+{
+ uint32_t index = start_index;
+
+ if (xg) {
+ index = xg->xg_index + 1;
+ xfs_group_rele(xg);
+ }
+ if (index > end_index)
+ return NULL;
+ return xfs_group_grab(mp, index, type);
+}
+
/*
* Find the next group after @xg, or the first group if @xg is NULL.
*/
diff --git a/fs/xfs/libxfs/xfs_group.h b/fs/xfs/libxfs/xfs_group.h
index f211108eb6ca4d..8c4169520c6c7a 100644
--- a/fs/xfs/libxfs/xfs_group.h
+++ b/fs/xfs/libxfs/xfs_group.h
@@ -20,6 +20,9 @@ void xfs_group_put(struct xfs_group *xg);

struct xfs_group *xfs_group_grab(struct xfs_mount *mp, uint32_t index,
enum xfs_group_type type);
+struct xfs_group *xfs_group_next_range(struct xfs_mount *mp,
+ struct xfs_group *xg, uint32_t start_index, uint32_t end_index,
+ enum xfs_group_type type);
struct xfs_group *xfs_group_grab_next_mark(struct xfs_mount *mp,
struct xfs_group *xg, xa_mark_t mark, enum xfs_group_type type);
void xfs_group_rele(struct xfs_group *xg);