Re: [PATCH v6 04/21] fsnotify: Reserve mark flag bits for backends

On Fri 13-08-21 10:28:27, Amir Goldstein wrote:

On Fri, Aug 13, 2021 at 12:40 AM Gabriel Krisman Bertazi
[off-list ref] wrote:

quoted

Split out the final bits of struct fsnotify_mark->flags for use by a
backend.

Signed-off-by: Gabriel Krisman Bertazi <redacted>

Changes since v1:
  - turn consts into defines (jan)
---
 include/linux/fsnotify_backend.h | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 1ce66748a2d2..ae1bd9f06808 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h

@@ -363,6 +363,20 @@ struct fsnotify_mark_connector {
        struct hlist_head list;
 };

+enum fsnotify_mark_bits {
+       FSN_MARK_FL_BIT_IGNORED_SURV_MODIFY,
+       FSN_MARK_FL_BIT_ALIVE,
+       FSN_MARK_FL_BIT_ATTACHED,
+       FSN_MARK_PRIVATE_FLAGS,
+};
+
+#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY \
+       (1 << FSN_MARK_FL_BIT_IGNORED_SURV_MODIFY)
+#define FSNOTIFY_MARK_FLAG_ALIVE \
+       (1 << FSN_MARK_FL_BIT_ALIVE)
+#define FSNOTIFY_MARK_FLAG_ATTACHED \
+       (1 << FSN_MARK_FL_BIT_ATTACHED)
+
 /*
  * A mark is simply an object attached to an in core inode which allows an
  * fsnotify listener to indicate they are either no longer interested in events

@@ -398,9 +412,7 @@ struct fsnotify_mark {
        struct fsnotify_mark_connector *connector;
        /* Events types to ignore [mark->lock, group->mark_mutex] */
        __u32 ignored_mask;
-#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY 0x01
-#define FSNOTIFY_MARK_FLAG_ALIVE               0x02
-#define FSNOTIFY_MARK_FLAG_ATTACHED            0x04
+       /* Upper bits [31:PRIVATE_FLAGS] are reserved for backend usage */

I don't understand what [31:PRIVATE_FLAGS] means

I think it should be [FSN_MARK_PRIVATE_FLAGS:31] (identifying a range of
bits). I'd maybe write just "Bits starting from FSN_MARK_PRIVATE_FLAGS are
reserved for backend usage". With this fixed feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza
-- 
Jan Kara [off-list ref]
SUSE Labs, CR