fsnotify: pass flags argument to fsnotify_alloc_group()

Add flags argument to fsnotify_alloc_group(), define and use the flag
FSNOTIFY_GROUP_USER in inotify and fanotify instead of the helper
fsnotify_alloc_user_group() to indicate user allocation.

Although the flag FSNOTIFY_GROUP_USER is currently not used after group
allocation, we store the flags argument in the group struct for future
use of other group flags.

Link: https://lore.kernel.org/r/20220422120327.3459282-5-amir73il@gmail.comSigned-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/nfsd/filecache.c

@@ -678,7 +678,8 @@ nfsd_file_cache_init(void)
 		goto out_shrinker;
 	}
 
-	nfsd_file_fsnotify_group = fsnotify_alloc_group(&nfsd_file_fsnotify_ops);
+	nfsd_file_fsnotify_group = fsnotify_alloc_group(&nfsd_file_fsnotify_ops,
+							0);
 	if (IS_ERR(nfsd_file_fsnotify_group)) {
 		pr_err("nfsd: unable to create fsnotify group: %ld\n",
 			PTR_ERR(nfsd_file_fsnotify_group));

fs/notify/dnotify/dnotify.c

@@ -401,7 +401,7 @@ static int __init dnotify_init(void)
 					  SLAB_PANIC|SLAB_ACCOUNT);
 	dnotify_mark_cache = KMEM_CACHE(dnotify_mark, SLAB_PANIC|SLAB_ACCOUNT);
 
-	dnotify_group = fsnotify_alloc_group(&dnotify_fsnotify_ops);
+	dnotify_group = fsnotify_alloc_group(&dnotify_fsnotify_ops, 0);
 	if (IS_ERR(dnotify_group))
 		panic("unable to allocate fsnotify group for dnotify\n");
 	dnotify_sysctl_init();

fs/notify/fanotify/fanotify_user.c

@@ -1355,7 +1355,8 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
 		f_flags |= O_NONBLOCK;
 
 	/* fsnotify_alloc_group takes a ref.  Dropped in fanotify_release */
-	group = fsnotify_alloc_user_group(&fanotify_fsnotify_ops);
+	group = fsnotify_alloc_group(&fanotify_fsnotify_ops,
+				     FSNOTIFY_GROUP_USER);
 	if (IS_ERR(group)) {
 		return PTR_ERR(group);
 	}

fs/notify/group.c

@@ -112,7 +112,8 @@ void fsnotify_put_group(struct fsnotify_group *group)
 EXPORT_SYMBOL_GPL(fsnotify_put_group);
 
 static struct fsnotify_group *__fsnotify_alloc_group(
-				const struct fsnotify_ops *ops, gfp_t gfp)
+				const struct fsnotify_ops *ops,
+				int flags, gfp_t gfp)
 {
 	struct fsnotify_group *group;
 
@@ -133,6 +134,7 @@ static struct fsnotify_group *__fsnotify_alloc_group(
 	INIT_LIST_HEAD(&group->marks_list);
 
 	group->ops = ops;
+	group->flags = flags;
 
 	return group;
 }
@@ -140,20 +142,15 @@ static struct fsnotify_group *__fsnotify_alloc_group(
 /*
  * Create a new fsnotify_group and hold a reference for the group returned.
  */
-struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops)
+struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops,
+					    int flags)
 {
-	return __fsnotify_alloc_group(ops, GFP_KERNEL);
-}
-EXPORT_SYMBOL_GPL(fsnotify_alloc_group);
+	gfp_t gfp = (flags & FSNOTIFY_GROUP_USER) ? GFP_KERNEL_ACCOUNT :
+						    GFP_KERNEL;
 
-/*
- * Create a new fsnotify_group and hold a reference for the group returned.
- */
-struct fsnotify_group *fsnotify_alloc_user_group(const struct fsnotify_ops *ops)
-{
-	return __fsnotify_alloc_group(ops, GFP_KERNEL_ACCOUNT);
+	return __fsnotify_alloc_group(ops, flags, gfp);
 }
-EXPORT_SYMBOL_GPL(fsnotify_alloc_user_group);
+EXPORT_SYMBOL_GPL(fsnotify_alloc_group);
 
 int fsnotify_fasync(int fd, struct file *file, int on)
 {

fs/notify/inotify/inotify_user.c

@@ -656,7 +656,8 @@ static struct fsnotify_group *inotify_new_group(unsigned int max_events)
 	struct fsnotify_group *group;
 	struct inotify_event_info *oevent;
 
-	group = fsnotify_alloc_user_group(&inotify_fsnotify_ops);
+	group = fsnotify_alloc_group(&inotify_fsnotify_ops,
+				     FSNOTIFY_GROUP_USER);
 	if (IS_ERR(group))
 		return group;
 

include/linux/fsnotify_backend.h

@@ -210,6 +210,9 @@ struct fsnotify_group {
 	unsigned int priority;
 	bool shutdown;		/* group is being shut down, don't queue more events */
 
+#define FSNOTIFY_GROUP_USER	0x01 /* user allocated group */
+	int flags;
+
 	/* stores all fastpath marks assoc with this group so they can be cleaned on unregister */
 	struct mutex mark_mutex;	/* protect marks_list */
 	atomic_t user_waits;		/* Number of tasks waiting for user
@@ -543,8 +546,9 @@ static inline void fsnotify_update_flags(struct dentry *dentry)
 /* called from fsnotify listeners, such as fanotify or dnotify */
 
 /* create a new group */
-extern struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops);
-extern struct fsnotify_group *fsnotify_alloc_user_group(const struct fsnotify_ops *ops);
+extern struct fsnotify_group *fsnotify_alloc_group(
+				const struct fsnotify_ops *ops,
+				int flags);
 /* get reference to a group */
 extern void fsnotify_get_group(struct fsnotify_group *group);
 /* drop reference on a group from fsnotify_alloc_group */

kernel/audit_fsnotify.c

@@ -181,7 +181,8 @@ static const struct fsnotify_ops audit_mark_fsnotify_ops = {
 
 static int __init audit_fsnotify_init(void)
 {
-	audit_fsnotify_group = fsnotify_alloc_group(&audit_mark_fsnotify_ops);
+	audit_fsnotify_group = fsnotify_alloc_group(&audit_mark_fsnotify_ops,
+						    0);
 	if (IS_ERR(audit_fsnotify_group)) {
 		audit_fsnotify_group = NULL;
 		audit_panic("cannot create audit fsnotify group");

kernel/audit_tree.c

@@ -1074,7 +1074,7 @@ static int __init audit_tree_init(void)
 
 	audit_tree_mark_cachep = KMEM_CACHE(audit_tree_mark, SLAB_PANIC);
 
-	audit_tree_group = fsnotify_alloc_group(&audit_tree_ops);
+	audit_tree_group = fsnotify_alloc_group(&audit_tree_ops, 0);
 	if (IS_ERR(audit_tree_group))
 		audit_panic("cannot initialize fsnotify group for rectree watches");
 

kernel/audit_watch.c

@@ -493,7 +493,7 @@ static const struct fsnotify_ops audit_watch_fsnotify_ops = {
 
 static int __init audit_watch_init(void)
 {
-	audit_watch_group = fsnotify_alloc_group(&audit_watch_fsnotify_ops);
+	audit_watch_group = fsnotify_alloc_group(&audit_watch_fsnotify_ops, 0);
 	if (IS_ERR(audit_watch_group)) {
 		audit_watch_group = NULL;
 		audit_panic("cannot create audit fsnotify group");