vfs: change iterate_supers callback to take an int arg instead of a void *

From: Jeff Layton <[email protected]>

All of the callback functions for iterate_supers either ignore the opaque argument, or dereference the pointer only to fetch the int to which it points.

Change iterate_supers to pass an opaque int arg to the callback instead of a void pointer.

Signed-off-by Jeff Layton <[email protected]>

---
 fs/drop_caches.c         |  4 ++--
 fs/quota/quota.c         |  6 ++----
 fs/super.c               |  3 ++-
 fs/sync.c                | 32 ++++++++++++++------------------
 include/linux/fs.h       |  2 +-
 mm/cleancache.c          |  4 ++--
 security/selinux/hooks.c |  4 ++--
 7 files changed, 25 insertions(+), 30 deletions(-)

fs/drop_caches.c +2 -2

index 82377017130f..1850e7276fdf 100644
@@ -14,7 +14,7 @@
 /* A global variable is a bit ugly, but it keeps the code simple */
 int sysctl_drop_caches;
 
-static void drop_pagecache_sb(struct super_block *sb, void *unused)
+static void drop_pagecache_sb(struct super_block *sb, int unused)
 {
 	struct inode *inode, *toput_inode = NULL;
 

@@ -52,7 +52,7 @@ int drop_caches_sysctl_handler(struct ctl_table *table, int write,
 		static int stfu;
 
 		if (sysctl_drop_caches & 1) {
-			iterate_supers(drop_pagecache_sb, NULL);
+			iterate_supers(drop_pagecache_sb, 0);
 			count_vm_event(DROP_PAGECACHE);
 		}
 		if (sysctl_drop_caches & 2) {

fs/quota/quota.c +2 -4

index 860bfbe7a07a..5f1e1c494c07 100644
@@ -46,10 +46,8 @@ static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
 	return security_quotactl(cmd, type, id, sb);
 }
 
-static void quota_sync_one(struct super_block *sb, void *arg)
+static void quota_sync_one(struct super_block *sb, int type)
 {
-	int type = *(int *)arg;
-
 	if (sb->s_qcop && sb->s_qcop->quota_sync &&
 	    (sb->s_quota_types & (1 << type)))
 		sb->s_qcop->quota_sync(sb, type);

@@ -63,7 +61,7 @@ static int quota_sync_all(int type)
 		return -EINVAL;
 	ret = security_quotactl(Q_SYNC, type, 0, NULL);
 	if (!ret)
-		iterate_supers(quota_sync_one, &type);
+		iterate_supers(quota_sync_one, type);
 	return ret;
 }
 

fs/super.c +2 -1

index 122c402049a2..30b7490bd049 100644
@@ -596,6 +596,7 @@ static void __iterate_supers(void (*f)(struct super_block *))
 		__put_super(p);
 	spin_unlock(&sb_lock);
 }
+
 /**
  *	iterate_supers - call function for all active superblocks
  *	@f: function to call

@@ -604,7 +605,7 @@ static void __iterate_supers(void (*f)(struct super_block *))
  *	Scans the superblock list and calls given function, passing it
  *	locked superblock and given argument.
  */
-void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
+void iterate_supers(void (*f)(struct super_block *, int), int arg)
 {
 	struct super_block *sb, *p = NULL;
 

fs/sync.c +14 -18

index b54e0541ad89..8c418da67e41 100644
@@ -68,16 +68,16 @@ int sync_filesystem(struct super_block *sb)
 }
 EXPORT_SYMBOL(sync_filesystem);
 
-static void sync_inodes_one_sb(struct super_block *sb, void *arg)
+static void sync_inodes_one_sb(struct super_block *sb, int unused)
 {
 	if (!sb_rdonly(sb))
 		sync_inodes_sb(sb);
 }
 
-static void sync_fs_one_sb(struct super_block *sb, void *arg)
+static void sync_fs_one_sb(struct super_block *sb, int arg)
 {
 	if (!sb_rdonly(sb) && sb->s_op->sync_fs)
-		sb->s_op->sync_fs(sb, *(int *)arg);
+		sb->s_op->sync_fs(sb, arg);
 }
 
 static void fdatawrite_one_bdev(struct block_device *bdev, void *arg)

@@ -107,14 +107,12 @@ static void fdatawait_one_bdev(struct block_device *bdev, void *arg)
  */
 void ksys_sync(void)
 {
-	int nowait = 0, wait = 1;
-
 	wakeup_flusher_threads(WB_REASON_SYNC);
-	iterate_supers(sync_inodes_one_sb, NULL);
-	iterate_supers(sync_fs_one_sb, &nowait);
-	iterate_supers(sync_fs_one_sb, &wait);
-	iterate_bdevs(fdatawrite_one_bdev, NULL);
-	iterate_bdevs(fdatawait_one_bdev, NULL);
+	iterate_supers(sync_inodes_one_sb, 0);
+	iterate_supers(sync_fs_one_sb, 0);
+	iterate_supers(sync_fs_one_sb, 1);
+	iterate_bdevs(fdatawrite_one_bdev, 0);
+	iterate_bdevs(fdatawait_one_bdev, 0);
 	if (unlikely(laptop_mode))
 		laptop_sync_completion();
 }

@@ -127,18 +125,16 @@ SYSCALL_DEFINE0(sync)
 
 static void do_sync_work(struct work_struct *work)
 {
-	int nowait = 0;
-
 	/*
 	 * Sync twice to reduce the possibility we skipped some inodes / pages
 	 * because they were temporarily locked
 	 */
-	iterate_supers(sync_inodes_one_sb, &nowait);
-	iterate_supers(sync_fs_one_sb, &nowait);
-	iterate_bdevs(fdatawrite_one_bdev, NULL);
-	iterate_supers(sync_inodes_one_sb, &nowait);
-	iterate_supers(sync_fs_one_sb, &nowait);
-	iterate_bdevs(fdatawrite_one_bdev, NULL);
+	iterate_supers(sync_inodes_one_sb, 0);
+	iterate_supers(sync_fs_one_sb, 0);
+	iterate_bdevs(fdatawrite_one_bdev, 0);
+	iterate_supers(sync_inodes_one_sb, 0);
+	iterate_supers(sync_fs_one_sb, 0);
+	iterate_bdevs(fdatawrite_one_bdev, 0);
 	printk("Emergency Sync complete\n");
 	kfree(work);
 }

include/linux/fs.h +1 -1

index 760d8da1b6c7..7107d291d853 100644
@@ -3115,7 +3115,7 @@ extern struct super_block *get_super_exclusive_thawed(struct block_device *bdev)
 extern struct super_block *get_active_super(struct block_device *bdev);
 extern void drop_super(struct super_block *sb);
 extern void drop_super_exclusive(struct super_block *sb);
-extern void iterate_supers(void (*)(struct super_block *, void *), void *);
+extern void iterate_supers(void (*)(struct super_block *, int), int);
 extern void iterate_supers_type(struct file_system_type *,
 			        void (*)(struct super_block *, void *), void *);
 

mm/cleancache.c +2 -2

index f7b9fdc79d97..92d27cc10274 100644
@@ -34,7 +34,7 @@ static u64 cleancache_failed_gets;
 static u64 cleancache_puts;
 static u64 cleancache_invalidates;
 
-static void cleancache_register_ops_sb(struct super_block *sb, void *unused)
+static void cleancache_register_ops_sb(struct super_block *sb, int unused)
 {
 	switch (sb->cleancache_poolid) {
 	case CLEANCACHE_NO_BACKEND:

@@ -105,7 +105,7 @@ int cleancache_register_ops(const struct cleancache_ops *ops)
 	 * until the corresponding ->init_fs has been actually called and
 	 * cleancache_ops has been set.
 	 */
-	iterate_supers(cleancache_register_ops_sb, NULL);
+	iterate_supers(cleancache_register_ops_sb, 0);
 	return 0;
 }
 EXPORT_SYMBOL(cleancache_register_ops);

security/selinux/hooks.c +2 -2

index 4cafe6a19167..91c13b72b427 100644
@@ -7138,7 +7138,7 @@ static __init int selinux_init(void)
 	return 0;
 }
 
-static void delayed_superblock_init(struct super_block *sb, void *unused)
+static void delayed_superblock_init(struct super_block *sb, int unused)
 {
 	superblock_doinit(sb, NULL);
 }

@@ -7149,7 +7149,7 @@ void selinux_complete_init(void)
 
 	/* Set up any superblocks initialized prior to the policy load. */
 	printk(KERN_DEBUG "SELinux:  Setting up existing superblocks.\n");
-	iterate_supers(delayed_superblock_init, NULL);
+	iterate_supers(delayed_superblock_init, 0);
 }
 
 /* SELinux requires early initialization in order to label

Signature · 1 line

2.17.0

Quoted 9 lines · Jeff Layton

From: Jeff Layton <[email protected]>

All of the callback functions for iterate_supers either ignore the opaque argument, or dereference the pointer only to fetch the int to which it points.

Change iterate_supers to pass an opaque int arg to the callback instead of a void pointer.

Quoted 1 line

Signed-off-by Jeff Layton <[email protected]>

Hum, I'm not sure if Luis didn't have any plan with the argument in his fs-freeze-during-hibernate series. Luis?

Honza

Quoted 208 lines

---
 fs/drop_caches.c         |  4 ++--
 fs/quota/quota.c         |  6 ++----
 fs/super.c               |  3 ++-
 fs/sync.c                | 32 ++++++++++++++------------------
 include/linux/fs.h       |  2 +-
 mm/cleancache.c          |  4 ++--
 security/selinux/hooks.c |  4 ++--
 7 files changed, 25 insertions(+), 30 deletions(-)

fs/drop_caches.c +2 -2

index 82377017130f..1850e7276fdf 100644
@@ -14,7 +14,7 @@
 /* A global variable is a bit ugly, but it keeps the code simple */
 int sysctl_drop_caches;
 
-static void drop_pagecache_sb(struct super_block *sb, void *unused)
+static void drop_pagecache_sb(struct super_block *sb, int unused)
 {
 	struct inode *inode, *toput_inode = NULL;
 

@@ -52,7 +52,7 @@ int drop_caches_sysctl_handler(struct ctl_table *table, int write,
 		static int stfu;
 
 		if (sysctl_drop_caches & 1) {
-			iterate_supers(drop_pagecache_sb, NULL);
+			iterate_supers(drop_pagecache_sb, 0);
 			count_vm_event(DROP_PAGECACHE);
 		}
 		if (sysctl_drop_caches & 2) {

fs/quota/quota.c +2 -4

index 860bfbe7a07a..5f1e1c494c07 100644
@@ -46,10 +46,8 @@ static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
 	return security_quotactl(cmd, type, id, sb);
 }
 
-static void quota_sync_one(struct super_block *sb, void *arg)
+static void quota_sync_one(struct super_block *sb, int type)
 {
-	int type = *(int *)arg;
-
 	if (sb->s_qcop && sb->s_qcop->quota_sync &&
 	    (sb->s_quota_types & (1 << type)))
 		sb->s_qcop->quota_sync(sb, type);

@@ -63,7 +61,7 @@ static int quota_sync_all(int type)
 		return -EINVAL;
 	ret = security_quotactl(Q_SYNC, type, 0, NULL);
 	if (!ret)
-		iterate_supers(quota_sync_one, &type);
+		iterate_supers(quota_sync_one, type);
 	return ret;
 }
 

fs/super.c +2 -1

index 122c402049a2..30b7490bd049 100644
@@ -596,6 +596,7 @@ static void __iterate_supers(void (*f)(struct super_block *))
 		__put_super(p);
 	spin_unlock(&sb_lock);
 }
+
 /**
  *	iterate_supers - call function for all active superblocks
  *	@f: function to call

@@ -604,7 +605,7 @@ static void __iterate_supers(void (*f)(struct super_block *))
  *	Scans the superblock list and calls given function, passing it
  *	locked superblock and given argument.
  */
-void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
+void iterate_supers(void (*f)(struct super_block *, int), int arg)
 {
 	struct super_block *sb, *p = NULL;
 

fs/sync.c +14 -18

index b54e0541ad89..8c418da67e41 100644
@@ -68,16 +68,16 @@ int sync_filesystem(struct super_block *sb)
 }
 EXPORT_SYMBOL(sync_filesystem);
 
-static void sync_inodes_one_sb(struct super_block *sb, void *arg)
+static void sync_inodes_one_sb(struct super_block *sb, int unused)
 {
 	if (!sb_rdonly(sb))
 		sync_inodes_sb(sb);
 }
 
-static void sync_fs_one_sb(struct super_block *sb, void *arg)
+static void sync_fs_one_sb(struct super_block *sb, int arg)
 {
 	if (!sb_rdonly(sb) && sb->s_op->sync_fs)
-		sb->s_op->sync_fs(sb, *(int *)arg);
+		sb->s_op->sync_fs(sb, arg);
 }
 
 static void fdatawrite_one_bdev(struct block_device *bdev, void *arg)

@@ -107,14 +107,12 @@ static void fdatawait_one_bdev(struct block_device *bdev, void *arg)
  */
 void ksys_sync(void)
 {
-	int nowait = 0, wait = 1;
-
 	wakeup_flusher_threads(WB_REASON_SYNC);
-	iterate_supers(sync_inodes_one_sb, NULL);
-	iterate_supers(sync_fs_one_sb, &nowait);
-	iterate_supers(sync_fs_one_sb, &wait);
-	iterate_bdevs(fdatawrite_one_bdev, NULL);
-	iterate_bdevs(fdatawait_one_bdev, NULL);
+	iterate_supers(sync_inodes_one_sb, 0);
+	iterate_supers(sync_fs_one_sb, 0);
+	iterate_supers(sync_fs_one_sb, 1);
+	iterate_bdevs(fdatawrite_one_bdev, 0);
+	iterate_bdevs(fdatawait_one_bdev, 0);
 	if (unlikely(laptop_mode))
 		laptop_sync_completion();
 }

@@ -127,18 +125,16 @@ SYSCALL_DEFINE0(sync)
 
 static void do_sync_work(struct work_struct *work)
 {
-	int nowait = 0;
-
 	/*
 	 * Sync twice to reduce the possibility we skipped some inodes / pages
 	 * because they were temporarily locked
 	 */
-	iterate_supers(sync_inodes_one_sb, &nowait);
-	iterate_supers(sync_fs_one_sb, &nowait);
-	iterate_bdevs(fdatawrite_one_bdev, NULL);
-	iterate_supers(sync_inodes_one_sb, &nowait);
-	iterate_supers(sync_fs_one_sb, &nowait);
-	iterate_bdevs(fdatawrite_one_bdev, NULL);
+	iterate_supers(sync_inodes_one_sb, 0);
+	iterate_supers(sync_fs_one_sb, 0);
+	iterate_bdevs(fdatawrite_one_bdev, 0);
+	iterate_supers(sync_inodes_one_sb, 0);
+	iterate_supers(sync_fs_one_sb, 0);
+	iterate_bdevs(fdatawrite_one_bdev, 0);
 	printk("Emergency Sync complete\n");
 	kfree(work);
 }

include/linux/fs.h +1 -1

index 760d8da1b6c7..7107d291d853 100644
@@ -3115,7 +3115,7 @@ extern struct super_block *get_super_exclusive_thawed(struct block_device *bdev)
 extern struct super_block *get_active_super(struct block_device *bdev);
 extern void drop_super(struct super_block *sb);
 extern void drop_super_exclusive(struct super_block *sb);
-extern void iterate_supers(void (*)(struct super_block *, void *), void *);
+extern void iterate_supers(void (*)(struct super_block *, int), int);
 extern void iterate_supers_type(struct file_system_type *,
 			        void (*)(struct super_block *, void *), void *);
 

mm/cleancache.c +2 -2

index f7b9fdc79d97..92d27cc10274 100644
@@ -34,7 +34,7 @@ static u64 cleancache_failed_gets;
 static u64 cleancache_puts;
 static u64 cleancache_invalidates;
 
-static void cleancache_register_ops_sb(struct super_block *sb, void *unused)
+static void cleancache_register_ops_sb(struct super_block *sb, int unused)
 {
 	switch (sb->cleancache_poolid) {
 	case CLEANCACHE_NO_BACKEND:

@@ -105,7 +105,7 @@ int cleancache_register_ops(const struct cleancache_ops *ops)
 	 * until the corresponding ->init_fs has been actually called and
 	 * cleancache_ops has been set.
 	 */
-	iterate_supers(cleancache_register_ops_sb, NULL);
+	iterate_supers(cleancache_register_ops_sb, 0);
 	return 0;
 }
 EXPORT_SYMBOL(cleancache_register_ops);

security/selinux/hooks.c +2 -2

index 4cafe6a19167..91c13b72b427 100644
@@ -7138,7 +7138,7 @@ static __init int selinux_init(void)
 	return 0;
 }
 
-static void delayed_superblock_init(struct super_block *sb, void *unused)
+static void delayed_superblock_init(struct super_block *sb, int unused)
 {
 	superblock_doinit(sb, NULL);
 }

@@ -7149,7 +7149,7 @@ void selinux_complete_init(void)
 
 	/* Set up any superblocks initialized prior to the policy load. */
 	printk(KERN_DEBUG "SELinux:  Setting up existing superblocks.\n");
-	iterate_supers(delayed_superblock_init, NULL);
+	iterate_supers(delayed_superblock_init, 0);
 }
 
 /* SELinux requires early initialization in order to label

Signature · 1 line

2.17.0

fs/sync.c static void fdatawait_one_bdev(struct block_device *bdev, void *arg) · line 115

Quoted 12 lines · Jeff Layton

fs/sync.c +2 -4

@@ -107,12 +109,10 @@ static void fdatawait_one_bdev(struct block_device *bdev, void *arg)
  */
 void ksys_sync(void)
 {
-	int nowait = 0, wait = 1;
-
 	wakeup_flusher_threads(WB_REASON_SYNC);
 	iterate_supers(sync_inodes_one_sb, NULL);
-	iterate_supers(sync_fs_one_sb, &nowait);
-	iterate_supers(sync_fs_one_sb, &wait);
+	iterate_supers(sync_fs_one_sb, NULL);
+	iterate_supers(sync_fs_one_sb, (void *)1UL);

I think this is actually less clear. How about:

	void *wait = (void *)1UL;

	iterate_supers(sync_fs_one_sb, !wait);
	iterate_supers(sync_fs_one_sb, wait);

From: Jeff Layton <[email protected]>

All of the callback functions for iterate_supers either ignore the opaque argument, or dereference the pointer only to fetch the int to which it points.

Change quota_sync_one to just cast the int from the pointer, and change sync_fs_one_sb to just use a NULL/non-NULL pointer as a flag.

Signed-off-by Jeff Layton <[email protected]>

---
 fs/quota/quota.c |  4 ++--
 fs/sync.c        | 20 +++++++++++---------
 2 files changed, 13 insertions(+), 11 deletions(-)

v3: reinstate wait/nowait variables for clarity

fs/quota/quota.c +2 -2

index 860bfbe7a07a..8dc76d5f87c7 100644
@@ -48,7 +48,7 @@ static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
 
 static void quota_sync_one(struct super_block *sb, void *arg)
 {
-	int type = *(int *)arg;
+	int type = (unsigned long)arg;
 
 	if (sb->s_qcop && sb->s_qcop->quota_sync &&
 	    (sb->s_quota_types & (1 << type)))

@@ -63,7 +63,7 @@ static int quota_sync_all(int type)
 		return -EINVAL;
 	ret = security_quotactl(Q_SYNC, type, 0, NULL);
 	if (!ret)
-		iterate_supers(quota_sync_one, &type);
+		iterate_supers(quota_sync_one, (void *)((unsigned long)type));
 	return ret;
 }
 

fs/sync.c +11 -9

index b54e0541ad89..a863cd2490ce 100644
@@ -76,8 +76,10 @@ static void sync_inodes_one_sb(struct super_block *sb, void *arg)
 
 static void sync_fs_one_sb(struct super_block *sb, void *arg)
 {
+	int wait = arg ? 1 : 0;
+
 	if (!sb_rdonly(sb) && sb->s_op->sync_fs)
-		sb->s_op->sync_fs(sb, *(int *)arg);
+		sb->s_op->sync_fs(sb, wait);
 }
 
 static void fdatawrite_one_bdev(struct block_device *bdev, void *arg)

@@ -107,12 +109,12 @@ static void fdatawait_one_bdev(struct block_device *bdev, void *arg)
  */
 void ksys_sync(void)
 {
-	int nowait = 0, wait = 1;
+	void *nowait = NULL, *wait = (void *)1UL;
 
 	wakeup_flusher_threads(WB_REASON_SYNC);
 	iterate_supers(sync_inodes_one_sb, NULL);
-	iterate_supers(sync_fs_one_sb, &nowait);
-	iterate_supers(sync_fs_one_sb, &wait);
+	iterate_supers(sync_fs_one_sb, nowait);
+	iterate_supers(sync_fs_one_sb, wait);
 	iterate_bdevs(fdatawrite_one_bdev, NULL);
 	iterate_bdevs(fdatawait_one_bdev, NULL);
 	if (unlikely(laptop_mode))

@@ -127,17 +129,17 @@ SYSCALL_DEFINE0(sync)
 
 static void do_sync_work(struct work_struct *work)
 {
-	int nowait = 0;
+	void *nowait = NULL;
 
 	/*
 	 * Sync twice to reduce the possibility we skipped some inodes / pages
 	 * because they were temporarily locked
 	 */
-	iterate_supers(sync_inodes_one_sb, &nowait);
-	iterate_supers(sync_fs_one_sb, &nowait);
+	iterate_supers(sync_inodes_one_sb, NULL);
+	iterate_supers(sync_fs_one_sb, nowait);
 	iterate_bdevs(fdatawrite_one_bdev, NULL);
-	iterate_supers(sync_inodes_one_sb, &nowait);
-	iterate_supers(sync_fs_one_sb, &nowait);
+	iterate_supers(sync_inodes_one_sb, NULL);
+	iterate_supers(sync_fs_one_sb, nowait);
 	iterate_bdevs(fdatawrite_one_bdev, NULL);
 	printk("Emergency Sync complete\n");
 	kfree(work);

Signature · 1 line

2.17.0