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From: Jeff Layton <jlayton@kernel.org>
To: viro@zeniv.linux.org.uk
Cc: jack@suse.com, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org
Subject: [PATCH] vfs: change iterate_supers callback to take an int arg instead of a void *
Date: Thu, 17 May 2018 11:46:46 -0400	[thread overview]
Message-ID: <20180517154646.18751-1-jlayton@kernel.org> (raw)

From: Jeff Layton <jlayton@redhat.com>

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 <jlayton@redhat.com>
---
 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(-)

diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 82377017130f..1850e7276fdf 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -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) {
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 860bfbe7a07a..5f1e1c494c07 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -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;
 }
 
diff --git a/fs/super.c b/fs/super.c
index 122c402049a2..30b7490bd049 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -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;
 
diff --git a/fs/sync.c b/fs/sync.c
index b54e0541ad89..8c418da67e41 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -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);
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 760d8da1b6c7..7107d291d853 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -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 *);
 
diff --git a/mm/cleancache.c b/mm/cleancache.c
index f7b9fdc79d97..92d27cc10274 100644
--- a/mm/cleancache.c
+++ b/mm/cleancache.c
@@ -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);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 4cafe6a19167..91c13b72b427 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -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
-- 
2.17.0

             reply	other threads:[~2018-05-17 15:46 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-17 15:46 Jeff Layton [this message]
2018-05-17 16:39 ` [PATCH] vfs: change iterate_supers callback to take an int arg instead of a void * Jan Kara
2018-05-17 16:55   ` Jeff Layton
2018-05-17 17:43 ` [PATCH v2] vfs: avoid dereferencing pointers in iterate_supers callbacks Jeff Layton
2018-05-17 18:26   ` Matthew Wilcox
2018-05-17 18:55     ` Jeff Layton
2018-05-17 21:54 ` [PATCH v3] " Jeff Layton
2018-05-18  9:32   ` Jan Kara

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