linux-kernel - Since sysfs_mount is static and used only in sysfs_init function, it could be just an automatic variable.

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Message-ID: <91b13c310712011231k3604214bx3559387c568cce09@mail.gmail.com>
Date:	Sun, 2 Dec 2007 04:31:09 +0800
From:	"rae l" <crquan@...il.com>
To:	linux-kernel@...r.kernel.org
Cc:	gregkh@...e.de
Subject: Since sysfs_mount is static and used only in sysfs_init function, it could be just an automatic variable.

---
and I still have questions about this code:
1. Why here kern_mount is needed?
	Or the first time user space `mount -t sysfs` won't do that?
2. If root executes many mounts to mount sysfs on /sys and many other places,
	are there many instances of struct vfsmount those have only
mnt_mountpoint different?

	For most common case, mount a virtual filesystem(proc, sysfs, ...) on
multiple mounting point,
	how to handle it more efficiently?

and where is a detailed explaination on kern_mount? could someone give
some comments or documentation pointers on this?

diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 7416826..add0dda 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -22,7 +22,6 @@
 /* Random magic number */
 #define SYSFS_MAGIC 0x62656572

-static struct vfsmount *sysfs_mount;
 struct super_block * sysfs_sb = NULL;
 struct kmem_cache *sysfs_dir_cachep;

@@ -98,11 +97,10 @@ int __init sysfs_init(void)

 	err = register_filesystem(&sysfs_fs_type);
 	if (!err) {
-		sysfs_mount = kern_mount(&sysfs_fs_type);
+		struct vfsmount *sysfs_mount = kern_mount(&sysfs_fs_type);
 		if (IS_ERR(sysfs_mount)) {
 			printk(KERN_ERR "sysfs: could not mount!\n");
 			err = PTR_ERR(sysfs_mount);
-			sysfs_mount = NULL;
 			unregister_filesystem(&sysfs_fs_type);
 			goto out_err;
 		}

-- 
Denis Cheng
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