Commit 09570f91 authored by David Howells's avatar David Howells Committed by Linus Torvalds
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proc: make struct proc_dir_entry::name a terminal array rather than a pointer 



Since __proc_create() appends the name it is given to the end of the PDE
structure that it allocates, there isn't a need to store a name pointer.
Instead we can just replace the name pointer with a terminal char array of
_unspecified_ length.  The compiler will simply append the string to statically
defined variables of PDE type overlapping any hole at the end of the structure
and, unlike specifying an explicitly _zero_ length array, won't give a warning
if you try to statically initialise it with a string of more than zero length.

Also, whilst we're at it:

 (1) Move namelen to end just prior to name and reduce it to a single byte
     (name shouldn't be longer than NAME_MAX).

 (2) Move pde_unload_lock two places further on so that if it's four bytes in
     size on a 64-bit machine, it won't cause an unused hole in the PDE struct.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5fd00b03

fs/proc/generic.c

+1 −2
Original line number Diff line number Diff line
@@ -620,8 +620,7 @@ static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent, 
	if (!ent) goto out;



	memset(ent, 0, sizeof(struct proc_dir_entry));

	memcpy(((char *) ent) + sizeof(struct proc_dir_entry), fn, len + 1);

	ent->name = ((char *) ent) + sizeof(*ent);

	memcpy(ent->name, fn, len + 1);

	ent->namelen = len;

	ent->mode = mode;

	ent->nlink = nlink;

fs/proc/proc_net.c

+2 −2
Original line number Diff line number Diff line
@@ -197,15 +197,15 @@ static __net_init int proc_net_ns_init(struct net *net) 
	int err;



	err = -ENOMEM;

	netd = kzalloc(sizeof(*netd), GFP_KERNEL);

	netd = kzalloc(sizeof(*netd) + 4, GFP_KERNEL);

	if (!netd)

		goto out;



	netd->data = net;

	netd->nlink = 2;

	netd->name = "net";

	netd->namelen = 3;

	netd->parent = &proc_root;

	memcpy(netd->name, "net", 4);



	err = -EEXIST;

	net_statd = proc_net_mkdir(net, "stat", netd);

fs/proc/root.c

+1 −1
Original line number Diff line number Diff line
@@ -186,13 +186,13 @@ static const struct inode_operations proc_root_inode_operations = { 
struct proc_dir_entry proc_root = {

	.low_ino	= PROC_ROOT_INO, 

	.namelen	= 5, 

	.name		= "/proc",

	.mode		= S_IFDIR | S_IRUGO | S_IXUGO, 

	.nlink		= 2, 

	.count		= ATOMIC_INIT(1),

	.proc_iops	= &proc_root_inode_operations, 

	.proc_fops	= &proc_root_operations,

	.parent		= &proc_root,

	.name		= "/proc",

};



int pid_ns_prepare_proc(struct pid_namespace *ns)

include/linux/proc_fs.h

+3 −3
Original line number Diff line number Diff line
@@ -50,8 +50,6 @@ typedef int (write_proc_t)(struct file *file, const char __user *buffer, 


struct proc_dir_entry {

	unsigned int low_ino;

	unsigned int namelen;

	const char *name;

	mode_t mode;

	nlink_t nlink;

	uid_t uid;
@@ -73,9 +71,11 @@ struct proc_dir_entry { 
	write_proc_t *write_proc;

	atomic_t count;		/* use count */

	int pde_users;	/* number of callers into module in progress */

	spinlock_t pde_unload_lock; /* proc_fops checks and pde_users bumps */

	struct completion *pde_unload_completion;

	struct list_head pde_openers;	/* who did ->open, but not ->release */

	spinlock_t pde_unload_lock; /* proc_fops checks and pde_users bumps */

	u8 namelen;

	char name[];

};



enum kcore_type {

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