From 09570f914914d2beb0db29c5a9c7344934f2fa8c Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 27 Jul 2011 21:47:03 +0300 Subject: 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: David Howells Signed-off-by: Alexey Dobriyan Signed-off-by: Linus Torvalds --- fs/proc/generic.c | 3 +-- fs/proc/proc_net.c | 4 ++-- fs/proc/root.c | 2 +- include/linux/proc_fs.h | 6 +++--- 4 files changed, 7 insertions(+), 8 deletions(-) diff --git a/fs/proc/generic.c b/fs/proc/generic.c index f1637f17c37c..9d99131d0d65 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -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; diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c index 9020ac15baaa..f738024ccc8e 100644 --- a/fs/proc/proc_net.c +++ b/fs/proc/proc_net.c @@ -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); diff --git a/fs/proc/root.c b/fs/proc/root.c index d6c3b416529b..9a8a2b77b874 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -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) diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index 650af6deaf8f..643b96c7a94f 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -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 { -- cgit v1.2.3