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proc: make struct proc_dir_entry::name a terminal array rather than a pointer

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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 <dhowells@redhat.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Howells
2011-07-27 21:47:03 +03:00
committed by Linus Torvalds
parent 5fd00b0315
commit 09570f9149
4 changed files with 7 additions and 8 deletions
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6
include/linux/proc_fs.h
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@@ -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 {