proc: switch struct proc_dir_entry::count to refcount

->count is honest reference count unlike ->in_use.

Link: http://lkml.kernel.org/r/20180313174550.GA4332@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 5dad2e8..fc0333f 100644 (file)
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -402,7 +402,7 @@ static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
        ent->mode = mode;
        ent->nlink = nlink;
        ent->subdir = RB_ROOT_CACHED;
-       atomic_set(&ent->count, 1);
+       refcount_set(&ent->refcnt, 1);
        spin_lock_init(&ent->pde_unload_lock);
        INIT_LIST_HEAD(&ent->pde_openers);
        proc_set_user(ent, (*parent)->uid, (*parent)->gid);
@@ -553,7 +553,7 @@ EXPORT_SYMBOL(proc_set_user);
 
 void pde_put(struct proc_dir_entry *pde)
 {
-       if (atomic_dec_and_test(&pde->count)) {
+       if (refcount_dec_and_test(&pde->refcnt)) {
                proc_free_inum(pde->low_ino);
                pde_free(pde);
        }

diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 0ead007..b7024f1 100644 (file)
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -11,6 +11,7 @@
 
 #include <linux/proc_fs.h>
 #include <linux/proc_ns.h>
+#include <linux/refcount.h>
 #include <linux/spinlock.h>
 #include <linux/atomic.h>
 #include <linux/binfmts.h>
@@ -36,7 +37,7 @@ struct proc_dir_entry {
         * negative -> it's going away RSN
         */
        atomic_t in_use;
-       atomic_t count;         /* use count */
+       refcount_t refcnt;
        struct list_head pde_openers;   /* who did ->open, but not ->release */
        /* protects ->pde_openers and all struct pde_opener instances */
        spinlock_t pde_unload_lock;
@@ -168,7 +169,7 @@ int proc_readdir_de(struct file *, struct dir_context *, struct proc_dir_entry *
 
 static inline struct proc_dir_entry *pde_get(struct proc_dir_entry *pde)
 {
-       atomic_inc(&pde->count);
+       refcount_inc(&pde->refcnt);
        return pde;
 }
 extern void pde_put(struct proc_dir_entry *);

diff --git a/fs/proc/root.c b/fs/proc/root.c
index 9e99204..76c9964 100644 (file)
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -199,7 +199,7 @@ struct proc_dir_entry proc_root = {
        .namelen        = 5, 
        .mode           = S_IFDIR | S_IRUGO | S_IXUGO, 
        .nlink          = 2, 
-       .count          = ATOMIC_INIT(1),
+       .refcnt         = REFCOUNT_INIT(1),
        .proc_iops      = &proc_root_inode_operations, 
        .proc_fops      = &proc_root_operations,
        .parent         = &proc_root,