procfs: preparations for remove_proc_entry() race fixes

* leave ->proc_fops alone; make ->pde_users negative instead
* trim pde_opener
* move relevant code in fs/proc/inode.c

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 2 insertions, 9 deletions

diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index bcc0e10ef1df..947ae7eb63ef 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -60,20 +60,13 @@ struct proc_dir_entry {
         kgid_t gid;
         loff_t size;
         const struct inode_operations *proc_iops;
-        /*
-         * NULL ->proc_fops means "PDE is going away RSN" or
-         * "PDE is just created". In either case, e.g. ->read_proc won't be
-         * called because it's too late or too early, respectively.
-         *
-         * If you're allocating ->proc_fops dynamically, save a pointer
-         * somewhere.
-         */
         const struct file_operations *proc_fops;
         struct proc_dir_entry *next, *parent, *subdir;
         void *data;
         read_proc_t *read_proc;
         atomic_t count;         /* use count */
-        int pde_users;  /* number of callers into module in progress */
+        int pde_users;  /* number of callers into module in progress; */
+                        /* negative -> it's going away RSN */
         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 */