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>
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index a6a1cb5..bec5832 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -39,7 +39,7 @@
/* buffer size is one page but our output routines use some slack for overruns */
#define PROC_BLOCK_SIZE (PAGE_SIZE - 1024)
-static ssize_t
+ssize_t
__proc_file_read(struct file *file, char __user *buf, size_t nbytes,
loff_t *ppos)
{
@@ -171,48 +171,6 @@
return retval;
}
-static ssize_t
-proc_file_read(struct file *file, char __user *buf, size_t nbytes,
- loff_t *ppos)
-{
- struct proc_dir_entry *pde = PDE(file_inode(file));
- ssize_t rv = -EIO;
-
- spin_lock(&pde->pde_unload_lock);
- if (!pde->proc_fops) {
- spin_unlock(&pde->pde_unload_lock);
- return rv;
- }
- pde->pde_users++;
- spin_unlock(&pde->pde_unload_lock);
-
- rv = __proc_file_read(file, buf, nbytes, ppos);
-
- pde_users_dec(pde);
- return rv;
-}
-
-static loff_t
-proc_file_lseek(struct file *file, loff_t offset, int orig)
-{
- loff_t retval = -EINVAL;
- switch (orig) {
- case 1:
- offset += file->f_pos;
- /* fallthrough */
- case 0:
- if (offset < 0 || offset > MAX_NON_LFS)
- break;
- file->f_pos = retval = offset;
- }
- return retval;
-}
-
-static const struct file_operations proc_file_operations = {
- .llseek = proc_file_lseek,
- .read = proc_file_read,
-};
-
static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
{
struct inode *inode = dentry->d_inode;
@@ -722,41 +680,6 @@
free_proc_entry(pde);
}
-static void entry_rundown(struct proc_dir_entry *de)
-{
- spin_lock(&de->pde_unload_lock);
- /*
- * Stop accepting new callers into module. If you're
- * dynamically allocating ->proc_fops, save a pointer somewhere.
- */
- de->proc_fops = NULL;
- /* Wait until all existing callers into module are done. */
- if (de->pde_users > 0) {
- DECLARE_COMPLETION_ONSTACK(c);
-
- if (!de->pde_unload_completion)
- de->pde_unload_completion = &c;
-
- spin_unlock(&de->pde_unload_lock);
-
- wait_for_completion(de->pde_unload_completion);
-
- spin_lock(&de->pde_unload_lock);
- }
-
- while (!list_empty(&de->pde_openers)) {
- struct pde_opener *pdeo;
-
- pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
- list_del(&pdeo->lh);
- spin_unlock(&de->pde_unload_lock);
- pdeo->release(pdeo->inode, pdeo->file);
- kfree(pdeo);
- spin_lock(&de->pde_unload_lock);
- }
- spin_unlock(&de->pde_unload_lock);
-}
-
/*
* Remove a /proc entry and free it if it's not currently in use.
*/
@@ -788,7 +711,7 @@
return;
}
- entry_rundown(de);
+ proc_entry_rundown(de);
if (S_ISDIR(de->mode))
parent->nlink--;
@@ -837,7 +760,7 @@
}
spin_unlock(&proc_subdir_lock);
- entry_rundown(de);
+ proc_entry_rundown(de);
next = de->parent;
if (S_ISDIR(de->mode))
next->nlink--;