#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/mount.h>
+#include <linux/magic.h>
#include <asm/uaccess.h>
sysctl_head_put(head);
}
/* Release any associated namespace */
- ns_ops = PROC_I(inode)->ns_ops;
- ns = PROC_I(inode)->ns;
+ ns_ops = PROC_I(inode)->ns.ns_ops;
+ ns = PROC_I(inode)->ns.ns;
if (ns_ops && ns)
ns_ops->put(ns);
}
ei->pde = NULL;
ei->sysctl = NULL;
ei->sysctl_entry = NULL;
- ei->ns = NULL;
- ei->ns_ops = NULL;
+ ei->ns.ns = NULL;
+ ei->ns.ns_ops = NULL;
inode = &ei->vfs_inode;
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
return inode;
.show_options = proc_show_options,
};
-static void __pde_users_dec(struct proc_dir_entry *pde)
+enum {BIAS = -1U<<31};
+
+static inline int use_pde(struct proc_dir_entry *pde)
+{
+ return atomic_inc_unless_negative(&pde->in_use);
+}
+
+static void unuse_pde(struct proc_dir_entry *pde)
{
- pde->pde_users--;
- if (pde->pde_unload_completion && pde->pde_users == 0)
+ if (atomic_dec_return(&pde->in_use) == BIAS)
complete(pde->pde_unload_completion);
}
-void pde_users_dec(struct proc_dir_entry *pde)
+/* pde is locked */
+static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
{
- spin_lock(&pde->pde_unload_lock);
- __pde_users_dec(pde);
- spin_unlock(&pde->pde_unload_lock);
+ if (pdeo->closing) {
+ /* somebody else is doing that, just wait */
+ DECLARE_COMPLETION_ONSTACK(c);
+ pdeo->c = &c;
+ spin_unlock(&pde->pde_unload_lock);
+ wait_for_completion(&c);
+ spin_lock(&pde->pde_unload_lock);
+ } else {
+ struct file *file;
+ pdeo->closing = 1;
+ spin_unlock(&pde->pde_unload_lock);
+ file = pdeo->file;
+ pde->proc_fops->release(file_inode(file), file);
+ spin_lock(&pde->pde_unload_lock);
+ list_del_init(&pdeo->lh);
+ if (pdeo->c)
+ complete(pdeo->c);
+ kfree(pdeo);
+ }
+}
+
+void proc_entry_rundown(struct proc_dir_entry *de)
+{
+ DECLARE_COMPLETION_ONSTACK(c);
+ /* Wait until all existing callers into module are done. */
+ de->pde_unload_completion = &c;
+ if (atomic_add_return(BIAS, &de->in_use) != BIAS)
+ wait_for_completion(&c);
+
+ 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);
+ close_pdeo(de, pdeo);
+ }
+ spin_unlock(&de->pde_unload_lock);
}
static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
{
struct proc_dir_entry *pde = PDE(file_inode(file));
loff_t rv = -EINVAL;
- loff_t (*llseek)(struct file *, loff_t, int);
-
- spin_lock(&pde->pde_unload_lock);
- /*
- * remove_proc_entry() is going to delete PDE (as part of module
- * cleanup sequence). No new callers into module allowed.
- */
- if (!pde->proc_fops) {
- spin_unlock(&pde->pde_unload_lock);
- return rv;
+ if (use_pde(pde)) {
+ loff_t (*llseek)(struct file *, loff_t, int);
+ llseek = pde->proc_fops->llseek;
+ if (!llseek)
+ llseek = default_llseek;
+ rv = llseek(file, offset, whence);
+ unuse_pde(pde);
}
- /*
- * Bump refcount so that remove_proc_entry will wail for ->llseek to
- * complete.
- */
- pde->pde_users++;
- /*
- * Save function pointer under lock, to protect against ->proc_fops
- * NULL'ifying right after ->pde_unload_lock is dropped.
- */
- llseek = pde->proc_fops->llseek;
- spin_unlock(&pde->pde_unload_lock);
-
- if (!llseek)
- llseek = default_llseek;
- rv = llseek(file, offset, whence);
-
- pde_users_dec(pde);
return rv;
}
static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
+ ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
struct proc_dir_entry *pde = PDE(file_inode(file));
ssize_t rv = -EIO;
- ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
-
- spin_lock(&pde->pde_unload_lock);
- if (!pde->proc_fops) {
- spin_unlock(&pde->pde_unload_lock);
- return rv;
+ if (use_pde(pde)) {
+ read = pde->proc_fops->read;
+ if (read)
+ rv = read(file, buf, count, ppos);
+ unuse_pde(pde);
}
- pde->pde_users++;
- read = pde->proc_fops->read;
- spin_unlock(&pde->pde_unload_lock);
-
- if (read)
- rv = read(file, buf, count, ppos);
-
- pde_users_dec(pde);
return rv;
}
static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
+ ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
struct proc_dir_entry *pde = PDE(file_inode(file));
ssize_t rv = -EIO;
- ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
-
- spin_lock(&pde->pde_unload_lock);
- if (!pde->proc_fops) {
- spin_unlock(&pde->pde_unload_lock);
- return rv;
+ if (use_pde(pde)) {
+ write = pde->proc_fops->write;
+ if (write)
+ rv = write(file, buf, count, ppos);
+ unuse_pde(pde);
}
- pde->pde_users++;
- write = pde->proc_fops->write;
- spin_unlock(&pde->pde_unload_lock);
-
- if (write)
- rv = write(file, buf, count, ppos);
-
- pde_users_dec(pde);
return rv;
}
struct proc_dir_entry *pde = PDE(file_inode(file));
unsigned int rv = DEFAULT_POLLMASK;
unsigned int (*poll)(struct file *, struct poll_table_struct *);
-
- spin_lock(&pde->pde_unload_lock);
- if (!pde->proc_fops) {
- spin_unlock(&pde->pde_unload_lock);
- return rv;
+ if (use_pde(pde)) {
+ poll = pde->proc_fops->poll;
+ if (poll)
+ rv = poll(file, pts);
+ unuse_pde(pde);
}
- pde->pde_users++;
- poll = pde->proc_fops->poll;
- spin_unlock(&pde->pde_unload_lock);
-
- if (poll)
- rv = poll(file, pts);
-
- pde_users_dec(pde);
return rv;
}
struct proc_dir_entry *pde = PDE(file_inode(file));
long rv = -ENOTTY;
long (*ioctl)(struct file *, unsigned int, unsigned long);
-
- spin_lock(&pde->pde_unload_lock);
- if (!pde->proc_fops) {
- spin_unlock(&pde->pde_unload_lock);
- return rv;
+ if (use_pde(pde)) {
+ ioctl = pde->proc_fops->unlocked_ioctl;
+ if (ioctl)
+ rv = ioctl(file, cmd, arg);
+ unuse_pde(pde);
}
- pde->pde_users++;
- ioctl = pde->proc_fops->unlocked_ioctl;
- spin_unlock(&pde->pde_unload_lock);
-
- if (ioctl)
- rv = ioctl(file, cmd, arg);
-
- pde_users_dec(pde);
return rv;
}
struct proc_dir_entry *pde = PDE(file_inode(file));
long rv = -ENOTTY;
long (*compat_ioctl)(struct file *, unsigned int, unsigned long);
-
- spin_lock(&pde->pde_unload_lock);
- if (!pde->proc_fops) {
- spin_unlock(&pde->pde_unload_lock);
- return rv;
+ if (use_pde(pde)) {
+ compat_ioctl = pde->proc_fops->compat_ioctl;
+ if (compat_ioctl)
+ rv = compat_ioctl(file, cmd, arg);
+ unuse_pde(pde);
}
- pde->pde_users++;
- compat_ioctl = pde->proc_fops->compat_ioctl;
- spin_unlock(&pde->pde_unload_lock);
-
- if (compat_ioctl)
- rv = compat_ioctl(file, cmd, arg);
-
- pde_users_dec(pde);
return rv;
}
#endif
struct proc_dir_entry *pde = PDE(file_inode(file));
int rv = -EIO;
int (*mmap)(struct file *, struct vm_area_struct *);
-
- spin_lock(&pde->pde_unload_lock);
- if (!pde->proc_fops) {
- spin_unlock(&pde->pde_unload_lock);
- return rv;
+ if (use_pde(pde)) {
+ mmap = pde->proc_fops->mmap;
+ if (mmap)
+ rv = mmap(file, vma);
+ unuse_pde(pde);
}
- pde->pde_users++;
- mmap = pde->proc_fops->mmap;
- spin_unlock(&pde->pde_unload_lock);
-
- if (mmap)
- rv = mmap(file, vma);
-
- pde_users_dec(pde);
return rv;
}
* by hand in remove_proc_entry(). For this, save opener's credentials
* for later.
*/
- pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL);
+ pdeo = kzalloc(sizeof(struct pde_opener), GFP_KERNEL);
if (!pdeo)
return -ENOMEM;
- spin_lock(&pde->pde_unload_lock);
- if (!pde->proc_fops) {
- spin_unlock(&pde->pde_unload_lock);
+ if (!use_pde(pde)) {
kfree(pdeo);
return -ENOENT;
}
- pde->pde_users++;
open = pde->proc_fops->open;
release = pde->proc_fops->release;
- spin_unlock(&pde->pde_unload_lock);
if (open)
rv = open(inode, file);
- spin_lock(&pde->pde_unload_lock);
if (rv == 0 && release) {
/* To know what to release. */
- pdeo->inode = inode;
pdeo->file = file;
/* Strictly for "too late" ->release in proc_reg_release(). */
- pdeo->release = release;
+ spin_lock(&pde->pde_unload_lock);
list_add(&pdeo->lh, &pde->pde_openers);
+ spin_unlock(&pde->pde_unload_lock);
} else
kfree(pdeo);
- __pde_users_dec(pde);
- spin_unlock(&pde->pde_unload_lock);
- return rv;
-}
-
-static struct pde_opener *find_pde_opener(struct proc_dir_entry *pde,
- struct inode *inode, struct file *file)
-{
- struct pde_opener *pdeo;
- list_for_each_entry(pdeo, &pde->pde_openers, lh) {
- if (pdeo->inode == inode && pdeo->file == file)
- return pdeo;
- }
- return NULL;
+ unuse_pde(pde);
+ return rv;
}
static int proc_reg_release(struct inode *inode, struct file *file)
{
struct proc_dir_entry *pde = PDE(inode);
- int rv = 0;
- int (*release)(struct inode *, struct file *);
struct pde_opener *pdeo;
-
spin_lock(&pde->pde_unload_lock);
- pdeo = find_pde_opener(pde, inode, file);
- if (!pde->proc_fops) {
- /*
- * Can't simply exit, __fput() will think that everything is OK,
- * and move on to freeing struct file. remove_proc_entry() will
- * find slacker in opener's list and will try to do non-trivial
- * things with struct file. Therefore, remove opener from list.
- *
- * But if opener is removed from list, who will ->release it?
- */
- if (pdeo) {
- list_del(&pdeo->lh);
- spin_unlock(&pde->pde_unload_lock);
- rv = pdeo->release(inode, file);
- kfree(pdeo);
- } else
- spin_unlock(&pde->pde_unload_lock);
- return rv;
- }
- pde->pde_users++;
- release = pde->proc_fops->release;
- if (pdeo) {
- list_del(&pdeo->lh);
- kfree(pdeo);
+ list_for_each_entry(pdeo, &pde->pde_openers, lh) {
+ if (pdeo->file == file) {
+ close_pdeo(pde, pdeo);
+ break;
+ }
}
spin_unlock(&pde->pde_unload_lock);
-
- if (release)
- rv = release(inode, file);
-
- pde_users_dec(pde);
- return rv;
+ return 0;
}
static const struct file_operations proc_reg_file_ops = {
inode->i_size = de->size;
if (de->nlink)
set_nlink(inode, de->nlink);
- if (de->proc_iops)
- inode->i_op = de->proc_iops;
+ WARN_ON(!de->proc_iops);
+ inode->i_op = de->proc_iops;
if (de->proc_fops) {
if (S_ISREG(inode->i_mode)) {
#ifdef CONFIG_COMPAT
return -ENOMEM;
}
- return 0;
+ return proc_setup_self(s);
}
projects / firefly-linux-kernel-4.4.55.git / blobdiff