[Devel] [PATCH RHEL8 COMMIT] ve/fs/binfmt: move all internal data to structure
Konstantin Khorenko
khorenko at virtuozzo.com
Thu May 28 12:24:16 MSK 2020
The commit is pushed to "branch-rh8-4.18.0-80.1.2.vz8.3.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh8-4.18.0-80.1.2.vz8.3.9
------>
commit cd1179093e6411bc115fdee11de3ef34099d5b0e
Author: Valeriy Vdovin <valeriy.vdovin at virtuozzo.com>
Date: Thu May 28 12:24:16 2020 +0300
ve/fs/binfmt: move all internal data to structure
Allows to simplify management in further patches.
Signed-off-by: Stanislav Kinsbursky <skinsbursky at parallels.com>
Signed-off-by: Konstantin Khlebnikov <khlebnikov at openvz.org>
(cherry picked from 19551dbbfb60e2803b8e4d553f283acc3753858a
due to https://jira.sw.ru/browse/PSBM-103973)
Signed-off-by: Valeriy Vdovin <valeriy.vdovin at virtuozzo.com>
---
fs/binfmt_misc.c | 74 +++++++++++++++++++++++++++++++++++---------------------
1 file changed, 46 insertions(+), 28 deletions(-)
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index aa4a7a23ff99..97bd44f1b297 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -38,9 +38,6 @@ enum {
VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */
};
-static LIST_HEAD(entries);
-static int enabled = 1;
-
enum {Enabled, Magic};
#define MISC_FMT_PRESERVE_ARGV0 (1 << 31)
#define MISC_FMT_OPEN_BINARY (1 << 30)
@@ -60,10 +57,22 @@ typedef struct {
struct file *interp_file;
} Node;
-static DEFINE_RWLOCK(entries_lock);
static struct file_system_type bm_fs_type;
-static struct vfsmount *bm_mnt;
-static int entry_count;
+
+struct binfmt_misc {
+ struct list_head entries;
+ int enabled;
+
+ rwlock_t entries_lock;
+ struct vfsmount *bm_mnt;
+ int entry_count;
+};
+
+struct binfmt_misc binfmt_data = {
+ .entries = LIST_HEAD_INIT(binfmt_data.entries),
+ .enabled = 1,
+ .entries_lock = __RW_LOCK_UNLOCKED(binfmt_data.entries_lock),
+};
/*
* Max length of the register string. Determined by:
@@ -85,13 +94,13 @@ static int entry_count;
* if we do, return the node, else NULL
* locking is done in load_misc_binary
*/
-static Node *check_file(struct linux_binprm *bprm)
+static Node *check_file(struct binfmt_misc *bm_data, struct linux_binprm *bprm)
{
char *p = strrchr(bprm->interp, '.');
struct list_head *l;
/* Walk all the registered handlers. */
- list_for_each(l, &entries) {
+ list_for_each(l, &bm_data->entries) {
Node *e = list_entry(l, Node, list);
char *s;
int j;
@@ -133,17 +142,18 @@ static int load_misc_binary(struct linux_binprm *bprm)
struct file *interp_file = NULL;
int retval;
int fd_binary = -1;
+ struct binfmt_misc *bm_data = &binfmt_data;
retval = -ENOEXEC;
- if (!enabled)
+ if (!bm_data || !bm_data->enabled)
return retval;
/* to keep locking time low, we copy the interpreter string */
- read_lock(&entries_lock);
- fmt = check_file(bprm);
+ read_lock(&bm_data->entries_lock);
+ fmt = check_file(bm_data, bprm);
if (fmt)
dget(fmt->dentry);
- read_unlock(&entries_lock);
+ read_unlock(&bm_data->entries_lock);
if (!fmt)
return retval;
@@ -609,19 +619,19 @@ static void bm_evict_inode(struct inode *inode)
kfree(e);
}
-static void kill_node(Node *e)
+static void kill_node(struct binfmt_misc *bm_data, Node *e)
{
struct dentry *dentry;
- write_lock(&entries_lock);
+ write_lock(&bm_data->entries_lock);
list_del_init(&e->list);
- write_unlock(&entries_lock);
+ write_unlock(&bm_data->entries_lock);
dentry = e->dentry;
drop_nlink(d_inode(dentry));
d_drop(dentry);
dput(dentry);
- simple_release_fs(&bm_mnt, &entry_count);
+ simple_release_fs(&bm_data->bm_mnt, &bm_data->entry_count);
}
/* /<entry> */
@@ -651,6 +661,8 @@ static ssize_t bm_entry_write(struct file *file, const char __user *buffer,
struct dentry *root;
Node *e = file_inode(file)->i_private;
int res = parse_command(buffer, count);
+ struct super_block *sb = file->f_path.dentry->d_sb;
+ struct binfmt_misc *bm_data = sb->s_fs_info;
switch (res) {
case 1:
@@ -667,7 +679,7 @@ static ssize_t bm_entry_write(struct file *file, const char __user *buffer,
inode_lock(d_inode(root));
if (!list_empty(&e->list))
- kill_node(e);
+ kill_node(bm_data, e);
inode_unlock(d_inode(root));
break;
@@ -692,6 +704,7 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer,
Node *e;
struct inode *inode;
struct super_block *sb = file_inode(file)->i_sb;
+ struct binfmt_misc *bm_data = sb->s_fs_info;
struct dentry *root = sb->s_root, *dentry;
int err = 0;
@@ -716,7 +729,7 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer,
if (!inode)
goto out2;
- err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count);
+ err = simple_pin_fs(&bm_fs_type, &bm_data->bm_mnt, &bm_data->entry_count);
if (err) {
iput(inode);
inode = NULL;
@@ -730,7 +743,7 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer,
if (IS_ERR(f)) {
err = PTR_ERR(f);
pr_notice("register: failed to install interpreter file %s\n", e->interpreter);
- simple_release_fs(&bm_mnt, &entry_count);
+ simple_release_fs(&bm_data->bm_mnt, &bm_data->entry_count);
iput(inode);
inode = NULL;
goto out2;
@@ -743,9 +756,9 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer,
inode->i_fop = &bm_entry_operations;
d_instantiate(dentry, inode);
- write_lock(&entries_lock);
- list_add(&e->list, &entries);
- write_unlock(&entries_lock);
+ write_lock(&bm_data->entries_lock);
+ list_add(&e->list, &bm_data->entries);
+ write_unlock(&bm_data->entries_lock);
err = 0;
out2:
@@ -770,7 +783,8 @@ static const struct file_operations bm_register_operations = {
static ssize_t
bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
{
- char *s = enabled ? "enabled\n" : "disabled\n";
+ struct binfmt_misc *bm_data = file->f_path.dentry->d_sb->s_fs_info;
+ char *s = bm_data->enabled ? "enabled\n" : "disabled\n";
return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s));
}
@@ -778,25 +792,27 @@ bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
static ssize_t bm_status_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
+ struct binfmt_misc *bm_data = file->f_path.dentry->d_sb->s_fs_info;
int res = parse_command(buffer, count);
struct dentry *root;
switch (res) {
case 1:
/* Disable all handlers. */
- enabled = 0;
+ bm_data->enabled = 0;
break;
case 2:
/* Enable all handlers. */
- enabled = 1;
+ bm_data->enabled = 1;
break;
case 3:
/* Delete all handlers. */
root = file_inode(file)->i_sb->s_root;
inode_lock(d_inode(root));
- while (!list_empty(&entries))
- kill_node(list_first_entry(&entries, Node, list));
+ while (!list_empty(&bm_data->entries))
+ kill_node(bm_data, list_first_entry(
+ &bm_data->entries, Node, list));
inode_unlock(d_inode(root));
break;
@@ -830,8 +846,10 @@ static int bm_fill_super(struct super_block *sb, void *data, int silent)
};
err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files);
- if (!err)
+ if (!err) {
sb->s_op = &s_ops;
+ sb->s_fs_info = &binfmt_data;
+ }
return err;
}
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