[PATCH v2 14/15] umd: Remove exit_umh

From: Eric W. Biederman
Date: Mon Jun 29 2020 - 16:12:11 EST



The bffilter code no longer uses the umd_info.cleanup callback. This
callback is what exit_umh exists to call. So remove exit_umh and all
of it's associated booking.

Link: https://lkml.kernel.org/r/87bll6dlte.fsf_-_@xxxxxxxxxxxxxxxxxxxxx
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
include/linux/sched.h | 1 -
include/linux/umd.h | 16 ----------------
kernel/exit.c | 3 ---
kernel/umd.c | 28 ----------------------------
4 files changed, 48 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 59d1e92bb88e..edb2020875ad 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1511,7 +1511,6 @@ extern struct pid *cad_pid;
#define PF_KTHREAD 0x00200000 /* I am a kernel thread */
#define PF_RANDOMIZE 0x00400000 /* Randomize virtual address space */
#define PF_SWAPWRITE 0x00800000 /* Allowed to write to swap */
-#define PF_UMH 0x02000000 /* I'm an Usermodehelper process */
#define PF_NO_SETAFFINITY 0x04000000 /* Userland is not allowed to meddle with cpus_mask */
#define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */
#define PF_MEMALLOC_NOCMA 0x10000000 /* All allocation request will have _GFP_MOVABLE cleared */
diff --git a/include/linux/umd.h b/include/linux/umd.h
index edb1c62c62f4..71d8f4a41ad7 100644
--- a/include/linux/umd.h
+++ b/include/linux/umd.h
@@ -4,26 +4,10 @@
#include <linux/umh.h>
#include <linux/path.h>

-#ifdef CONFIG_BPFILTER
-void __exit_umh(struct task_struct *tsk);
-
-static inline void exit_umh(struct task_struct *tsk)
-{
- if (unlikely(tsk->flags & PF_UMH))
- __exit_umh(tsk);
-}
-#else
-static inline void exit_umh(struct task_struct *tsk)
-{
-}
-#endif
-
struct umd_info {
const char *driver_name;
struct file *pipe_to_umh;
struct file *pipe_from_umh;
- struct list_head list;
- void (*cleanup)(struct umd_info *info);
struct path wd;
struct pid *tgid;
};
diff --git a/kernel/exit.c b/kernel/exit.c
index b53107abdd31..42f079eb71e5 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -63,7 +63,6 @@
#include <linux/random.h>
#include <linux/rcuwait.h>
#include <linux/compat.h>
-#include <linux/umd.h>

#include <linux/uaccess.h>
#include <asm/unistd.h>
@@ -805,8 +804,6 @@ void __noreturn do_exit(long code)
exit_task_namespaces(tsk);
exit_task_work(tsk);
exit_thread(tsk);
- if (group_dead)
- exit_umh(tsk);

/*
* Flush inherited counters to the parent - before the parent
diff --git a/kernel/umd.c b/kernel/umd.c
index c1e8eccaee76..4188b71de267 100644
--- a/kernel/umd.c
+++ b/kernel/umd.c
@@ -9,9 +9,6 @@
#include <linux/task_work.h>
#include <linux/umd.h>

-static LIST_HEAD(umh_list);
-static DEFINE_MUTEX(umh_list_lock);
-
static struct vfsmount *blob_to_mnt(const void *data, size_t len, const char *name)
{
struct file_system_type *type;
@@ -134,7 +131,6 @@ static int umd_setup(struct subprocess_info *info, struct cred *new)
umd_info->pipe_to_umh = to_umh[1];
umd_info->pipe_from_umh = from_umh[0];
umd_info->tgid = get_pid(task_tgid(current));
- current->flags |= PF_UMH;
return 0;
}

@@ -182,11 +178,6 @@ int fork_usermode_driver(struct umd_info *info)
goto out;

err = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
- if (!err) {
- mutex_lock(&umh_list_lock);
- list_add(&info->list, &umh_list);
- mutex_unlock(&umh_list_lock);
- }
out:
if (argv)
argv_free(argv);
@@ -194,23 +185,4 @@ int fork_usermode_driver(struct umd_info *info)
}
EXPORT_SYMBOL_GPL(fork_usermode_driver);

-void __exit_umh(struct task_struct *tsk)
-{
- struct umd_info *info;
- struct pid *tgid = task_tgid(tsk);
-
- mutex_lock(&umh_list_lock);
- list_for_each_entry(info, &umh_list, list) {
- if (info->tgid == tgid) {
- list_del(&info->list);
- mutex_unlock(&umh_list_lock);
- goto out;
- }
- }
- mutex_unlock(&umh_list_lock);
- return;
-out:
- if (info->cleanup)
- info->cleanup(info);
-}

--
2.25.0