* [PATCH 2/2] umd: Remove
2024-11-14 2:23 [PATCH 0/2] bpf/umd possible deadcode linux
2024-11-14 2:23 ` [PATCH 1/2] bpf: Don't select USERMODE_DRIVER linux
@ 2024-11-14 2:24 ` linux
2025-01-27 13:55 ` [PATCH 0/2] bpf/umd possible deadcode Dr. David Alan Gilbert
2 siblings, 0 replies; 4+ messages in thread
From: linux @ 2024-11-14 2:24 UTC (permalink / raw)
To: ast, daniel, andrii, martin.lau, roberto.sassu, bpf
Cc: linux-kernel, Dr. David Alan Gilbert
From: "Dr. David Alan Gilbert" <linux@treblig.org>
The last use of the usermode driver code was removed by
commit 98e20e5e13d2 ("bpfilter: remove bpfilter")
Remove the code.
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
---
include/linux/usermode_driver.h | 19 ----
kernel/Makefile | 1 -
kernel/bpf/preload/Kconfig | 4 -
kernel/usermode_driver.c | 191 --------------------------------
4 files changed, 215 deletions(-)
delete mode 100644 include/linux/usermode_driver.h
delete mode 100644 kernel/usermode_driver.c
diff --git a/include/linux/usermode_driver.h b/include/linux/usermode_driver.h
deleted file mode 100644
index ad970416260d..000000000000
--- a/include/linux/usermode_driver.h
+++ /dev/null
@@ -1,19 +0,0 @@
-#ifndef __LINUX_USERMODE_DRIVER_H__
-#define __LINUX_USERMODE_DRIVER_H__
-
-#include <linux/umh.h>
-#include <linux/path.h>
-
-struct umd_info {
- const char *driver_name;
- struct file *pipe_to_umh;
- struct file *pipe_from_umh;
- struct path wd;
- struct pid *tgid;
-};
-int umd_load_blob(struct umd_info *info, const void *data, size_t len);
-int umd_unload_blob(struct umd_info *info);
-int fork_usermode_driver(struct umd_info *info);
-void umd_cleanup_helper(struct umd_info *info);
-
-#endif /* __LINUX_USERMODE_DRIVER_H__ */
diff --git a/kernel/Makefile b/kernel/Makefile
index 87866b037fbe..25d58da2a6ee 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -12,7 +12,6 @@ obj-y = fork.o exec_domain.o panic.o \
notifier.o ksysfs.o cred.o reboot.o \
async.o range.o smpboot.o ucount.o regset.o ksyms_common.o
-obj-$(CONFIG_USERMODE_DRIVER) += usermode_driver.o
obj-$(CONFIG_MULTIUSER) += groups.o
obj-$(CONFIG_VHOST_TASK) += vhost_task.o
diff --git a/kernel/bpf/preload/Kconfig b/kernel/bpf/preload/Kconfig
index f9b11d01c3b5..aef7b0bc96d6 100644
--- a/kernel/bpf/preload/Kconfig
+++ b/kernel/bpf/preload/Kconfig
@@ -1,8 +1,4 @@
# SPDX-License-Identifier: GPL-2.0-only
-config USERMODE_DRIVER
- bool
- default n
-
menuconfig BPF_PRELOAD
bool "Preload BPF file system with kernel specific program and map iterators"
depends on BPF
diff --git a/kernel/usermode_driver.c b/kernel/usermode_driver.c
deleted file mode 100644
index 8303f4c7ca71..000000000000
--- a/kernel/usermode_driver.c
+++ /dev/null
@@ -1,191 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * umd - User mode driver support
- */
-#include <linux/shmem_fs.h>
-#include <linux/pipe_fs_i.h>
-#include <linux/mount.h>
-#include <linux/fs_struct.h>
-#include <linux/task_work.h>
-#include <linux/usermode_driver.h>
-
-static struct vfsmount *blob_to_mnt(const void *data, size_t len, const char *name)
-{
- struct file_system_type *type;
- struct vfsmount *mnt;
- struct file *file;
- ssize_t written;
- loff_t pos = 0;
-
- type = get_fs_type("tmpfs");
- if (!type)
- return ERR_PTR(-ENODEV);
-
- mnt = kern_mount(type);
- put_filesystem(type);
- if (IS_ERR(mnt))
- return mnt;
-
- file = file_open_root_mnt(mnt, name, O_CREAT | O_WRONLY, 0700);
- if (IS_ERR(file)) {
- kern_unmount(mnt);
- return ERR_CAST(file);
- }
-
- written = kernel_write(file, data, len, &pos);
- if (written != len) {
- int err = written;
- if (err >= 0)
- err = -ENOMEM;
- filp_close(file, NULL);
- kern_unmount(mnt);
- return ERR_PTR(err);
- }
-
- fput(file);
-
- /* Flush delayed fput so exec can open the file read-only */
- flush_delayed_fput();
- task_work_run();
- return mnt;
-}
-
-/**
- * umd_load_blob - Remember a blob of bytes for fork_usermode_driver
- * @info: information about usermode driver
- * @data: a blob of bytes that can be executed as a file
- * @len: The lentgh of the blob
- *
- */
-int umd_load_blob(struct umd_info *info, const void *data, size_t len)
-{
- struct vfsmount *mnt;
-
- if (WARN_ON_ONCE(info->wd.dentry || info->wd.mnt))
- return -EBUSY;
-
- mnt = blob_to_mnt(data, len, info->driver_name);
- if (IS_ERR(mnt))
- return PTR_ERR(mnt);
-
- info->wd.mnt = mnt;
- info->wd.dentry = mnt->mnt_root;
- return 0;
-}
-EXPORT_SYMBOL_GPL(umd_load_blob);
-
-/**
- * umd_unload_blob - Disassociate @info from a previously loaded blob
- * @info: information about usermode driver
- *
- */
-int umd_unload_blob(struct umd_info *info)
-{
- if (WARN_ON_ONCE(!info->wd.mnt ||
- !info->wd.dentry ||
- info->wd.mnt->mnt_root != info->wd.dentry))
- return -EINVAL;
-
- kern_unmount(info->wd.mnt);
- info->wd.mnt = NULL;
- info->wd.dentry = NULL;
- return 0;
-}
-EXPORT_SYMBOL_GPL(umd_unload_blob);
-
-static int umd_setup(struct subprocess_info *info, struct cred *new)
-{
- struct umd_info *umd_info = info->data;
- struct file *from_umh[2];
- struct file *to_umh[2];
- int err;
-
- /* create pipe to send data to umh */
- err = create_pipe_files(to_umh, 0);
- if (err)
- return err;
- err = replace_fd(0, to_umh[0], 0);
- fput(to_umh[0]);
- if (err < 0) {
- fput(to_umh[1]);
- return err;
- }
-
- /* create pipe to receive data from umh */
- err = create_pipe_files(from_umh, 0);
- if (err) {
- fput(to_umh[1]);
- replace_fd(0, NULL, 0);
- return err;
- }
- err = replace_fd(1, from_umh[1], 0);
- fput(from_umh[1]);
- if (err < 0) {
- fput(to_umh[1]);
- replace_fd(0, NULL, 0);
- fput(from_umh[0]);
- return err;
- }
-
- set_fs_pwd(current->fs, &umd_info->wd);
- umd_info->pipe_to_umh = to_umh[1];
- umd_info->pipe_from_umh = from_umh[0];
- umd_info->tgid = get_pid(task_tgid(current));
- return 0;
-}
-
-static void umd_cleanup(struct subprocess_info *info)
-{
- struct umd_info *umd_info = info->data;
-
- /* cleanup if umh_setup() was successful but exec failed */
- if (info->retval)
- umd_cleanup_helper(umd_info);
-}
-
-/**
- * umd_cleanup_helper - release the resources which were allocated in umd_setup
- * @info: information about usermode driver
- */
-void umd_cleanup_helper(struct umd_info *info)
-{
- fput(info->pipe_to_umh);
- fput(info->pipe_from_umh);
- put_pid(info->tgid);
- info->tgid = NULL;
-}
-EXPORT_SYMBOL_GPL(umd_cleanup_helper);
-
-/**
- * fork_usermode_driver - fork a usermode driver
- * @info: information about usermode driver (shouldn't be NULL)
- *
- * Returns either negative error or zero which indicates success in
- * executing a usermode driver. In such case 'struct umd_info *info'
- * is populated with two pipes and a tgid of the process. The caller is
- * responsible for health check of the user process, killing it via
- * tgid, and closing the pipes when user process is no longer needed.
- */
-int fork_usermode_driver(struct umd_info *info)
-{
- struct subprocess_info *sub_info;
- const char *argv[] = { info->driver_name, NULL };
- int err;
-
- if (WARN_ON_ONCE(info->tgid))
- return -EBUSY;
-
- err = -ENOMEM;
- sub_info = call_usermodehelper_setup(info->driver_name,
- (char **)argv, NULL, GFP_KERNEL,
- umd_setup, umd_cleanup, info);
- if (!sub_info)
- goto out;
-
- err = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
-out:
- return err;
-}
-EXPORT_SYMBOL_GPL(fork_usermode_driver);
-
-
--
2.47.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH 0/2] bpf/umd possible deadcode
2024-11-14 2:23 [PATCH 0/2] bpf/umd possible deadcode linux
2024-11-14 2:23 ` [PATCH 1/2] bpf: Don't select USERMODE_DRIVER linux
2024-11-14 2:24 ` [PATCH 2/2] umd: Remove linux
@ 2025-01-27 13:55 ` Dr. David Alan Gilbert
2 siblings, 0 replies; 4+ messages in thread
From: Dr. David Alan Gilbert @ 2025-01-27 13:55 UTC (permalink / raw)
To: ast, daniel, andrii, martin.lau, roberto.sassu, bpf; +Cc: linux-kernel
* linux@treblig.org (linux@treblig.org) wrote:
> From: "Dr. David Alan Gilbert" <linux@treblig.org>
>
>
> Hi,
> I'm not 100% sure about these, since I'm not quite
> sure how to test it properly.
>
> As far as I can tell the UMD isn't needed by bpf itself
> any more; so I've got one patch that just removes that select.
> But then that leaves no users of umd itself; and I split that
> separately since I saw there was still some discussion this year
> on other uses.
Hi,
Does anyone have any views on this pair?
Thanks,
Dave
> Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
>
> Dave
>
> Dr. David Alan Gilbert (2):
> bpf: Don't select USERMODE_DRIVER
> umd: Remove
>
> include/linux/usermode_driver.h | 19 ----
> kernel/Makefile | 1 -
> kernel/bpf/preload/Kconfig | 5 -
> kernel/usermode_driver.c | 191 --------------------------------
> 4 files changed, 216 deletions(-)
> delete mode 100644 include/linux/usermode_driver.h
> delete mode 100644 kernel/usermode_driver.c
>
> --
> 2.47.0
>
--
-----Open up your eyes, open up your mind, open up your code -------
/ Dr. David Alan Gilbert | Running GNU/Linux | Happy \
\ dave @ treblig.org | | In Hex /
\ _________________________|_____ http://www.treblig.org |_______/
^ permalink raw reply [flat|nested] 4+ messages in thread