Commit 5e787dbf authored by Dominik Brodowski's avatar Dominik Brodowski
Browse files

devtmpfs: use do_mount() instead of ksys_mount() 



In devtmpfs, do_mount() can be called directly instead of complex wrapping
by ksys_mount():
- the first and third arguments are const strings in the kernel,
  and do not need to be copied over from userspace;
- the fifth argument is NULL, and therefore no page needs to be
  copied over from userspace;
- the second and fourth argument are passed through anyway.

Signed-off-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
parent ae4b064e

drivers/base/devtmpfs.c

+3 −3
Original line number Diff line number Diff line
@@ -359,7 +359,7 @@ static int handle_remove(const char *nodename, struct device *dev) 
 * If configured, or requested by the commandline, devtmpfs will be

 * auto-mounted after the kernel mounted the root filesystem.

 */

int devtmpfs_mount(const char *mntdir)

int devtmpfs_mount(void)

{

	int err;
@@ -369,7 +369,7 @@ int devtmpfs_mount(const char *mntdir) 
	if (!thread)

		return 0;



	err = ksys_mount("devtmpfs", mntdir, "devtmpfs", MS_SILENT, NULL);

	err = do_mount("devtmpfs", "dev", "devtmpfs", MS_SILENT, NULL);

	if (err)

		printk(KERN_INFO "devtmpfs: error mounting %i\n", err);

	else
@@ -394,7 +394,7 @@ static int devtmpfsd(void *p) 
	*err = ksys_unshare(CLONE_NEWNS);

	if (*err)

		goto out;

	*err = ksys_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, NULL);

	*err = do_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, NULL);

	if (*err)

		goto out;

	ksys_chdir("/.."); /* will traverse into overmounted root */

include/linux/device.h

+2 −2
Original line number Diff line number Diff line
@@ -1666,11 +1666,11 @@ extern bool kill_device(struct device *dev); 
#ifdef CONFIG_DEVTMPFS

extern int devtmpfs_create_node(struct device *dev);

extern int devtmpfs_delete_node(struct device *dev);

extern int devtmpfs_mount(const char *mntdir);

extern int devtmpfs_mount(void);

#else

static inline int devtmpfs_create_node(struct device *dev) { return 0; }

static inline int devtmpfs_delete_node(struct device *dev) { return 0; }

static inline int devtmpfs_mount(const char *mountpoint) { return 0; }

static inline int devtmpfs_mount(void) { return 0; }

#endif



/* drivers/base/power/shutdown.c */

init/do_mounts.c

+1 −1
Original line number Diff line number Diff line
@@ -670,7 +670,7 @@ void __init prepare_namespace(void) 


	mount_root();

out:

	devtmpfs_mount("dev");

	devtmpfs_mount();

	ksys_mount(".", "/", NULL, MS_MOVE, NULL);

	ksys_chroot(".");

}

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