From: Dominik Brodowski <linux@dominikbrodowski.net>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
linux-kernel@vger.kernel.org
Subject: [PATCH 1/3] devtmpfs: use do_mount() instead of ksys_mount()
Date: Thu, 12 Dec 2019 14:57:22 +0100 [thread overview]
Message-ID: <20191212135724.331342-2-linux@dominikbrodowski.net> (raw)
In-Reply-To: <20191212135724.331342-1-linux@dominikbrodowski.net>
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: Dominik Brodowski <linux@dominikbrodowski.net>
---
drivers/base/devtmpfs.c | 6 +++---
include/linux/device.h | 4 ++--
init/do_mounts.c | 2 +-
3 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 30d0523014e0..6cdbf1531238 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -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 */
diff --git a/include/linux/device.h b/include/linux/device.h
index e226030c1df3..96ff76731e93 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -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 */
diff --git a/init/do_mounts.c b/init/do_mounts.c
index af9cda887a23..43f6d098c880 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -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(".");
}
--
2.24.1
next prev parent reply other threads:[~2019-12-12 13:59 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-12 13:57 [PATCH 0/3] use do_mount() instead of ksys_mount() Dominik Brodowski
2019-12-12 13:57 ` Dominik Brodowski [this message]
2019-12-12 13:57 ` [PATCH 2/3] initrd: " Dominik Brodowski
2019-12-12 13:57 ` [PATCH 3/3] init: " Dominik Brodowski
2019-12-16 1:35 ` Ondřej Jirman
2019-12-16 1:36 ` Ondřej Jirman
2019-12-16 3:50 ` Linus Torvalds
2019-12-16 5:13 ` Eric Biggers
2019-12-16 13:21 ` Geert Uytterhoeven
2019-12-16 15:04 ` Guenter Roeck
2019-12-16 15:53 ` Guido Günther
2019-12-16 21:12 ` Nick Desaulniers
2019-12-17 6:38 ` Dominik Brodowski
2019-12-17 18:04 ` Nick Desaulniers
2019-12-12 17:11 ` [PATCH 0/3] " Linus Torvalds
2019-12-12 18:37 ` Al Viro
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