[PATCH 086/109] fs: add ksys_ioctl() helper; remove in-kernel calls to sys_ioctl()
From: Dominik Brodowski
Date: Thu Mar 29 2018 - 07:55:42 EST
Using this helper allows us to avoid the in-kernel calls to the
sys_ioctl() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it
uses the same calling convention as sys_ioctl().
After careful review, at least some of these calls could be converted
to do_vfs_ioctl() in future.
This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@xxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
---
fs/ioctl.c | 7 ++++++-
include/linux/syscalls.h | 1 +
init/do_mounts.c | 8 ++++----
init/do_mounts_initrd.c | 2 +-
init/do_mounts_md.c | 15 ++++++++-------
init/do_mounts_rd.c | 4 ++--
6 files changed, 22 insertions(+), 15 deletions(-)
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 5ace7efb0d04..4823431d1c9d 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -689,7 +689,7 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
return error;
}
-SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
+int ksys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
{
int error;
struct fd f = fdget(fd);
@@ -702,3 +702,8 @@ SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
fdput(f);
return error;
}
+
+SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
+{
+ return ksys_ioctl(fd, cmd, arg);
+}
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index c056aff6d7ad..5a959efd8fb7 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -957,6 +957,7 @@ int ksys_fchmod(unsigned int fd, umode_t mode);
int ksys_fchown(unsigned int fd, uid_t user, gid_t group);
int ksys_getdents64(unsigned int fd, struct linux_dirent64 __user *dirent,
unsigned int count);
+int ksys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg);
/*
* The following kernel syscall equivalents are just wrappers to fs-internal
diff --git a/init/do_mounts.c b/init/do_mounts.c
index cc1103477071..b17e0095eb4e 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -491,18 +491,18 @@ void __init change_floppy(char *fmt, ...)
va_end(args);
fd = ksys_open("/dev/root", O_RDWR | O_NDELAY, 0);
if (fd >= 0) {
- sys_ioctl(fd, FDEJECT, 0);
+ ksys_ioctl(fd, FDEJECT, 0);
ksys_close(fd);
}
printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
fd = ksys_open("/dev/console", O_RDWR, 0);
if (fd >= 0) {
- sys_ioctl(fd, TCGETS, (long)&termios);
+ ksys_ioctl(fd, TCGETS, (long)&termios);
termios.c_lflag &= ~ICANON;
- sys_ioctl(fd, TCSETSF, (long)&termios);
+ ksys_ioctl(fd, TCSETSF, (long)&termios);
sys_read(fd, &c, 1);
termios.c_lflag |= ICANON;
- sys_ioctl(fd, TCSETSF, (long)&termios);
+ ksys_ioctl(fd, TCSETSF, (long)&termios);
ksys_close(fd);
}
}
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index cedca8fd2590..03ec0c1b7553 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -110,7 +110,7 @@ static void __init handle_initrd(void)
if (fd < 0) {
error = fd;
} else {
- error = sys_ioctl(fd, BLKFLSBUF, 0);
+ error = ksys_ioctl(fd, BLKFLSBUF, 0);
ksys_close(fd);
}
printk(!error ? "okay\n" : "failed\n");
diff --git a/init/do_mounts_md.c b/init/do_mounts_md.c
index 76dcfaada3ed..7d85d172bc7e 100644
--- a/init/do_mounts_md.c
+++ b/init/do_mounts_md.c
@@ -187,7 +187,7 @@ static void __init md_setup_drive(void)
"array %s\n", name);
continue;
}
- if (sys_ioctl(fd, SET_ARRAY_INFO, 0) == -EBUSY) {
+ if (ksys_ioctl(fd, SET_ARRAY_INFO, 0) == -EBUSY) {
printk(KERN_WARNING
"md: Ignoring md=%d, already autodetected. (Use raid=noautodetect)\n",
minor);
@@ -210,7 +210,7 @@ static void __init md_setup_drive(void)
ainfo.state = (1 << MD_SB_CLEAN);
ainfo.layout = 0;
ainfo.chunk_size = md_setup_args[ent].chunk;
- err = sys_ioctl(fd, SET_ARRAY_INFO, (long)&ainfo);
+ err = ksys_ioctl(fd, SET_ARRAY_INFO, (long)&ainfo);
for (i = 0; !err && i <= MD_SB_DISKS; i++) {
dev = devices[i];
if (!dev)
@@ -220,7 +220,8 @@ static void __init md_setup_drive(void)
dinfo.state = (1<<MD_DISK_ACTIVE)|(1<<MD_DISK_SYNC);
dinfo.major = MAJOR(dev);
dinfo.minor = MINOR(dev);
- err = sys_ioctl(fd, ADD_NEW_DISK, (long)&dinfo);
+ err = ksys_ioctl(fd, ADD_NEW_DISK,
+ (long)&dinfo);
}
} else {
/* persistent */
@@ -230,11 +231,11 @@ static void __init md_setup_drive(void)
break;
dinfo.major = MAJOR(dev);
dinfo.minor = MINOR(dev);
- sys_ioctl(fd, ADD_NEW_DISK, (long)&dinfo);
+ ksys_ioctl(fd, ADD_NEW_DISK, (long)&dinfo);
}
}
if (!err)
- err = sys_ioctl(fd, RUN_ARRAY, 0);
+ err = ksys_ioctl(fd, RUN_ARRAY, 0);
if (err)
printk(KERN_WARNING "md: starting md%d failed\n", minor);
else {
@@ -245,7 +246,7 @@ static void __init md_setup_drive(void)
*/
ksys_close(fd);
fd = ksys_open(name, 0, 0);
- sys_ioctl(fd, BLKRRPART, 0);
+ ksys_ioctl(fd, BLKRRPART, 0);
}
ksys_close(fd);
}
@@ -296,7 +297,7 @@ static void __init autodetect_raid(void)
fd = ksys_open("/dev/md0", 0, 0);
if (fd >= 0) {
- sys_ioctl(fd, RAID_AUTORUN, raid_autopart);
+ ksys_ioctl(fd, RAID_AUTORUN, raid_autopart);
ksys_close(fd);
}
}
diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index a6706314baa7..4dafaed5736f 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -218,7 +218,7 @@ int __init rd_load_image(char *from)
* NOTE NOTE: nblocks is not actually blocks but
* the number of kibibytes of data to load into a ramdisk.
*/
- if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
+ if (ksys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
rd_blocks = 0;
else
rd_blocks >>= 1;
@@ -232,7 +232,7 @@ int __init rd_load_image(char *from)
/*
* OK, time to copy in the data
*/
- if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
+ if (ksys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
devblocks = 0;
else
devblocks >>= 1;
--
2.16.3