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fs: add ksys_ioctl() helper; remove in-kernel calls to sys_ioctl() 

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@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
This commit is contained in:
Dominik Brodowski 2018-03-13 21:43:59 +01:00
parent 454dab3f96
commit cbb60b924b
6 changed files with 22 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
fs/ioctl.c
View File

@ -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);
}

1
include/linux/syscalls.h
View File

@ -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

8
init/do_mounts.c
View File

@ -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);
}
}

2
init/do_mounts_initrd.c
View File

@ -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");

15
init/do_mounts_md.c
View File

@ -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);
}
}

4
init/do_mounts_rd.c
View File

@ -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;