Using this wrapper allows us to avoid the in-kernel calls to the sys_open() 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_open(). 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: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx> --- fs/open.c | 2 +- include/linux/syscalls.h | 11 +++++++++++ init/do_mounts.c | 4 ++-- init/do_mounts_initrd.c | 4 ++-- init/do_mounts_md.c | 6 +++--- init/do_mounts_rd.c | 6 +++--- init/initramfs.c | 6 +++--- init/main.c | 2 +- 8 files changed, 26 insertions(+), 15 deletions(-) diff --git a/fs/open.c b/fs/open.c index 710102fc262b..8a42a2961130 100644 --- a/fs/open.c +++ b/fs/open.c @@ -1151,7 +1151,7 @@ COMPAT_SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, fla */ SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode) { - return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode); + return ksys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode); } #endif diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 38805f3447ea..f9df17dcec1c 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -1057,4 +1057,15 @@ static inline int ksys_close(unsigned int fd) return __close_fd(current->files, fd); } +extern long do_sys_open(int dfd, const char __user *filename, int flags, + umode_t mode); + +static inline long ksys_open(const char __user *filename, int flags, + umode_t mode) +{ + if (force_o_largefile()) + flags |= O_LARGEFILE; + return do_sys_open(AT_FDCWD, filename, flags, mode); +} + #endif diff --git a/init/do_mounts.c b/init/do_mounts.c index a28dd42d1f84..cc1103477071 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -489,13 +489,13 @@ void __init change_floppy(char *fmt, ...) va_start(args, fmt); vsprintf(buf, fmt, args); va_end(args); - fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0); + fd = ksys_open("/dev/root", O_RDWR | O_NDELAY, 0); if (fd >= 0) { sys_ioctl(fd, FDEJECT, 0); ksys_close(fd); } printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf); - fd = sys_open("/dev/console", O_RDWR, 0); + fd = ksys_open("/dev/console", O_RDWR, 0); if (fd >= 0) { sys_ioctl(fd, TCGETS, (long)&termios); termios.c_lflag &= ~ICANON; diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c index 6907c6dbc443..cedca8fd2590 100644 --- a/init/do_mounts_initrd.c +++ b/init/do_mounts_initrd.c @@ -38,7 +38,7 @@ static int init_linuxrc(struct subprocess_info *info, struct cred *new) { sys_unshare(CLONE_FS | CLONE_FILES); /* stdin/stdout/stderr for /linuxrc */ - sys_open("/dev/console", O_RDWR, 0); + ksys_open("/dev/console", O_RDWR, 0); ksys_dup(0); ksys_dup(0); /* move initrd over / and chdir/chroot in initrd root */ @@ -99,7 +99,7 @@ static void __init handle_initrd(void) if (!error) printk("okay\n"); else { - int fd = sys_open("/dev/root.old", O_RDWR, 0); + int fd = ksys_open("/dev/root.old", O_RDWR, 0); if (error == -ENOENT) printk("/initrd does not exist. Ignored.\n"); else diff --git a/init/do_mounts_md.c b/init/do_mounts_md.c index ebd4013d589e..76dcfaada3ed 100644 --- a/init/do_mounts_md.c +++ b/init/do_mounts_md.c @@ -181,7 +181,7 @@ static void __init md_setup_drive(void) partitioned ? "_d" : "", minor, md_setup_args[ent].device_names); - fd = sys_open(name, 0, 0); + fd = ksys_open(name, 0, 0); if (fd < 0) { printk(KERN_ERR "md: open failed - cannot start " "array %s\n", name); @@ -244,7 +244,7 @@ static void __init md_setup_drive(void) * array without it */ ksys_close(fd); - fd = sys_open(name, 0, 0); + fd = ksys_open(name, 0, 0); sys_ioctl(fd, BLKRRPART, 0); } ksys_close(fd); @@ -294,7 +294,7 @@ static void __init autodetect_raid(void) wait_for_device_probe(); - fd = sys_open("/dev/md0", 0, 0); + fd = ksys_open("/dev/md0", 0, 0); if (fd >= 0) { sys_ioctl(fd, RAID_AUTORUN, raid_autopart); ksys_close(fd); diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c index f1aa341862d3..a6706314baa7 100644 --- a/init/do_mounts_rd.c +++ b/init/do_mounts_rd.c @@ -196,11 +196,11 @@ int __init rd_load_image(char *from) char rotator[4] = { '|' , '/' , '-' , '\\' }; #endif - out_fd = sys_open("/dev/ram", O_RDWR, 0); + out_fd = ksys_open("/dev/ram", O_RDWR, 0); if (out_fd < 0) goto out; - in_fd = sys_open(from, O_RDONLY, 0); + in_fd = ksys_open(from, O_RDONLY, 0); if (in_fd < 0) goto noclose_input; @@ -262,7 +262,7 @@ int __init rd_load_image(char *from) goto noclose_input; } change_floppy("disk #%d", disk); - in_fd = sys_open(from, O_RDONLY, 0); + in_fd = ksys_open(from, O_RDONLY, 0); if (in_fd < 0) { printk("Error opening disk.\n"); goto noclose_input; diff --git a/init/initramfs.c b/init/initramfs.c index ce2bcad97cdf..5f2ff1d2370e 100644 --- a/init/initramfs.c +++ b/init/initramfs.c @@ -340,7 +340,7 @@ static int __init do_name(void) int openflags = O_WRONLY|O_CREAT; if (ml != 1) openflags |= O_TRUNC; - wfd = sys_open(collected, openflags, mode); + wfd = ksys_open(collected, openflags, mode); if (wfd >= 0) { ksys_fchown(wfd, uid, gid); @@ -567,7 +567,7 @@ static void __init clean_rootfs(void) struct linux_dirent64 *dirp; int num; - fd = sys_open("/", O_RDONLY, 0); + fd = ksys_open("/", O_RDONLY, 0); WARN_ON(fd < 0); if (fd < 0) return; @@ -629,7 +629,7 @@ static int __init populate_rootfs(void) } printk(KERN_INFO "rootfs image is not initramfs (%s)" "; looks like an initrd\n", err); - fd = sys_open("/initrd.image", + fd = ksys_open("/initrd.image", O_WRONLY|O_CREAT, 0700); if (fd >= 0) { ssize_t written = xwrite(fd, (char *)initrd_start, diff --git a/init/main.c b/init/main.c index d0ded4322c6b..e77951ae2c19 100644 --- a/init/main.c +++ b/init/main.c @@ -1074,7 +1074,7 @@ static noinline void __init kernel_init_freeable(void) do_basic_setup(); /* Open the /dev/console on the rootfs, this should never fail */ - if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0) + if (ksys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0) pr_err("Warning: unable to open an initial console.\n"); (void) ksys_dup(0); -- 2.16.3
