fs: add ksys_open() wrapper; remove in-kernel calls to sys_open()
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@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
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@ -1151,7 +1151,7 @@ COMPAT_SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, fla
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*/
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SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
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{
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return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
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return ksys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
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}
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#endif
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@ -1057,4 +1057,15 @@ static inline int ksys_close(unsigned int fd)
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return __close_fd(current->files, fd);
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}
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extern long do_sys_open(int dfd, const char __user *filename, int flags,
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umode_t mode);
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static inline long ksys_open(const char __user *filename, int flags,
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umode_t mode)
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{
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if (force_o_largefile())
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flags |= O_LARGEFILE;
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return do_sys_open(AT_FDCWD, filename, flags, mode);
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}
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#endif
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@ -489,13 +489,13 @@ void __init change_floppy(char *fmt, ...)
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va_start(args, fmt);
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vsprintf(buf, fmt, args);
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va_end(args);
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fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
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fd = ksys_open("/dev/root", O_RDWR | O_NDELAY, 0);
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if (fd >= 0) {
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sys_ioctl(fd, FDEJECT, 0);
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ksys_close(fd);
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}
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printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
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fd = sys_open("/dev/console", O_RDWR, 0);
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fd = ksys_open("/dev/console", O_RDWR, 0);
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if (fd >= 0) {
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sys_ioctl(fd, TCGETS, (long)&termios);
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termios.c_lflag &= ~ICANON;
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@ -38,7 +38,7 @@ static int init_linuxrc(struct subprocess_info *info, struct cred *new)
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{
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sys_unshare(CLONE_FS | CLONE_FILES);
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/* stdin/stdout/stderr for /linuxrc */
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sys_open("/dev/console", O_RDWR, 0);
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ksys_open("/dev/console", O_RDWR, 0);
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ksys_dup(0);
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ksys_dup(0);
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/* move initrd over / and chdir/chroot in initrd root */
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@ -99,7 +99,7 @@ static void __init handle_initrd(void)
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if (!error)
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printk("okay\n");
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else {
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int fd = sys_open("/dev/root.old", O_RDWR, 0);
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int fd = ksys_open("/dev/root.old", O_RDWR, 0);
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if (error == -ENOENT)
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printk("/initrd does not exist. Ignored.\n");
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else
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@ -181,7 +181,7 @@ static void __init md_setup_drive(void)
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partitioned ? "_d" : "", minor,
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md_setup_args[ent].device_names);
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fd = sys_open(name, 0, 0);
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fd = ksys_open(name, 0, 0);
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if (fd < 0) {
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printk(KERN_ERR "md: open failed - cannot start "
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"array %s\n", name);
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@ -244,7 +244,7 @@ static void __init md_setup_drive(void)
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* array without it
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*/
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ksys_close(fd);
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fd = sys_open(name, 0, 0);
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fd = ksys_open(name, 0, 0);
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sys_ioctl(fd, BLKRRPART, 0);
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}
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ksys_close(fd);
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@ -294,7 +294,7 @@ static void __init autodetect_raid(void)
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wait_for_device_probe();
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fd = sys_open("/dev/md0", 0, 0);
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fd = ksys_open("/dev/md0", 0, 0);
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if (fd >= 0) {
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sys_ioctl(fd, RAID_AUTORUN, raid_autopart);
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ksys_close(fd);
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@ -196,11 +196,11 @@ int __init rd_load_image(char *from)
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char rotator[4] = { '|' , '/' , '-' , '\\' };
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#endif
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out_fd = sys_open("/dev/ram", O_RDWR, 0);
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out_fd = ksys_open("/dev/ram", O_RDWR, 0);
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if (out_fd < 0)
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goto out;
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in_fd = sys_open(from, O_RDONLY, 0);
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in_fd = ksys_open(from, O_RDONLY, 0);
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if (in_fd < 0)
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goto noclose_input;
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@ -262,7 +262,7 @@ int __init rd_load_image(char *from)
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goto noclose_input;
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}
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change_floppy("disk #%d", disk);
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in_fd = sys_open(from, O_RDONLY, 0);
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in_fd = ksys_open(from, O_RDONLY, 0);
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if (in_fd < 0) {
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printk("Error opening disk.\n");
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goto noclose_input;
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@ -340,7 +340,7 @@ static int __init do_name(void)
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int openflags = O_WRONLY|O_CREAT;
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if (ml != 1)
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openflags |= O_TRUNC;
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wfd = sys_open(collected, openflags, mode);
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wfd = ksys_open(collected, openflags, mode);
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if (wfd >= 0) {
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ksys_fchown(wfd, uid, gid);
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@ -567,7 +567,7 @@ static void __init clean_rootfs(void)
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struct linux_dirent64 *dirp;
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int num;
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fd = sys_open("/", O_RDONLY, 0);
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fd = ksys_open("/", O_RDONLY, 0);
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WARN_ON(fd < 0);
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if (fd < 0)
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return;
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@ -629,7 +629,7 @@ static int __init populate_rootfs(void)
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}
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printk(KERN_INFO "rootfs image is not initramfs (%s)"
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"; looks like an initrd\n", err);
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fd = sys_open("/initrd.image",
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fd = ksys_open("/initrd.image",
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O_WRONLY|O_CREAT, 0700);
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if (fd >= 0) {
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ssize_t written = xwrite(fd, (char *)initrd_start,
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@ -1074,7 +1074,7 @@ static noinline void __init kernel_init_freeable(void)
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do_basic_setup();
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/* Open the /dev/console on the rootfs, this should never fail */
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if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
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if (ksys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
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pr_err("Warning: unable to open an initial console.\n");
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(void) ksys_dup(0);
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