fs: add ksys_read() helper; remove in-kernel calls to sys_read()
Using this helper allows us to avoid the in-kernel calls to the sys_read() 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_read(). 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>
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@ -460,7 +460,7 @@ COMPAT_SYSCALL_DEFINE3(s390_read, unsigned int, fd, char __user *, buf, compat_s
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if ((compat_ssize_t) count < 0)
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return -EINVAL;
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return sys_read(fd, buf, count);
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return ksys_read(fd, buf, count);
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}
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COMPAT_SYSCALL_DEFINE3(s390_write, unsigned int, fd, const char __user *, buf, compat_size_t, count)
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@ -568,7 +568,7 @@ static inline void file_pos_write(struct file *file, loff_t pos)
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file->f_pos = pos;
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}
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SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
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ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count)
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{
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struct fd f = fdget_pos(fd);
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ssize_t ret = -EBADF;
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@ -583,6 +583,11 @@ SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
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return ret;
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}
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SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
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{
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return ksys_read(fd, buf, count);
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}
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ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count)
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{
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struct fd f = fdget_pos(fd);
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@ -959,6 +959,7 @@ int ksys_getdents64(unsigned int fd, struct linux_dirent64 __user *dirent,
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unsigned int count);
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int ksys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg);
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off_t ksys_lseek(unsigned int fd, off_t offset, unsigned int whence);
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ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count);
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/*
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* The following kernel syscall equivalents are just wrappers to fs-internal
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@ -500,7 +500,7 @@ void __init change_floppy(char *fmt, ...)
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ksys_ioctl(fd, TCGETS, (long)&termios);
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termios.c_lflag &= ~ICANON;
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ksys_ioctl(fd, TCSETSF, (long)&termios);
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sys_read(fd, &c, 1);
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ksys_read(fd, &c, 1);
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termios.c_lflag |= ICANON;
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ksys_ioctl(fd, TCSETSF, (long)&termios);
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ksys_close(fd);
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@ -91,7 +91,7 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
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* Read block 0 to test for compressed kernel
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*/
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ksys_lseek(fd, start_block * BLOCK_SIZE, 0);
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sys_read(fd, buf, size);
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ksys_read(fd, buf, size);
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*decompressor = decompress_method(buf, size, &compress_name);
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if (compress_name) {
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@ -137,7 +137,7 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
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* Read 512 bytes further to check if cramfs is padded
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*/
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ksys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
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sys_read(fd, buf, size);
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ksys_read(fd, buf, size);
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if (cramfsb->magic == CRAMFS_MAGIC) {
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printk(KERN_NOTICE
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@ -151,7 +151,7 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
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* Read block 1 to test for minix and ext2 superblock
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*/
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ksys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
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sys_read(fd, buf, size);
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ksys_read(fd, buf, size);
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/* Try minix */
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if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
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@ -269,7 +269,7 @@ int __init rd_load_image(char *from)
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}
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printk("Loading disk #%d... ", disk);
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}
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sys_read(in_fd, buf, BLOCK_SIZE);
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ksys_read(in_fd, buf, BLOCK_SIZE);
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ksys_write(out_fd, buf, BLOCK_SIZE);
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#if !defined(CONFIG_S390)
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if (!(i % 16)) {
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@ -307,7 +307,7 @@ static int crd_infd, crd_outfd;
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static long __init compr_fill(void *buf, unsigned long len)
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{
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long r = sys_read(crd_infd, buf, len);
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long r = ksys_read(crd_infd, buf, len);
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if (r < 0)
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printk(KERN_ERR "RAMDISK: error while reading compressed data");
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else if (r == 0)
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