fs: add ksys_write() helper; remove in-kernel calls to sys_write()
Using this helper allows us to avoid the in-kernel calls to the sys_write() 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_write(). In the near future, the do_mounts / initramfs callers of ksys_write() should be converted to use filp_open() and vfs_write() instead. 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> Cc: linux-s390@vger.kernel.org Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
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@ -468,7 +468,7 @@ COMPAT_SYSCALL_DEFINE3(s390_write, unsigned int, fd, const char __user *, buf, c
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if ((compat_ssize_t) count < 0)
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return -EINVAL;
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return sys_write(fd, buf, count);
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return ksys_write(fd, buf, count);
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}
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/*
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@ -578,8 +578,7 @@ 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(write, unsigned int, fd, const char __user *, buf,
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size_t, count)
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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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ssize_t ret = -EBADF;
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@ -595,6 +594,12 @@ SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
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return ret;
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}
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SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
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size_t, count)
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{
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return ksys_write(fd, buf, count);
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}
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SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,
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size_t, count, loff_t, pos)
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{
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@ -951,5 +951,6 @@ int ksys_mount(char __user *dev_name, char __user *dir_name, char __user *type,
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int ksys_umount(char __user *name, int flags);
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int ksys_dup(unsigned int fildes);
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int ksys_chroot(const char __user *filename);
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ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
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#endif
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@ -270,7 +270,7 @@ int __init rd_load_image(char *from)
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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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sys_write(out_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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pr_cont("%c\b", rotator[rotate & 0x3]);
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@ -317,7 +317,7 @@ static long __init compr_fill(void *buf, unsigned long len)
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static long __init compr_flush(void *window, unsigned long outcnt)
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{
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long written = sys_write(crd_outfd, window, outcnt);
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long written = ksys_write(crd_outfd, window, outcnt);
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if (written != outcnt) {
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if (decompress_error == 0)
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printk(KERN_ERR
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@ -27,7 +27,7 @@ static ssize_t __init xwrite(int fd, const char *p, size_t count)
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/* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
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while (count) {
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ssize_t rv = sys_write(fd, p, count);
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ssize_t rv = ksys_write(fd, p, count);
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if (rv < 0) {
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if (rv == -EINTR || rv == -EAGAIN)
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