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authorDominik Brodowski <linux@dominikbrodowski.net>2018-03-11 11:34:53 +0100
committerDominik Brodowski <linux@dominikbrodowski.net>2018-04-02 20:15:57 +0200
commit46ea89eb652a365e10257016d09dcf1aaf23cf63 (patch)
tree4bee67aac3e8b19f76aa076ed863f6336013c945 /fs
parent87c4e19262d81862886207be3c8795f6576d5a52 (diff)
fs: add do_linkat() helper and ksys_link() wrapper; remove in-kernel calls to syscall
Using the fs-internal do_linkat() helper allows us to get rid of fs-internal calls to the sys_linkat() syscall. Introducing the ksys_link() wrapper allows us to avoid the in-kernel calls to sys_link() 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_link(). In the near future, the only fs-external user of ksys_link() should be converted to use vfs_link() 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: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Diffstat (limited to 'fs')
-rw-r--r--fs/internal.h2
-rw-r--r--fs/namei.c12
2 files changed, 11 insertions, 3 deletions
diff --git a/fs/internal.h b/fs/internal.h
index 4f0b67054c54..91e6fc93fcb5 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -62,6 +62,8 @@ long do_rmdir(int dfd, const char __user *pathname);
long do_unlinkat(int dfd, struct filename *name);
long do_symlinkat(const char __user *oldname, int newdfd,
const char __user *newname);
+int do_linkat(int olddfd, const char __user *oldname, int newdfd,
+ const char __user *newname, int flags);
/*
* namespace.c
diff --git a/fs/namei.c b/fs/namei.c
index 8459a18cdd18..10148235829f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4250,8 +4250,8 @@ EXPORT_SYMBOL(vfs_link);
* with linux 2.0, and to avoid hard-linking to directories
* and other special files. --ADM
*/
-SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
- int, newdfd, const char __user *, newname, int, flags)
+int do_linkat(int olddfd, const char __user *oldname, int newdfd,
+ const char __user *newname, int flags)
{
struct dentry *new_dentry;
struct path old_path, new_path;
@@ -4315,9 +4315,15 @@ out:
return error;
}
+SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
+ int, newdfd, const char __user *, newname, int, flags)
+{
+ return do_linkat(olddfd, oldname, newdfd, newname, flags);
+}
+
SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname)
{
- return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
+ return do_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
}
/**