mm: add ksys_fadvise64_64() helper; remove in-kernel call to sys_fadvise64_64()

Using the ksys_fadvise64_64() helper allows us to avoid the in-kernel
calls to the sys_fadvise64_64() 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 ksys_fadvise64_64().

Some compat stubs called sys_fadvise64(), which then just passed through
the arguments to sys_fadvise64_64(). Get rid of this indirection, and call
ksys_fadvise64_64() directly.

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: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/xtensa/kernel/syscall.c b/arch/xtensa/kernel/syscall.c
index 74afbf0..8201748 100644
--- a/arch/xtensa/kernel/syscall.c
+++ b/arch/xtensa/kernel/syscall.c
@@ -55,7 +55,7 @@ asmlinkage long xtensa_shmat(int shmid, char __user *shmaddr, int shmflg)
 asmlinkage long xtensa_fadvise64_64(int fd, int advice,
 		unsigned long long offset, unsigned long long len)
 {
-	return sys_fadvise64_64(fd, offset, len, advice);
+	return ksys_fadvise64_64(fd, offset, len, advice);
 }
 
 #ifdef CONFIG_MMU