compat: fs: Generic compat_sys_sendfile implementation

This function is used by sparc, powerpc and arm64 for compat support.
The patch adds a generic implementation which calls do_sendfile()
directly and avoids set_fs().

The sparc architecture has wrappers for the sign extensions while
powerpc relies on the compiler to do the this. The patch adds wrappers
for powerpc to handle the u32->int type conversion.

compat_sys_sendfile64() can be replaced by a sys_sendfile() call since
compat_loff_t has the same size as off_t on a 64-bit system.

On powerpc, the patch also changes the 64-bit sendfile call from
sys_sendile64 to sys_sendfile.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/compat.h b/include/linux/compat.h
index 09b28b7369d7..fd4e29956d1c 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -590,6 +590,9 @@ asmlinkage ssize_t compat_sys_process_vm_writev(compat_pid_t pid,
                 unsigned long liovcnt, const struct compat_iovec __user *rvec,
                 unsigned long riovcnt, unsigned long flags);
 
+asmlinkage long compat_sys_sendfile(int out_fd, int in_fd,
+                                    compat_off_t __user *offset, compat_size_t count);
+
 #else
 
 #define is_compat_task() (0)