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>
diff --git a/arch/powerpc/kernel/sys_ppc32.c b/arch/powerpc/kernel/sys_ppc32.c
index 81c5706..abd1112 100644
--- a/arch/powerpc/kernel/sys_ppc32.c
+++ b/arch/powerpc/kernel/sys_ppc32.c
@@ -143,48 +143,17 @@
* proper conversion (sign extension) between the register representation of a signed int (msr in 32-bit mode)
* and the register representation of a signed int (msr in 64-bit mode) is performed.
*/
-asmlinkage long compat_sys_sendfile(u32 out_fd, u32 in_fd, compat_off_t __user * offset, u32 count)
+asmlinkage long compat_sys_sendfile_wrapper(u32 out_fd, u32 in_fd,
+ compat_off_t __user *offset, u32 count)
{
- mm_segment_t old_fs = get_fs();
- int ret;
- off_t of;
- off_t __user *up;
-
- if (offset && get_user(of, offset))
- return -EFAULT;
-
- /* The __user pointer cast is valid because of the set_fs() */
- set_fs(KERNEL_DS);
- up = offset ? (off_t __user *) &of : NULL;
- ret = sys_sendfile((int)out_fd, (int)in_fd, up, count);
- set_fs(old_fs);
-
- if (offset && put_user(of, offset))
- return -EFAULT;
-
- return ret;
+ return compat_sys_sendfile((int)out_fd, (int)in_fd, offset, count);
}
-asmlinkage int compat_sys_sendfile64(int out_fd, int in_fd, compat_loff_t __user *offset, s32 count)
+asmlinkage long compat_sys_sendfile64_wrapper(u32 out_fd, u32 in_fd,
+ compat_loff_t __user *offset, u32 count)
{
- mm_segment_t old_fs = get_fs();
- int ret;
- loff_t lof;
- loff_t __user *up;
-
- if (offset && get_user(lof, offset))
- return -EFAULT;
-
- /* The __user pointer cast is valid because of the set_fs() */
- set_fs(KERNEL_DS);
- up = offset ? (loff_t __user *) &lof : NULL;
- ret = sys_sendfile64(out_fd, in_fd, up, count);
- set_fs(old_fs);
-
- if (offset && put_user(lof, offset))
- return -EFAULT;
-
- return ret;
+ return sys_sendfile((int)out_fd, (int)in_fd,
+ (off_t __user *)offset, count);
}
long compat_sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,