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>

3 files changed, 2 insertions, 47 deletions

diff --git a/arch/sparc/include/asm/unistd.h b/arch/sparc/include/asm/unistd.h
index fb2693464807..d9a677c51926 100644
--- a/arch/sparc/include/asm/unistd.h
+++ b/arch/sparc/include/asm/unistd.h
@@ -447,6 +447,7 @@
 #else
 #define __ARCH_WANT_COMPAT_SYS_TIME
 #define __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND
+#define __ARCH_WANT_COMPAT_SYS_SENDFILE
 #endif
 
 /*
diff --git a/arch/sparc/kernel/sys32.S b/arch/sparc/kernel/sys32.S
index d97f3eb72e06..44025f4ba41f 100644
--- a/arch/sparc/kernel/sys32.S
+++ b/arch/sparc/kernel/sys32.S
@@ -90,7 +90,7 @@ SIGN1(sys32_mkdir, sys_mkdir, %o1)
 SIGN3(sys32_futex, compat_sys_futex, %o1, %o2, %o5)
 SIGN1(sys32_sysfs, compat_sys_sysfs, %o0)
 SIGN2(sys32_sendfile, compat_sys_sendfile, %o0, %o1)
-SIGN2(sys32_sendfile64, compat_sys_sendfile64, %o0, %o1)
+SIGN2(sys32_sendfile64, sys_sendfile, %o0, %o1)
 SIGN1(sys32_prctl, sys_prctl, %o0)
 SIGN1(sys32_sched_rr_get_interval, compat_sys_sched_rr_get_interval, %o0)
 SIGN2(sys32_waitpid, sys_waitpid, %o0, %o2)
diff --git a/arch/sparc/kernel/sys_sparc32.c b/arch/sparc/kernel/sys_sparc32.c
index f7392336961f..d862499eb01c 100644
--- a/arch/sparc/kernel/sys_sparc32.c
+++ b/arch/sparc/kernel/sys_sparc32.c
@@ -506,52 +506,6 @@ long compat_sys_fadvise64_64(int fd,
 				advice);
 }
 
-asmlinkage long compat_sys_sendfile(int out_fd, int in_fd,
-				    compat_off_t __user *offset,
-				    compat_size_t count)
-{
-	mm_segment_t old_fs = get_fs();
-	int ret;
-	off_t of;
-	
-	if (offset && get_user(of, offset))
-		return -EFAULT;
-		
-	set_fs(KERNEL_DS);
-	ret = sys_sendfile(out_fd, in_fd,
-			   offset ? (off_t __user *) &of : NULL,
-			   count);
-	set_fs(old_fs);
-	
-	if (offset && put_user(of, offset))
-		return -EFAULT;
-		
-	return ret;
-}
-
-asmlinkage long compat_sys_sendfile64(int out_fd, int in_fd,
-				      compat_loff_t __user *offset,
-				      compat_size_t count)
-{
-	mm_segment_t old_fs = get_fs();
-	int ret;
-	loff_t lof;
-	
-	if (offset && get_user(lof, offset))
-		return -EFAULT;
-		
-	set_fs(KERNEL_DS);
-	ret = sys_sendfile64(out_fd, in_fd,
-			     offset ? (loff_t __user *) &lof : NULL,
-			     count);
-	set_fs(old_fs);
-	
-	if (offset && put_user(lof, offset))
-		return -EFAULT;
-		
-	return ret;
-}
-
 /* This is just a version for 32-bit applications which does
  * not force O_LARGEFILE on.
  */