Introduce fixed sys_sync_file_range2() syscall, implement on PowerPC and ARM

Not all the world is an i386.  Many architectures need 64-bit arguments to be
aligned in suitable pairs of registers, and the original
sys_sync_file_range(int, loff_t, loff_t, int) was therefore wasting an
argument register for padding after the first integer.  Since we don't
normally have more than 6 arguments for system calls, that left no room for
the final argument on some architectures.

Fix this by introducing sys_sync_file_range2(int, int, loff_t, loff_t) which
all fits nicely.  In fact, ARM already had that, but called it
sys_arm_sync_file_range.  Move it to fs/sync.c and rename it, then implement
the needed compatibility routine.  And stop the missing syscall check from
bitching about the absence of sys_sync_file_range() if we've implemented
sys_sync_file_range2() instead.

Tested on PPC32 and with 32-bit and 64-bit userspace on PPC64.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 3 insertions, 1 deletions

diff --git a/include/asm-powerpc/systbl.h b/include/asm-powerpc/systbl.h
index 700ca5928741..1cc3f9cb6f4e 100644
--- a/include/asm-powerpc/systbl.h
+++ b/include/asm-powerpc/systbl.h
@@ -311,3 +311,4 @@ COMPAT_SYS_SPU(utimensat)
 COMPAT_SYS_SPU(signalfd)
 COMPAT_SYS_SPU(timerfd)
 SYSCALL_SPU(eventfd)
+COMPAT_SYS_SPU(sync_file_range2)
diff --git a/include/asm-powerpc/unistd.h b/include/asm-powerpc/unistd.h
index e3c28dc31abf..f71c6061f1ec 100644
--- a/include/asm-powerpc/unistd.h
+++ b/include/asm-powerpc/unistd.h
@@ -330,10 +330,11 @@
 #define __NR_signalfd           305
 #define __NR_timerfd            306
 #define __NR_eventfd            307
+#define __NR_sync_file_range2   308
 
 #ifdef __KERNEL__
 
-#define __NR_syscalls           308
+#define __NR_syscalls           309
 
 #define __NR__exit __NR_exit
 #define NR_syscalls     __NR_syscalls