tools: Fixed MIPS builds due to struct flock re-definition

Building perf for MIPS failed after 9f79b8b7 ("uapi: simplify
__ARCH_FLOCK{,64}_PAD a little") with the following error:

  CC
/home/fainelli/work/buildroot/output/bmips/build/linux-custom/tools/perf/trace/beauty/fcntl.o
In file included from
../../../../host/mipsel-buildroot-linux-gnu/sysroot/usr/include/asm/fcntl.h:77,
                 from ../include/uapi/linux/fcntl.h:5,
                 from trace/beauty/fcntl.c:10:
../include/uapi/asm-generic/fcntl.h:188:8: error: redefinition of
'struct flock'
 struct flock {
        ^~~~~
In file included from ../include/uapi/linux/fcntl.h:5,
                 from trace/beauty/fcntl.c:10:
../../../../host/mipsel-buildroot-linux-gnu/sysroot/usr/include/asm/fcntl.h:63:8:
note: originally defined here
 struct flock {
        ^~~~~

This is due to the local copy under
tools/include/uapi/asm-generic/fcntl.h including the toolchain's kernel
headers which already define 'struct flock' and define
HAVE_ARCH_STRUCT_FLOCK to future inclusions make a decision as to
whether re-defining 'struct flock' is appropriate or not.

Make sure what do not re-define 'struct flock'
when HAVE_ARCH_STRUCT_FLOCK is already defined.

Fixes: 9f79b8b7 ("uapi: simplify __ARCH_FLOCK{,64}_PAD a little")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
[arnd: sync with include/uapi/asm-generic/fcntl.h as well]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

include/uapi/asm-generic/fcntl.h

@@ -192,6 +192,7 @@ struct f_owner_ex {
 
 #define F_LINUX_SPECIFIC_BASE	1024
 
+#ifndef HAVE_ARCH_STRUCT_FLOCK
 struct flock {
 	short	l_type;
 	short	l_whence;
@@ -216,5 +217,6 @@ struct flock64 {
 	__ARCH_FLOCK64_PAD
 #endif
 };
+#endif /* HAVE_ARCH_STRUCT_FLOCK */
 
 #endif /* _ASM_GENERIC_FCNTL_H */

tools/include/uapi/asm-generic/fcntl.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 #ifndef _ASM_GENERIC_FCNTL_H
 #define _ASM_GENERIC_FCNTL_H
 
@@ -90,7 +91,7 @@
 
 /* a horrid kludge trying to make sure that this will fail on old kernels */
 #define O_TMPFILE (__O_TMPFILE | O_DIRECTORY)
-#define O_TMPFILE_MASK (__O_TMPFILE | O_DIRECTORY | O_CREAT)
+#define O_TMPFILE_MASK (__O_TMPFILE | O_DIRECTORY | O_CREAT)      
 
 #ifndef O_NDELAY
 #define O_NDELAY	O_NONBLOCK
@@ -115,11 +116,13 @@
 #define F_GETSIG	11	/* for sockets. */
 #endif
 
+#if __BITS_PER_LONG == 32 || defined(__KERNEL__)
 #ifndef F_GETLK64
 #define F_GETLK64	12	/*  using 'struct flock64' */
 #define F_SETLK64	13
 #define F_SETLKW64	14
 #endif
+#endif /* __BITS_PER_LONG == 32 || defined(__KERNEL__) */
 
 #ifndef F_SETOWN_EX
 #define F_SETOWN_EX	15
@@ -178,6 +181,10 @@ struct f_owner_ex {
 				   blocking */
 #define LOCK_UN		8	/* remove lock */
 
+/*
+ * LOCK_MAND support has been removed from the kernel. We leave the symbols
+ * here to not break legacy builds, but these should not be used in new code.
+ */
 #define LOCK_MAND	32	/* This is a mandatory flock ... */
 #define LOCK_READ	64	/* which allows concurrent read operations */
 #define LOCK_WRITE	128	/* which allows concurrent write operations */
@@ -185,6 +192,7 @@ struct f_owner_ex {
 
 #define F_LINUX_SPECIFIC_BASE	1024
 
+#ifndef HAVE_ARCH_STRUCT_FLOCK
 struct flock {
 	short	l_type;
 	short	l_whence;
@@ -209,5 +217,6 @@ struct flock64 {
 	__ARCH_FLOCK64_PAD
 #endif
 };
+#endif /* HAVE_ARCH_STRUCT_FLOCK */
 
 #endif /* _ASM_GENERIC_FCNTL_H */