Re: [PATCH 1/2] mm: introduce MAP_FIXED_SAFE
From: Michal Hocko
Date: Wed Dec 06 2017 - 05:02:54 EST
On Wed 06-12-17 10:27:24, Michal Hocko wrote:
> On Wed 06-12-17 16:15:24, Michael Ellerman wrote:
[...]
> > So I think I proved above that all the arches that are using 0x80000 are
> > also using mman-common.h, and vice-versa.
> >
> > So you can put this in mman-common.h can't your?
>
> Yes it seems I can. I would have to double check. It is true that
> defining the new flag closer to MAP_FIXED makes some sense
OK, so some recap
those which include generic mman-common.h directly
arch/sparc/include/uapi/asm/mman.h:#include <asm-generic/mman-common.h>
arch/powerpc/include/uapi/asm/mman.h:#include <asm-generic/mman-common.h>
arch/tile/include/uapi/asm/mman.h:#include <asm-generic/mman-common.h>
then we have
arch/metag/include/asm/mman.h
which includes uapi/asm/mman.h and that is a generic one
arch/metag/include/uapi/asm/Kbuild:generic-y += mman.h
others include generic mman.h
arch/arm/include/uapi/asm/mman.h:#include <asm-generic/mman.h>
arch/frv/include/uapi/asm/mman.h:#include <asm-generic/mman.h>
arch/ia64/include/uapi/asm/mman.h:#include <asm-generic/mman.h>
arch/m32r/include/uapi/asm/mman.h:#include <asm-generic/mman.h>
arch/mn10300/include/uapi/asm/mman.h:#include <asm-generic/mman.h>
arch/score/include/uapi/asm/mman.h:#include <asm-generic/mman.h>
arch/x86/include/uapi/asm/mman.h:#include <asm-generic/mman.h>
which includes mman-common.h as well
and then we are left with
arch/alpha/include/uapi/asm/mman.h
arch/mips/include/uapi/asm/mman.h
arch/parisc/include/uapi/asm/mman.h
arch/xtensa/include/uapi/asm/mman.h
which do not include anything. So the patch can be indeed simplified.
I will fold the following into the patch. I hope nothing got left behind
but my defconfig compile test on all arches which i have a cross
compiler for succeeded.
---
commit 52a9272f419f428cb079d340f64113325516ef9b
Author: Michal Hocko <mhocko@xxxxxxxx>
Date: Wed Dec 6 10:46:16 2017 +0100
- define MAP_FIXED_SAFE in asm-generic/mman-common.h as per Michael
Ellerman because all architecture which use this header can share
the same value. This will leave us with only 4 arches which need
special handling.
diff --git a/arch/alpha/include/uapi/asm/mman.h b/arch/alpha/include/uapi/asm/mman.h
index ef3770262925..7287dbf1e11b 100644
--- a/arch/alpha/include/uapi/asm/mman.h
+++ b/arch/alpha/include/uapi/asm/mman.h
@@ -31,7 +31,6 @@
#define MAP_NONBLOCK 0x40000 /* do not block on IO */
#define MAP_STACK 0x80000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x100000 /* create a huge page mapping */
-
#define MAP_FIXED_SAFE 0x200000 /* MAP_FIXED which doesn't unmap underlying mapping */
#define MS_ASYNC 1 /* sync memory asynchronously */
diff --git a/arch/powerpc/include/uapi/asm/mman.h b/arch/powerpc/include/uapi/asm/mman.h
index 3ffd284e7160..e63bc37e33af 100644
--- a/arch/powerpc/include/uapi/asm/mman.h
+++ b/arch/powerpc/include/uapi/asm/mman.h
@@ -29,6 +29,5 @@
#define MAP_NONBLOCK 0x10000 /* do not block on IO */
#define MAP_STACK 0x20000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x40000 /* create a huge page mapping */
-#define MAP_FIXED_SAFE 0x800000 /* MAP_FIXED which doesn't unmap underlying mapping */
#endif /* _UAPI_ASM_POWERPC_MMAN_H */
diff --git a/arch/sparc/include/uapi/asm/mman.h b/arch/sparc/include/uapi/asm/mman.h
index 0c282c09fae8..d21bffd5d3dc 100644
--- a/arch/sparc/include/uapi/asm/mman.h
+++ b/arch/sparc/include/uapi/asm/mman.h
@@ -24,7 +24,5 @@
#define MAP_NONBLOCK 0x10000 /* do not block on IO */
#define MAP_STACK 0x20000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x40000 /* create a huge page mapping */
-#define MAP_FIXED_SAFE 0x80000 /* MAP_FIXED which doesn't unmap underlying mapping */
-
#endif /* _UAPI__SPARC_MMAN_H__ */
diff --git a/arch/tile/include/uapi/asm/mman.h b/arch/tile/include/uapi/asm/mman.h
index b212f5fd5345..9b7add95926b 100644
--- a/arch/tile/include/uapi/asm/mman.h
+++ b/arch/tile/include/uapi/asm/mman.h
@@ -30,7 +30,6 @@
#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
#define MAP_HUGETLB 0x4000 /* create a huge page mapping */
-#define MAP_FIXED_SAFE 0x8000 /* MAP_FIXED which doesn't unmap underlying mapping */
/*
diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h
index 6d319c46fd90..1eca2cb10d44 100644
--- a/include/uapi/asm-generic/mman-common.h
+++ b/include/uapi/asm-generic/mman-common.h
@@ -25,6 +25,7 @@
#else
# define MAP_UNINITIALIZED 0x0 /* Don't support this flag */
#endif
+#define MAP_FIXED_SAFE 0x80000 /* MAP_FIXED which doesn't unmap underlying mapping */
/*
* Flags for mlock
diff --git a/include/uapi/asm-generic/mman.h b/include/uapi/asm-generic/mman.h
index 56cde132a80a..2dffcbf705b3 100644
--- a/include/uapi/asm-generic/mman.h
+++ b/include/uapi/asm-generic/mman.h
@@ -13,7 +13,6 @@
#define MAP_NONBLOCK 0x10000 /* do not block on IO */
#define MAP_STACK 0x20000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x40000 /* create a huge page mapping */
-#define MAP_FIXED_SAFE 0x80000 /* MAP_FIXED which doesn't unmap underlying mapping */
/* Bits [26:31] are reserved, see mman-common.h for MAP_HUGETLB usage */
--
Michal Hocko
SUSE Labs