[PATCH 16/16] mm: vm_flags_t strict type checking

Konstantin Khlebnikov
2012-03-21T06:57:45Z

Now nobody uses VM_* constants in macro-expressions, so we can add type to them.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
---
include/linux/mm.h | 138 ++++++++++++++++++++++++++++++++--------------
include/linux/mm_types.h | 4 +
2 files changed, 97 insertions(+), 45 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index be35c2f..b432c28 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -74,59 +74,111 @@ extern unsigned int kobjsize(const void *objp);
* vm_flags in vm_area_struct, see mm_types.h.
*/

-#define VM_NONE 0x00000000
+enum {
+ __VM_READ,
+ __VM_WRITE,
+ __VM_EXEC,
+ __VM_SHARED,
+
+ __VM_MAYREAD,
+ __VM_MAYWRITE,
+ __VM_MAYEXEC,
+ __VM_MAYSHARE,
+
+ __VM_GROWSDOWN,
+#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
+ __VM_GROWSUP,
+#else
+ __VM_NOHUGEPAGE,
+#endif
+ __VM_PFNMAP,
+ __VM_DENYWRITE,
+
+ __VM_EXECUTABLE,
+ __VM_LOCKED,
+ __VM_IO,
+ __VM_SEQ_READ,
+
+ __VM_RAND_READ,
+ __VM_DONTCOPY,
+ __VM_DONTEXPAND,
+ __VM_RESERVED,

-#define VM_READ 0x00000001 /* currently active flags */
-#define VM_WRITE 0x00000002
-#define VM_EXEC 0x00000004
-#define VM_SHARED 0x00000008
+ __VM_ACCOUNT,
+ __VM_NORESERVE,
+ __VM_HUGETLB,
+ __VM_NONLINEAR,
+
+#ifndef CONFIG_TRANSPARENT_HUGEPAGE
+ __VM_MAPPED_COPY,
+#else
+ __VM_HUGEPAGE,
+#endif
+ __VM_INSERTPAGE,
+ __VM_ALWAYSDUMP,
+ __VM_CAN_NONLINEAR,
+
+ __VM_MIXEDMAP,
+ __VM_SAO,
+ __VM_PFN_AT_MMAP,
+ __VM_MERGEABLE,
+
+ __NR_VMA_FLAGS
+};
+
+#define VM_NONE ((__force vm_flags_t)0)
+
+#define __VMF(name) ((__force vm_flags_t)(1ull << (__VM_##name)))
+
+#define VM_READ __VMF(READ) /* currently active flags */
+#define VM_WRITE __VMF(WRITE)
+#define VM_EXEC __VMF(EXEC)
+#define VM_SHARED __VMF(SHARED)

/* mprotect() hardcodes VM_MAYREAD >> 4 == VM_READ, and so for r/w/x bits. */
-#define VM_MAYREAD 0x00000010 /* limits for mprotect() etc */
-#define VM_MAYWRITE 0x00000020
-#define VM_MAYEXEC 0x00000040
-#define VM_MAYSHARE 0x00000080
+#define VM_MAYREAD __VMF(MAYREAD) /* limits for mprotect() etc */
+#define VM_MAYWRITE __VMF(MAYWRITE)
+#define VM_MAYEXEC __VMF(MAYEXEC)
+#define VM_MAYSHARE __VMF(MAYSHARE)

-#define VM_GROWSDOWN 0x00000100 /* general info on the segment */
+#define VM_GROWSDOWN __VMF(GROWSDOWN) /* general info on the segment */
#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
-#define VM_GROWSUP 0x00000200
+#define VM_GROWSUP __VMF(GROWSUP)
#else
-#define VM_GROWSUP 0x00000000
-#define VM_NOHUGEPAGE 0x00000200 /* MADV_NOHUGEPAGE marked this vma */
+#define VM_GROWSUP VM_NONE
+#define VM_NOHUGEPAGE __VMF(NOHUGEPAGE) /* MADV_NOHUGEPAGE marked this vma */
#endif
-#define VM_PFNMAP 0x00000400 /* Page-ranges managed without "struct page", just pure PFN */
-#define VM_DENYWRITE 0x00000800 /* ETXTBSY on write attempts.. */
-
-#define VM_EXECUTABLE 0x00001000
-#define VM_LOCKED 0x00002000
-#define VM_IO 0x00004000 /* Memory mapped I/O or similar */
-
- /* Used by sys_madvise() */
-#define VM_SEQ_READ 0x00008000 /* App will access data sequentially */
-#define VM_RAND_READ 0x00010000 /* App will not benefit from clustered reads */
-
-#define VM_DONTCOPY 0x00020000 /* Do not copy this vma on fork */
-#define VM_DONTEXPAND 0x00040000 /* Cannot expand with mremap() */
-#define VM_RESERVED 0x00080000 /* Count as reserved_vm like IO */
-#define VM_ACCOUNT 0x00100000 /* Is a VM accounted object */
-#define VM_NORESERVE 0x00200000 /* should the VM suppress accounting */
-#define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */
-#define VM_NONLINEAR 0x00800000 /* Is non-linear (remap_file_pages) */
+#define VM_PFNMAP __VMF(PFNMAP) /* Page-ranges managed without "struct page", just pure PFN */
+#define VM_DENYWRITE __VMF(DENYWRITE) /* ETXTBSY on write attempts.. */
+
+#define VM_EXECUTABLE __VMF(EXECUTABLE)
+#define VM_LOCKED __VMF(LOCKED)
+#define VM_IO __VMF(IO) /* Memory mapped I/O or similar */
+
+ /* Used by sys_madvise() */
+#define VM_SEQ_READ __VMF(SEQ_READ) /* App will access data sequentially */
+#define VM_RAND_READ __VMF(RAND_READ) /* App will not benefit from clustered reads */
+
+#define VM_DONTCOPY __VMF(DONTCOPY) /* Do not copy this vma on fork */
+#define VM_DONTEXPAND __VMF(DONTEXPAND) /* Cannot expand with mremap() */
+#define VM_RESERVED __VMF(RESERVED) /* Count as reserved_vm like IO */
+#define VM_ACCOUNT __VMF(ACCOUNT) /* Is a VM accounted object */
+#define VM_NORESERVE __VMF(NORESERVE) /* should the VM suppress accounting */
+#define VM_HUGETLB __VMF(HUGETLB) /* Huge TLB Page VM */
+#define VM_NONLINEAR __VMF(NONLINEAR) /* Is non-linear (remap_file_pages) */
#ifndef CONFIG_TRANSPARENT_HUGEPAGE
-#define VM_MAPPED_COPY 0x01000000 /* T if mapped copy of data (nommu mmap) */
+#define VM_MAPPED_COPY __VMF(MAPPED_COPY) /* T if mapped copy of data (nommu mmap) */
#else
-#define VM_HUGEPAGE 0x01000000 /* MADV_HUGEPAGE marked this vma */
+#define VM_HUGEPAGE __VMF(HUGEPAGE) /* MADV_HUGEPAGE marked this vma */
#endif
-#define VM_INSERTPAGE 0x02000000 /* The vma has had "vm_insert_page()" done on it */
-#define VM_ALWAYSDUMP 0x04000000 /* Always include in core dumps */
-
-#define VM_CAN_NONLINEAR 0x08000000 /* Has ->fault & does nonlinear pages */
-#define VM_MIXEDMAP 0x10000000 /* Can contain "struct page" and pure PFN pages */
-#define VM_SAO 0x20000000 /* Strong Access Ordering (powerpc) */
-#define VM_PFN_AT_MMAP 0x40000000 /* PFNMAP vma that is fully mapped at mmap time */
-#define VM_MERGEABLE 0x80000000 /* KSM may merge identical pages */
-
-#define __NR_VMA_FLAGS 32
+#define VM_INSERTPAGE __VMF(INSERTPAGE) /* The vma has had "vm_insert_page()" done on it */
+#define VM_ALWAYSDUMP __VMF(ALWAYSDUMP) /* Always include in core dumps */
+
+#define VM_CAN_NONLINEAR __VMF(CAN_NONLINEAR) /* Has ->fault & does nonlinear pages */
+#define VM_MIXEDMAP __VMF(MIXEDMAP) /* Can contain "struct page" and pure PFN pages */
+#define VM_SAO __VMF(SAO) /* Strong Access Ordering (powerpc) */
+#define VM_PFN_AT_MMAP __VMF(PFN_AT_MMAP) /* PFNMAP vma that is fully mapped at mmap time */
+#define VM_MERGEABLE __VMF(MERGEABLE) /* KSM may merge identical pages */

#ifndef __GENERATING_BOUNDS_H

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index d57e764..f14cc5e 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -172,9 +172,9 @@ struct page_frag {
};

#if (NR_VMA_FLAGS > 32)
-typedef unsigned long long __nocast vm_flags_t;
+typedef unsigned long long __bitwise__ vm_flags_t;
#else
-typedef unsigned long __nocast vm_flags_t;
+typedef unsigned long __bitwise__ vm_flags_t;
#endif

/*