On Fri 13-10-17 13:44:44, Ross Zwisler wrote:
> On Wed, Oct 11, 2017 at 10:05:56PM +0200, Jan Kara wrote:
> > Define new MAP_SYNC flag and corresponding VMA VM_SYNC flag. As the
> > MAP_SYNC flag is not part of LEGACY_MAP_MASK, currently it will be
> > refused by all MAP_SHARED_VALIDATE map attempts and silently ignored for
> > everything else.
> >
> > Signed-off-by: Jan Kara <jack@xxxxxxx>
> > ---
> > arch/xtensa/include/uapi/asm/mman.h | 1 +
> > fs/proc/task_mmu.c | 1 +
> > include/linux/mm.h | 1 +
> > include/linux/mman.h | 3 ++-
> > include/uapi/asm-generic/mman.h | 1 +
> > 5 files changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/xtensa/include/uapi/asm/mman.h b/arch/xtensa/include/uapi/asm/mman.h
> > index ec597900eec7..b62a7ce166fb 100644
> > --- a/arch/xtensa/include/uapi/asm/mman.h
> > +++ b/arch/xtensa/include/uapi/asm/mman.h
> > @@ -56,6 +56,7 @@
> > #define MAP_NONBLOCK 0x20000 /* do not block on IO */
> > #define MAP_STACK 0x40000 /* give out an address that is best suited for process/thread stacks */
> > #define MAP_HUGETLB 0x80000 /* create a huge page mapping */
> > +#define MAP_SYNC 0x100000 /* perform synchronous page faults for the mapping */
>
> Why define MAP_SYNC for this one architecture, but not for the rest that have
> their own arch/*/include/uapi/asm/mman.h? AFAIK xtensa doesn't support DAX,
> so has no need for MAP_SYNC?
Yeah, good point. I guess I'll just define it in asm-generic (which covers
x86 as well) and just define MAP_SYNC to 0 if not defined in linux/mman.h.
That should make the code compile and make sure userspace gets error if he
tries to use MAP_SYNC somehow on arch without its definition. Attached is a
new version of the patch.
> Other than this one question, this patch looks fine:
>
> Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Thanks.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
>From e15030463a8be760e10843fc9cf08c082a783c22 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@xxxxxxx>
Date: Thu, 17 Aug 2017 11:55:26 +0200
Subject: [PATCH] mm: Define MAP_SYNC and VM_SYNC flags
Define new MAP_SYNC flag and corresponding VMA VM_SYNC flag. As the
MAP_SYNC flag is not part of LEGACY_MAP_MASK, currently it will be
refused by all MAP_SHARED_VALIDATE map attempts and silently ignored for
everything else.
Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/proc/task_mmu.c | 1 +
include/linux/mm.h | 1 +
include/linux/mman.h | 8 ++++++--
include/uapi/asm-generic/mman.h | 1 +
4 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 5589b4bd4b85..ea78b37deeaa 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -664,6 +664,7 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
[ilog2(VM_ACCOUNT)] = "ac",
[ilog2(VM_NORESERVE)] = "nr",
[ilog2(VM_HUGETLB)] = "ht",
+ [ilog2(VM_SYNC)] = "sf",
[ilog2(VM_ARCH_1)] = "ar",
[ilog2(VM_WIPEONFORK)] = "wf",
[ilog2(VM_DONTDUMP)] = "dd",
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 55a9d2d109d9..cb62f2127314 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -189,6 +189,7 @@ extern unsigned int kobjsize(const void *objp);
#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_SYNC 0x00800000 /* Synchronous page faults */
#define VM_ARCH_1 0x01000000 /* Architecture-specific flag */
#define VM_WIPEONFORK 0x02000000 /* Wipe VMA contents in child. */
#define VM_DONTDUMP 0x04000000 /* Do not include in the core dump */
diff --git a/include/linux/mman.h b/include/linux/mman.h
index 94b63b4d71ff..8f7cc87828e6 100644
--- a/include/linux/mman.h
+++ b/include/linux/mman.h
@@ -9,7 +9,7 @@
/*
* Arrange for legacy / undefined architecture specific flags to be
- * ignored by default in LEGACY_MAP_MASK.
+ * ignored by mmap handling code.
*/
#ifndef MAP_32BIT
#define MAP_32BIT 0
@@ -23,6 +23,9 @@
#ifndef MAP_UNINITIALIZED
#define MAP_UNINITIALIZED 0
#endif
+#ifndef MAP_SYNC
+#define MAP_SYNC 0
+#endif
/*
* The historical set of flags that all mmap implementations implicitly
@@ -125,7 +128,8 @@ calc_vm_flag_bits(unsigned long flags)
{
return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) |
_calc_vm_trans(flags, MAP_DENYWRITE, VM_DENYWRITE ) |
- _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED );
+ _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) |
+ _calc_vm_trans(flags, MAP_SYNC, VM_SYNC );
}
unsigned long vm_commit_limit(void);
diff --git a/include/uapi/asm-generic/mman.h b/include/uapi/asm-generic/mman.h
index 7162cd4cca73..00e55627d2df 100644
--- a/include/uapi/asm-generic/mman.h
+++ b/include/uapi/asm-generic/mman.h
@@ -12,6 +12,7 @@
#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_SYNC 0x80000 /* perform synchronous page faults for the mapping */
/* Bits [26:31] are reserved, see mman-common.h for MAP_HUGETLB usage */
--
2.12.3
