* [mmotm:master 371/385] arch/x86/mm/mpx.c:71:54: sparse: implicit cast to nocast type
@ 2015-07-24 8:18 kbuild test robot
2015-07-24 10:09 ` vm_flags, vm_flags_t and __nocast Kirill A. Shutemov
0 siblings, 1 reply; 6+ messages in thread
From: kbuild test robot @ 2015-07-24 8:18 UTC (permalink / raw)
To: Oleg Nesterov
Cc: kbuild-all, Johannes Weiner, Kirill A. Shutemov, Andrew Morton,
Linux Memory Management List
tree: git://git.cmpxchg.org/linux-mmotm.git master
head: 61f5f835b6f06fbc233481b5d3c0afd71ecf54e8
commit: b9e95c5dd1134d35b6c9aeaa3967ab5b3945ba73 [371/385] mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()
reproduce:
# apt-get install sparse
git checkout b9e95c5dd1134d35b6c9aeaa3967ab5b3945ba73
make ARCH=x86_64 allmodconfig
make C=1 CF=-D__CHECK_ENDIAN__
sparse warnings: (new ones prefixed by >>)
>> arch/x86/mm/mpx.c:71:54: sparse: implicit cast to nocast type
arch/x86/mm/mpx.c:312:27: sparse: incompatible types in comparison expression (different address spaces)
--
>> include/linux/mm.h:1812:54: sparse: implicit cast to nocast type
--
mm/mmap.c:1343:47: sparse: implicit cast to nocast type
mm/mmap.c:1345:45: sparse: implicit cast to nocast type
mm/mmap.c:1354:45: sparse: implicit cast to nocast type
mm/mmap.c:1375:47: sparse: implicit cast to nocast type
mm/mmap.c:1395:37: sparse: implicit cast to nocast type
mm/mmap.c:1399:37: sparse: implicit cast to nocast type
mm/mmap.c:1443:33: sparse: implicit cast to nocast type
mm/mmap.c:1578:29: sparse: implicit cast to nocast type
mm/internal.h:253:43: sparse: implicit cast to nocast type
mm/mmap.c:2650:37: sparse: implicit cast to nocast type
mm/mmap.c:2690:34: sparse: implicit cast to nocast type
mm/mmap.c:2693:34: sparse: implicit cast to nocast type
>> include/linux/mm.h:1812:54: sparse: implicit cast to nocast type
mm/internal.h:253:43: sparse: implicit cast to nocast type
vim +71 arch/x86/mm/mpx.c
55 * bounds tables (the bounds directory is user-allocated).
56 *
57 * Later on, we use the vma->vm_ops to uniquely identify these
58 * VMAs.
59 */
60 static unsigned long mpx_mmap(unsigned long len)
61 {
62 struct mm_struct *mm = current->mm;
63 unsigned long addr, populate;
64
65 /* Only bounds table can be allocated here */
66 if (len != mpx_bt_size_bytes(mm))
67 return -EINVAL;
68
69 down_write(&mm->mmap_sem);
70 addr = do_mmap(NULL, 0, len, PROT_READ | PROT_WRITE,
> 71 MAP_ANONYMOUS | MAP_PRIVATE, VM_MPX, 0, &populate);
72 up_write(&mm->mmap_sem);
73 if (populate)
74 mm_populate(addr, populate);
75
76 return addr;
77 }
78
79 enum reg_type {
---
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^ permalink raw reply [flat|nested] 6+ messages in thread* vm_flags, vm_flags_t and __nocast
2015-07-24 8:18 [mmotm:master 371/385] arch/x86/mm/mpx.c:71:54: sparse: implicit cast to nocast type kbuild test robot
@ 2015-07-24 10:09 ` Kirill A. Shutemov
2015-07-24 20:15 ` David Rientjes
0 siblings, 1 reply; 6+ messages in thread
From: Kirill A. Shutemov @ 2015-07-24 10:09 UTC (permalink / raw)
To: Andrew Morton, Linus Torvalds
Cc: kbuild test robot, Oleg Nesterov, kbuild-all, Johannes Weiner,
Kirill A. Shutemov, Linux Memory Management List
On Fri, Jul 24, 2015 at 04:18:30PM +0800, kbuild test robot wrote:
> tree: git://git.cmpxchg.org/linux-mmotm.git master
> head: 61f5f835b6f06fbc233481b5d3c0afd71ecf54e8
> commit: b9e95c5dd1134d35b6c9aeaa3967ab5b3945ba73 [371/385] mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()
> reproduce:
> # apt-get install sparse
> git checkout b9e95c5dd1134d35b6c9aeaa3967ab5b3945ba73
> make ARCH=x86_64 allmodconfig
> make C=1 CF=-D__CHECK_ENDIAN__
>
>
> sparse warnings: (new ones prefixed by >>)
>
> >> arch/x86/mm/mpx.c:71:54: sparse: implicit cast to nocast type
> arch/x86/mm/mpx.c:312:27: sparse: incompatible types in comparison expression (different address spaces)
> --
> >> include/linux/mm.h:1812:54: sparse: implicit cast to nocast type
> --
> mm/mmap.c:1343:47: sparse: implicit cast to nocast type
> mm/mmap.c:1345:45: sparse: implicit cast to nocast type
> mm/mmap.c:1354:45: sparse: implicit cast to nocast type
> mm/mmap.c:1375:47: sparse: implicit cast to nocast type
> mm/mmap.c:1395:37: sparse: implicit cast to nocast type
> mm/mmap.c:1399:37: sparse: implicit cast to nocast type
> mm/mmap.c:1443:33: sparse: implicit cast to nocast type
> mm/mmap.c:1578:29: sparse: implicit cast to nocast type
> mm/internal.h:253:43: sparse: implicit cast to nocast type
> mm/mmap.c:2650:37: sparse: implicit cast to nocast type
> mm/mmap.c:2690:34: sparse: implicit cast to nocast type
> mm/mmap.c:2693:34: sparse: implicit cast to nocast type
> >> include/linux/mm.h:1812:54: sparse: implicit cast to nocast type
> mm/internal.h:253:43: sparse: implicit cast to nocast type
sparse complains on each and every vm_flags_t initialization, even with
proper VM_* constants.
Do we really want to fix that?
To me it's too much pain and no gain. __nocast is not beneficial here.
And I'm not sure that vm_flags_t typedef was a good idea after all.
Originally, it was intended to become 64-bit one day, but four years later
it's still unsigned long. Plain unsigned long works fine for other bit
field.
What is special about vm_flags?
> vim +71 arch/x86/mm/mpx.c
>
> 55 * bounds tables (the bounds directory is user-allocated).
> 56 *
> 57 * Later on, we use the vma->vm_ops to uniquely identify these
> 58 * VMAs.
> 59 */
> 60 static unsigned long mpx_mmap(unsigned long len)
> 61 {
> 62 struct mm_struct *mm = current->mm;
> 63 unsigned long addr, populate;
> 64
> 65 /* Only bounds table can be allocated here */
> 66 if (len != mpx_bt_size_bytes(mm))
> 67 return -EINVAL;
> 68
> 69 down_write(&mm->mmap_sem);
> 70 addr = do_mmap(NULL, 0, len, PROT_READ | PROT_WRITE,
> > 71 MAP_ANONYMOUS | MAP_PRIVATE, VM_MPX, 0, &populate);
> 72 up_write(&mm->mmap_sem);
> 73 if (populate)
> 74 mm_populate(addr, populate);
> 75
> 76 return addr;
> 77 }
> 78
> 79 enum reg_type {
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
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> see: http://www.linux-mm.org/ .
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--
Kirill A. Shutemov
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: vm_flags, vm_flags_t and __nocast
2015-07-24 10:09 ` vm_flags, vm_flags_t and __nocast Kirill A. Shutemov
@ 2015-07-24 20:15 ` David Rientjes
2015-08-03 15:51 ` Kirill A. Shutemov
0 siblings, 1 reply; 6+ messages in thread
From: David Rientjes @ 2015-07-24 20:15 UTC (permalink / raw)
To: Kirill A. Shutemov
Cc: Andrew Morton, Linus Torvalds, kbuild test robot, Oleg Nesterov,
kbuild-all, Johannes Weiner, Kirill A. Shutemov,
Linux Memory Management List
On Fri, 24 Jul 2015, Kirill A. Shutemov wrote:
> sparse complains on each and every vm_flags_t initialization, even with
> proper VM_* constants.
>
> Do we really want to fix that?
>
> To me it's too much pain and no gain. __nocast is not beneficial here.
>
> And I'm not sure that vm_flags_t typedef was a good idea after all.
> Originally, it was intended to become 64-bit one day, but four years later
> it's still unsigned long. Plain unsigned long works fine for other bit
> field.
>
> What is special about vm_flags?
>
Maybe remove the __nocast until it's a different type? Seems like all
these sites would have to be audited when that happens anyway.
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: vm_flags, vm_flags_t and __nocast
2015-07-24 20:15 ` David Rientjes
@ 2015-08-03 15:51 ` Kirill A. Shutemov
2015-08-03 17:33 ` Oleg Nesterov
2015-08-06 2:07 ` David Rientjes
0 siblings, 2 replies; 6+ messages in thread
From: Kirill A. Shutemov @ 2015-08-03 15:51 UTC (permalink / raw)
To: David Rientjes
Cc: Kirill A. Shutemov, Andrew Morton, Linus Torvalds,
kbuild test robot, Oleg Nesterov, kbuild-all, Johannes Weiner,
Kirill A. Shutemov, Linux Memory Management List
David Rientjes wrote:
> On Fri, 24 Jul 2015, Kirill A. Shutemov wrote:
>
> > sparse complains on each and every vm_flags_t initialization, even with
> > proper VM_* constants.
> >
> > Do we really want to fix that?
> >
> > To me it's too much pain and no gain. __nocast is not beneficial here.
> >
> > And I'm not sure that vm_flags_t typedef was a good idea after all.
> > Originally, it was intended to become 64-bit one day, but four years later
> > it's still unsigned long. Plain unsigned long works fine for other bit
> > field.
> >
> > What is special about vm_flags?
> >
>
> Maybe remove the __nocast until it's a different type? Seems like all
> these sites would have to be audited when that happens anyway.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: vm_flags, vm_flags_t and __nocast
2015-08-03 15:51 ` Kirill A. Shutemov
@ 2015-08-03 17:33 ` Oleg Nesterov
2015-08-06 2:07 ` David Rientjes
1 sibling, 0 replies; 6+ messages in thread
From: Oleg Nesterov @ 2015-08-03 17:33 UTC (permalink / raw)
To: Kirill A. Shutemov
Cc: David Rientjes, Kirill A. Shutemov, Andrew Morton, Linus Torvalds,
kbuild test robot, kbuild-all, Johannes Weiner,
Linux Memory Management List
On 08/03, Kirill A. Shutemov wrote:
>
> Subject: [PATCH] mm: drop __nocast from vm_flags_t definition
>
> __nocast does no good for vm_flags_t. It only produces useless sparse
> warnings.
>
> Let's drop it.
Personally I like this change.
I too see no value in this "__nocast".
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
> include/linux/mm_types.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 1fb4e46a1736..b9134cc27c4d 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -226,7 +226,7 @@ struct page_frag {
> #endif
> };
>
> -typedef unsigned long __nocast vm_flags_t;
> +typedef unsigned long vm_flags_t;
>
> /*
> * A region containing a mapping of a non-memory backed file under NOMMU
> --
> 2.4.6
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: vm_flags, vm_flags_t and __nocast
2015-08-03 15:51 ` Kirill A. Shutemov
2015-08-03 17:33 ` Oleg Nesterov
@ 2015-08-06 2:07 ` David Rientjes
1 sibling, 0 replies; 6+ messages in thread
From: David Rientjes @ 2015-08-06 2:07 UTC (permalink / raw)
To: Kirill A. Shutemov
Cc: Kirill A. Shutemov, Andrew Morton, Linus Torvalds,
kbuild test robot, Oleg Nesterov, kbuild-all, Johannes Weiner,
Linux Memory Management List
On Mon, 3 Aug 2015, Kirill A. Shutemov wrote:
> From f690ec43103e55d0ed533fc977f9ac3cfa29d8f6 Mon Sep 17 00:00:00 2001
> From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> Date: Mon, 3 Aug 2015 18:49:18 +0300
> Subject: [PATCH] mm: drop __nocast from vm_flags_t definition
>
> __nocast does no good for vm_flags_t. It only produces useless sparse
> warnings.
>
> Let's drop it.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: David Rientjes <rientjes@google.com>
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^ permalink raw reply [flat|nested] 6+ messages in thread
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2015-07-24 10:09 ` vm_flags, vm_flags_t and __nocast Kirill A. Shutemov
2015-07-24 20:15 ` David Rientjes
2015-08-03 15:51 ` Kirill A. Shutemov
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