[PATCH] arm/mm: fix compiler warning in pmdp_invalidate() (in -next)

[PATCH] arm/mm: fix compiler warning in pmdp_invalidate() (in -next)

[Andre Przywara]

Commit ff61d185f4e7 ("mm: convert p[te|md]_mknonnuma and remaining
page table manipulations") removed a check in
mm/pgtable-generic.c:pmdp_invalidate(), which leaves the
pmd_mknotpresent macro the only user of the entry variable.
For ARM/LPAE we use a constant 0 without referencing the argument to
mark this condition, so the entry variable is no longer used here:

mm/pgtable-generic.c: In function 'pmdp_invalidate':
mm/pgtable-generic.c:195:8: warning: unused variable 'entry' [-Wunused-variable]
  pmd_t entry = *pmdp;
        ^

Replace the ARM macro implementation with a static inline function to
get rid of this warning.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 arch/arm/include/asm/pgtable-3level.h |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index 370684d..0e51fbe 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -259,7 +259,10 @@ PMD_BIT_FUNC(mkyoung,   |= PMD_SECT_AF);
 #define mk_pmd(page,prot)	pfn_pmd(page_to_pfn(page),prot)
 
 /* represent a notpresent pmd by zero, this is used by pmdp_invalidate */
-#define pmd_mknotpresent(pmd)	(__pmd(0))
+static inline pmd_t pmd_mknotpresent(pmd_t pmd)
+{
+	return 0;
+}
 
 static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
 {
-- 
1.7.9.5

[PATCH] arm/mm: fix compiler warning in pmdp_invalidate() (in -next)

[Mel Gorman]

On Thu, Jan 29, 2015 at 05:48:00PM +0000, Andre Przywara wrote:
> Commit ff61d185f4e7 ("mm: convert p[te|md]_mknonnuma and remaining
> page table manipulations") removed a check in
> mm/pgtable-generic.c:pmdp_invalidate(), which leaves the
> pmd_mknotpresent macro the only user of the entry variable.
> For ARM/LPAE we use a constant 0 without referencing the argument to
> mark this condition, so the entry variable is no longer used here:
> 
> mm/pgtable-generic.c: In function 'pmdp_invalidate':
> mm/pgtable-generic.c:195:8: warning: unused variable 'entry' [-Wunused-variable]
>   pmd_t entry = *pmdp;
>         ^
> 
> Replace the ARM macro implementation with a static inline function to
> get rid of this warning.
> 
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>

Patch looks fine to me but this is against a mmotm patch that is
included in mmotm. The commit ID is not going to last. This should be
sent to Andrew Morton with a note saying it's a fix to the mmotm patch
mm-convert-p_mknonnuma-and-remaining-page-table-manipulations.patch .
He'll then fold your fix into the original patch so that bisection works
correctly when merged to mainline. Do you mind doing that please?

-- 
Mel Gorman
SUSE Labs

[PATCH] arm/mm: fix compiler warning in pmdp_invalidate() (in -next)

[Andre Przywara]

Commit ff61d185f4e7 ("mm: convert p[te|md]_mknonnuma and remaining
page table manipulations") removed a check in
mm/pgtable-generic.c:pmdp_invalidate(), which leaves the
pmd_mknotpresent macro the only user of the entry variable.
For ARM/LPAE we use a constant 0 without referencing the argument to
mark this condition, so the entry variable is no longer used here:

mm/pgtable-generic.c: In function 'pmdp_invalidate':
mm/pgtable-generic.c:195:8: warning: unused variable 'entry' [-Wunused-variable]
  pmd_t entry = *pmdp;
        ^

Replace the ARM macro implementation with a static inline function to
get rid of this warning.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
Hi Andrew,

Mel mentioned that I should send that simple fix below to you to
merge it with his original mmotm patch:
mm-convert-p_mknonnuma-and-remaining-page-table-manipulations.patch
The commit message above contains the mmotm-reference to this patch,
which will break when it hits mainline.

Can you consider this? Given that's only a warning fix I am also
happy with resending it after -rc1, if you reckon that this arch/arm
change should not go via mmotm.


On 30/01/15 10:06, Mel Gorman wrote:
> Patch looks fine to me but this is against a mmotm patch that is
> included in mmotm. The commit ID is not going to last. This should be
> sent to Andrew Morton with a note saying it's a fix to the mmotm patch
> mm-convert-p_mknonnuma-and-remaining-page-table-manipulations.patch .
> He'll then fold your fix into the original patch so that bisection works
> correctly when merged to mainline. Do you mind doing that please?

Cheers,
Andre

 arch/arm/include/asm/pgtable-3level.h |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index 370684d..0e51fbe 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -259,7 +259,10 @@ PMD_BIT_FUNC(mkyoung,   |= PMD_SECT_AF);
 #define mk_pmd(page,prot)	pfn_pmd(page_to_pfn(page),prot)
 
 /* represent a notpresent pmd by zero, this is used by pmdp_invalidate */
-#define pmd_mknotpresent(pmd)	(__pmd(0))
+static inline pmd_t pmd_mknotpresent(pmd_t pmd)
+{
+	return 0;
+}
 
 static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
 {
-- 
1.7.9.5

[PATCH] arm/mm: fix compiler warning in pmdp_invalidate() (in -next)

[Russell King - ARM Linux]

On Fri, Jan 30, 2015 at 04:37:32PM +0000, Andre Przywara wrote:
> Commit ff61d185f4e7 ("mm: convert p[te|md]_mknonnuma and remaining
> page table manipulations") removed a check in
> mm/pgtable-generic.c:pmdp_invalidate(), which leaves the
> pmd_mknotpresent macro the only user of the entry variable.
> For ARM/LPAE we use a constant 0 without referencing the argument to
> mark this condition, so the entry variable is no longer used here:
> 
> mm/pgtable-generic.c: In function 'pmdp_invalidate':
> mm/pgtable-generic.c:195:8: warning: unused variable 'entry' [-Wunused-variable]
>   pmd_t entry = *pmdp;
>         ^
> 
> Replace the ARM macro implementation with a static inline function to
> get rid of this warning.
>  
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
> Hi Andrew,
> 
> Mel mentioned that I should send that simple fix below to you to
> merge it with his original mmotm patch:
> mm-convert-p_mknonnuma-and-remaining-page-table-manipulations.patch
> The commit message above contains the mmotm-reference to this patch,
> which will break when it hits mainline.
> 
> Can you consider this? Given that's only a warning fix I am also
> happy with resending it after -rc1, if you reckon that this arch/arm
> change should not go via mmotm.

This isn't correct though.

>  /* represent a notpresent pmd by zero, this is used by pmdp_invalidate */
> -#define pmd_mknotpresent(pmd)	(__pmd(0))
> +static inline pmd_t pmd_mknotpresent(pmd_t pmd)
> +{
> +	return 0;
> +}

typedef struct { pmdval_t pmd; } pmd_t;

typedef u32 pmdval_t;

"0" is not compatible with pmd_t when STRICT_MM_TYPECHECKS is enabled.

-- 
FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up
according to speedtest.net.

[PATCH] arm/mm: fix compiler warning in pmdp_invalidate() (in -next)

[Andrew Morton]

On Fri, 30 Jan 2015 16:40:15 +0000 Russell King - ARM Linux <linux@arm.linux.org.uk> wrote:

> On Fri, Jan 30, 2015 at 04:37:32PM +0000, Andre Przywara wrote:
> > Commit ff61d185f4e7 ("mm: convert p[te|md]_mknonnuma and remaining
> > page table manipulations") removed a check in
> > mm/pgtable-generic.c:pmdp_invalidate(), which leaves the
> > pmd_mknotpresent macro the only user of the entry variable.
> > For ARM/LPAE we use a constant 0 without referencing the argument to
> > mark this condition, so the entry variable is no longer used here:
> > 
> > mm/pgtable-generic.c: In function 'pmdp_invalidate':
> > mm/pgtable-generic.c:195:8: warning: unused variable 'entry' [-Wunused-variable]
> >   pmd_t entry = *pmdp;
> >         ^
> > 
> > Replace the ARM macro implementation with a static inline function to
> > get rid of this warning.
> >  
> > Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> > ---
> > Hi Andrew,
> > 
> > Mel mentioned that I should send that simple fix below to you to
> > merge it with his original mmotm patch:
> > mm-convert-p_mknonnuma-and-remaining-page-table-manipulations.patch
> > The commit message above contains the mmotm-reference to this patch,
> > which will break when it hits mainline.
> > 
> > Can you consider this? Given that's only a warning fix I am also
> > happy with resending it after -rc1, if you reckon that this arch/arm
> > change should not go via mmotm.
> 
> This isn't correct though.
> 
> >  /* represent a notpresent pmd by zero, this is used by pmdp_invalidate */
> > -#define pmd_mknotpresent(pmd)	(__pmd(0))
> > +static inline pmd_t pmd_mknotpresent(pmd_t pmd)
> > +{
> > +	return 0;
> > +}
> 
> typedef struct { pmdval_t pmd; } pmd_t;
> 
> typedef u32 pmdval_t;
> 
> "0" is not compatible with pmd_t when STRICT_MM_TYPECHECKS is enabled.

This?

--- a/arch/arm/include/asm/pgtable-3level.h~mm-convert-p_mknonnuma-and-remaining-page-table-manipulations-fix-fix
+++ a/arch/arm/include/asm/pgtable-3level.h
@@ -259,7 +259,7 @@ PMD_BIT_FUNC(mkyoung,   |= PMD_SECT_AF);
 /* represent a notpresent pmd by zero, this is used by pmdp_invalidate */
 static inline pmd_t pmd_mknotpresent(pmd_t pmd)
 {
-	return 0;
+	return __pmd(0);
 }
 
 static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)