[v6,04/11] powerpc/mce_power: Use functions to track lockless pgtbl walks
diff mbox series

Message ID 20200206030900.147032-5-leonardo@linux.ibm.com
State Superseded
Headers show
Series
  • Introduces new functions for tracking lockless pagetable walks
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snowpatch_ozlabs/needsstable success Patch has no Fixes tags
snowpatch_ozlabs/checkpatch success total: 0 errors, 0 warnings, 0 checks, 24 lines checked
snowpatch_ozlabs/apply_patch success Successfully applied on branch powerpc/merge (530a1cfd52af0aba1af4b1c9a7bc66a202a459b1)

Commit Message

Leonardo Bras Feb. 6, 2020, 3:08 a.m. UTC
Applies the new functions used for tracking lockless pgtable walks on
addr_to_pfn().

local_irq_{save,restore} is already inside {begin,end}_lockless_pgtbl_walk,
so there is no need to repeat it here.

Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
---
 arch/powerpc/kernel/mce_power.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Christophe Leroy Feb. 6, 2020, 5:48 a.m. UTC | #1
Le 06/02/2020 à 04:08, Leonardo Bras a écrit :
> Applies the new functions used for tracking lockless pgtable walks on
> addr_to_pfn().
> 
> local_irq_{save,restore} is already inside {begin,end}_lockless_pgtbl_walk,
> so there is no need to repeat it here.
> 
> Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
> ---
>   arch/powerpc/kernel/mce_power.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c
> index 1cbf7f1a4e3d..a9e38ef4e437 100644
> --- a/arch/powerpc/kernel/mce_power.c
> +++ b/arch/powerpc/kernel/mce_power.c
> @@ -29,7 +29,7 @@ unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
>   {
>   	pte_t *ptep;
>   	unsigned int shift;
> -	unsigned long pfn, flags;
> +	unsigned long pfn, irq_mask;

Why change the name ? flags is a well known historical name.

>   	struct mm_struct *mm;
>   
>   	if (user_mode(regs))
> @@ -37,7 +37,7 @@ unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
>   	else
>   		mm = &init_mm;
>   
> -	local_irq_save(flags);
> +	irq_mask = begin_lockless_pgtbl_walk();
>   	ptep = __find_linux_pte(mm->pgd, addr, NULL, &shift);
>   
>   	if (!ptep || pte_special(*ptep)) {
> @@ -53,7 +53,7 @@ unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
>   	}
>   
>   out:
> -	local_irq_restore(flags);
> +	end_lockless_pgtbl_walk(irq_mask);
>   	return pfn;
>   }
>   
> 

Christophe
Leonardo Bras Feb. 7, 2020, 4 a.m. UTC | #2
On Thu, 2020-02-06 at 06:48 +0100, Christophe Leroy wrote:
> > --- a/arch/powerpc/kernel/mce_power.c
> > +++ b/arch/powerpc/kernel/mce_power.c
> > @@ -29,7 +29,7 @@ unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
> >   {
> >   	pte_t *ptep;
> >   	unsigned int shift;
> > -	unsigned long pfn, flags;
> > +	unsigned long pfn, irq_mask;
> 
> Why change the name ? flags is a well known historical name.

Oh, this commit missed the reasoning for flags name change.

For local_irq_{save,restore} a parameter named flags makes sense, for
the reader, as it could only be flags regarding irq.

I thougt passing flags to {begin,end}_lockless_pgtbl_walk would lose
it's meaning, given that it would only mean "flags for these functions"

So, changing it to irq_mask would make the reader more aware of what it
does mean.

For other commits, I added:

"Variable that saves the irq mask was renamed from flags to irq_mask so
it doesn't lose meaning now it's not directly passed to local_irq_*
functions." 

I can add it to this commit message.

Thanks for the feedback,

Leonardo Bras

Patch
diff mbox series

diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c
index 1cbf7f1a4e3d..a9e38ef4e437 100644
--- a/arch/powerpc/kernel/mce_power.c
+++ b/arch/powerpc/kernel/mce_power.c
@@ -29,7 +29,7 @@  unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
 {
 	pte_t *ptep;
 	unsigned int shift;
-	unsigned long pfn, flags;
+	unsigned long pfn, irq_mask;
 	struct mm_struct *mm;
 
 	if (user_mode(regs))
@@ -37,7 +37,7 @@  unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
 	else
 		mm = &init_mm;
 
-	local_irq_save(flags);
+	irq_mask = begin_lockless_pgtbl_walk();
 	ptep = __find_linux_pte(mm->pgd, addr, NULL, &shift);
 
 	if (!ptep || pte_special(*ptep)) {
@@ -53,7 +53,7 @@  unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
 	}
 
 out:
-	local_irq_restore(flags);
+	end_lockless_pgtbl_walk(irq_mask);
 	return pfn;
 }