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* [PATCH] mm: Release a semaphore in 'get_vaddr_frames()'
@ 2017-12-09  7:09 ` Christophe JAILLET
  0 siblings, 0 replies; 7+ messages in thread
From: Christophe JAILLET @ 2017-12-09  7:09 UTC (permalink / raw)
  To: dan.j.williams, akpm, borntraeger, mhocko, dsterba, gregkh
  Cc: linux-mm, linux-kernel, kernel-janitors, Christophe JAILLET

A semaphore is acquired before this check, so we must release it before
leaving.

Fixes: b7f0554a56f2 ("mm: fail get_vaddr_frames() for filesystem-dax mappings")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
-- Untested --

The wording of the commit entry and log description could be improved
but I didn't find something better.
---
 mm/frame_vector.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/frame_vector.c b/mm/frame_vector.c
index 297c7238f7d4..e0c5e659fa82 100644
--- a/mm/frame_vector.c
+++ b/mm/frame_vector.c
@@ -62,8 +62,10 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
 	 * get_user_pages_longterm() and disallow it for filesystem-dax
 	 * mappings.
 	 */
-	if (vma_is_fsdax(vma))
+	if (vma_is_fsdax(vma)) {
+		up_read(&mm->mmap_sem);
 		return -EOPNOTSUPP;
+	}
 
 	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
 		vec->got_ref = true;
-- 
2.14.1

^ permalink raw reply related	[flat|nested] 7+ messages in thread
* [PATCH] mm: Release a semaphore in 'get_vaddr_frames()'
@ 2017-12-09  7:09 ` Christophe JAILLET
  0 siblings, 0 replies; 7+ messages in thread
From: Christophe JAILLET @ 2017-12-09  7:09 UTC (permalink / raw)
  To: dan.j.williams, akpm, borntraeger, mhocko, dsterba, gregkh
  Cc: linux-mm, linux-kernel, kernel-janitors, Christophe JAILLET

A semaphore is acquired before this check, so we must release it before
leaving.

Fixes: b7f0554a56f2 ("mm: fail get_vaddr_frames() for filesystem-dax mappings")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
-- Untested --

The wording of the commit entry and log description could be improved
but I didn't find something better.
---
 mm/frame_vector.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/frame_vector.c b/mm/frame_vector.c
index 297c7238f7d4..e0c5e659fa82 100644
--- a/mm/frame_vector.c
+++ b/mm/frame_vector.c
@@ -62,8 +62,10 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
 	 * get_user_pages_longterm() and disallow it for filesystem-dax
 	 * mappings.
 	 */
-	if (vma_is_fsdax(vma))
+	if (vma_is_fsdax(vma)) {
+		up_read(&mm->mmap_sem);
 		return -EOPNOTSUPP;
+	}
 
 	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
 		vec->got_ref = true;
-- 
2.14.1


^ permalink raw reply related	[flat|nested] 7+ messages in thread
* [PATCH] mm: Release a semaphore in 'get_vaddr_frames()'
@ 2017-12-09  7:09 ` Christophe JAILLET
  0 siblings, 0 replies; 7+ messages in thread
From: Christophe JAILLET @ 2017-12-09  7:09 UTC (permalink / raw)
  To: dan.j.williams, akpm, borntraeger, mhocko, dsterba, gregkh
  Cc: linux-mm, linux-kernel, kernel-janitors, Christophe JAILLET

A semaphore is acquired before this check, so we must release it before
leaving.

Fixes: b7f0554a56f2 ("mm: fail get_vaddr_frames() for filesystem-dax mappings")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
-- Untested --

The wording of the commit entry and log description could be improved
but I didn't find something better.
---
 mm/frame_vector.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/frame_vector.c b/mm/frame_vector.c
index 297c7238f7d4..e0c5e659fa82 100644
--- a/mm/frame_vector.c
+++ b/mm/frame_vector.c
@@ -62,8 +62,10 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
 	 * get_user_pages_longterm() and disallow it for filesystem-dax
 	 * mappings.
 	 */
-	if (vma_is_fsdax(vma))
+	if (vma_is_fsdax(vma)) {
+		up_read(&mm->mmap_sem);
 		return -EOPNOTSUPP;
+	}
 
 	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
 		vec->got_ref = true;
-- 
2.14.1

--
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^ permalink raw reply related	[flat|nested] 7+ messages in thread
* Re: [PATCH] mm: Release a semaphore in 'get_vaddr_frames()'
  2017-12-09  7:09 ` Christophe JAILLET
  (?)
@ 2017-12-10  9:45   ` Michal Hocko
  -1 siblings, 0 replies; 7+ messages in thread
From: Michal Hocko @ 2017-12-10  9:45 UTC (permalink / raw)
  To: Christophe JAILLET
  Cc: dan.j.williams, akpm, borntraeger, dsterba, gregkh, linux-mm,
	linux-kernel, kernel-janitors

On Sat 09-12-17 08:09:41, Christophe JAILLET wrote:
> A semaphore is acquired before this check, so we must release it before
> leaving.
> 
> Fixes: b7f0554a56f2 ("mm: fail get_vaddr_frames() for filesystem-dax mappings")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> -- Untested --
> 
> The wording of the commit entry and log description could be improved
> but I didn't find something better.

The changelog is ok imo.

> ---
>  mm/frame_vector.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/frame_vector.c b/mm/frame_vector.c
> index 297c7238f7d4..e0c5e659fa82 100644
> --- a/mm/frame_vector.c
> +++ b/mm/frame_vector.c
> @@ -62,8 +62,10 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
>  	 * get_user_pages_longterm() and disallow it for filesystem-dax
>  	 * mappings.
>  	 */
> -	if (vma_is_fsdax(vma))
> +	if (vma_is_fsdax(vma)) {
> +		up_read(&mm->mmap_sem);
>  		return -EOPNOTSUPP;
> +	}

Is there any reason to do a different error handling than other error
paths? Namely not going without goto out?

>  
>  	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
>  		vec->got_ref = true;
> -- 
> 2.14.1
> 

-- 
Michal Hocko
SUSE Labs

^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: [PATCH] mm: Release a semaphore in 'get_vaddr_frames()'
@ 2017-12-10  9:45   ` Michal Hocko
  0 siblings, 0 replies; 7+ messages in thread
From: Michal Hocko @ 2017-12-10  9:45 UTC (permalink / raw)
  To: Christophe JAILLET
  Cc: dan.j.williams, akpm, borntraeger, dsterba, gregkh, linux-mm,
	linux-kernel, kernel-janitors

On Sat 09-12-17 08:09:41, Christophe JAILLET wrote:
> A semaphore is acquired before this check, so we must release it before
> leaving.
> 
> Fixes: b7f0554a56f2 ("mm: fail get_vaddr_frames() for filesystem-dax mappings")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> -- Untested --
> 
> The wording of the commit entry and log description could be improved
> but I didn't find something better.

The changelog is ok imo.

> ---
>  mm/frame_vector.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/frame_vector.c b/mm/frame_vector.c
> index 297c7238f7d4..e0c5e659fa82 100644
> --- a/mm/frame_vector.c
> +++ b/mm/frame_vector.c
> @@ -62,8 +62,10 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
>  	 * get_user_pages_longterm() and disallow it for filesystem-dax
>  	 * mappings.
>  	 */
> -	if (vma_is_fsdax(vma))
> +	if (vma_is_fsdax(vma)) {
> +		up_read(&mm->mmap_sem);
>  		return -EOPNOTSUPP;
> +	}

Is there any reason to do a different error handling than other error
paths? Namely not going without goto out?

>  
>  	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
>  		vec->got_ref = true;
> -- 
> 2.14.1
> 

-- 
Michal Hocko
SUSE Labs

^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: [PATCH] mm: Release a semaphore in 'get_vaddr_frames()'
@ 2017-12-10  9:45   ` Michal Hocko
  0 siblings, 0 replies; 7+ messages in thread
From: Michal Hocko @ 2017-12-10  9:45 UTC (permalink / raw)
  To: Christophe JAILLET
  Cc: dan.j.williams, akpm, borntraeger, dsterba, gregkh, linux-mm,
	linux-kernel, kernel-janitors

On Sat 09-12-17 08:09:41, Christophe JAILLET wrote:
> A semaphore is acquired before this check, so we must release it before
> leaving.
> 
> Fixes: b7f0554a56f2 ("mm: fail get_vaddr_frames() for filesystem-dax mappings")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> -- Untested --
> 
> The wording of the commit entry and log description could be improved
> but I didn't find something better.

The changelog is ok imo.

> ---
>  mm/frame_vector.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/frame_vector.c b/mm/frame_vector.c
> index 297c7238f7d4..e0c5e659fa82 100644
> --- a/mm/frame_vector.c
> +++ b/mm/frame_vector.c
> @@ -62,8 +62,10 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
>  	 * get_user_pages_longterm() and disallow it for filesystem-dax
>  	 * mappings.
>  	 */
> -	if (vma_is_fsdax(vma))
> +	if (vma_is_fsdax(vma)) {
> +		up_read(&mm->mmap_sem);
>  		return -EOPNOTSUPP;
> +	}

Is there any reason to do a different error handling than other error
paths? Namely not going without goto out?

>  
>  	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
>  		vec->got_ref = true;
> -- 
> 2.14.1
> 

-- 
Michal Hocko
SUSE Labs

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: [PATCH] mm: Release a semaphore in 'get_vaddr_frames()'
  2017-12-10  9:45   ` Michal Hocko
  (?)
  (?)
@ 2017-12-11  7:28   ` Christophe JAILLET
  -1 siblings, 0 replies; 7+ messages in thread
From: Christophe JAILLET @ 2017-12-11  7:28 UTC (permalink / raw)
  To: linux-kernel; +Cc: linux-mm, kernel-janitors

Le 10/12/2017 à 10:45, Michal Hocko a écrit :
> On Sat 09-12-17 08:09:41, Christophe JAILLET wrote:
>> A semaphore is acquired before this check, so we must release it before
>> leaving.
>>
>> Fixes: b7f0554a56f2 ("mm: fail get_vaddr_frames() for filesystem-dax mappings")
>> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
>> ---
>> -- Untested --
>>
>> The wording of the commit entry and log description could be improved
>> but I didn't find something better.
> The changelog is ok imo.
>
>> ---
>>   mm/frame_vector.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/frame_vector.c b/mm/frame_vector.c
>> index 297c7238f7d4..e0c5e659fa82 100644
>> --- a/mm/frame_vector.c
>> +++ b/mm/frame_vector.c
>> @@ -62,8 +62,10 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
>>   	 * get_user_pages_longterm() and disallow it for filesystem-dax
>>   	 * mappings.
>>   	 */
>> -	if (vma_is_fsdax(vma))
>> +	if (vma_is_fsdax(vma)) {
>> +		up_read(&mm->mmap_sem);
>>   		return -EOPNOTSUPP;
>> +	}
> Is there any reason to do a different error handling than other error
> paths? Namely not going without goto out?

You are right, I misread the code after out:.
I thought it would override the returned value, but I was wrong.
'goto out' is definitively better, IMHO. I'll propose a v2.

CJ

^ permalink raw reply	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2017-12-11  7:29 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-12-09  7:09 [PATCH] mm: Release a semaphore in 'get_vaddr_frames()' Christophe JAILLET
2017-12-09  7:09 ` Christophe JAILLET
2017-12-09  7:09 ` Christophe JAILLET
2017-12-10  9:45 ` Michal Hocko
2017-12-10  9:45   ` Michal Hocko
2017-12-10  9:45   ` Michal Hocko
2017-12-11  7:28   ` Christophe JAILLET

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