RE: [PATCH v3] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create

[Jon Maloy]

> -Original Message-
> From: Ying Xue [mailto:ying@windriver.com]
> Sent: Wednesday, April 11, 2018 06:27
> To: Jia-Ju Bai <baijiaju1...@gmail.com>; Jon Maloy
> <jon.ma...@ericsson.com>; da...@davemloft.net
> Cc: net...@vger.kernel.org; tipc-discuss...@lists.sourceforge.net; linux-
> ker...@vger.kernel.org
> Subject: Re: [PATCH v3] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in
> tipc_mon_create
> 
> On 04/11/2018 06:24 PM, Jia-Ju Bai wrote:
> > tipc_mon_create() is never called in atomic context.
> >
> > The call chain ending up at tipc_mon_create() is:
> > [1] tipc_mon_create() <- tipc_enable_bearer() <-
> > tipc_nl_bearer_enable()
> > tipc_nl_bearer_enable() calls rtnl_lock(), which indicates this
> > function is not called in atomic context.
> >
> > Despite never getting called from atomic context,
> > tipc_mon_create() calls kzalloc() with GFP_ATOMIC, which does not
> > sleep for allocation.
> > GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
> which
> > can sleep and improve the possibility of successful allocation.
> >
> > This is found by a static analysis tool named DCNS written by myself.
> > And I also manually check it.
> >
> > Signed-off-by: Jia-Ju Bai <baijiaju1...@gmail.com>
> 
> Acked-by: Ying Xue <ying@windriver.com>
Acked-by: Jon Maloy <jon.ma...@ericsson.com>
> 
> > ---
> > v2:
> > * Modify the description of GFP_ATOMIC in v1.
> >   Thank Eric for good advice.
> > v3:
> > * Modify wrong text in description in v2.
> >   Thank Ying for good advice.
> > ---
> >  net/tipc/monitor.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c index
> > 9e109bb..9714d80 100644
> > --- a/net/tipc/monitor.c
> > +++ b/net/tipc/monitor.c
> > @@ -604,9 +604,9 @@ int tipc_mon_create(struct net *net, int bearer_id)
> > if (tn->monitors[bearer_id])
> > return 0;
> >
> > -   mon = kzalloc(sizeof(*mon), GFP_ATOMIC);
> > -   self = kzalloc(sizeof(*self), GFP_ATOMIC);
> > -   dom = kzalloc(sizeof(*dom), GFP_ATOMIC);
> > +   mon = kzalloc(sizeof(*mon), GFP_KERNEL);
> > +   self = kzalloc(sizeof(*self), GFP_KERNEL);
> > +   dom = kzalloc(sizeof(*dom), GFP_KERNEL);
> > if (!mon || !self || !dom) {
> > kfree(mon);
> > kfree(self);
> >

RE: [PATCH v3] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create

[Jon Maloy]

> -Original Message-
> From: Ying Xue [mailto:ying@windriver.com]
> Sent: Wednesday, April 11, 2018 06:27
> To: Jia-Ju Bai ; Jon Maloy
> ; da...@davemloft.net
> Cc: net...@vger.kernel.org; tipc-discuss...@lists.sourceforge.net; linux-
> ker...@vger.kernel.org
> Subject: Re: [PATCH v3] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in
> tipc_mon_create
> 
> On 04/11/2018 06:24 PM, Jia-Ju Bai wrote:
> > tipc_mon_create() is never called in atomic context.
> >
> > The call chain ending up at tipc_mon_create() is:
> > [1] tipc_mon_create() <- tipc_enable_bearer() <-
> > tipc_nl_bearer_enable()
> > tipc_nl_bearer_enable() calls rtnl_lock(), which indicates this
> > function is not called in atomic context.
> >
> > Despite never getting called from atomic context,
> > tipc_mon_create() calls kzalloc() with GFP_ATOMIC, which does not
> > sleep for allocation.
> > GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
> which
> > can sleep and improve the possibility of successful allocation.
> >
> > This is found by a static analysis tool named DCNS written by myself.
> > And I also manually check it.
> >
> > Signed-off-by: Jia-Ju Bai 
> 
> Acked-by: Ying Xue 
Acked-by: Jon Maloy 
> 
> > ---
> > v2:
> > * Modify the description of GFP_ATOMIC in v1.
> >   Thank Eric for good advice.
> > v3:
> > * Modify wrong text in description in v2.
> >   Thank Ying for good advice.
> > ---
> >  net/tipc/monitor.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c index
> > 9e109bb..9714d80 100644
> > --- a/net/tipc/monitor.c
> > +++ b/net/tipc/monitor.c
> > @@ -604,9 +604,9 @@ int tipc_mon_create(struct net *net, int bearer_id)
> > if (tn->monitors[bearer_id])
> > return 0;
> >
> > -   mon = kzalloc(sizeof(*mon), GFP_ATOMIC);
> > -   self = kzalloc(sizeof(*self), GFP_ATOMIC);
> > -   dom = kzalloc(sizeof(*dom), GFP_ATOMIC);
> > +   mon = kzalloc(sizeof(*mon), GFP_KERNEL);
> > +   self = kzalloc(sizeof(*self), GFP_KERNEL);
> > +   dom = kzalloc(sizeof(*dom), GFP_KERNEL);
> > if (!mon || !self || !dom) {
> > kfree(mon);
> > kfree(self);
> >

Re: [PATCH v3] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create

[Ying Xue]

On 04/11/2018 06:24 PM, Jia-Ju Bai wrote:
> tipc_mon_create() is never called in atomic context.
> 
> The call chain ending up at tipc_mon_create() is:
> [1] tipc_mon_create() <- tipc_enable_bearer() <- tipc_nl_bearer_enable()
> tipc_nl_bearer_enable() calls rtnl_lock(), which indicates this function
> is not called in atomic context.
> 
> Despite never getting called from atomic context,
> tipc_mon_create() calls kzalloc() with GFP_ATOMIC,
> which does not sleep for allocation.
> GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
> which can sleep and improve the possibility of successful allocation.
> 
> This is found by a static analysis tool named DCNS written by myself.
> And I also manually check it.
> 
> Signed-off-by: Jia-Ju Bai 

Acked-by: Ying Xue 

> ---
> v2:
> * Modify the description of GFP_ATOMIC in v1.
>   Thank Eric for good advice.
> v3:
> * Modify wrong text in description in v2.
>   Thank Ying for good advice.
> ---
>  net/tipc/monitor.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c
> index 9e109bb..9714d80 100644
> --- a/net/tipc/monitor.c
> +++ b/net/tipc/monitor.c
> @@ -604,9 +604,9 @@ int tipc_mon_create(struct net *net, int bearer_id)
>   if (tn->monitors[bearer_id])
>   return 0;
>  
> - mon = kzalloc(sizeof(*mon), GFP_ATOMIC);
> - self = kzalloc(sizeof(*self), GFP_ATOMIC);
> - dom = kzalloc(sizeof(*dom), GFP_ATOMIC);
> + mon = kzalloc(sizeof(*mon), GFP_KERNEL);
> + self = kzalloc(sizeof(*self), GFP_KERNEL);
> + dom = kzalloc(sizeof(*dom), GFP_KERNEL);
>   if (!mon || !self || !dom) {
>   kfree(mon);
>   kfree(self);
> 

Re: [PATCH v3] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create

[Ying Xue]

On 04/11/2018 06:24 PM, Jia-Ju Bai wrote:
> tipc_mon_create() is never called in atomic context.
> 
> The call chain ending up at tipc_mon_create() is:
> [1] tipc_mon_create() <- tipc_enable_bearer() <- tipc_nl_bearer_enable()
> tipc_nl_bearer_enable() calls rtnl_lock(), which indicates this function
> is not called in atomic context.
> 
> Despite never getting called from atomic context,
> tipc_mon_create() calls kzalloc() with GFP_ATOMIC,
> which does not sleep for allocation.
> GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
> which can sleep and improve the possibility of successful allocation.
> 
> This is found by a static analysis tool named DCNS written by myself.
> And I also manually check it.
> 
> Signed-off-by: Jia-Ju Bai 

Acked-by: Ying Xue 

> ---
> v2:
> * Modify the description of GFP_ATOMIC in v1.
>   Thank Eric for good advice.
> v3:
> * Modify wrong text in description in v2.
>   Thank Ying for good advice.
> ---
>  net/tipc/monitor.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c
> index 9e109bb..9714d80 100644
> --- a/net/tipc/monitor.c
> +++ b/net/tipc/monitor.c
> @@ -604,9 +604,9 @@ int tipc_mon_create(struct net *net, int bearer_id)
>   if (tn->monitors[bearer_id])
>   return 0;
>  
> - mon = kzalloc(sizeof(*mon), GFP_ATOMIC);
> - self = kzalloc(sizeof(*self), GFP_ATOMIC);
> - dom = kzalloc(sizeof(*dom), GFP_ATOMIC);
> + mon = kzalloc(sizeof(*mon), GFP_KERNEL);
> + self = kzalloc(sizeof(*self), GFP_KERNEL);
> + dom = kzalloc(sizeof(*dom), GFP_KERNEL);
>   if (!mon || !self || !dom) {
>   kfree(mon);
>   kfree(self);
> 

[PATCH v3] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create

[Jia-Ju Bai]

tipc_mon_create() is never called in atomic context.

The call chain ending up at tipc_mon_create() is:
[1] tipc_mon_create() <- tipc_enable_bearer() <- tipc_nl_bearer_enable()
tipc_nl_bearer_enable() calls rtnl_lock(), which indicates this function
is not called in atomic context.

Despite never getting called from atomic context,
tipc_mon_create() calls kzalloc() with GFP_ATOMIC,
which does not sleep for allocation.
GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
which can sleep and improve the possibility of successful allocation.

This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.

Signed-off-by: Jia-Ju Bai 
---
v2:
* Modify the description of GFP_ATOMIC in v1.
  Thank Eric for good advice.
v3:
* Modify wrong text in description in v2.
  Thank Ying for good advice.
---
 net/tipc/monitor.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c
index 9e109bb..9714d80 100644
--- a/net/tipc/monitor.c
+++ b/net/tipc/monitor.c
@@ -604,9 +604,9 @@ int tipc_mon_create(struct net *net, int bearer_id)
if (tn->monitors[bearer_id])
return 0;
 
-   mon = kzalloc(sizeof(*mon), GFP_ATOMIC);
-   self = kzalloc(sizeof(*self), GFP_ATOMIC);
-   dom = kzalloc(sizeof(*dom), GFP_ATOMIC);
+   mon = kzalloc(sizeof(*mon), GFP_KERNEL);
+   self = kzalloc(sizeof(*self), GFP_KERNEL);
+   dom = kzalloc(sizeof(*dom), GFP_KERNEL);
if (!mon || !self || !dom) {
kfree(mon);
kfree(self);
-- 
1.9.1

[PATCH v3] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create

[Jia-Ju Bai]

tipc_mon_create() is never called in atomic context.

The call chain ending up at tipc_mon_create() is:
[1] tipc_mon_create() <- tipc_enable_bearer() <- tipc_nl_bearer_enable()
tipc_nl_bearer_enable() calls rtnl_lock(), which indicates this function
is not called in atomic context.

Despite never getting called from atomic context,
tipc_mon_create() calls kzalloc() with GFP_ATOMIC,
which does not sleep for allocation.
GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
which can sleep and improve the possibility of successful allocation.

This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.

Signed-off-by: Jia-Ju Bai 
---
v2:
* Modify the description of GFP_ATOMIC in v1.
  Thank Eric for good advice.
v3:
* Modify wrong text in description in v2.
  Thank Ying for good advice.
---
 net/tipc/monitor.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c
index 9e109bb..9714d80 100644
--- a/net/tipc/monitor.c
+++ b/net/tipc/monitor.c
@@ -604,9 +604,9 @@ int tipc_mon_create(struct net *net, int bearer_id)
if (tn->monitors[bearer_id])
return 0;
 
-   mon = kzalloc(sizeof(*mon), GFP_ATOMIC);
-   self = kzalloc(sizeof(*self), GFP_ATOMIC);
-   dom = kzalloc(sizeof(*dom), GFP_ATOMIC);
+   mon = kzalloc(sizeof(*mon), GFP_KERNEL);
+   self = kzalloc(sizeof(*self), GFP_KERNEL);
+   dom = kzalloc(sizeof(*dom), GFP_KERNEL);
if (!mon || !self || !dom) {
kfree(mon);
kfree(self);
-- 
1.9.1