[PATCH 0/4] add missing of_node_put

[PATCH 0/4] add missing of_node_put

[Julia Lawall]

The various for_each device_node iterators performs an of_node_get on each
iteration, so a break out of the loop requires an of_node_put.

The complete semantic patch that fixes this problem is
(http://coccinelle.lip6.fr):

// <smpl>
@r@
local idexpression n;
expression e1,e2;
iterator name for_each_node_by_name, for_each_node_by_type,
for_each_compatible_node, for_each_matching_node,
for_each_matching_node_and_match, for_each_child_of_node,
for_each_available_child_of_node, for_each_node_with_property;
iterator i;
statement S;
expression list [n1] es;
@@

(
(
for_each_node_by_name(n,e1) S
|
for_each_node_by_type(n,e1) S
|
for_each_compatible_node(n,e1,e2) S
|
for_each_matching_node(n,e1) S
|
for_each_matching_node_and_match(n,e1,e2) S
|
for_each_child_of_node(e1,n) S
|
for_each_available_child_of_node(e1,n) S
|
for_each_node_with_property(n,e1) S
)
&
i(es,n,...) S
)

@@
local idexpression r.n;
iterator r.i;
expression e;
expression list [r.n1] es;
@@

 i(es,n,...) {
   ...
(
   of_node_put(n);
|
   e = n
|
   return n;
|
+  of_node_put(n);
?  return ...;
)
   ...
 }

@@
local idexpression r.n;
iterator r.i;
expression e;
expression list [r.n1] es;
@@

 i(es,n,...) {
   ...
(
   of_node_put(n);
|
   e = n
|
+  of_node_put(n);
?  break;
)
   ...
 }
... when != n

@@
local idexpression r.n;
iterator r.i;
expression e;
identifier l;
expression list [r.n1] es;
@@

 i(es,n,...) {
   ...
(
   of_node_put(n);
|
   e = n
|
+  of_node_put(n);
?  goto l;
)
   ...
 }
...
l: ... when != n// </smpl>

---

 drivers/iio/adc/qcom-spmi-vadc.c     |    4 +++-
 drivers/mtd/nand/brcmnand/brcmnand.c |   14 ++++++++++----
 drivers/mtd/nand/sunxi_nand.c        |    4 +++-
 drivers/power/reset/at91-reset.c     |    1 +
 4 files changed, 17 insertions(+), 6 deletions(-)

[PATCH 1/4] mtd: brcmnand: improve memory management

[Julia Lawall]

This patch addresses several related memory management issues in the probe
function:

1. for_each_available_child_of_node performs an of_node_get on each
iteration, so a break out of the loop requires an of_node_put.

A simplified version of the semantic patch that fixes this problem is as
follows (http://coccinelle.lip6.fr):

// <smpl>
@@
expression root,e;
local idexpression child;
@@

 for_each_available_child_of_node(root, child) {
   ... when != of_node_put(child)
       when != e = child
(
   return child;
|
+  of_node_put(child);
?  return ...;
)
   ...
 }
// </smpl>

2. The devm_kzalloc'd data is not used if brcmnand_init_cs fails.  Free it
immediately, using devm_kfree in this case, instead of waiting for the
remove function.

3. If the continue is not taken, then host is added to a list, that has a
lifetime beyond the end of the for_each_available_child_of_node loop body.
Thus, of_node_get is needed on child, which is referenced by host.  A
corresponding of_node_put is needed in the remove function.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---

One could consider whether the of_node_get should be on host->of_node,
which looks more similar to the thing that is stored in the list.  I used
child, to be more similar to the of_node_put in the same function.

 drivers/mtd/nand/brcmnand/brcmnand.c |   14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
index 2a437c7..b0cb55d 100644
--- a/drivers/mtd/nand/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/brcmnand/brcmnand.c
@@ -2237,16 +2237,20 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
 			struct brcmnand_host *host;
 
 			host = devm_kzalloc(dev, sizeof(*host), GFP_KERNEL);
-			if (!host)
+			if (!host) {
+				of_node_put(child);
 				return -ENOMEM;
+			}
 			host->pdev = pdev;
 			host->ctrl = ctrl;
 			host->of_node = child;
 
 			ret = brcmnand_init_cs(host);
-			if (ret)
+			if (ret) {
+				devm_kfree(dev, host);
 				continue; /* Try all chip-selects */
-
+			}
+			of_node_get(child);
 			list_add_tail(&host->node, &ctrl->host_list);
 		}
 	}
@@ -2264,8 +2268,10 @@ int brcmnand_remove(struct platform_device *pdev)
 	struct brcmnand_controller *ctrl = dev_get_drvdata(&pdev->dev);
 	struct brcmnand_host *host;
 
-	list_for_each_entry(host, &ctrl->host_list, node)
+	list_for_each_entry(host, &ctrl->host_list, node) {
+		of_node_put(host->of_node);
 		nand_release(&host->mtd);
+	}
 
 	dev_set_drvdata(&pdev->dev, NULL);
 

[PATCH 2/4] mtd: nand: sunxi: add missing of_node_put

[Julia Lawall]

for_each_child_of_node performs an of_node_get on each iteration, so
a break out of the loop requires an of_node_put.

A simplified version of the semantic patch that fixes this problem is as
follows (http://coccinelle.lip6.fr):

// <smpl>
@@
expression root,e;
local idexpression child;
@@

 for_each_child_of_node(root, child) {
   ... when != of_node_put(child)
       when != e = child
(
   return child;
|
+  of_node_put(child);
?  return ...;
)
   ...
 }
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
 drivers/mtd/nand/sunxi_nand.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/sunxi_nand.c b/drivers/mtd/nand/sunxi_nand.c
index 2ed52e4..1bbcc0c 100644
--- a/drivers/mtd/nand/sunxi_nand.c
+++ b/drivers/mtd/nand/sunxi_nand.c
@@ -1391,8 +1391,10 @@ static int sunxi_nand_chips_init(struct device *dev, struct sunxi_nfc *nfc)
 
 	for_each_child_of_node(np, nand_np) {
 		ret = sunxi_nand_chip_init(dev, nfc, nand_np);
-		if (ret)
+		if (ret) {
+			of_node_put(nand_np);
 			return ret;
+		}
 	}
 
 	return 0;

Re: [PATCH 1/4] mtd: brcmnand: improve memory management

[Brian Norris]

On Wed, Nov 18, 2015 at 11:04:11PM +0100, Julia Lawall wrote:
> This patch addresses several related memory management issues in the probe
> function:
> 
> 1. for_each_available_child_of_node performs an of_node_get on each
> iteration, so a break out of the loop requires an of_node_put.
> 
> A simplified version of the semantic patch that fixes this problem is as
> follows (http://coccinelle.lip6.fr):
> 
> // <smpl>
> @@
> expression root,e;
> local idexpression child;
> @@
> 
>  for_each_available_child_of_node(root, child) {
>    ... when != of_node_put(child)
>        when != e = child
> (
>    return child;
> |
> +  of_node_put(child);
> ?  return ...;
> )
>    ...
>  }
> // </smpl>

Good catch again

> 2. The devm_kzalloc'd data is not used if brcmnand_init_cs fails.  Free it
> immediately, using devm_kfree in this case, instead of waiting for the
> remove function.

Same

> 3. If the continue is not taken, then host is added to a list, that has a
> lifetime beyond the end of the for_each_available_child_of_node loop body.
> Thus, of_node_get is needed on child, which is referenced by host.  A
> corresponding of_node_put is needed in the remove function.

This one's a bit silly. We really shouldn't be keeping the reference in
'host' at all. Also, as of commit 215a02fd3087 ("mtd: grab a reference to
the MTD of_node before registering it"), the MTD core will actually be
refcounting the node for us, too, so this isn't really necessary.

I have a patch to remove brcmnand_host::of_node (appended below), which
should make this step obsolete, and be more obvious that no extra
of_node_get()'ing is required.

> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
> 
> ---
> 
> One could consider whether the of_node_get should be on host->of_node,
> which looks more similar to the thing that is stored in the list.  I used
> child, to be more similar to the of_node_put in the same function.
> 
>  drivers/mtd/nand/brcmnand/brcmnand.c |   14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
> index 2a437c7..b0cb55d 100644
> --- a/drivers/mtd/nand/brcmnand/brcmnand.c
> +++ b/drivers/mtd/nand/brcmnand/brcmnand.c
> @@ -2237,16 +2237,20 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
>  			struct brcmnand_host *host;
>  
>  			host = devm_kzalloc(dev, sizeof(*host), GFP_KERNEL);
> -			if (!host)
> +			if (!host) {
> +				of_node_put(child);
>  				return -ENOMEM;

In code reading, I noticed that we don't actually cleanup for prior
iterations of brcmnand_init_cs() here. i.e., if we're exiting here, we
should be doing nand_release() on all previously-registered chips.

> +			}
>  			host->pdev = pdev;
>  			host->ctrl = ctrl;
>  			host->of_node = child;
>  
>  			ret = brcmnand_init_cs(host);
> -			if (ret)
> +			if (ret) {
> +				devm_kfree(dev, host);
>  				continue; /* Try all chip-selects */
> -
> +			}
> +			of_node_get(child);
>  			list_add_tail(&host->node, &ctrl->host_list);
>  		}
>  	}
> @@ -2264,8 +2268,10 @@ int brcmnand_remove(struct platform_device *pdev)
>  	struct brcmnand_controller *ctrl = dev_get_drvdata(&pdev->dev);
>  	struct brcmnand_host *host;
>  
> -	list_for_each_entry(host, &ctrl->host_list, node)
> +	list_for_each_entry(host, &ctrl->host_list, node) {
> +		of_node_put(host->of_node);
>  		nand_release(&host->mtd);
> +	}
>  
>  	dev_set_drvdata(&pdev->dev, NULL);
>  

Patch to kill off some of this:

---8<---
>From 6c51a9ef1325e7b06a7623c1fbca1adf6eeb8253 Mon Sep 17 00:00:00 2001
From: Brian Norris <computersforpeace@gmail.com>
Date: Wed, 18 Nov 2015 14:33:24 -0800
Subject: [PATCH] mtd: brcmnand: drop brcmnand_host::of_node field

We don't actually need to stash a copy of this device_node indefinitely;
we only need it in brcmnand_init_cs().

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Cc: <bcm-kernel-feedback-list@broadcom.com>
Cc: Kamal Dasu <kdasu.kdev@gmail.com>
---
 drivers/mtd/nand/brcmnand/brcmnand.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
index c395b4a75fb1..351438a62aaa 100644
--- a/drivers/mtd/nand/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/brcmnand/brcmnand.c
@@ -176,7 +176,6 @@ struct brcmnand_cfg {
 
 struct brcmnand_host {
 	struct list_head	node;
-	struct device_node	*of_node;
 
 	struct nand_chip	chip;
 	struct mtd_info		mtd;
@@ -1896,10 +1895,9 @@ static int brcmnand_setup_dev(struct brcmnand_host *host)
 	return 0;
 }
 
-static int brcmnand_init_cs(struct brcmnand_host *host)
+static int brcmnand_init_cs(struct brcmnand_host *host, struct device_node *dn)
 {
 	struct brcmnand_controller *ctrl = host->ctrl;
-	struct device_node *dn = host->of_node;
 	struct platform_device *pdev = host->pdev;
 	struct mtd_info *mtd;
 	struct nand_chip *chip;
@@ -2231,9 +2229,8 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
 				return -ENOMEM;
 			host->pdev = pdev;
 			host->ctrl = ctrl;
-			host->of_node = child;
 
-			ret = brcmnand_init_cs(host);
+			ret = brcmnand_init_cs(host, child);
 			if (ret)
 				continue; /* Try all chip-selects */
 
-- 
2.6.0.rc2.230.g3dd15c0

Re: [PATCH 1/4] mtd: brcmnand: improve memory management

[Julia Lawall]

On Wed, 18 Nov 2015, Brian Norris wrote:

> On Wed, Nov 18, 2015 at 11:04:11PM +0100, Julia Lawall wrote:
> > This patch addresses several related memory management issues in the probe
> > function:
> > 
> > 1. for_each_available_child_of_node performs an of_node_get on each
> > iteration, so a break out of the loop requires an of_node_put.
> > 
> > A simplified version of the semantic patch that fixes this problem is as
> > follows (http://coccinelle.lip6.fr):
> > 
> > // <smpl>
> > @@
> > expression root,e;
> > local idexpression child;
> > @@
> > 
> >  for_each_available_child_of_node(root, child) {
> >    ... when != of_node_put(child)
> >        when != e = child
> > (
> >    return child;
> > |
> > +  of_node_put(child);
> > ?  return ...;
> > )
> >    ...
> >  }
> > // </smpl>
> 
> Good catch again
> 
> > 2. The devm_kzalloc'd data is not used if brcmnand_init_cs fails.  Free it
> > immediately, using devm_kfree in this case, instead of waiting for the
> > remove function.
> 
> Same
> 
> > 3. If the continue is not taken, then host is added to a list, that has a
> > lifetime beyond the end of the for_each_available_child_of_node loop body.
> > Thus, of_node_get is needed on child, which is referenced by host.  A
> > corresponding of_node_put is needed in the remove function.
> 
> This one's a bit silly. We really shouldn't be keeping the reference in
> 'host' at all. Also, as of commit 215a02fd3087 ("mtd: grab a reference to
> the MTD of_node before registering it"), the MTD core will actually be
> refcounting the node for us, too, so this isn't really necessary.
> 
> I have a patch to remove brcmnand_host::of_node (appended below), which
> should make this step obsolete, and be more obvious that no extra
> of_node_get()'ing is required.

OK.  Should I resend my patch without this change?

julia

> > Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
> > 
> > ---
> > 
> > One could consider whether the of_node_get should be on host->of_node,
> > which looks more similar to the thing that is stored in the list.  I used
> > child, to be more similar to the of_node_put in the same function.
> > 
> >  drivers/mtd/nand/brcmnand/brcmnand.c |   14 ++++++++++----
> >  1 file changed, 10 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
> > index 2a437c7..b0cb55d 100644
> > --- a/drivers/mtd/nand/brcmnand/brcmnand.c
> > +++ b/drivers/mtd/nand/brcmnand/brcmnand.c
> > @@ -2237,16 +2237,20 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
> >  			struct brcmnand_host *host;
> >  
> >  			host = devm_kzalloc(dev, sizeof(*host), GFP_KERNEL);
> > -			if (!host)
> > +			if (!host) {
> > +				of_node_put(child);
> >  				return -ENOMEM;
> 
> In code reading, I noticed that we don't actually cleanup for prior
> iterations of brcmnand_init_cs() here. i.e., if we're exiting here, we
> should be doing nand_release() on all previously-registered chips.
> 
> > +			}
> >  			host->pdev = pdev;
> >  			host->ctrl = ctrl;
> >  			host->of_node = child;
> >  
> >  			ret = brcmnand_init_cs(host);
> > -			if (ret)
> > +			if (ret) {
> > +				devm_kfree(dev, host);
> >  				continue; /* Try all chip-selects */
> > -
> > +			}
> > +			of_node_get(child);
> >  			list_add_tail(&host->node, &ctrl->host_list);
> >  		}
> >  	}
> > @@ -2264,8 +2268,10 @@ int brcmnand_remove(struct platform_device *pdev)
> >  	struct brcmnand_controller *ctrl = dev_get_drvdata(&pdev->dev);
> >  	struct brcmnand_host *host;
> >  
> > -	list_for_each_entry(host, &ctrl->host_list, node)
> > +	list_for_each_entry(host, &ctrl->host_list, node) {
> > +		of_node_put(host->of_node);
> >  		nand_release(&host->mtd);
> > +	}
> >  
> >  	dev_set_drvdata(&pdev->dev, NULL);
> >  
> 
> Patch to kill off some of this:
> 
> ---8<---
> From 6c51a9ef1325e7b06a7623c1fbca1adf6eeb8253 Mon Sep 17 00:00:00 2001
> From: Brian Norris <computersforpeace@gmail.com>
> Date: Wed, 18 Nov 2015 14:33:24 -0800
> Subject: [PATCH] mtd: brcmnand: drop brcmnand_host::of_node field
> 
> We don't actually need to stash a copy of this device_node indefinitely;
> we only need it in brcmnand_init_cs().
> 
> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
> Cc: <bcm-kernel-feedback-list@broadcom.com>
> Cc: Kamal Dasu <kdasu.kdev@gmail.com>
> ---
>  drivers/mtd/nand/brcmnand/brcmnand.c | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
> index c395b4a75fb1..351438a62aaa 100644
> --- a/drivers/mtd/nand/brcmnand/brcmnand.c
> +++ b/drivers/mtd/nand/brcmnand/brcmnand.c
> @@ -176,7 +176,6 @@ struct brcmnand_cfg {
>  
>  struct brcmnand_host {
>  	struct list_head	node;
> -	struct device_node	*of_node;
>  
>  	struct nand_chip	chip;
>  	struct mtd_info		mtd;
> @@ -1896,10 +1895,9 @@ static int brcmnand_setup_dev(struct brcmnand_host *host)
>  	return 0;
>  }
>  
> -static int brcmnand_init_cs(struct brcmnand_host *host)
> +static int brcmnand_init_cs(struct brcmnand_host *host, struct device_node *dn)
>  {
>  	struct brcmnand_controller *ctrl = host->ctrl;
> -	struct device_node *dn = host->of_node;
>  	struct platform_device *pdev = host->pdev;
>  	struct mtd_info *mtd;
>  	struct nand_chip *chip;
> @@ -2231,9 +2229,8 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
>  				return -ENOMEM;
>  			host->pdev = pdev;
>  			host->ctrl = ctrl;
> -			host->of_node = child;
>  
> -			ret = brcmnand_init_cs(host);
> +			ret = brcmnand_init_cs(host, child);
>  			if (ret)
>  				continue; /* Try all chip-selects */
>  
> -- 
> 2.6.0.rc2.230.g3dd15c0
> 
> --
> To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: [PATCH 1/4] mtd: brcmnand: improve memory management

[Brian Norris]

On Thu, Nov 19, 2015 at 07:13:45AM +0100, Julia Lawall wrote:
> On Wed, 18 Nov 2015, Brian Norris wrote:
> > On Wed, Nov 18, 2015 at 11:04:11PM +0100, Julia Lawall wrote:
> > > 3. If the continue is not taken, then host is added to a list, that has a
> > > lifetime beyond the end of the for_each_available_child_of_node loop body.
> > > Thus, of_node_get is needed on child, which is referenced by host.  A
> > > corresponding of_node_put is needed in the remove function.
> > 
> > This one's a bit silly. We really shouldn't be keeping the reference in
> > 'host' at all. Also, as of commit 215a02fd3087 ("mtd: grab a reference to
> > the MTD of_node before registering it"), the MTD core will actually be
> > refcounting the node for us, too, so this isn't really necessary.
> > 
> > I have a patch to remove brcmnand_host::of_node (appended below), which
> > should make this step obsolete, and be more obvious that no extra
> > of_node_get()'ing is required.
> 
> OK.  Should I resend my patch without this change?

Sure, that'd be good. Then I could merge/rebase mine on top.

Thanks,
Brian

[PATCH 1/4 v2] mtd: brcmnand: improve memory management

[Julia Lawall]

This patch addresses two related memory management issues in the probe
function:

1. for_each_available_child_of_node performs an of_node_get on each
iteration, so a break out of the loop requires an of_node_put.

A simplified version of the semantic patch that fixes this problem is as
follows (http://coccinelle.lip6.fr):

// <smpl>
@@
expression root,e;
local idexpression child;
@@

 for_each_available_child_of_node(root, child) {
   ... when != of_node_put(child)
       when != e = child
(
   return child;
|
+  of_node_put(child);
?  return ...;
)
   ...
 }
// </smpl>

2. The devm_kzalloc'd data is not used if brcmnand_init_cs fails.  Free it
immediately, using devm_kfree in this case, instead of waiting for the
remove function.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---

v2: Drop of_node_get addition, as another patch will get rid of the need
for it completely.

 drivers/mtd/nand/brcmnand/brcmnand.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
index 2a437c7..551d474 100644
--- a/drivers/mtd/nand/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/brcmnand/brcmnand.c
@@ -2237,15 +2237,19 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
 			struct brcmnand_host *host;
 
 			host = devm_kzalloc(dev, sizeof(*host), GFP_KERNEL);
-			if (!host)
+			if (!host) {
+				of_node_put(child);
 				return -ENOMEM;
+			}
 			host->pdev = pdev;
 			host->ctrl = ctrl;
 			host->of_node = child;
 
 			ret = brcmnand_init_cs(host);
-			if (ret)
+			if (ret) {
+				devm_kfree(dev, host);
 				continue; /* Try all chip-selects */
+			}
 
 			list_add_tail(&host->node, &ctrl->host_list);
 		}

Re: [PATCH 2/4] mtd: nand: sunxi: add missing of_node_put

[Chen-Yu Tsai]

On Thu, Nov 19, 2015 at 6:04 AM, Julia Lawall <Julia.Lawall@lip6.fr> wrote:
> for_each_child_of_node performs an of_node_get on each iteration, so
> a break out of the loop requires an of_node_put.
>
> A simplified version of the semantic patch that fixes this problem is as
> follows (http://coccinelle.lip6.fr):
>
> // <smpl>
> @@
> expression root,e;
> local idexpression child;
> @@
>
>  for_each_child_of_node(root, child) {
>    ... when != of_node_put(child)
>        when != e = child
> (
>    return child;
> |
> +  of_node_put(child);
> ?  return ...;
> )
>    ...
>  }
> // </smpl>
>
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

Acked-by: Chen-Yu Tsai <wens@csie.org>

Re: [PATCH 2/4] mtd: nand: sunxi: add missing of_node_put

[Boris Brezillon]

On Wed, 18 Nov 2015 23:04:12 +0100
Julia Lawall <Julia.Lawall@lip6.fr> wrote:

> for_each_child_of_node performs an of_node_get on each iteration, so
> a break out of the loop requires an of_node_put.
> 
> A simplified version of the semantic patch that fixes this problem is as
> follows (http://coccinelle.lip6.fr):
> 
> // <smpl>
> @@
> expression root,e;
> local idexpression child;
> @@
> 
>  for_each_child_of_node(root, child) {
>    ... when != of_node_put(child)
>        when != e = child
> (
>    return child;
> |
> +  of_node_put(child);
> ?  return ...;
> )
>    ...
>  }
> // </smpl>
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Thanks,

Boris

-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

Re: [PATCH 1/4 v2] mtd: brcmnand: improve memory management

[Brian Norris]

On Thu, Nov 19, 2015 at 10:32:15PM +0100, Julia Lawall wrote:
> This patch addresses two related memory management issues in the probe
> function:
> 
> 1. for_each_available_child_of_node performs an of_node_get on each
> iteration, so a break out of the loop requires an of_node_put.
> 
> A simplified version of the semantic patch that fixes this problem is as
> follows (http://coccinelle.lip6.fr):
> 
> // <smpl>
> @@
> expression root,e;
> local idexpression child;
> @@
> 
>  for_each_available_child_of_node(root, child) {
>    ... when != of_node_put(child)
>        when != e = child
> (
>    return child;
> |
> +  of_node_put(child);
> ?  return ...;
> )
>    ...
>  }
> // </smpl>
> 
> 2. The devm_kzalloc'd data is not used if brcmnand_init_cs fails.  Free it
> immediately, using devm_kfree in this case, instead of waiting for the
> remove function.
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
> 
> ---
> 
> v2: Drop of_node_get addition, as another patch will get rid of the need
> for it completely.

Pushed to l2-mtd.git

Re: [PATCH 2/4] mtd: nand: sunxi: add missing of_node_put

[Brian Norris]

On Wed, Nov 18, 2015 at 11:04:12PM +0100, Julia Lawall wrote:
> for_each_child_of_node performs an of_node_get on each iteration, so
> a break out of the loop requires an of_node_put.
> 
> A simplified version of the semantic patch that fixes this problem is as
> follows (http://coccinelle.lip6.fr):
> 
> // <smpl>
> @@
> expression root,e;
> local idexpression child;
> @@
> 
>  for_each_child_of_node(root, child) {
>    ... when != of_node_put(child)
>        when != e = child
> (
>    return child;
> |
> +  of_node_put(child);
> ?  return ...;
> )
>    ...
>  }
> // </smpl>
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
> 

Pushed to l2-mtd.git