diff mbox series

[v4,3/3] PCI: endpoint: pci_epf_create: remove goto labels

Message ID 20180228130719.31218-4-embedded24@evers-fischer.de
State Superseded
Headers show
Series pci: endpoint: Fix double free in pci_epf_create() | expand

Commit Message

Rolf Evers-Fischer Feb. 28, 2018, 1:07 p.m. UTC 
From: Rolf Evers-Fischer <rolf.evers.fischer@aptiv.com>

Removes the goto labels completely, handles the errors at the
respective call site and just returns instead of jumping around.

Signed-off-by: Rolf Evers-Fischer <rolf.evers.fischer@aptiv.com>
---
 drivers/pci/endpoint/pci-epf-core.c | 30 +++++++++---------------------
 1 file changed, 9 insertions(+), 21 deletions(-)

Comments

Kishon Vijay Abraham I Feb. 28, 2018, 1:27 p.m. UTC | #1 
Hi,

On Wednesday 28 February 2018 06:37 PM, Rolf Evers-Fischer wrote:
> From: Rolf Evers-Fischer <rolf.evers.fischer@aptiv.com>
> 
> Removes the goto labels completely, handles the errors at the
> respective call site and just returns instead of jumping around.
> 
> Signed-off-by: Rolf Evers-Fischer <rolf.evers.fischer@aptiv.com>
> ---
>  drivers/pci/endpoint/pci-epf-core.c | 30 +++++++++---------------------
>  1 file changed, 9 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
> index 1878a6776519..cf2c4f6590a0 100644
> --- a/drivers/pci/endpoint/pci-epf-core.c
> +++ b/drivers/pci/endpoint/pci-epf-core.c
> @@ -203,16 +203,14 @@ struct pci_epf *pci_epf_create(const char *name)
>  	int len;
>  
>  	epf = kzalloc(sizeof(*epf), GFP_KERNEL);
> -	if (!epf) {
> -		ret = -ENOMEM;
> -		goto err_ret;
> -	}
> +	if (!epf)
> +		return ERR_PTR(-ENOMEM);
>  
>  	len = strchrnul(name, '.') - name;
>  	epf->name = kstrndup(name, len, GFP_KERNEL);
>  	if (!epf->name) {
> -		ret = -ENOMEM;
> -		goto free_epf;
> +		kfree(epf);
> +		return ERR_PTR(-ENOMEM);
>  	}
>  
>  	dev = &epf->dev;
> @@ -221,24 +219,14 @@ struct pci_epf *pci_epf_create(const char *name)
>  	dev->type = &pci_epf_type;
>  
>  	ret = dev_set_name(dev, "%s", name);
> -	if (ret)
> -		goto put_dev;
> -
> -	ret = device_add(dev);
> -	if (ret)
> -		goto put_dev;
> -
> -	return epf;
> +	if (!ret) {
> +		ret = device_add(dev);
> +		if (!ret)
> +			return epf;

I don't prefer the correct return value being hidden under two levels of 'if'.

Thanks
Kishon
Lorenzo Pieralisi Feb. 28, 2018, 1:33 p.m. UTC | #2 
On Wed, Feb 28, 2018 at 02:07:19PM +0100, Rolf Evers-Fischer wrote:
> From: Rolf Evers-Fischer <rolf.evers.fischer@aptiv.com>
> 
> Removes the goto labels completely, handles the errors at the
> respective call site and just returns instead of jumping around.
> 
> Signed-off-by: Rolf Evers-Fischer <rolf.evers.fischer@aptiv.com>
> ---
>  drivers/pci/endpoint/pci-epf-core.c | 30 +++++++++---------------------
>  1 file changed, 9 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
> index 1878a6776519..cf2c4f6590a0 100644
> --- a/drivers/pci/endpoint/pci-epf-core.c
> +++ b/drivers/pci/endpoint/pci-epf-core.c
> @@ -203,16 +203,14 @@ struct pci_epf *pci_epf_create(const char *name)
>  	int len;
>  
>  	epf = kzalloc(sizeof(*epf), GFP_KERNEL);
> -	if (!epf) {
> -		ret = -ENOMEM;
> -		goto err_ret;
> -	}
> +	if (!epf)
> +		return ERR_PTR(-ENOMEM);
>  
>  	len = strchrnul(name, '.') - name;
>  	epf->name = kstrndup(name, len, GFP_KERNEL);
>  	if (!epf->name) {
> -		ret = -ENOMEM;
> -		goto free_epf;
> +		kfree(epf);
> +		return ERR_PTR(-ENOMEM);
>  	}
>  
>  	dev = &epf->dev;
> @@ -221,24 +219,14 @@ struct pci_epf *pci_epf_create(const char *name)
>  	dev->type = &pci_epf_type;
>  
>  	ret = dev_set_name(dev, "%s", name);
> -	if (ret)
> -		goto put_dev;
> -
> -	ret = device_add(dev);
> -	if (ret)
> -		goto put_dev;
> -
> -	return epf;
> +	if (!ret) {
> +		ret = device_add(dev);
> +		if (!ret)
> +			return epf;
> +	}

This is ugly, sorry. I should have been more explicit, I prefer
this construct:

ret = dev_set_name(dev, "%s", name);
if (ret) {
	kfree(epf->name);
	kfree(epf);
	return ERR_PTR(ret);
}

ret = device_add(dev);
if (ret) {
	put_device(dev);
	return ERR_PTR(ret);
}

return epf;

Please send a v5 and let's be done with it.

Thanks,
Lorenzo

> -put_dev:
>  	put_device(dev);
>  	return ERR_PTR(ret);
> -
> -free_epf:
> -	kfree(epf);
> -
> -err_ret:
> -	return ERR_PTR(ret);
>  }
>  EXPORT_SYMBOL_GPL(pci_epf_create);
>  
> -- 
> 2.16.2
>
Rolf Evers-Fischer Feb. 28, 2018, 2:46 p.m. UTC | #3 
Hi Kishon and Lorenzo,

On Wed, 28 Feb 2018, Lorenzo Pieralisi wrote:

> On Wed, Feb 28, 2018 at 02:07:19PM +0100, Rolf Evers-Fischer wrote:
> > From: Rolf Evers-Fischer <rolf.evers.fischer@aptiv.com>
> > 
> > Removes the goto labels completely, handles the errors at the
> > respective call site and just returns instead of jumping around.
> > 
> > Signed-off-by: Rolf Evers-Fischer <rolf.evers.fischer@aptiv.com>
> > ---
> >  drivers/pci/endpoint/pci-epf-core.c | 30 +++++++++---------------------
> >  1 file changed, 9 insertions(+), 21 deletions(-)
> > 
> > diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
> > index 1878a6776519..cf2c4f6590a0 100644
> > --- a/drivers/pci/endpoint/pci-epf-core.c
> > +++ b/drivers/pci/endpoint/pci-epf-core.c
> > @@ -203,16 +203,14 @@ struct pci_epf *pci_epf_create(const char *name)
> >  	int len;
> >  
> >  	epf = kzalloc(sizeof(*epf), GFP_KERNEL);
> > -	if (!epf) {
> > -		ret = -ENOMEM;
> > -		goto err_ret;
> > -	}
> > +	if (!epf)
> > +		return ERR_PTR(-ENOMEM);
> >  
> >  	len = strchrnul(name, '.') - name;
> >  	epf->name = kstrndup(name, len, GFP_KERNEL);
> >  	if (!epf->name) {
> > -		ret = -ENOMEM;
> > -		goto free_epf;
> > +		kfree(epf);
> > +		return ERR_PTR(-ENOMEM);
> >  	}
> >  
> >  	dev = &epf->dev;
> > @@ -221,24 +219,14 @@ struct pci_epf *pci_epf_create(const char *name)
> >  	dev->type = &pci_epf_type;
> >  
> >  	ret = dev_set_name(dev, "%s", name);
> > -	if (ret)
> > -		goto put_dev;
> > -
> > -	ret = device_add(dev);
> > -	if (ret)
> > -		goto put_dev;
> > -
> > -	return epf;
> > +	if (!ret) {
> > +		ret = device_add(dev);
> > +		if (!ret)
> > +			return epf;
> > +	}
> 
> This is ugly, sorry. I should have been more explicit, I prefer
> this construct:
> 
> ret = dev_set_name(dev, "%s", name);
> if (ret) {
> 	kfree(epf->name);
> 	kfree(epf);
> 	return ERR_PTR(ret);
> }
> 
> ret = device_add(dev);
> if (ret) {
> 	put_device(dev);
> 	return ERR_PTR(ret);
> }
> 
> return epf;
> 
> Please send a v5 and let's be done with it.
> 

Thank you for your feedback. I agree with you. Hiding the correct return 
value under two levels of 'if' is not the best idea.

I will send a v5 containing the proposal from Lorenzo. There is only one
difference: We must call 'put_device()' in both error cases, because
we have already initialized the device before. We had also jumped into
'put_dev:' in both situations before.

The modified code will then look like this:

 ret = dev_set_name(dev, "%s", name);
 if (ret) {
 	put_device(dev);
 	return ERR_PTR(ret);
 }

 ret = device_add(dev);
 if (ret) {
 	put_device(dev);
 	return ERR_PTR(ret);
 }

 return epf;

Best regards,
 Rolf

> > -put_dev:
> >  	put_device(dev);
> >  	return ERR_PTR(ret);
> > -
> > -free_epf:
> > -	kfree(epf);
> > -
> > -err_ret:
> > -	return ERR_PTR(ret);
> >  }
> >  EXPORT_SYMBOL_GPL(pci_epf_create);
> >  
> > -- 
> > 2.16.2
> > 
>
diff mbox series

Patch

diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
index 1878a6776519..cf2c4f6590a0 100644
--- a/drivers/pci/endpoint/pci-epf-core.c
+++ b/drivers/pci/endpoint/pci-epf-core.c
@@ -203,16 +203,14 @@  struct pci_epf *pci_epf_create(const char *name)
 	int len;
 
 	epf = kzalloc(sizeof(*epf), GFP_KERNEL);
-	if (!epf) {
-		ret = -ENOMEM;
-		goto err_ret;
-	}
+	if (!epf)
+		return ERR_PTR(-ENOMEM);
 
 	len = strchrnul(name, '.') - name;
 	epf->name = kstrndup(name, len, GFP_KERNEL);
 	if (!epf->name) {
-		ret = -ENOMEM;
-		goto free_epf;
+		kfree(epf);
+		return ERR_PTR(-ENOMEM);
 	}
 
 	dev = &epf->dev;
@@ -221,24 +219,14 @@  struct pci_epf *pci_epf_create(const char *name)
 	dev->type = &pci_epf_type;
 
 	ret = dev_set_name(dev, "%s", name);
-	if (ret)
-		goto put_dev;
-
-	ret = device_add(dev);
-	if (ret)
-		goto put_dev;
-
-	return epf;
+	if (!ret) {
+		ret = device_add(dev);
+		if (!ret)
+			return epf;
+	}
 
-put_dev:
 	put_device(dev);
 	return ERR_PTR(ret);
-
-free_epf:
-	kfree(epf);
-
-err_ret:
-	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(pci_epf_create);