[PATCH] PCI: xilinx-nwl: Simplify code and fix a memory leak

[PATCH] PCI: xilinx-nwl: Simplify code and fix a memory leak

[Christophe JAILLET]

Allocate space for 'bitmap' in 'struct nwl_msi' at build time instead of
dynamically allocating the memory at runtime.

This simplifies code (especially error handling paths) and avoid some
open-coded arithmetic in allocator arguments

This also fixes a potential memory leak. The bitmap was never freed. It is
now part of a managed resource.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
 drivers/pci/controller/pcie-xilinx-nwl.c | 30 ++++++------------------
 1 file changed, 7 insertions(+), 23 deletions(-)

diff --git a/drivers/pci/controller/pcie-xilinx-nwl.c b/drivers/pci/controller/pcie-xilinx-nwl.c
index a72b4f9a2b00..40d070e54ad2 100644
--- a/drivers/pci/controller/pcie-xilinx-nwl.c
+++ b/drivers/pci/controller/pcie-xilinx-nwl.c
@@ -146,7 +146,7 @@
 
 struct nwl_msi {			/* MSI information */
 	struct irq_domain *msi_domain;
-	unsigned long *bitmap;
+	DECLARE_BITMAP(bitmap, INT_PCI_MSI_NR);
 	struct irq_domain *dev_domain;
 	struct mutex lock;		/* protect bitmap variable */
 	int irq_msi0;
@@ -335,12 +335,10 @@ static void nwl_pcie_leg_handler(struct irq_desc *desc)
 
 static void nwl_pcie_handle_msi_irq(struct nwl_pcie *pcie, u32 status_reg)
 {
-	struct nwl_msi *msi;
+	struct nwl_msi *msi = &pcie->msi;
 	unsigned long status;
 	u32 bit;
 
-	msi = &pcie->msi;
-
 	while ((status = nwl_bridge_readl(pcie, status_reg)) != 0) {
 		for_each_set_bit(bit, &status, 32) {
 			nwl_bridge_writel(pcie, 1 << bit, status_reg);
@@ -560,30 +558,21 @@ static int nwl_pcie_enable_msi(struct nwl_pcie *pcie)
 	struct nwl_msi *msi = &pcie->msi;
 	unsigned long base;
 	int ret;
-	int size = BITS_TO_LONGS(INT_PCI_MSI_NR) * sizeof(long);
 
 	mutex_init(&msi->lock);
 
-	msi->bitmap = kzalloc(size, GFP_KERNEL);
-	if (!msi->bitmap)
-		return -ENOMEM;
-
 	/* Get msi_1 IRQ number */
 	msi->irq_msi1 = platform_get_irq_byname(pdev, "msi1");
-	if (msi->irq_msi1 < 0) {
-		ret = -EINVAL;
-		goto err;
-	}
+	if (msi->irq_msi1 < 0)
+		return -EINVAL;
 
 	irq_set_chained_handler_and_data(msi->irq_msi1,
 					 nwl_pcie_msi_handler_high, pcie);
 
 	/* Get msi_0 IRQ number */
 	msi->irq_msi0 = platform_get_irq_byname(pdev, "msi0");
-	if (msi->irq_msi0 < 0) {
-		ret = -EINVAL;
-		goto err;
-	}
+	if (msi->irq_msi0 < 0)
+		return -EINVAL;
 
 	irq_set_chained_handler_and_data(msi->irq_msi0,
 					 nwl_pcie_msi_handler_low, pcie);
@@ -592,8 +581,7 @@ static int nwl_pcie_enable_msi(struct nwl_pcie *pcie)
 	ret = nwl_bridge_readl(pcie, I_MSII_CAPABILITIES) & MSII_PRESENT;
 	if (!ret) {
 		dev_err(dev, "MSI not present\n");
-		ret = -EIO;
-		goto err;
+		return -EIO;
 	}
 
 	/* Enable MSII */
@@ -632,10 +620,6 @@ static int nwl_pcie_enable_msi(struct nwl_pcie *pcie)
 	nwl_bridge_writel(pcie, MSGF_MSI_SR_LO_MASK, MSGF_MSI_MASK_LO);
 
 	return 0;
-err:
-	kfree(msi->bitmap);
-	msi->bitmap = NULL;
-	return ret;
 }
 
 static int nwl_pcie_bridge_init(struct nwl_pcie *pcie)
-- 
2.30.2

Re: [PATCH] PCI: xilinx-nwl: Simplify code and fix a memory leak

[Krzysztof Wilczyński]

Hi Christophe,

> Allocate space for 'bitmap' in 'struct nwl_msi' at build time instead of
> dynamically allocating the memory at runtime.
> 
> This simplifies code (especially error handling paths) and avoid some
> open-coded arithmetic in allocator arguments
> 
> This also fixes a potential memory leak. The bitmap was never freed. It is
> now part of a managed resource.

Just to confirm - you mean potentially leaking when the driver would be
unloaded?  Not the error handling path, correct?

> --- a/drivers/pci/controller/pcie-xilinx-nwl.c
> +++ b/drivers/pci/controller/pcie-xilinx-nwl.c
> @@ -146,7 +146,7 @@
>  
>  struct nwl_msi {			/* MSI information */
>  	struct irq_domain *msi_domain;
> -	unsigned long *bitmap;
> +	DECLARE_BITMAP(bitmap, INT_PCI_MSI_NR);
>  	struct irq_domain *dev_domain;
>  	struct mutex lock;		/* protect bitmap variable */
>  	int irq_msi0;
> @@ -335,12 +335,10 @@ static void nwl_pcie_leg_handler(struct irq_desc *desc)
>  
>  static void nwl_pcie_handle_msi_irq(struct nwl_pcie *pcie, u32 status_reg)
>  {
> -	struct nwl_msi *msi;
> +	struct nwl_msi *msi = &pcie->msi;
>  	unsigned long status;
>  	u32 bit;
>  
> -	msi = &pcie->msi;
> -
>  	while ((status = nwl_bridge_readl(pcie, status_reg)) != 0) {
>  		for_each_set_bit(bit, &status, 32) {
>  			nwl_bridge_writel(pcie, 1 << bit, status_reg);
> @@ -560,30 +558,21 @@ static int nwl_pcie_enable_msi(struct nwl_pcie *pcie)
>  	struct nwl_msi *msi = &pcie->msi;
>  	unsigned long base;
>  	int ret;
> -	int size = BITS_TO_LONGS(INT_PCI_MSI_NR) * sizeof(long);
>  
>  	mutex_init(&msi->lock);
>  
> -	msi->bitmap = kzalloc(size, GFP_KERNEL);
> -	if (!msi->bitmap)
> -		return -ENOMEM;
> -
>  	/* Get msi_1 IRQ number */
>  	msi->irq_msi1 = platform_get_irq_byname(pdev, "msi1");
> -	if (msi->irq_msi1 < 0) {
> -		ret = -EINVAL;
> -		goto err;
> -	}
> +	if (msi->irq_msi1 < 0)
> +		return -EINVAL;
>  
>  	irq_set_chained_handler_and_data(msi->irq_msi1,
>  					 nwl_pcie_msi_handler_high, pcie);
>  
>  	/* Get msi_0 IRQ number */
>  	msi->irq_msi0 = platform_get_irq_byname(pdev, "msi0");
> -	if (msi->irq_msi0 < 0) {
> -		ret = -EINVAL;
> -		goto err;
> -	}
> +	if (msi->irq_msi0 < 0)
> +		return -EINVAL;
>  
>  	irq_set_chained_handler_and_data(msi->irq_msi0,
>  					 nwl_pcie_msi_handler_low, pcie);
> @@ -592,8 +581,7 @@ static int nwl_pcie_enable_msi(struct nwl_pcie *pcie)
>  	ret = nwl_bridge_readl(pcie, I_MSII_CAPABILITIES) & MSII_PRESENT;
>  	if (!ret) {
>  		dev_err(dev, "MSI not present\n");
> -		ret = -EIO;
> -		goto err;
> +		return -EIO;
>  	}
>  
>  	/* Enable MSII */
> @@ -632,10 +620,6 @@ static int nwl_pcie_enable_msi(struct nwl_pcie *pcie)
>  	nwl_bridge_writel(pcie, MSGF_MSI_SR_LO_MASK, MSGF_MSI_MASK_LO);
>  
>  	return 0;
> -err:
> -	kfree(msi->bitmap);
> -	msi->bitmap = NULL;
> -	return ret;

Thank you!

Reviewed-by: Krzysztof Wilczyński <kw@linux.com>

	Krzysztof

Re: [PATCH] PCI: xilinx-nwl: Simplify code and fix a memory leak

[Christophe JAILLET]

Le 08/11/2021 à 01:31, Krzysztof Wilczyński a écrit :
> Hi Christophe,
> 
>> Allocate space for 'bitmap' in 'struct nwl_msi' at build time instead of
>> dynamically allocating the memory at runtime.
>>
>> This simplifies code (especially error handling paths) and avoid some
>> open-coded arithmetic in allocator arguments
>>
>> This also fixes a potential memory leak. The bitmap was never freed. It is
>> now part of a managed resource.
> 
> Just to confirm - you mean potentially leaking when the driver would be
> unloaded?  Not the error handling path, correct?

Correct, the leak would happen on driver unload only.

CJ

> 
>> --- a/drivers/pci/controller/pcie-xilinx-nwl.c
>> +++ b/drivers/pci/controller/pcie-xilinx-nwl.c
>> @@ -146,7 +146,7 @@
>>   
>>   struct nwl_msi {			/* MSI information */
>>   	struct irq_domain *msi_domain;
>> -	unsigned long *bitmap;
>> +	DECLARE_BITMAP(bitmap, INT_PCI_MSI_NR);
>>   	struct irq_domain *dev_domain;
>>   	struct mutex lock;		/* protect bitmap variable */
>>   	int irq_msi0;
>> @@ -335,12 +335,10 @@ static void nwl_pcie_leg_handler(struct irq_desc *desc)
>>   
>>   static void nwl_pcie_handle_msi_irq(struct nwl_pcie *pcie, u32 status_reg)
>>   {
>> -	struct nwl_msi *msi;
>> +	struct nwl_msi *msi = &pcie->msi;
>>   	unsigned long status;
>>   	u32 bit;
>>   
>> -	msi = &pcie->msi;
>> -
>>   	while ((status = nwl_bridge_readl(pcie, status_reg)) != 0) {
>>   		for_each_set_bit(bit, &status, 32) {
>>   			nwl_bridge_writel(pcie, 1 << bit, status_reg);
>> @@ -560,30 +558,21 @@ static int nwl_pcie_enable_msi(struct nwl_pcie *pcie)
>>   	struct nwl_msi *msi = &pcie->msi;
>>   	unsigned long base;
>>   	int ret;
>> -	int size = BITS_TO_LONGS(INT_PCI_MSI_NR) * sizeof(long);
>>   
>>   	mutex_init(&msi->lock);
>>   
>> -	msi->bitmap = kzalloc(size, GFP_KERNEL);
>> -	if (!msi->bitmap)
>> -		return -ENOMEM;
>> -
>>   	/* Get msi_1 IRQ number */
>>   	msi->irq_msi1 = platform_get_irq_byname(pdev, "msi1");
>> -	if (msi->irq_msi1 < 0) {
>> -		ret = -EINVAL;
>> -		goto err;
>> -	}
>> +	if (msi->irq_msi1 < 0)
>> +		return -EINVAL;
>>   
>>   	irq_set_chained_handler_and_data(msi->irq_msi1,
>>   					 nwl_pcie_msi_handler_high, pcie);
>>   
>>   	/* Get msi_0 IRQ number */
>>   	msi->irq_msi0 = platform_get_irq_byname(pdev, "msi0");
>> -	if (msi->irq_msi0 < 0) {
>> -		ret = -EINVAL;
>> -		goto err;
>> -	}
>> +	if (msi->irq_msi0 < 0)
>> +		return -EINVAL;
>>   
>>   	irq_set_chained_handler_and_data(msi->irq_msi0,
>>   					 nwl_pcie_msi_handler_low, pcie);
>> @@ -592,8 +581,7 @@ static int nwl_pcie_enable_msi(struct nwl_pcie *pcie)
>>   	ret = nwl_bridge_readl(pcie, I_MSII_CAPABILITIES) & MSII_PRESENT;
>>   	if (!ret) {
>>   		dev_err(dev, "MSI not present\n");
>> -		ret = -EIO;
>> -		goto err;
>> +		return -EIO;
>>   	}
>>   
>>   	/* Enable MSII */
>> @@ -632,10 +620,6 @@ static int nwl_pcie_enable_msi(struct nwl_pcie *pcie)
>>   	nwl_bridge_writel(pcie, MSGF_MSI_SR_LO_MASK, MSGF_MSI_MASK_LO);
>>   
>>   	return 0;
>> -err:
>> -	kfree(msi->bitmap);
>> -	msi->bitmap = NULL;
>> -	return ret;
> 
> Thank you!
> 
> Reviewed-by: Krzysztof Wilczyński <kw@linux.com>
> 
> 	Krzysztof
> 

Re: [PATCH] PCI: xilinx-nwl: Simplify code and fix a memory leak

[Lorenzo Pieralisi]

On Sun, 7 Nov 2021 11:04:43 +0100, Christophe JAILLET wrote:
> Allocate space for 'bitmap' in 'struct nwl_msi' at build time instead of
> dynamically allocating the memory at runtime.
> 
> This simplifies code (especially error handling paths) and avoid some
> open-coded arithmetic in allocator arguments
> 
> This also fixes a potential memory leak. The bitmap was never freed. It is
> now part of a managed resource.
> 
> [...]

Applied to pci/xilinx-nwl, thanks!

[1/1] PCI: xilinx-nwl: Simplify code and fix a memory leak
      https://git.kernel.org/lpieralisi/pci/c/e2b86f9777

Thanks,
Lorenzo

Re: [PATCH] PCI: xilinx-nwl: Simplify code and fix a memory leak

[Bjorn Helgaas]

On Sun, Nov 07, 2021 at 11:04:43AM +0100, Christophe JAILLET wrote:
> Allocate space for 'bitmap' in 'struct nwl_msi' at build time instead of
> dynamically allocating the memory at runtime.

Definitely a good change.  To be pedantic, I don't think this converts
the alloc to *build* time.  It converts it to probe-time, when
nwl_pcie_probe() calls devm_pci_alloc_host_bridge().

> This simplifies code (especially error handling paths) and avoid some
> open-coded arithmetic in allocator arguments
> 
> This also fixes a potential memory leak. The bitmap was never freed. It is
> now part of a managed resource.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
>  drivers/pci/controller/pcie-xilinx-nwl.c | 30 ++++++------------------
>  1 file changed, 7 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-xilinx-nwl.c b/drivers/pci/controller/pcie-xilinx-nwl.c
> index a72b4f9a2b00..40d070e54ad2 100644
> --- a/drivers/pci/controller/pcie-xilinx-nwl.c
> +++ b/drivers/pci/controller/pcie-xilinx-nwl.c
> @@ -146,7 +146,7 @@
>  
>  struct nwl_msi {			/* MSI information */
>  	struct irq_domain *msi_domain;
> -	unsigned long *bitmap;
> +	DECLARE_BITMAP(bitmap, INT_PCI_MSI_NR);
>  	struct irq_domain *dev_domain;
>  	struct mutex lock;		/* protect bitmap variable */
>  	int irq_msi0;
> @@ -335,12 +335,10 @@ static void nwl_pcie_leg_handler(struct irq_desc *desc)
>  
>  static void nwl_pcie_handle_msi_irq(struct nwl_pcie *pcie, u32 status_reg)
>  {
> -	struct nwl_msi *msi;
> +	struct nwl_msi *msi = &pcie->msi;
>  	unsigned long status;
>  	u32 bit;
>  
> -	msi = &pcie->msi;
> -
>  	while ((status = nwl_bridge_readl(pcie, status_reg)) != 0) {
>  		for_each_set_bit(bit, &status, 32) {
>  			nwl_bridge_writel(pcie, 1 << bit, status_reg);
> @@ -560,30 +558,21 @@ static int nwl_pcie_enable_msi(struct nwl_pcie *pcie)
>  	struct nwl_msi *msi = &pcie->msi;
>  	unsigned long base;
>  	int ret;
> -	int size = BITS_TO_LONGS(INT_PCI_MSI_NR) * sizeof(long);
>  
>  	mutex_init(&msi->lock);
>  
> -	msi->bitmap = kzalloc(size, GFP_KERNEL);
> -	if (!msi->bitmap)
> -		return -ENOMEM;
> -
>  	/* Get msi_1 IRQ number */
>  	msi->irq_msi1 = platform_get_irq_byname(pdev, "msi1");
> -	if (msi->irq_msi1 < 0) {
> -		ret = -EINVAL;
> -		goto err;
> -	}
> +	if (msi->irq_msi1 < 0)
> +		return -EINVAL;
>  
>  	irq_set_chained_handler_and_data(msi->irq_msi1,
>  					 nwl_pcie_msi_handler_high, pcie);
>  
>  	/* Get msi_0 IRQ number */
>  	msi->irq_msi0 = platform_get_irq_byname(pdev, "msi0");
> -	if (msi->irq_msi0 < 0) {
> -		ret = -EINVAL;
> -		goto err;
> -	}
> +	if (msi->irq_msi0 < 0)
> +		return -EINVAL;
>  
>  	irq_set_chained_handler_and_data(msi->irq_msi0,
>  					 nwl_pcie_msi_handler_low, pcie);
> @@ -592,8 +581,7 @@ static int nwl_pcie_enable_msi(struct nwl_pcie *pcie)
>  	ret = nwl_bridge_readl(pcie, I_MSII_CAPABILITIES) & MSII_PRESENT;
>  	if (!ret) {
>  		dev_err(dev, "MSI not present\n");
> -		ret = -EIO;
> -		goto err;
> +		return -EIO;
>  	}
>  
>  	/* Enable MSII */
> @@ -632,10 +620,6 @@ static int nwl_pcie_enable_msi(struct nwl_pcie *pcie)
>  	nwl_bridge_writel(pcie, MSGF_MSI_SR_LO_MASK, MSGF_MSI_MASK_LO);
>  
>  	return 0;
> -err:
> -	kfree(msi->bitmap);
> -	msi->bitmap = NULL;
> -	return ret;
>  }
>  
>  static int nwl_pcie_bridge_init(struct nwl_pcie *pcie)
> -- 
> 2.30.2
>