[PATCH v2] ACPI: PCI: Release excess memory usage.

[PATCH v2] ACPI: PCI: Release excess memory usage.

[Zhe Qiao]

In the pci_acpi_scan_root() function, if the PCI bus creation failed,
the allocated memory should be released to avoid memory occupation.

Fixes: 789befdfa389 ("arm64: PCI: Migrate ACPI related functions to pci-acpi.c")
Signed-off-by: Zhe Qiao <qiaozhe@iscas.ac.cn>

---
V1 -> V2:
Modified labels for better readability.

---
 drivers/pci/pci-acpi.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index af370628e583..bde104ecac80 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -1677,15 +1677,12 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
 
 	root_ops = kzalloc(sizeof(*root_ops), GFP_KERNEL);
 	if (!root_ops) {
-		kfree(ri);
-		return NULL;
+		goto free_ri;
 	}
 
 	ri->cfg = pci_acpi_setup_ecam_mapping(root);
 	if (!ri->cfg) {
-		kfree(ri);
-		kfree(root_ops);
-		return NULL;
+		goto free_root_ops;
 	}
 
 	root_ops->release_info = pci_acpi_generic_release_info;
@@ -1693,7 +1690,7 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
 	root_ops->pci_ops = (struct pci_ops *)&ri->cfg->ops->pci_ops;
 	bus = acpi_pci_root_create(root, root_ops, &ri->common, ri->cfg);
 	if (!bus)
-		return NULL;
+		goto free_root_ops;
 
 	/* If we must preserve the resource configuration, claim now */
 	host = pci_find_host_bridge(bus);
@@ -1710,6 +1707,12 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
 		pcie_bus_configure_settings(child);
 
 	return bus;
+
+free_root_ops:
+	kfree(root_ops);
+free_ri:
+	kfree(ri);
+	return NULL;
 }
 
 void pcibios_add_bus(struct pci_bus *bus)
-- 
2.43.0

Re: [PATCH v2] ACPI: PCI: Release excess memory usage.

[Jonathan Cameron]

On Tue, 29 Apr 2025 17:10:51 +0800
Zhe Qiao <qiaozhe@iscas.ac.cn> wrote:

> In the pci_acpi_scan_root() function, if the PCI bus creation failed,
> the allocated memory should be released to avoid memory occupation.
> 
> Fixes: 789befdfa389 ("arm64: PCI: Migrate ACPI related functions to pci-acpi.c")
> Signed-off-by: Zhe Qiao <qiaozhe@iscas.ac.cn>
> 
> ---
> V1 -> V2:
> Modified labels for better readability.
> 
> ---
>  drivers/pci/pci-acpi.c | 15 +++++++++------
>  1 file changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
> index af370628e583..bde104ecac80 100644
> --- a/drivers/pci/pci-acpi.c
> +++ b/drivers/pci/pci-acpi.c
> @@ -1677,15 +1677,12 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
>  
>  	root_ops = kzalloc(sizeof(*root_ops), GFP_KERNEL);
>  	if (!root_ops) {
> -		kfree(ri);
> -		return NULL;
> +		goto free_ri;
>  	}
>  
>  	ri->cfg = pci_acpi_setup_ecam_mapping(root);
>  	if (!ri->cfg) {
> -		kfree(ri);
> -		kfree(root_ops);
> -		return NULL;
> +		goto free_root_ops;
>  	}
>  
>  	root_ops->release_info = pci_acpi_generic_release_info;
> @@ -1693,7 +1690,7 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
>  	root_ops->pci_ops = (struct pci_ops *)&ri->cfg->ops->pci_ops;
>  	bus = acpi_pci_root_create(root, root_ops, &ri->common, ri->cfg);
>  	if (!bus)
> -		return NULL;

Do we also need to tear down the ecam mapping done in pci_acpi_setup_ecam_mapping()?
Might just be pci_ecam_free(ri->cfg);


> +		goto free_root_ops;
>  
>  	/* If we must preserve the resource configuration, claim now */
>  	host = pci_find_host_bridge(bus);
> @@ -1710,6 +1707,12 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
>  		pcie_bus_configure_settings(child);
>  
>  	return bus;
> +
> +free_root_ops:
> +	kfree(root_ops);
> +free_ri:
> +	kfree(ri);
> +	return NULL;
>  }
>  
>  void pcibios_add_bus(struct pci_bus *bus)

Re: [PATCH v2] ACPI: PCI: Release excess memory usage.

[Markus Elfring]

…
> the allocated memory should be released to avoid memory occupation.

Will an imperative wording be more desirable for an improved change description?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.15-rc4#n94

Do you propose to complete the exception handling?


How will development interests grow for the application of the attribute “__free”?
https://elixir.bootlin.com/linux/v6.15-rc4/source/include/linux/slab.h#L476

Regards,
Markus

Re: [PATCH v2] ACPI: PCI: Release excess memory usage

[Markus Elfring]

…
> +++ b/drivers/pci/pci-acpi.c
> @@ -1677,15 +1677,12 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
>  
>  	root_ops = kzalloc(sizeof(*root_ops), GFP_KERNEL);
>  	if (!root_ops) {
> -		kfree(ri);
> -		return NULL;
> +		goto free_ri;
>  	}

Would you like to omit curly brackets around a single statement?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/coding-style.rst?h=v6.15-rc4#n197

Regards,
Markus