[PATCHv2] platform/x86: panasonic-laptop: simplify allocation of sinf

[PATCHv2] platform/x86: panasonic-laptop: simplify allocation of sinf

[Rosen Penev]

Change to a flexible array member to allocate once instead of twice.

Allows using __counted_by for extra runtime analysis. Move the counting
variable assignment to right after allocation as required by
__counted_by.

Remove + 1 to allocation. It's already done in the previous line.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 v2: Rebased.
 drivers/platform/x86/panasonic-laptop.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/drivers/platform/x86/panasonic-laptop.c b/drivers/platform/x86/panasonic-laptop.c
index 1337f7c49805..2fe8ff0d32a8 100644
--- a/drivers/platform/x86/panasonic-laptop.c
+++ b/drivers/platform/x86/panasonic-laptop.c
@@ -246,11 +246,11 @@ struct pcc_acpi {
 	int			ac_brightness;
 	int			dc_brightness;
 	int			current_brightness;
-	u32			*sinf;
 	struct acpi_device	*device;
 	struct input_dev	*input_dev;
 	struct backlight_device	*backlight;
 	struct platform_device	*platform;
+	u32			sinf[] __counted_by(num_sifr);
 };

 /*
@@ -1003,21 +1003,15 @@ static int acpi_pcc_hotkey_probe(struct platform_device *pdev)
 	 */
 	num_sifr++;

-	pcc = kzalloc_obj(struct pcc_acpi);
+	pcc = kzalloc_flex(*pcc, sinf, num_sifr);
 	if (!pcc) {
 		pr_err("Couldn't allocate mem for pcc");
 		return -ENOMEM;
 	}

-	pcc->sinf = kcalloc(num_sifr + 1, sizeof(u32), GFP_KERNEL);
-	if (!pcc->sinf) {
-		result = -ENOMEM;
-		goto out_hotkey;
-	}
-
+	pcc->num_sifr = num_sifr;
 	pcc->device = device;
 	pcc->handle = device->handle;
-	pcc->num_sifr = num_sifr;
 	device->driver_data = pcc;
 	strscpy(acpi_device_name(device), ACPI_PCC_DEVICE_NAME);
 	strscpy(acpi_device_class(device), ACPI_PCC_CLASS);
@@ -1025,7 +1019,7 @@ static int acpi_pcc_hotkey_probe(struct platform_device *pdev)
 	result = acpi_pcc_init_input(pcc);
 	if (result) {
 		pr_err("Error installing keyinput handler\n");
-		goto out_sinf;
+		goto out_hotkey;
 	}

 	if (!acpi_pcc_retrieve_biosdata(pcc)) {
@@ -1106,10 +1100,8 @@ static int acpi_pcc_hotkey_probe(struct platform_device *pdev)
 	backlight_device_unregister(pcc->backlight);
 out_input:
 	input_unregister_device(pcc->input_dev);
-out_sinf:
-	device->driver_data = NULL;
-	kfree(pcc->sinf);
 out_hotkey:
+	device->driver_data = NULL;
 	kfree(pcc);

 	return result;
@@ -1139,7 +1131,6 @@ static void acpi_pcc_hotkey_remove(struct platform_device *pdev)

 	device->driver_data = NULL;

-	kfree(pcc->sinf);
 	kfree(pcc);
 }

--
2.53.0

Re: [PATCHv2] platform/x86: panasonic-laptop: simplify allocation of sinf

[Ilpo Järvinen]

On Wed, 25 Mar 2026 19:45:25 -0700, Rosen Penev wrote:

> Change to a flexible array member to allocate once instead of twice.
> 
> Allows using __counted_by for extra runtime analysis. Move the counting
> variable assignment to right after allocation as required by
> __counted_by.
> 
> Remove + 1 to allocation. It's already done in the previous line.
> 
> [...]


Thank you for your contribution, it has been applied to my local
review-ilpo-next branch. Note it will show up in the public
platform-drivers-x86/review-ilpo-next branch only once I've pushed my
local branch there, which might take a while.

The list of commits applied:
[1/1] platform/x86: panasonic-laptop: simplify allocation of sinf
      commit: e75869527c720c4ed1458cfbe25e92186950e43a

--
 i.

Re: [PATCHv2] platform/x86: panasonic-laptop: simplify allocation of sinf

[Gustavo A. R. Silva]

On 3/31/26 09:02, Ilpo Järvinen wrote:
> On Wed, 25 Mar 2026 19:45:25 -0700, Rosen Penev wrote:
> 
>> Change to a flexible array member to allocate once instead of twice.
>>
>> Allows using __counted_by for extra runtime analysis. Move the counting
>> variable assignment to right after allocation as required by
>> __counted_by.

This is misinformation and should be phrased differently[1]

-Gustavo

[1] https://lore.kernel.org/linux-hardening/37378f49-437f-438b-ad6c-d60480feb306@embeddedor.com/

>>
>> Remove + 1 to allocation. It's already done in the previous line.
>>
>> [...]
> 
> 
> Thank you for your contribution, it has been applied to my local
> review-ilpo-next branch. Note it will show up in the public
> platform-drivers-x86/review-ilpo-next branch only once I've pushed my
> local branch there, which might take a while.
> 
> The list of commits applied:
> [1/1] platform/x86: panasonic-laptop: simplify allocation of sinf
>        commit: e75869527c720c4ed1458cfbe25e92186950e43a
> 
> --
>   i.
> 
> 

Re: [PATCHv2] platform/x86: panasonic-laptop: simplify allocation of sinf

[Ilpo Järvinen]

[-- Attachment #1: Type: text/plain, Size: 1250 bytes --]

On Tue, 31 Mar 2026, Gustavo A. R. Silva wrote:

> 
> 
> On 3/31/26 09:02, Ilpo Järvinen wrote:
> > On Wed, 25 Mar 2026 19:45:25 -0700, Rosen Penev wrote:
> > 
> > > Change to a flexible array member to allocate once instead of twice.
> > > 
> > > Allows using __counted_by for extra runtime analysis. Move the counting
> > > variable assignment to right after allocation as required by
> > > __counted_by.
> 
> This is misinformation and should be phrased differently[1]

Okay. I'll drop the patch for now.

--
 i.

> 
> -Gustavo
> 
> [1]
> https://lore.kernel.org/linux-hardening/37378f49-437f-438b-ad6c-d60480feb306@embeddedor.com/
> 
> > > 
> > > Remove + 1 to allocation. It's already done in the previous line.
> > > 
> > > [...]
> > 
> > 
> > Thank you for your contribution, it has been applied to my local
> > review-ilpo-next branch. Note it will show up in the public
> > platform-drivers-x86/review-ilpo-next branch only once I've pushed my
> > local branch there, which might take a while.
> > 
> > The list of commits applied:
> > [1/1] platform/x86: panasonic-laptop: simplify allocation of sinf
> >        commit: e75869527c720c4ed1458cfbe25e92186950e43a
> > 
> > --
> >   i.
> > 
> > 
>