[PATCH] platform/x86/intel/vsec: Use mutex for ida_alloc() and ida_free()

[PATCH] platform/x86/intel/vsec: Use mutex for ida_alloc() and ida_free()

[Srinivas Pandruvada]

ID alloc and free functions don't have in built protection for parallel
invocation of ida_alloc() and ida_free(). With the current flow in the
vsec driver, there is no such scenario. But add mutex protection for
potential future changes.

Suggested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 drivers/platform/x86/intel/vsec.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/platform/x86/intel/vsec.c b/drivers/platform/x86/intel/vsec.c
index b936fc5776d7..f1680b7e64f5 100644
--- a/drivers/platform/x86/intel/vsec.c
+++ b/drivers/platform/x86/intel/vsec.c
@@ -129,11 +129,16 @@ static void intel_vsec_remove_aux(void *data)
 	auxiliary_device_uninit(data);
 }
 
+static DEFINE_MUTEX(vsec_ida_lock);
+
 static void intel_vsec_dev_release(struct device *dev)
 {
 	struct intel_vsec_device *intel_vsec_dev = dev_to_ivdev(dev);
 
+	mutex_lock(&vsec_ida_lock);
 	ida_free(intel_vsec_dev->ida, intel_vsec_dev->auxdev.id);
+	mutex_unlock(&vsec_ida_lock);
+
 	kfree(intel_vsec_dev->resource);
 	kfree(intel_vsec_dev);
 }
@@ -145,7 +150,9 @@ int intel_vsec_add_aux(struct pci_dev *pdev, struct device *parent,
 	struct auxiliary_device *auxdev = &intel_vsec_dev->auxdev;
 	int ret, id;
 
+	mutex_lock(&vsec_ida_lock);
 	ret = ida_alloc(intel_vsec_dev->ida, GFP_KERNEL);
+	mutex_unlock(&vsec_ida_lock);
 	if (ret < 0) {
 		kfree(intel_vsec_dev);
 		return ret;
@@ -161,7 +168,9 @@ int intel_vsec_add_aux(struct pci_dev *pdev, struct device *parent,
 
 	ret = auxiliary_device_init(auxdev);
 	if (ret < 0) {
+		mutex_lock(&vsec_ida_lock);
 		ida_free(intel_vsec_dev->ida, auxdev->id);
+		mutex_unlock(&vsec_ida_lock);
 		kfree(intel_vsec_dev->resource);
 		kfree(intel_vsec_dev);
 		return ret;
-- 
2.39.1

Re: [PATCH] platform/x86/intel/vsec: Use mutex for ida_alloc() and ida_free()

[Hans de Goede]

Hi,

On 2/7/23 13:58, Srinivas Pandruvada wrote:
> ID alloc and free functions don't have in built protection for parallel
> invocation of ida_alloc() and ida_free(). With the current flow in the
> vsec driver, there is no such scenario. But add mutex protection for
> potential future changes.
> 
> Suggested-by: Hans de Goede <hdegoede@redhat.com>
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

Thank you for your patch, I've applied this patch to my review-hans 
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.

Regards,

Hans


> ---
>  drivers/platform/x86/intel/vsec.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/platform/x86/intel/vsec.c b/drivers/platform/x86/intel/vsec.c
> index b936fc5776d7..f1680b7e64f5 100644
> --- a/drivers/platform/x86/intel/vsec.c
> +++ b/drivers/platform/x86/intel/vsec.c
> @@ -129,11 +129,16 @@ static void intel_vsec_remove_aux(void *data)
>  	auxiliary_device_uninit(data);
>  }
>  
> +static DEFINE_MUTEX(vsec_ida_lock);
> +
>  static void intel_vsec_dev_release(struct device *dev)
>  {
>  	struct intel_vsec_device *intel_vsec_dev = dev_to_ivdev(dev);
>  
> +	mutex_lock(&vsec_ida_lock);
>  	ida_free(intel_vsec_dev->ida, intel_vsec_dev->auxdev.id);
> +	mutex_unlock(&vsec_ida_lock);
> +
>  	kfree(intel_vsec_dev->resource);
>  	kfree(intel_vsec_dev);
>  }
> @@ -145,7 +150,9 @@ int intel_vsec_add_aux(struct pci_dev *pdev, struct device *parent,
>  	struct auxiliary_device *auxdev = &intel_vsec_dev->auxdev;
>  	int ret, id;
>  
> +	mutex_lock(&vsec_ida_lock);
>  	ret = ida_alloc(intel_vsec_dev->ida, GFP_KERNEL);
> +	mutex_unlock(&vsec_ida_lock);
>  	if (ret < 0) {
>  		kfree(intel_vsec_dev);
>  		return ret;
> @@ -161,7 +168,9 @@ int intel_vsec_add_aux(struct pci_dev *pdev, struct device *parent,
>  
>  	ret = auxiliary_device_init(auxdev);
>  	if (ret < 0) {
> +		mutex_lock(&vsec_ida_lock);
>  		ida_free(intel_vsec_dev->ida, auxdev->id);
> +		mutex_unlock(&vsec_ida_lock);
>  		kfree(intel_vsec_dev->resource);
>  		kfree(intel_vsec_dev);
>  		return ret;