From:   Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
To:     hdegoede@redhat.com, markgross@kernel.org, david.e.box@intel.com
Cc:     platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Subject: [PATCH] platform/x86/intel/vsec: Use mutex for ida_alloc() and ida_free()
Date:   Tue,  7 Feb 2023 04:58:21 -0800
Message-Id: <20230207125821.3837799-1-srinivas.pandruvada@linux.intel.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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