dmaengine: idxd: fix memory leak in error handling path of idxd_alloc

commit 46a5cca upstream.

Memory allocated for idxd is not freed if an error occurs during
idxd_alloc(). To fix it, free the allocated memory in the reverse order
of allocation before exiting the function in case of an error.

Fixes: a8563a3 ("dmanegine: idxd: reformat opcap output to match bitmap_parse() input")
Cc: stable@vger.kernel.org
Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Link: https://lore.kernel.org/r/20250404120217.48772-7-xueshuai@linux.alibaba.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/dma/idxd/init.c

@@ -537,28 +537,34 @@ static struct idxd_device *idxd_alloc(struct pci_dev *pdev, struct idxd_driver_d
 	idxd_dev_set_type(&idxd->idxd_dev, idxd->data->type);
 	idxd->id = ida_alloc(&idxd_ida, GFP_KERNEL);
 	if (idxd->id < 0)
-		return NULL;
+		goto err_ida;
 
 	idxd->opcap_bmap = bitmap_zalloc_node(IDXD_MAX_OPCAP_BITS, GFP_KERNEL, dev_to_node(dev));
-	if (!idxd->opcap_bmap) {
-		ida_free(&idxd_ida, idxd->id);
-		return NULL;
-	}
+	if (!idxd->opcap_bmap)
+		goto err_opcap;
 
 	device_initialize(conf_dev);
 	conf_dev->parent = dev;
 	conf_dev->bus = &dsa_bus_type;
 	conf_dev->type = idxd->data->dev_type;
 	rc = dev_set_name(conf_dev, "%s%d", idxd->data->name_prefix, idxd->id);
-	if (rc < 0) {
-		put_device(conf_dev);
-		return NULL;
-	}
+	if (rc < 0)
+		goto err_name;
 
 	spin_lock_init(&idxd->dev_lock);
 	spin_lock_init(&idxd->cmd_lock);
 
 	return idxd;
+
+err_name:
+	put_device(conf_dev);
+	bitmap_free(idxd->opcap_bmap);
+err_opcap:
+	ida_free(&idxd_ida, idxd->id);
+err_ida:
+	kfree(idxd);
+
+	return NULL;
 }
 
 static int idxd_enable_system_pasid(struct idxd_device *idxd)