ata: libahci_platform: use flex array for platform PHYs

Modify struct ahci_host_priv to use a flexible array member for an adapter
port PHYs and use struct_size to combine the allocation of this array
together with the adapter private data structure. __counted_by() annotation
is added for the phys field to support runtime analysis.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Niklas Cassel <cassel@kernel.org>

Author: neheb

drivers/ata/ahci.h

@@ -357,7 +357,6 @@ struct ahci_host_priv {
 	 * If platform uses PHYs. There is a 1:1 relation between the port number and
 	 * the PHY position in this array.
 	 */
-	struct phy		**phys;
 	unsigned		nports;		/* Number of ports */
 	void			*plat_data;	/* Other platform data */
 	unsigned int		irq;		/* interrupt line */
@@ -379,6 +378,8 @@ struct ahci_host_priv {
 	/* only required for per-port MSI(-X) support */
 	int			(*get_irq_vector)(struct ata_host *host,
 						  int port);
+
+	struct phy		*phys[] __counted_by(nports);
 };
 
 /*

drivers/ata/libahci_platform.c

@@ -482,15 +482,29 @@ struct ahci_host_priv *ahci_platform_get_resources(struct platform_device *pdev,
 	struct ahci_host_priv *hpriv;
 	u32 mask_port_map = 0;
 	u32 max_port;
+	int nports;
 
 	if (!devres_open_group(dev, NULL, GFP_KERNEL))
 		return ERR_PTR(-ENOMEM);
 
-	hpriv = devres_alloc(ahci_platform_put_resources, sizeof(*hpriv),
+	/* find maximum port id for allocating structures */
+	max_port = ahci_platform_find_max_port_id(dev);
+	/*
+	 * Set nports according to maximum port id. Clamp at
+	 * AHCI_MAX_PORTS, warning message for invalid port id
+	 * is generated later.
+	 * When DT has no sub-nodes max_port is 0, nports is 1,
+	 * in order to be able to use the
+	 * ahci_platform_[en|dis]able_[phys|regulators] functions.
+	 */
+	nports = min(AHCI_MAX_PORTS, max_port + 1);
+	hpriv = devres_alloc(ahci_platform_put_resources, struct_size(hpriv, phys, nports),
 			     GFP_KERNEL);
 	if (!hpriv)
 		goto err_out;
 
+	hpriv->nports = nports;
+
 	devres_add(dev, hpriv);
 
 	/*
@@ -573,23 +587,6 @@ struct ahci_host_priv *ahci_platform_get_resources(struct platform_device *pdev,
 		goto err_out;
 	}
 
-	/* find maximum port id for allocating structures */
-	max_port = ahci_platform_find_max_port_id(dev);
-	/*
-	 * Set nports according to maximum port id. Clamp at
-	 * AHCI_MAX_PORTS, warning message for invalid port id
-	 * is generated later.
-	 * When DT has no sub-nodes max_port is 0, nports is 1,
-	 * in order to be able to use the
-	 * ahci_platform_[en|dis]able_[phys|regulators] functions.
-	 */
-	hpriv->nports = min(AHCI_MAX_PORTS, max_port + 1);
-
-	hpriv->phys = devm_kcalloc(dev, hpriv->nports, sizeof(*hpriv->phys), GFP_KERNEL);
-	if (!hpriv->phys) {
-		rc = -ENOMEM;
-		goto err_out;
-	}
 	/*
 	 * We cannot use devm_ here, since ahci_platform_put_resources() uses
 	 * target_pwrs after devm_ have freed memory