Re: [PATCH] net: phy: don't issue a module request if a driver is available
From: "Russell King (Oracle)" <linux@armlinux.org.uk>
Date: 2025-01-02 11:06:21
On Thu, Jan 02, 2025 at 12:51:22AM +0100, Francesco Valla wrote:
Whenever a new PHY device is created, request_module() is called unconditionally, without checking if a driver for the new PHY is already available (either built-in or from a previous probe). This conflicts with async probing of the underlying MDIO bus and always throws a warning (because if a driver is loaded it _might_ cause a deadlock, if in turn it calls async_synchronize_full()).
Why aren't any of the phylib maintainers seeing this warning? Where does the warning come from?
+static bool phy_driver_exists(u32 phy_id)
+{
+ bool found = false;
+ struct phy_drv_node *node;
+
+ down_read(&phy_drv_list_sem);
+ list_for_each_entry(node, &phy_drv_list, list) {
+ if (phy_id_compare(phy_id, node->drv->phy_id, node->drv->phy_id_mask)) {
+ found = true;
+ break;
+ }
+ }
+ up_read(&phy_drv_list_sem);
+
+ return found;
+}
+Why do we need this, along with the associated additional memory allocations? What's wrong with bus_for_each_drv() which the core code provides? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!