net: phy: fixed_phy: replace list of fixed PHYs with static array

Due to max 32 PHY addresses being available per mii bus, using a list
can't support more fixed PHY's. And there's no known use case for as
much as 32 fixed PHY's on a system. 8 should be plenty of fixed PHY's,
so use an array of that size instead of a list. This allows to
significantly reduce the code size and complexity.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/8610d30c-eac7-4100-9008-d3b6cee6a5cd@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/phy/fixed_phy.c b/drivers/net/phy/fixed_phy.c
index 50684271f81a9c22121f5d87e5fa5b0e02edae48..7d6078d15709d61a49feaecb3e93c2822e6f176d 100644 (file)
--- a/drivers/net/phy/fixed_phy.c
+++ b/drivers/net/phy/fixed_phy.c
@@ -10,7 +10,6 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/list.h>
 #include <linux/mii.h>
 #include <linux/phy.h>
 #include <linux/phy_fixed.h>
@@ -22,27 +21,24 @@
 
 #include "swphy.h"
 
+/* The DSA loop driver may allocate 4 fixed PHY's, and 4 additional
+ * fixed PHY's for a system should be sufficient.
+ */
+#define NUM_FP 8
+
 struct fixed_phy {
-       int addr;
        struct phy_device *phydev;
        struct fixed_phy_status status;
        int (*link_update)(struct net_device *, struct fixed_phy_status *);
-       struct list_head node;
 };
 
+static struct fixed_phy fmb_fixed_phys[NUM_FP];
 static struct mii_bus *fmb_mii_bus;
-static LIST_HEAD(fmb_phys);
+static DEFINE_IDA(phy_fixed_ida);
 
 static struct fixed_phy *fixed_phy_find(int addr)
 {
-       struct fixed_phy *fp;
-
-       list_for_each_entry(fp, &fmb_phys, node) {
-               if (fp->addr == addr)
-                       return fp;
-       }
-
-       return NULL;
+       return ida_exists(&phy_fixed_ida, addr) ? fmb_fixed_phys + addr : NULL;
 }
 
 int fixed_phy_change_carrier(struct net_device *dev, bool new_carrier)
@@ -108,31 +104,6 @@ int fixed_phy_set_link_update(struct phy_device *phydev,
 }
 EXPORT_SYMBOL_GPL(fixed_phy_set_link_update);
 
-static int __fixed_phy_add(int phy_addr,
-                          const struct fixed_phy_status *status)
-{
-       struct fixed_phy *fp;
-       int ret;
-
-       ret = swphy_validate_state(status);
-       if (ret < 0)
-               return ret;
-
-       fp = kzalloc(sizeof(*fp), GFP_KERNEL);
-       if (!fp)
-               return -ENOMEM;
-
-       fp->addr = phy_addr;
-       fp->status = *status;
-       fp->status.link = true;
-
-       list_add_tail(&fp->node, &fmb_phys);
-
-       return 0;
-}
-
-static DEFINE_IDA(phy_fixed_ida);
-
 static void fixed_phy_del(int phy_addr)
 {
        struct fixed_phy *fp;
@@ -141,8 +112,7 @@ static void fixed_phy_del(int phy_addr)
        if (!fp)
                return;
 
-       list_del(&fp->node);
-       kfree(fp);
+       memset(fp, 0, sizeof(*fp));
        ida_free(&phy_fixed_ida, phy_addr);
 }
 
@@ -153,19 +123,20 @@ struct phy_device *fixed_phy_register(const struct fixed_phy_status *status,
        int phy_addr;
        int ret;
 
+       ret = swphy_validate_state(status);
+       if (ret < 0)
+               return ERR_PTR(ret);
+
        if (!fmb_mii_bus || fmb_mii_bus->state != MDIOBUS_REGISTERED)
                return ERR_PTR(-EPROBE_DEFER);
 
-       /* Get the next available PHY address, up to PHY_MAX_ADDR */
-       phy_addr = ida_alloc_max(&phy_fixed_ida, PHY_MAX_ADDR - 1, GFP_KERNEL);
+       /* Get the next available PHY address, up to NUM_FP */
+       phy_addr = ida_alloc_max(&phy_fixed_ida, NUM_FP - 1, GFP_KERNEL);
        if (phy_addr < 0)
                return ERR_PTR(phy_addr);
 
-       ret = __fixed_phy_add(phy_addr, status);
-       if (ret < 0) {
-               ida_free(&phy_fixed_ida, phy_addr);
-               return ERR_PTR(ret);
-       }
+       fmb_fixed_phys[phy_addr].status = *status;
+       fmb_fixed_phys[phy_addr].status.link = true;
 
        phy = get_phy_device(fmb_mii_bus, phy_addr, false);
        if (IS_ERR(phy)) {
@@ -237,15 +208,9 @@ module_init(fixed_mdio_bus_init);
 
 static void __exit fixed_mdio_bus_exit(void)
 {
-       struct fixed_phy *fp, *tmp;
-
        mdiobus_unregister(fmb_mii_bus);
        mdiobus_free(fmb_mii_bus);
 
-       list_for_each_entry_safe(fp, tmp, &fmb_phys, node) {
-               list_del(&fp->node);
-               kfree(fp);
-       }
        ida_destroy(&phy_fixed_ida);
 }
 module_exit(fixed_mdio_bus_exit);