[PATCH 3.16 250/305] net: phy: Manage fixed PHY address space using IDA

Ben Hutchings
2016-08-14T11:00:50Z

From: Florian Fainelli <f.fainelli@gmail.com>

commit 69fc58a57e56bf5e39b48809aefffdaa1b04c945 upstream.

If we have a system which uses fixed PHY devices and calls
fixed_phy_register() then fixed_phy_unregister() we can exhaust the
number of fixed PHYs available after a while, since we keep incrementing
the variable phy_fixed_addr, but we never decrement it.

This patch fixes that by converting the fixed PHY allocation to using
IDA, which takes care of the allocation/dealloaction of the PHY
addresses for us.

Fixes: a75951217472 ("net: phy: extend fixed driver with fixed_phy_register()")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.16:
- Adjust filename, context
- fixed_phy_register() returns an integer, not a pointer/error]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/net/phy/fixed.c | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)

--- a/drivers/net/phy/fixed.c
+++ b/drivers/net/phy/fixed.c
@@ -22,6 +22,7 @@
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/of.h>
+#include <linux/idr.h>

#define MII_REGS_NUM 29

@@ -204,6 +205,8 @@ err_regs:
}
EXPORT_SYMBOL_GPL(fixed_phy_add);

+static DEFINE_IDA(phy_fixed_ida);
+
void fixed_phy_del(int phy_addr)
{
struct fixed_mdio_bus *fmb = &platform_fmb;
@@ -213,15 +216,13 @@ void fixed_phy_del(int phy_addr)
if (fp->addr == phy_addr) {
list_del(&fp->node);
kfree(fp);
+ ida_simple_remove(&phy_fixed_ida, phy_addr);
return;
}
}
}
EXPORT_SYMBOL_GPL(fixed_phy_del);

-static int phy_fixed_addr;
-static DEFINE_SPINLOCK(phy_fixed_addr_lock);
-
int fixed_phy_register(unsigned int irq,
struct fixed_phy_status *status,
struct device_node *np)
@@ -232,17 +233,15 @@ int fixed_phy_register(unsigned int irq,
int ret;

/* Get the next available PHY address, up to PHY_MAX_ADDR */
- spin_lock(&phy_fixed_addr_lock);
- if (phy_fixed_addr == PHY_MAX_ADDR) {
- spin_unlock(&phy_fixed_addr_lock);
- return -ENOSPC;
- }
- phy_addr = phy_fixed_addr++;
- spin_unlock(&phy_fixed_addr_lock);
+ phy_addr = ida_simple_get(&phy_fixed_ida, 0, PHY_MAX_ADDR, GFP_KERNEL);
+ if (phy_addr < 0)
+ return phy_addr;

ret = fixed_phy_add(irq, phy_addr, status);
- if (ret < 0)
+ if (ret < 0) {
+ ida_simple_remove(&phy_fixed_ida, phy_addr);
return ret;
+ }

phy = get_phy_device(fmb->mii_bus, phy_addr, false);
if (!phy || IS_ERR(phy)) {
@@ -317,6 +316,7 @@ static void __exit fixed_mdio_bus_exit(v
list_del(&fp->node);
kfree(fp);
}
+ ida_destroy(&phy_fixed_ida);
}
module_exit(fixed_mdio_bus_exit);