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authorDavid S. Miller <[email protected]>2021-09-21 13:52:16 +0100
committerDavid S. Miller <[email protected]>2021-09-21 13:52:16 +0100
commitb3f98404bd629a243c0a15a3ade32b1cf9fbe0da (patch)
tree47d513bd1a6faead4589b3f42467ff81e0148fb5
parent3e95cfa24e24fbd7fb7675ab972a5aa507c7a89c (diff)
parent74b6d7d13307b016f4b5bba8198297824c0ee6df (diff)
Merge branch 'dsa-devres'
Vladimir Oltean says: ==================== Fix mdiobus users with devres Commit ac3a68d56651 ("net: phy: don't abuse devres in devm_mdiobus_register()") by Bartosz Golaszewski has introduced two classes of potential bugs by making the devres callback of devm_mdiobus_alloc stop calling mdiobus_unregister. The exact buggy circumstances are presented in the individual commit messages. I have searched the tree for other occurrences, but at the moment: - for issue (a) I have no concrete proof that other buses except SPI and I2C suffer from it, and the only SPI or I2C device drivers that call of_mdiobus_alloc are the DSA drivers that leave a NULL ds->slave_mii_bus and a non-NULL ds->ops->phy_read, aka ksz9477, ksz8795, lan9303_i2c, vsc73xx-spi. - for issue (b), all drivers which call of_mdiobus_alloc either use of_mdiobus_register too, or call mdiobus_unregister sometime within the ->remove path. Although at this point I've seen enough strangeness caused by this "device_del during ->shutdown" that I'm just going to copy the SPI and I2C subsystem maintainers to this patch series, to get their feedback whether they've had reports about things like this before. I don't think other buses behave in this way, it forces SPI and I2C devices to have to protect themselves from a really strange set of issues. ==================== Signed-off-by: David S. Miller <[email protected]>
-rw-r--r--drivers/net/dsa/realtek-smi-core.c2
-rw-r--r--net/dsa/dsa2.c12
2 files changed, 10 insertions, 4 deletions
diff --git a/drivers/net/dsa/realtek-smi-core.c b/drivers/net/dsa/realtek-smi-core.c
index dd2f0d6208b3..2fcfd917b876 100644
--- a/drivers/net/dsa/realtek-smi-core.c
+++ b/drivers/net/dsa/realtek-smi-core.c
@@ -368,7 +368,7 @@ int realtek_smi_setup_mdio(struct realtek_smi *smi)
smi->slave_mii_bus->parent = smi->dev;
smi->ds->slave_mii_bus = smi->slave_mii_bus;
- ret = of_mdiobus_register(smi->slave_mii_bus, mdio_np);
+ ret = devm_of_mdiobus_register(smi->dev, smi->slave_mii_bus, mdio_np);
if (ret) {
dev_err(smi->dev, "unable to register MDIO bus %s\n",
smi->slave_mii_bus->id);
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index f54639a3a822..b29262eee00b 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -880,7 +880,7 @@ static int dsa_switch_setup(struct dsa_switch *ds)
devlink_params_publish(ds->devlink);
if (!ds->slave_mii_bus && ds->ops->phy_read) {
- ds->slave_mii_bus = devm_mdiobus_alloc(ds->dev);
+ ds->slave_mii_bus = mdiobus_alloc();
if (!ds->slave_mii_bus) {
err = -ENOMEM;
goto teardown;
@@ -890,13 +890,16 @@ static int dsa_switch_setup(struct dsa_switch *ds)
err = mdiobus_register(ds->slave_mii_bus);
if (err < 0)
- goto teardown;
+ goto free_slave_mii_bus;
}
ds->setup = true;
return 0;
+free_slave_mii_bus:
+ if (ds->slave_mii_bus && ds->ops->phy_read)
+ mdiobus_free(ds->slave_mii_bus);
teardown:
if (ds->ops->teardown)
ds->ops->teardown(ds);
@@ -921,8 +924,11 @@ static void dsa_switch_teardown(struct dsa_switch *ds)
if (!ds->setup)
return;
- if (ds->slave_mii_bus && ds->ops->phy_read)
+ if (ds->slave_mii_bus && ds->ops->phy_read) {
mdiobus_unregister(ds->slave_mii_bus);
+ mdiobus_free(ds->slave_mii_bus);
+ ds->slave_mii_bus = NULL;
+ }
dsa_switch_unregister_notifier(ds);