.setup() can run again within one registration: removing another switch
from the tree tears the whole tree down, and re-probing sets every
member switch up again.
The hardware reset at the start of .setup() brings the MIB counters back
to zero, but a MIB block kept across that cycle still holds the old
software buffer, so the next yt921x_mib_read() treats the small value as
a 32-bit wrap and adds 2^32 to every counter it extends.
The old claim, get_stats64() not being synchronized with
.port_teardown(), is not true, so free the MIB block in
.port_teardown(), which pairs with every successful .port_setup()
including the error unwinds, so the next setup allocates zeroed blocks.
Not carrying a fix tag since there are no known multi-chip yt921x users.
Signed-off-by: David Yang <mmyangfl@gmail.com>
---
drivers/net/dsa/motorcomm/chip.c | 18 +++++-------------
1 file changed, 5 insertions(+), 13 deletions(-)
diff --git a/drivers/net/dsa/motorcomm/chip.c b/drivers/net/dsa/motorcomm/chip.c
index 33e5fc127244..fd737c3e2e18 100644
--- a/drivers/net/dsa/motorcomm/chip.c
+++ b/drivers/net/dsa/motorcomm/chip.c
@@ -1994,11 +1994,11 @@ static void yt921x_dsa_port_teardown(struct dsa_switch *ds, int port)
struct yt921x_port *pp = &priv->ports[port];
struct yt921x_mib *pm = pp->mib;
- /* get_stats64() might not be synchronized with port_teardown(), hold
- * the MIB block till the device teardown
- */
- if (pm)
+ if (pm) {
disable_delayed_work_sync(&pm->work);
+ pp->mib = NULL;
+ kvfree(pm);
+ }
}
static int yt921x_dsa_port_setup(struct dsa_switch *ds, int port)@@ -2006,12 +2006,11 @@ static int yt921x_dsa_port_setup(struct dsa_switch *ds, int port)
struct yt921x_priv *priv = dsa_to_yt921x_priv(ds);
struct yt921x_port *pp = &priv->ports[port];
const struct yt921x_info *info = priv->info;
- struct device *dev = yt921x_priv_to_device(priv);
struct yt921x_mib *pm = pp->mib;
int res;
if (!pm && (BIT(port) & yt921x_info_ports_mask(info))) {
- pm = devm_kzalloc(dev, sizeof(*pm), GFP_KERNEL);
+ pm = kvzalloc_obj(*pm);
if (!pm)
return -ENOMEM;
pp->mib = pm;@@ -2019,10 +2018,6 @@ static int yt921x_dsa_port_setup(struct dsa_switch *ds, int port)
pm->port = pp;
u64_stats_init(&pm->syncp);
INIT_DELAYED_WORK(&pm->work, yt921x_mib_poll);
- /* Start disabled, so that the enable below always pairs with
- * either this disable or the one from a previous teardown
- */
- disable_delayed_work_sync(&pm->work);
}
mutex_lock(&priv->reg_lock);
@@ -2031,9 +2026,6 @@ static int yt921x_dsa_port_setup(struct dsa_switch *ds, int port)
if (res)
return res;
- if (pm)
- enable_delayed_work(&pm->work);
-
return 0;
}
--
2.53.0