From 31c7292f185b06b66044f17d675c4f465f340f6d Mon Sep 17 00:00:00 2001
From: Robert Hancock <hancock@sedsystems.ca>
Date: Fri, 7 Jun 2019 10:42:36 -0600
Subject: [PATCH 1/2] net: sfp: add mutex to prevent concurrent state checks
Patch-mainline: v5.3-rc1
Git-commit: 2158e856f56bb762ef90f3ec244d41a519826f75
References: git-fixes
sfp_check_state can potentially be called by both a threaded IRQ handler
and delayed work. If it is concurrently called, it could result in
incorrect state management. Add a st_mutex to protect the state - this
lock gets taken outside of code that checks and handle state changes, and
the existing sm_mutex nests inside of it.
Suggested-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Robert Hancock <hancock@sedsystems.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
drivers/net/phy/sfp.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index ae0fe0f7180e..c66ab07997fa 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -112,10 +112,11 @@ struct sfp {
struct gpio_desc *gpio[GPIO_MAX];
bool attached;
+ struct mutex st_mutex; /* Protects state */
unsigned int state;
struct delayed_work poll;
struct delayed_work timeout;
- struct mutex sm_mutex;
+ struct mutex sm_mutex; /* Protects state machine */
unsigned char sm_mod_state;
unsigned char sm_dev_state;
unsigned short sm_state;
@@ -721,6 +722,7 @@ static void sfp_check_state(struct sfp *sfp)
{
unsigned int state, i, changed;
+ mutex_lock(&sfp->st_mutex);
state = sfp_get_state(sfp);
changed = state ^ sfp->state;
changed &= SFP_F_PRESENT | SFP_F_LOS | SFP_F_TX_FAULT;
@@ -746,6 +748,7 @@ static void sfp_check_state(struct sfp *sfp)
sfp_sm_event(sfp, state & SFP_F_LOS ?
SFP_E_LOS_HIGH : SFP_E_LOS_LOW);
rtnl_unlock();
+ mutex_unlock(&sfp->st_mutex);
}
static irqreturn_t sfp_irq(int irq, void *data)
@@ -776,6 +779,7 @@ static struct sfp *sfp_alloc(struct device *dev)
sfp->dev = dev;
mutex_init(&sfp->sm_mutex);
+ mutex_init(&sfp->st_mutex);
INIT_DELAYED_WORK(&sfp->poll, sfp_poll);
INIT_DELAYED_WORK(&sfp->timeout, sfp_timeout);
--
2.16.4