From: Robert Hancock hancock@sedsystems.ca
[ Upstream commit 2158e856f56bb762ef90f3ec244d41a519826f75 ]
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: Sasha Levin sashal@kernel.org --- 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 8807a806cc47..418522aa2f71 100644 --- a/drivers/net/phy/sfp.c +++ b/drivers/net/phy/sfp.c @@ -185,10 +185,11 @@ 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; @@ -1718,6 +1719,7 @@ 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; @@ -1743,6 +1745,7 @@ 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) @@ -1773,6 +1776,7 @@ 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);