Commit 2158e856 authored by Robert Hancock's avatar Robert Hancock Committed by David S. Miller
Browse files

net: sfp: add mutex to prevent concurrent state checks 



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: default avatarRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: default avatarRobert Hancock <hancock@sedsystems.ca>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 257c2559

drivers/net/phy/sfp.c

+5 −1
Original line number Diff line number Diff line
@@ -188,10 +188,11 @@ struct sfp { 
	int gpio_irq[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;
@@ -1721,6 +1722,7 @@ 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;
@@ -1746,6 +1748,7 @@ 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)
@@ -1776,6 +1779,7 @@ 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);

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