Commit 1974fd3b authored by Russell King (Oracle)'s avatar Russell King (Oracle) Committed by Jakub Kicinski
Browse files

net: sfp: change st_mutex locking 



Change st_mutex's use within SFP such that it only protects the various
state members, as it was originally supposed to, and isn't held while
making various calls outside the driver.

Reviewed-by: default avatarSimon Horman <simon.horman@corigine.com>
Signed-off-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 97a49205

drivers/net/phy/sfp.c

+42 −14
Original line number Diff line number Diff line
@@ -242,10 +242,17 @@ struct sfp { 


	bool need_poll;



	/* Access rules:

	 * state_hw_drive: st_mutex held

	 * state_hw_mask: st_mutex held

	 * state_soft_mask: st_mutex held

	 * state: st_mutex held unless reading input bits

	 */

	struct mutex st_mutex;			/* Protects state */

	unsigned int state_hw_mask;

	unsigned int state_soft_mask;

	unsigned int state;



	struct delayed_work poll;

	struct delayed_work timeout;

	struct mutex sm_mutex;			/* Protects state machine */
@@ -692,7 +699,6 @@ static void sfp_soft_start_poll(struct sfp *sfp) 
	const struct sfp_eeprom_id *id = &sfp->id;

	unsigned int mask = 0;



	sfp->state_soft_mask = 0;

	if (id->ext.enhopts & SFP_ENHOPTS_SOFT_TX_DISABLE)

		mask |= SFP_F_TX_DISABLE;

	if (id->ext.enhopts & SFP_ENHOPTS_SOFT_TX_FAULT)
@@ -700,19 +706,26 @@ static void sfp_soft_start_poll(struct sfp *sfp) 
	if (id->ext.enhopts & SFP_ENHOPTS_SOFT_RX_LOS)

		mask |= SFP_F_LOS;



	mutex_lock(&sfp->st_mutex);

	// Poll the soft state for hardware pins we want to ignore

	sfp->state_soft_mask = ~sfp->state_hw_mask & mask;



	if (sfp->state_soft_mask & (SFP_F_LOS | SFP_F_TX_FAULT) &&

	    !sfp->need_poll)

		mod_delayed_work(system_wq, &sfp->poll, poll_jiffies);

	mutex_unlock(&sfp->st_mutex);

}



static void sfp_soft_stop_poll(struct sfp *sfp)

{

	mutex_lock(&sfp->st_mutex);

	sfp->state_soft_mask = 0;

	mutex_unlock(&sfp->st_mutex);

}



/* sfp_get_state() - must be called with st_mutex held, or in the

 * initialisation path.

 */

static unsigned int sfp_get_state(struct sfp *sfp)

{

	unsigned int soft = sfp->state_soft_mask & (SFP_F_LOS | SFP_F_TX_FAULT);
@@ -725,6 +738,9 @@ static unsigned int sfp_get_state(struct sfp *sfp) 
	return state;

}



/* sfp_set_state() - must be called with st_mutex held, or in the

 * initialisation path.

 */

static void sfp_set_state(struct sfp *sfp, unsigned int state)

{

	sfp->set_state(sfp, state);
@@ -736,8 +752,10 @@ static void sfp_set_state(struct sfp *sfp, unsigned int state) 


static void sfp_mod_state(struct sfp *sfp, unsigned int mask, unsigned int set)

{

	mutex_lock(&sfp->st_mutex);

	sfp->state = (sfp->state & ~mask) | set;

	sfp_set_state(sfp, sfp->state);

	mutex_unlock(&sfp->st_mutex);

}



static unsigned int sfp_check(void *buf, size_t len)
@@ -1603,17 +1621,19 @@ static void sfp_debugfs_exit(struct sfp *sfp) 


static void sfp_module_tx_fault_reset(struct sfp *sfp)

{

	unsigned int state = sfp->state;



	if (state & SFP_F_TX_DISABLE)

		return;

	unsigned int state;



	mutex_lock(&sfp->st_mutex);

	state = sfp->state;

	if (!(state & SFP_F_TX_DISABLE)) {

		sfp_set_state(sfp, state | SFP_F_TX_DISABLE);



		udelay(T_RESET_US);



		sfp_set_state(sfp, state);

	}

	mutex_unlock(&sfp->st_mutex);

}



/* SFP state machine */

static void sfp_sm_set_timer(struct sfp *sfp, unsigned int timeout)
@@ -1957,6 +1977,7 @@ static int sfp_sm_mod_probe(struct sfp *sfp, bool report) 
	/* SFP module inserted - read I2C data */

	struct sfp_eeprom_id id;

	bool cotsworks_sfbg;

	unsigned int mask;

	bool cotsworks;

	u8 check;

	int ret;
@@ -2096,14 +2117,13 @@ static int sfp_sm_mod_probe(struct sfp *sfp, bool report) 
	if (ret < 0)

		return ret;



	/* Initialise state bits to use from hardware */

	sfp->state_hw_mask = SFP_F_PRESENT;

	mask = SFP_F_PRESENT;

	if (sfp->gpio[GPIO_TX_DISABLE])

		sfp->state_hw_mask |= SFP_F_TX_DISABLE;

		mask |= SFP_F_TX_DISABLE;

	if (sfp->gpio[GPIO_TX_FAULT])

		sfp->state_hw_mask |= SFP_F_TX_FAULT;

		mask |= SFP_F_TX_FAULT;

	if (sfp->gpio[GPIO_LOS])

		sfp->state_hw_mask |= SFP_F_LOS;

		mask |= SFP_F_LOS;



	sfp->module_t_start_up = T_START_UP;

	sfp->module_t_wait = T_WAIT;
@@ -2121,8 +2141,14 @@ static int sfp_sm_mod_probe(struct sfp *sfp, bool report) 
		sfp->mdio_protocol = MDIO_I2C_NONE;



	sfp->quirk = sfp_lookup_quirk(&id);



	mutex_lock(&sfp->st_mutex);

	/* Initialise state bits to use from hardware */

	sfp->state_hw_mask = mask;



	if (sfp->quirk && sfp->quirk->fixup)

		sfp->quirk->fixup(sfp);

	mutex_unlock(&sfp->st_mutex);



	return 0;

}
@@ -2619,6 +2645,7 @@ static void sfp_check_state(struct sfp *sfp) 


	state |= sfp->state & (SFP_F_TX_DISABLE | SFP_F_RATE_SELECT);

	sfp->state = state;

	mutex_unlock(&sfp->st_mutex);



	mutex_lock(&sfp->sm_mutex);

	if (changed & SFP_F_PRESENT)
@@ -2633,7 +2660,6 @@ static void sfp_check_state(struct sfp *sfp) 
		__sfp_sm_event(sfp, state & SFP_F_LOS ?

				    SFP_E_LOS_HIGH : SFP_E_LOS_LOW);

	mutex_unlock(&sfp->sm_mutex);

	mutex_unlock(&sfp->st_mutex);

	rtnl_unlock();

}
@@ -2652,6 +2678,8 @@ static void sfp_poll(struct work_struct *work) 


	sfp_check_state(sfp);



	// st_mutex doesn't need to be held here for state_soft_mask,

	// it's unimportant if we race while reading this.

	if (sfp->state_soft_mask & (SFP_F_LOS | SFP_F_TX_FAULT) ||

	    sfp->need_poll)

		mod_delayed_work(system_wq, &sfp->poll, poll_jiffies);