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Date: Wed, 17 May 2023 11:38:07 +0100
From: "Russell King (Oracle)" <rmk+kernel@...linux.org.uk>
To: Andrew Lunn <andrew@...n.ch>,
Heiner Kallweit <hkallweit1@...il.com>
Cc: Marek Behún <kabel@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
netdev@...r.kernel.org
Subject: [PATCH net-next 5/7] 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: Simon Horman <simon.horman@...igine.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@...linux.org.uk>
---
drivers/net/phy/sfp.c | 56 ++++++++++++++++++++++++++++++++-----------
1 file changed, 42 insertions(+), 14 deletions(-)
diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index e5cd36e3a421..bf7dac9977e1 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -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)
@@ -1603,16 +1621,18 @@ 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;
- sfp_set_state(sfp, state | SFP_F_TX_DISABLE);
+ 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);
+ udelay(T_RESET_US);
- sfp_set_state(sfp, state);
+ sfp_set_state(sfp, state);
+ }
+ mutex_unlock(&sfp->st_mutex);
}
/* SFP state machine */
@@ -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);
--
2.30.2
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