[PATCH RFC] drivers: parport: Ask user for irqreturn_t value

From: Matwey V. Kornilov
Date: Sun Sep 28 2014 - 04:02:47 EST

Current parport_irq_handler behaviour is not correct when IRQ is shared.
LDDv3 on page 279 requires us:

"Be sure to return IRQ_NONE whenever your handler is called and finds
the device is not interrupting."

This is not the case of parport_irq_handler.
Current implementation of IRQ handling use this to optimize shared IRQ processing.
When an action returns IRQ_HANDLED no other actions are processed.

Modify callback function void (*irq_func)(void *) to irqreturn_t (*irq_func)(void *) and return the value in parport_irq_handler

This also fixes https://bugzilla.kernel.org/show_bug.cgi?id=85221

Signed-off-by: Matwey V. Kornilov <matwey@xxxxxxxxxx>
---
drivers/char/ppdev.c | 4 +++-
drivers/i2c/busses/i2c-parport.c | 5 ++++-
drivers/input/joystick/walkera0701.c | 6 ++++--
drivers/net/hamradio/baycom_par.c | 4 +++-
drivers/net/plip/plip.c | 8 +++++---
drivers/parport/share.c | 6 ++----
drivers/pps/clients/pps_parport.c | 6 +++---
drivers/staging/media/lirc/lirc_parallel.c | 12 +++++++-----
include/linux/parport.h | 12 ++++++++----
9 files changed, 39 insertions(+), 24 deletions(-)

diff --git a/drivers/char/ppdev.c b/drivers/char/ppdev.c
index ae0b42b..61fec51 100644
--- a/drivers/char/ppdev.c
+++ b/drivers/char/ppdev.c
@@ -264,7 +264,7 @@ static ssize_t pp_write (struct file * file, const char __user * buf,
return bytes_written;
}

-static void pp_irq (void *private)
+static irqreturn_t pp_irq (void *private)
{
struct pp_struct *pp = private;

@@ -275,6 +275,8 @@ static void pp_irq (void *private)

atomic_inc (&pp->irqc);
wake_up_interruptible (&pp->irq_wait);
+
+ return IRQ_HANDLED;
}

static int register_device (int minor, struct pp_struct *pp)
diff --git a/drivers/i2c/busses/i2c-parport.c b/drivers/i2c/busses/i2c-parport.c
index a27aae2..7549e10 100644
--- a/drivers/i2c/busses/i2c-parport.c
+++ b/drivers/i2c/busses/i2c-parport.c
@@ -151,7 +151,7 @@ static const struct i2c_algo_bit_data parport_algo_data = {

/* ----- I2c and parallel port call-back functions and structures --------- */

-static void i2c_parport_irq(void *data)
+static irqreturn_t i2c_parport_irq(void *data)
{
struct i2c_par *adapter = data;
struct i2c_client *ara = adapter->ara;
@@ -159,9 +159,12 @@ static void i2c_parport_irq(void *data)
if (ara) {
dev_dbg(&ara->dev, "SMBus alert received\n");
i2c_handle_smbus_alert(ara);
+ return IRQ_HANDLED;
} else
dev_dbg(&adapter->adapter.dev,
"SMBus alert received but no ARA client!\n");
+
+ return IRQ_NONE;
}

static void i2c_parport_attach(struct parport *port)
diff --git a/drivers/input/joystick/walkera0701.c b/drivers/input/joystick/walkera0701.c
index b76ac58..f3903a6 100644
--- a/drivers/input/joystick/walkera0701.c
+++ b/drivers/input/joystick/walkera0701.c
@@ -124,7 +124,7 @@ static inline int read_ack(struct pardevice *p)
}

/* falling edge, prepare to BIN value calculation */
-static void walkera0701_irq_handler(void *handler_data)
+static irqreturn_t walkera0701_irq_handler(void *handler_data)
{
u64 pulse_time;
struct walkera_dev *w = handler_data;
@@ -136,7 +136,7 @@ static void walkera0701_irq_handler(void *handler_data)
/* cancel timer, if in handler or active do resync */
if (unlikely(0 != hrtimer_try_to_cancel(&w->timer))) {
w->counter = NO_SYNC;
- return;
+ return IRQ_HANDLED;
}

if (w->counter < NO_SYNC) {
@@ -166,6 +166,8 @@ static void walkera0701_irq_handler(void *handler_data)
w->counter = 0;

hrtimer_start(&w->timer, ktime_set(0, BIN_SAMPLE), HRTIMER_MODE_REL);
+
+ return IRQ_HANDLED;
}

static enum hrtimer_restart timer_handler(struct hrtimer
diff --git a/drivers/net/hamradio/baycom_par.c b/drivers/net/hamradio/baycom_par.c
index acb6369..1fd9a7b 100644
--- a/drivers/net/hamradio/baycom_par.c
+++ b/drivers/net/hamradio/baycom_par.c
@@ -269,7 +269,7 @@ static __inline__ void par96_rx(struct net_device *dev, struct baycom_state *bc)

/* --------------------------------------------------------------------- */

-static void par96_interrupt(void *dev_id)
+static irqreturn_t par96_interrupt(void *dev_id)
{
struct net_device *dev = dev_id;
struct baycom_state *bc = netdev_priv(dev);
@@ -292,6 +292,8 @@ static void par96_interrupt(void *dev_id)
hdlcdrv_transmitter(dev, &bc->hdrv);
hdlcdrv_receiver(dev, &bc->hdrv);
local_irq_disable();
+
+ return IRQ_HANDLED;
}

/* --------------------------------------------------------------------- */
diff --git a/drivers/net/plip/plip.c b/drivers/net/plip/plip.c
index 040b897..00a8b3a 100644
--- a/drivers/net/plip/plip.c
+++ b/drivers/net/plip/plip.c
@@ -143,7 +143,7 @@ static void plip_bh(struct work_struct *work);
static void plip_timer_bh(struct work_struct *work);

/* Interrupt handler */
-static void plip_interrupt(void *dev_id);
+static irqreturn_t plip_interrupt(void *dev_id);

/* Functions for DEV methods */
static int plip_tx_packet(struct sk_buff *skb, struct net_device *dev);
@@ -900,7 +900,7 @@ plip_error(struct net_device *dev, struct net_local *nl,
}

/* Handle the parallel port interrupts. */
-static void
+static irqreturn_t
plip_interrupt(void *dev_id)
{
struct net_device *dev = dev_id;
@@ -919,7 +919,7 @@ plip_interrupt(void *dev_id)
if ((dev->irq != -1) && (net_debug > 1))
printk(KERN_DEBUG "%s: spurious interrupt\n", dev->name);
spin_unlock_irqrestore (&nl->lock, flags);
- return;
+ return IRQ_NONE;
}

if (net_debug > 3)
@@ -948,6 +948,8 @@ plip_interrupt(void *dev_id)
}

spin_unlock_irqrestore(&nl->lock, flags);
+
+ return IRQ_HANDLED;
}

static int
diff --git a/drivers/parport/share.c b/drivers/parport/share.c
index 3fa6624..1fd8dc2 100644
--- a/drivers/parport/share.c
+++ b/drivers/parport/share.c
@@ -523,7 +523,7 @@ void parport_remove_port(struct parport *port)
struct pardevice *
parport_register_device(struct parport *port, const char *name,
int (*pf)(void *), void (*kf)(void *),
- void (*irq_func)(void *),
+ irqreturn_t (*irq_func)(void *),
int flags, void *handle)
{
struct pardevice *tmp;
@@ -1006,9 +1006,7 @@ irqreturn_t parport_irq_handler(int irq, void *dev_id)
{
struct parport *port = dev_id;

- parport_generic_irq(port);
-
- return IRQ_HANDLED;
+ return parport_generic_irq(port);
}

/* Exported symbols for modules. */
diff --git a/drivers/pps/clients/pps_parport.c b/drivers/pps/clients/pps_parport.c
index 38a8bbe..9acf376 100644
--- a/drivers/pps/clients/pps_parport.c
+++ b/drivers/pps/clients/pps_parport.c
@@ -64,7 +64,7 @@ static inline int signal_is_set(struct parport *port)
}

/* parport interrupt handler */
-static void parport_irq(void *handle)
+static irqreturn_t parport_irq(void *handle)
{
struct pps_event_time ts_assert, ts_clear;
struct pps_client_pp *dev = handle;
@@ -122,7 +122,7 @@ out_assert:
/* fire assert event */
pps_event(dev->pps, &ts_assert,
PPS_CAPTUREASSERT, NULL);
- return;
+ return IRQ_HANDLED;

out_both:
/* fire assert event */
@@ -131,7 +131,7 @@ out_both:
/* fire clear event */
pps_event(dev->pps, &ts_clear,
PPS_CAPTURECLEAR, NULL);
- return;
+ return IRQ_HANDLED;
}

static void parport_attach(struct parport *port)
diff --git a/drivers/staging/media/lirc/lirc_parallel.c b/drivers/staging/media/lirc/lirc_parallel.c
index 672858a..63fdc27 100644
--- a/drivers/staging/media/lirc/lirc_parallel.c
+++ b/drivers/staging/media/lirc/lirc_parallel.c
@@ -219,7 +219,7 @@ static void rbuf_write(int signal)
wptr = nwptr;
}

-static void lirc_lirc_irq_handler(void *blah)
+static irqreturn_t lirc_lirc_irq_handler(void *blah)
{
struct timeval tv;
static struct timeval lasttv;
@@ -230,10 +230,10 @@ static void lirc_lirc_irq_handler(void *blah)
unsigned int timeout;

if (!is_open)
- return;
+ return IRQ_NONE;

if (!is_claimed)
- return;
+ return IRQ_NONE;

#if 0
/* disable interrupt */
@@ -241,7 +241,7 @@ static void lirc_lirc_irq_handler(void *blah)
out(LIRC_PORT_IRQ, in(LIRC_PORT_IRQ) & (~LP_PINTEN));
#endif
if (check_pselecd && (in(1) & LP_PSELECD))
- return;
+ return IRQ_NONE;

#ifdef LIRC_TIMER
if (init) {
@@ -265,7 +265,7 @@ static void lirc_lirc_irq_handler(void *blah)
*/
timer = init_lirc_timer();
/* enable_irq(irq); */
- return;
+ return IRQ_HANDLED;
}
init = 1;
}
@@ -314,6 +314,8 @@ static void lirc_lirc_irq_handler(void *blah)
enable_irq(irq);
out(LIRC_PORT_IRQ, in(LIRC_PORT_IRQ)|LP_PINTEN);
*/
+
+ return IRQ_HANDLED;
}

/*** file operations ***/
diff --git a/include/linux/parport.h b/include/linux/parport.h
index c22f125..2ab774c 100644
--- a/include/linux/parport.h
+++ b/include/linux/parport.h
@@ -141,7 +141,7 @@ struct pardevice {
int (*preempt)(void *);
void (*wakeup)(void *);
void *private;
- void (*irq_func)(void *);
+ irqreturn_t (*irq_func)(void *);
unsigned int flags;
struct pardevice *next;
struct pardevice *prev;
@@ -298,7 +298,7 @@ extern void parport_put_port (struct parport *);
struct pardevice *parport_register_device(struct parport *port,
const char *name,
int (*pf)(void *), void (*kf)(void *),
- void (*irq_func)(void *),
+ irqreturn_t (*irq_func)(void *),
int flags, void *handle);

/* parport_unregister unlinks a device from the chain. */
@@ -429,13 +429,17 @@ extern void parport_daisy_deselect_all (struct parport *port);
extern int parport_daisy_select (struct parport *port, int daisy, int mode);

/* Lowlevel drivers _can_ call this support function to handle irqs. */
-static inline void parport_generic_irq(struct parport *port)
+static inline irqreturn_t parport_generic_irq(struct parport *port)
{
+ irqreturn_t ret = IRQ_NONE;
+
parport_ieee1284_interrupt (port);
read_lock(&port->cad_lock);
if (port->cad && port->cad->irq_func)
- port->cad->irq_func(port->cad->private);
+ ret = port->cad->irq_func(port->cad->private);
read_unlock(&port->cad_lock);
+
+ return ret;
}

/* Prototypes from parport_procfs */
--
2.1.0

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