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CAPI: Use tty_port to keep track of capiminor's tty
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Use the reference management features of tty_port to look up and drop
again the tty_struct associated with a capiminor.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Jan Kiszka authored and David S. Miller committed Feb 17, 2010
1 parent 4632451 commit fb4b488
Showing 1 changed file with 62 additions and 32 deletions.
94 changes: 62 additions & 32 deletions drivers/isdn/capi/capi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -94,7 +94,7 @@ struct capiminor {
u16 datahandle;
u16 msgid;

struct tty_struct *tty;
struct tty_port port;
int ttyinstop;
int ttyoutstop;
struct sk_buff *ttyskb;
Expand Down Expand Up @@ -212,6 +212,8 @@ static void capiminor_del_all_ack(struct capiminor *mp)

/* -------- struct capiminor ---------------------------------------- */

static const struct tty_port_operations capiminor_port_ops; /* we have none */

static struct capiminor *capiminor_alloc(struct capi20_appl *ap, u32 ncci)
{
struct capiminor *mp;
Expand All @@ -237,6 +239,9 @@ static struct capiminor *capiminor_alloc(struct capi20_appl *ap, u32 ncci)
skb_queue_head_init(&mp->inqueue);
skb_queue_head_init(&mp->outqueue);

tty_port_init(&mp->port);
mp->port.ops = &capiminor_port_ops;

/* Allocate the least unused minor number. */
write_lock_irqsave(&capiminors_lock, flags);
for (minor = 0; minor < capi_ttyminors; minor++)
Expand Down Expand Up @@ -335,18 +340,22 @@ static void capincci_alloc_minor(struct capidev *cdev, struct capincci *np)
static void capincci_free_minor(struct capincci *np)
{
struct capiminor *mp = np->minorp;
struct tty_struct *tty;

if (mp) {
capifs_free_ncci(mp->capifs_dentry);
if (mp->tty) {

tty = tty_port_tty_get(&mp->port);
if (tty) {
mp->nccip = NULL;
#ifdef _DEBUG_REFCOUNT
printk(KERN_DEBUG "reset mp->nccip\n");
#endif
tty_hangup(mp->tty);
} else {
capiminor_free(mp);
tty_hangup(tty);
tty_kref_put(tty);
}

capiminor_free(mp);
}
}

Expand Down Expand Up @@ -433,65 +442,70 @@ gen_data_b3_resp_for(struct capiminor *mp, struct sk_buff *skb)

static int handle_recv_skb(struct capiminor *mp, struct sk_buff *skb)
{
struct tty_struct *tty;
struct sk_buff *nskb;
int datalen;
u16 errcode, datahandle;
struct tty_ldisc *ld;

int ret = -1;

datalen = skb->len - CAPIMSG_LEN(skb->data);
if (mp->tty == NULL)
{

tty = tty_port_tty_get(&mp->port);
if (!tty) {
#ifdef _DEBUG_DATAFLOW
printk(KERN_DEBUG "capi: currently no receiver\n");
#endif
return -1;
}

ld = tty_ldisc_ref(mp->tty);
if (ld == NULL)
return -1;
ld = tty_ldisc_ref(tty);
if (!ld)
goto out1;

if (ld->ops->receive_buf == NULL) {
#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)
printk(KERN_DEBUG "capi: ldisc has no receive_buf function\n");
#endif
goto bad;
goto out2;
}
if (mp->ttyinstop) {
#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)
printk(KERN_DEBUG "capi: recv tty throttled\n");
#endif
goto bad;
goto out2;
}
if (mp->tty->receive_room < datalen) {
if (tty->receive_room < datalen) {
#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)
printk(KERN_DEBUG "capi: no room in tty\n");
#endif
goto bad;
goto out2;
}
if ((nskb = gen_data_b3_resp_for(mp, skb)) == NULL) {
printk(KERN_ERR "capi: gen_data_b3_resp failed\n");
goto bad;
goto out2;
}
datahandle = CAPIMSG_U16(skb->data,CAPIMSG_BASELEN+4);
errcode = capi20_put_message(mp->ap, nskb);
if (errcode != CAPI_NOERROR) {
printk(KERN_ERR "capi: send DATA_B3_RESP failed=%x\n",
errcode);
kfree_skb(nskb);
goto bad;
goto out2;
}
(void)skb_pull(skb, CAPIMSG_LEN(skb->data));
#ifdef _DEBUG_DATAFLOW
printk(KERN_DEBUG "capi: DATA_B3_RESP %u len=%d => ldisc\n",
datahandle, skb->len);
#endif
ld->ops->receive_buf(mp->tty, skb->data, NULL, skb->len);
ld->ops->receive_buf(tty, skb->data, NULL, skb->len);
kfree_skb(skb);
ret = 0;
out2:
tty_ldisc_deref(ld);
return 0;
bad:
tty_ldisc_deref(ld);
return -1;
out1:
tty_kref_put(tty);
return ret;
}

static void handle_minor_recv(struct capiminor *mp)
Expand All @@ -510,16 +524,22 @@ static void handle_minor_recv(struct capiminor *mp)

static int handle_minor_send(struct capiminor *mp)
{
struct tty_struct *tty;
struct sk_buff *skb;
u16 len;
int count = 0;
u16 errcode;
u16 datahandle;

if (mp->tty && mp->ttyoutstop) {
tty = tty_port_tty_get(&mp->port);
if (!tty)
return 0;

if (mp->ttyoutstop) {
#if defined(_DEBUG_DATAFLOW) || defined(_DEBUG_TTYFUNCS)
printk(KERN_DEBUG "capi: send: tty stopped\n");
#endif
tty_kref_put(tty);
return 0;
}

Expand All @@ -542,6 +562,7 @@ static int handle_minor_send(struct capiminor *mp)
if (capiminor_add_ack(mp, datahandle) < 0) {
skb_pull(skb, CAPI_DATA_B3_REQ_LEN);
skb_queue_head(&mp->outqueue, skb);
tty_kref_put(tty);
return count;
}
errcode = capi20_put_message(mp->ap, skb);
Expand All @@ -568,6 +589,7 @@ static int handle_minor_send(struct capiminor *mp)
mp->outbytes -= len;
kfree_skb(skb);
}
tty_kref_put(tty);
return count;
}

Expand All @@ -578,6 +600,7 @@ static void capi_recv_message(struct capi20_appl *ap, struct sk_buff *skb)
{
struct capidev *cdev = ap->private;
#ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
struct tty_struct *tty;
struct capiminor *mp;
u16 datahandle;
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
Expand Down Expand Up @@ -641,8 +664,11 @@ static void capi_recv_message(struct capi20_appl *ap, struct sk_buff *skb)
#endif
kfree_skb(skb);
(void)capiminor_del_ack(mp, datahandle);
if (mp->tty)
tty_wakeup(mp->tty);
tty = tty_port_tty_get(&mp->port);
if (tty) {
tty_wakeup(tty);
tty_kref_put(tty);
}
(void)handle_minor_send(mp);

} else {
Expand Down Expand Up @@ -1029,14 +1055,17 @@ static void capinc_tty_cleanup(struct tty_struct *tty)
capiminor_put(mp);
}

static int capinc_tty_open(struct tty_struct * tty, struct file * file)
static int capinc_tty_open(struct tty_struct *tty, struct file *filp)
{
struct capiminor *mp = tty->driver_data;
unsigned long flags;
int err;

err = tty_port_open(&mp->port, tty, filp);
if (err)
return err;

spin_lock_irqsave(&workaround_lock, flags);
if (atomic_read(&mp->ttyopencount) == 0)
mp->tty = tty;
atomic_inc(&mp->ttyopencount);
#ifdef _DEBUG_REFCOUNT
printk(KERN_DEBUG "capinc_tty_open ocount=%d\n", atomic_read(&mp->ttyopencount));
Expand All @@ -1046,25 +1075,23 @@ static int capinc_tty_open(struct tty_struct * tty, struct file * file)
return 0;
}

static void capinc_tty_close(struct tty_struct * tty, struct file * file)
static void capinc_tty_close(struct tty_struct *tty, struct file *filp)
{
struct capiminor *mp = tty->driver_data;

if (atomic_dec_and_test(&mp->ttyopencount)) {
#ifdef _DEBUG_REFCOUNT
printk(KERN_DEBUG "capinc_tty_close lastclose\n");
#endif
mp->tty = NULL;
}
#ifdef _DEBUG_REFCOUNT
printk(KERN_DEBUG "capinc_tty_close ocount=%d\n", atomic_read(&mp->ttyopencount));
#endif
if (mp->nccip == NULL)
capiminor_free(mp);

#ifdef _DEBUG_REFCOUNT
printk(KERN_DEBUG "capinc_tty_close\n");
#endif
tty_port_close(&mp->port, tty, filp);
}

static int capinc_tty_write(struct tty_struct * tty,
Expand Down Expand Up @@ -1292,9 +1319,12 @@ static void capinc_tty_start(struct tty_struct *tty)

static void capinc_tty_hangup(struct tty_struct *tty)
{
struct capiminor *mp = tty->driver_data;

#ifdef _DEBUG_TTYFUNCS
printk(KERN_DEBUG "capinc_tty_hangup\n");
#endif
tty_port_hangup(&mp->port);
}

static int capinc_tty_break_ctl(struct tty_struct *tty, int state)
Expand Down

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