stallion: Use krefs

Use tty_port_init and krefs in the stallion drivers to protect us from devices
going away underneath us. As with the other drives some rearranging is done to
pass the tty structure down properly on the user side.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 57 insertions, 50 deletions

diff --git a/drivers/char/istallion.c b/drivers/char/istallion.c
index 843a2afaf204..96ee1121acef 100644
--- a/drivers/char/istallion.c
+++ b/drivers/char/istallion.c
@@ -623,24 +623,25 @@ static int	stli_memioctl(struct inode *ip, struct file *fp, unsigned int cmd, un
 static void     stli_brdpoll(struct stlibrd *brdp, cdkhdr_t __iomem *hdrp);
 static void     stli_poll(unsigned long arg);
 static int      stli_hostcmd(struct stlibrd *brdp, struct stliport *portp);
-static int      stli_initopen(struct stlibrd *brdp, struct stliport *portp);
+static int      stli_initopen(struct tty_struct *tty, struct stlibrd *brdp, struct stliport *portp);
 static int      stli_rawopen(struct stlibrd *brdp, struct stliport *portp, unsigned long arg, int wait);
 static int      stli_rawclose(struct stlibrd *brdp, struct stliport *portp, unsigned long arg, int wait);
-static int      stli_waitcarrier(struct stlibrd *brdp, struct stliport *portp, struct file *filp);
-static int      stli_setport(struct stliport *portp);
+static int      stli_waitcarrier(struct tty_struct *tty, struct stlibrd *brdp,
+                                struct stliport *portp, struct file *filp);
+static int      stli_setport(struct tty_struct *tty);
 static int      stli_cmdwait(struct stlibrd *brdp, struct stliport *portp, unsigned long cmd, void *arg, int size, int copyback);
 static void     stli_sendcmd(struct stlibrd *brdp, struct stliport *portp, unsigned long cmd, void *arg, int size, int copyback);
 static void     __stli_sendcmd(struct stlibrd *brdp, struct stliport *portp, unsigned long cmd, void *arg, int size, int copyback);
 static void     stli_dodelaycmd(struct stliport *portp, cdkctrl_t __iomem *cp);
-static void     stli_mkasyport(struct stliport *portp, asyport_t *pp, struct ktermios *tiosp);
+static void     stli_mkasyport(struct tty_struct *tty, struct stliport *portp, asyport_t *pp, struct ktermios *tiosp);
 static void     stli_mkasysigs(asysigs_t *sp, int dtr, int rts);
 static long     stli_mktiocm(unsigned long sigvalue);
 static void     stli_read(struct stlibrd *brdp, struct stliport *portp);
 static int      stli_getserial(struct stliport *portp, struct serial_struct __user *sp);
-static int      stli_setserial(struct stliport *portp, struct serial_struct __user *sp);
+static int      stli_setserial(struct tty_struct *tty, struct serial_struct __user *sp);
 static int      stli_getbrdstats(combrd_t __user *bp);
-static int      stli_getportstats(struct stliport *portp, comstats_t __user *cp);
-static int      stli_portcmdstats(struct stliport *portp);
+static int      stli_getportstats(struct tty_struct *tty, struct stliport *portp, comstats_t __user *cp);
+static int      stli_portcmdstats(struct tty_struct *tty, struct stliport *portp);
 static int      stli_clrportstats(struct stliport *portp, comstats_t __user *cp);
 static int      stli_getportstruct(struct stliport __user *arg);
 static int      stli_getbrdstruct(struct stlibrd __user *arg);
@@ -731,12 +732,16 @@ static void stli_cleanup_ports(struct stlibrd *brdp)
 {
         struct stliport *portp;
         unsigned int j;
+        struct tty_struct *tty;
 
         for (j = 0; j < STL_MAXPORTS; j++) {
                 portp = brdp->ports[j];
                 if (portp != NULL) {
-                        if (portp->port.tty != NULL)
-                                tty_hangup(portp->port.tty);
+                        tty = tty_port_tty_get(&portp->port);
+                        if (tty != NULL) {
+                                tty_hangup(tty);
+                                tty_kref_put(tty);
+                        }
                         kfree(portp);
                 }
         }
@@ -824,7 +829,7 @@ static int stli_open(struct tty_struct *tty, struct file *filp)
  *      requires several commands to the board we will need to wait for any
  *      other open that is already initializing the port.
  */
-        portp->port.tty = tty;
+        tty_port_tty_set(&portp->port, tty);
         tty->driver_data = portp;
         portp->port.count++;
 
@@ -835,7 +840,7 @@ static int stli_open(struct tty_struct *tty, struct file *filp)
 
         if ((portp->port.flags & ASYNC_INITIALIZED) == 0) {
                 set_bit(ST_INITIALIZING, &portp->state);
-                if ((rc = stli_initopen(brdp, portp)) >= 0) {
+                if ((rc = stli_initopen(tty, brdp, portp)) >= 0) {
                         portp->port.flags |= ASYNC_INITIALIZED;
                         clear_bit(TTY_IO_ERROR, &tty->flags);
                 }
@@ -864,7 +869,7 @@ static int stli_open(struct tty_struct *tty, struct file *filp)
  *      then also we might have to wait for carrier.
  */
         if (!(filp->f_flags & O_NONBLOCK)) {
-                if ((rc = stli_waitcarrier(brdp, portp, filp)) != 0)
+                if ((rc = stli_waitcarrier(tty, brdp, portp, filp)) != 0)
                         return rc;
         }
         portp->port.flags |= ASYNC_NORMAL_ACTIVE;
@@ -930,7 +935,7 @@ static void stli_close(struct tty_struct *tty, struct file *filp)
         stli_flushbuffer(tty);
 
         tty->closing = 0;
-        portp->port.tty = NULL;
+        tty_port_tty_set(&portp->port, NULL);
 
         if (portp->openwaitcnt) {
                 if (portp->close_delay)
@@ -952,9 +957,9 @@ static void stli_close(struct tty_struct *tty, struct file *filp)
  *      this still all happens pretty quickly.
  */
 
-static int stli_initopen(struct stlibrd *brdp, struct stliport *portp)
+static int stli_initopen(struct tty_struct *tty,
+                                struct stlibrd *brdp, struct stliport *portp)
 {
-        struct tty_struct *tty;
         asynotify_t nt;
         asyport_t aport;
         int rc;
@@ -969,10 +974,7 @@ static int stli_initopen(struct stlibrd *brdp, struct stliport *portp)
             sizeof(asynotify_t), 0)) < 0)
                 return rc;
 
-        tty = portp->port.tty;
-        if (tty == NULL)
-                return -ENODEV;
-        stli_mkasyport(portp, &aport, tty->termios);
+        stli_mkasyport(tty, portp, &aport, tty->termios);
         if ((rc = stli_cmdwait(brdp, portp, A_SETPORT, &aport,
             sizeof(asyport_t), 0)) < 0)
                 return rc;
@@ -1161,22 +1163,21 @@ static int stli_cmdwait(struct stlibrd *brdp, struct stliport *portp, unsigned l
  *      waiting for the command to complete - so must have user context.
  */
 
-static int stli_setport(struct stliport *portp)
+static int stli_setport(struct tty_struct *tty)
 {
+        struct stliport *portp = tty->driver_data;
         struct stlibrd *brdp;
         asyport_t aport;
 
         if (portp == NULL)
                 return -ENODEV;
-        if (portp->port.tty == NULL)
-                return -ENODEV;
         if (portp->brdnr >= stli_nrbrds)
                 return -ENODEV;
         brdp = stli_brds[portp->brdnr];
         if (brdp == NULL)
                 return -ENODEV;
 
-        stli_mkasyport(portp, &aport, portp->port.tty->termios);
+        stli_mkasyport(tty, portp, &aport, tty->termios);
         return(stli_cmdwait(brdp, portp, A_SETPORT, &aport, sizeof(asyport_t), 0));
 }
 
@@ -1187,7 +1188,8 @@ static int stli_setport(struct stliport *portp)
  *      maybe because if we are clocal then we don't need to wait...
  */
 
-static int stli_waitcarrier(struct stlibrd *brdp, struct stliport *portp, struct file *filp)
+static int stli_waitcarrier(struct tty_struct *tty, struct stlibrd *brdp,
+                                struct stliport *portp, struct file *filp)
 {
         unsigned long flags;
         int rc, doclocal;
@@ -1195,7 +1197,7 @@ static int stli_waitcarrier(struct stlibrd *brdp, struct stliport *portp, struct
         rc = 0;
         doclocal = 0;
 
-        if (portp->port.tty->termios->c_cflag & CLOCAL)
+        if (tty->termios->c_cflag & CLOCAL)
                 doclocal++;
 
         spin_lock_irqsave(&stli_lock, flags);
@@ -1572,10 +1574,11 @@ static int stli_getserial(struct stliport *portp, struct serial_struct __user *s
  *      just quietly ignore any requests to change irq, etc.
  */
 
-static int stli_setserial(struct stliport *portp, struct serial_struct __user *sp)
+static int stli_setserial(struct tty_struct *tty, struct serial_struct __user *sp)
 {
         struct serial_struct sio;
         int rc;
+        struct stliport *portp = tty->driver_data;
 
         if (copy_from_user(&sio, sp, sizeof(struct serial_struct)))
                 return -EFAULT;
@@ -1594,7 +1597,7 @@ static int stli_setserial(struct stliport *portp, struct serial_struct __user *s
         portp->closing_wait = sio.closing_wait;
         portp->custom_divisor = sio.custom_divisor;
 
-        if ((rc = stli_setport(portp)) < 0)
+        if ((rc = stli_setport(tty)) < 0)
                 return rc;
         return 0;
 }
@@ -1685,17 +1688,17 @@ static int stli_ioctl(struct tty_struct *tty, struct file *file, unsigned int cm
                 rc = stli_getserial(portp, argp);
                 break;
         case TIOCSSERIAL:
-                rc = stli_setserial(portp, argp);
+                rc = stli_setserial(tty, argp);
                 break;
         case STL_GETPFLAG:
                 rc = put_user(portp->pflag, (unsigned __user *)argp);
                 break;
         case STL_SETPFLAG:
                 if ((rc = get_user(portp->pflag, (unsigned __user *)argp)) == 0)
-                        stli_setport(portp);
+                        stli_setport(tty);
                 break;
         case COM_GETPORTSTATS:
-                rc = stli_getportstats(portp, argp);
+                rc = stli_getportstats(tty, portp, argp);
                 break;
         case COM_CLRPORTSTATS:
                 rc = stli_clrportstats(portp, argp);
@@ -1742,7 +1745,7 @@ static void stli_settermios(struct tty_struct *tty, struct ktermios *old)
 
         tiosp = tty->termios;
 
-        stli_mkasyport(portp, &aport, tiosp);
+        stli_mkasyport(tty, portp, &aport, tiosp);
         stli_cmdwait(brdp, portp, A_SETPORT, &aport, sizeof(asyport_t), 0);
         stli_mkasysigs(&portp->asig, ((tiosp->c_cflag & CBAUD) ? 1 : 0), -1);
         stli_cmdwait(brdp, portp, A_SETSIGNALS, &portp->asig,
@@ -1854,7 +1857,7 @@ static void stli_hangup(struct tty_struct *tty)
         clear_bit(ST_TXBUSY, &portp->state);
         clear_bit(ST_RXSTOP, &portp->state);
         set_bit(TTY_IO_ERROR, &tty->flags);
-        portp->port.tty = NULL;
+        tty_port_tty_set(&portp->port, NULL);
         portp->port.flags &= ~ASYNC_NORMAL_ACTIVE;
         portp->port.count = 0;
         spin_unlock_irqrestore(&stli_lock, flags);
@@ -1998,7 +2001,7 @@ static int stli_portinfo(struct stlibrd *brdp, struct stliport *portp, int portn
         char *sp, *uart;
         int rc, cnt;
 
-        rc = stli_portcmdstats(portp);
+        rc = stli_portcmdstats(NULL, portp);
 
         uart = "UNKNOWN";
         if (brdp->state & BST_STARTED) {
@@ -2188,7 +2191,7 @@ static void stli_read(struct stlibrd *brdp, struct stliport *portp)
 
         if (test_bit(ST_RXSTOP, &portp->state))
                 return;
-        tty = portp->port.tty;
+        tty = tty_port_tty_get(&portp->port);
         if (tty == NULL)
                 return;
 
@@ -2230,6 +2233,7 @@ static void stli_read(struct stlibrd *brdp, struct stliport *portp)
                 set_bit(ST_RXING, &portp->state);
 
         tty_schedule_flip(tty);
+        tty_kref_put(tty);
 }
 
 /*****************************************************************************/
@@ -2362,7 +2366,7 @@ static int stli_hostcmd(struct stlibrd *brdp, struct stliport *portp)
         if (ap->notify) {
                 nt = ap->changed;
                 ap->notify = 0;
-                tty = portp->port.tty;
+                tty = tty_port_tty_get(&portp->port);
 
                 if (nt.signal & SG_DCD) {
                         oldsigs = portp->sigs;
@@ -2399,6 +2403,7 @@ static int stli_hostcmd(struct stlibrd *brdp, struct stliport *portp)
                                 tty_schedule_flip(tty);
                         }
                 }
+                tty_kref_put(tty);
 
                 if (nt.data & DT_RXBUSY) {
                         donerx++;
@@ -2535,14 +2540,15 @@ static void stli_poll(unsigned long arg)
  *      the slave.
  */
 
-static void stli_mkasyport(struct stliport *portp, asyport_t *pp, struct ktermios *tiosp)
+static void stli_mkasyport(struct tty_struct *tty, struct stliport *portp,
+                                asyport_t *pp, struct ktermios *tiosp)
 {
         memset(pp, 0, sizeof(asyport_t));
 
 /*
  *      Start of by setting the baud, char size, parity and stop bit info.
  */
-        pp->baudout = tty_get_baud_rate(portp->port.tty);
+        pp->baudout = tty_get_baud_rate(tty);
         if ((tiosp->c_cflag & CBAUD) == B38400) {
                 if ((portp->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
                         pp->baudout = 57600;
@@ -2695,7 +2701,7 @@ static int stli_initports(struct stlibrd *brdp)
                         printk("STALLION: failed to allocate port structure\n");
                         continue;
                 }
-
+                tty_port_init(&portp->port);
                 portp->magic = STLI_PORTMAGIC;
                 portp->portnr = i;
                 portp->brdnr = brdp->brdnr;
@@ -4220,7 +4226,7 @@ static struct stliport *stli_getport(unsigned int brdnr, unsigned int panelnr,
  *      what port to get stats for (used through board control device).
  */
 
-static int stli_portcmdstats(struct stliport *portp)
+static int stli_portcmdstats(struct tty_struct *tty, struct stliport *portp)
 {
         unsigned long   flags;
         struct stlibrd  *brdp;
@@ -4249,15 +4255,15 @@ static int stli_portcmdstats(struct stliport *portp)
         stli_comstats.flags = portp->port.flags;
 
         spin_lock_irqsave(&brd_lock, flags);
-        if (portp->port.tty != NULL) {
-                if (portp->port.tty->driver_data == portp) {
-                        stli_comstats.ttystate = portp->port.tty->flags;
+        if (tty != NULL) {
+                if (portp->port.tty == tty) {
+                        stli_comstats.ttystate = tty->flags;
                         stli_comstats.rxbuffered = -1;
-                        if (portp->port.tty->termios != NULL) {
-                                stli_comstats.cflags = portp->port.tty->termios->c_cflag;
-                                stli_comstats.iflags = portp->port.tty->termios->c_iflag;
-                                stli_comstats.oflags = portp->port.tty->termios->c_oflag;
-                                stli_comstats.lflags = portp->port.tty->termios->c_lflag;
+                        if (tty->termios != NULL) {
+                                stli_comstats.cflags = tty->termios->c_cflag;
+                                stli_comstats.iflags = tty->termios->c_iflag;
+                                stli_comstats.oflags = tty->termios->c_oflag;
+                                stli_comstats.lflags = tty->termios->c_lflag;
                         }
                 }
         }
@@ -4294,7 +4300,8 @@ static int stli_portcmdstats(struct stliport *portp)
  *      what port to get stats for (used through board control device).
  */
 
-static int stli_getportstats(struct stliport *portp, comstats_t __user *cp)
+static int stli_getportstats(struct tty_struct *tty, struct stliport *portp,
+                                                        comstats_t __user *cp)
 {
         struct stlibrd *brdp;
         int rc;
@@ -4312,7 +4319,7 @@ static int stli_getportstats(struct stliport *portp, comstats_t __user *cp)
         if (!brdp)
                 return -ENODEV;
 
-        if ((rc = stli_portcmdstats(portp)) < 0)
+        if ((rc = stli_portcmdstats(tty, portp)) < 0)
                 return rc;
 
         return copy_to_user(cp, &stli_comstats, sizeof(comstats_t)) ?
@@ -4427,7 +4434,7 @@ static int stli_memioctl(struct inode *ip, struct file *fp, unsigned int cmd, un
 
         switch (cmd) {
         case COM_GETPORTSTATS:
-                rc = stli_getportstats(NULL, argp);
+                rc = stli_getportstats(NULL, NULL, argp);
                 done++;
                 break;
         case COM_CLRPORTSTATS: