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, 64 insertions, 41 deletions

diff --git a/drivers/char/stallion.c b/drivers/char/stallion.c
index 19db1eb87c26..81b3234127db 100644
--- a/drivers/char/stallion.c
+++ b/drivers/char/stallion.c
@@ -405,9 +405,9 @@ static unsigned int	stl_baudrates[] = {
 
 static int      stl_memioctl(struct inode *ip, struct file *fp, unsigned int cmd, unsigned long arg);
 static int      stl_brdinit(struct stlbrd *brdp);
-static int      stl_getportstats(struct stlport *portp, comstats_t __user *cp);
+static int      stl_getportstats(struct tty_struct *tty, struct stlport *portp, comstats_t __user *cp);
 static int      stl_clrportstats(struct stlport *portp, comstats_t __user *cp);
-static int      stl_waitcarrier(struct stlport *portp, struct file *filp);
+static int      stl_waitcarrier(struct tty_struct *tty, struct stlport *portp, struct file *filp);
 
 /*
  *      CD1400 uart specific handling functions.
@@ -612,8 +612,9 @@ static struct class *stallion_class;
 static void stl_cd_change(struct stlport *portp)
 {
         unsigned int oldsigs = portp->sigs;
+        struct tty_struct *tty = tty_port_tty_get(&portp->port);
 
-        if (!portp->port.tty)
+        if (!tty)
                 return;
 
         portp->sigs = stl_getsignals(portp);
@@ -623,7 +624,8 @@ static void stl_cd_change(struct stlport *portp)
 
         if ((oldsigs & TIOCM_CD) && ((portp->sigs & TIOCM_CD) == 0))
                 if (portp->port.flags & ASYNC_CHECK_CD)
-                        tty_hangup(portp->port.tty);
+                        tty_hangup(tty);
+        tty_kref_put(tty);
 }
 
 /*
@@ -734,7 +736,7 @@ static int stl_open(struct tty_struct *tty, struct file *filp)
  *      On the first open of the device setup the port hardware, and
  *      initialize the per port data structure.
  */
-        portp->port.tty = tty;
+        tty_port_tty_set(&portp->port, tty);
         tty->driver_data = portp;
         portp->port.count++;
 
@@ -774,7 +776,7 @@ static int stl_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 = stl_waitcarrier(portp, filp)) != 0)
+                if ((rc = stl_waitcarrier(tty, portp, filp)) != 0)
                         return rc;
 
         portp->port.flags |= ASYNC_NORMAL_ACTIVE;
@@ -789,7 +791,8 @@ static int stl_open(struct tty_struct *tty, struct file *filp)
  *      maybe because if we are clocal then we don't need to wait...
  */
 
-static int stl_waitcarrier(struct stlport *portp, struct file *filp)
+static int stl_waitcarrier(struct tty_struct *tty, struct stlport *portp,
+                                                        struct file *filp)
 {
         unsigned long   flags;
         int             rc, doclocal;
@@ -801,7 +804,7 @@ static int stl_waitcarrier(struct stlport *portp, struct file *filp)
 
         spin_lock_irqsave(&stallion_lock, flags);
 
-        if (portp->port.tty->termios->c_cflag & CLOCAL)
+        if (tty->termios->c_cflag & CLOCAL)
                 doclocal++;
 
         portp->openwaitcnt++;
@@ -949,7 +952,7 @@ static void stl_close(struct tty_struct *tty, struct file *filp)
         tty_ldisc_flush(tty);
 
         tty->closing = 0;
-        portp->port.tty = NULL;
+        tty_port_tty_set(&portp->port, NULL);
 
         if (portp->openwaitcnt) {
                 if (portp->close_delay)
@@ -1183,8 +1186,9 @@ static int stl_getserial(struct stlport *portp, struct serial_struct __user *sp)
  *      just quietly ignore any requests to change irq, etc.
  */
 
-static int stl_setserial(struct stlport *portp, struct serial_struct __user *sp)
+static int stl_setserial(struct tty_struct *tty, struct serial_struct __user *sp)
 {
+        struct stlport *        portp = tty->driver_data;
         struct serial_struct    sio;
 
         pr_debug("stl_setserial(portp=%p,sp=%p)\n", portp, sp);
@@ -1205,7 +1209,7 @@ static int stl_setserial(struct stlport *portp, struct serial_struct __user *sp)
         portp->close_delay = sio.close_delay;
         portp->closing_wait = sio.closing_wait;
         portp->custom_divisor = sio.custom_divisor;
-        stl_setport(portp, portp->port.tty->termios);
+        stl_setport(portp, tty->termios);
         return 0;
 }
 
@@ -1282,10 +1286,10 @@ static int stl_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd
                 rc = stl_getserial(portp, argp);
                 break;
         case TIOCSSERIAL:
-                rc = stl_setserial(portp, argp);
+                rc = stl_setserial(tty, argp);
                 break;
         case COM_GETPORTSTATS:
-                rc = stl_getportstats(portp, argp);
+                rc = stl_getportstats(tty, portp, argp);
                 break;
         case COM_CLRPORTSTATS:
                 rc = stl_clrportstats(portp, argp);
@@ -1452,7 +1456,7 @@ static void stl_hangup(struct tty_struct *tty)
                 portp->tx.head = NULL;
                 portp->tx.tail = NULL;
         }
-        portp->port.tty = NULL;
+        tty_port_tty_set(&portp->port, NULL);
         portp->port.flags &= ~ASYNC_NORMAL_ACTIVE;
         portp->port.count = 0;
         wake_up_interruptible(&portp->port.open_wait);
@@ -1805,7 +1809,7 @@ static int __devinit stl_initports(struct stlbrd *brdp, struct stlpanel *panelp)
                                 "(size=%Zd)\n", sizeof(struct stlport));
                         break;
                 }
-
+                tty_port_init(&portp->port);
                 portp->magic = STL_PORTMAGIC;
                 portp->portnr = i;
                 portp->brdnr = panelp->brdnr;
@@ -1832,6 +1836,7 @@ static void stl_cleanup_panels(struct stlbrd *brdp)
         struct stlpanel *panelp;
         struct stlport *portp;
         unsigned int j, k;
+        struct tty_struct *tty;
 
         for (j = 0; j < STL_MAXPANELS; j++) {
                 panelp = brdp->panels[j];
@@ -1841,8 +1846,11 @@ static void stl_cleanup_panels(struct stlbrd *brdp)
                         portp = panelp->ports[k];
                         if (portp == NULL)
                                 continue;
-                        if (portp->port.tty != NULL)
-                                stl_hangup(portp->port.tty);
+                        tty = tty_port_tty_get(&portp->port);
+                        if (tty != NULL) {
+                                stl_hangup(tty);
+                                tty_kref_put(tty);
+                        }
                         kfree(portp->tx.buf);
                         kfree(portp);
                 }
@@ -2498,7 +2506,7 @@ static struct stlport *stl_getport(int brdnr, int panelnr, int portnr)
  *      what port to get stats for (used through board control device).
  */
 
-static int stl_getportstats(struct stlport *portp, comstats_t __user *cp)
+static int stl_getportstats(struct tty_struct *tty, struct stlport *portp, comstats_t __user *cp)
 {
         comstats_t      stl_comstats;
         unsigned char   *head, *tail;
@@ -2525,18 +2533,17 @@ static int stl_getportstats(struct stlport *portp, comstats_t __user *cp)
         portp->stats.rxbuffered = 0;
 
         spin_lock_irqsave(&stallion_lock, flags);
-        if (portp->port.tty != NULL)
-                if (portp->port.tty->driver_data == portp) {
-                        portp->stats.ttystate = portp->port.tty->flags;
-                        /* No longer available as a statistic */
-                        portp->stats.rxbuffered = 1; /*portp->port.tty->flip.count; */
-                        if (portp->port.tty->termios != NULL) {
-                                portp->stats.cflags = portp->port.tty->termios->c_cflag;
-                                portp->stats.iflags = portp->port.tty->termios->c_iflag;
-                                portp->stats.oflags = portp->port.tty->termios->c_oflag;
-                                portp->stats.lflags = portp->port.tty->termios->c_lflag;
-                        }
+        if (tty != NULL && portp->port.tty == tty) {
+                portp->stats.ttystate = tty->flags;
+                /* No longer available as a statistic */
+                portp->stats.rxbuffered = 1; /*tty->flip.count; */
+                if (tty->termios != NULL) {
+                        portp->stats.cflags = tty->termios->c_cflag;
+                        portp->stats.iflags = tty->termios->c_iflag;
+                        portp->stats.oflags = tty->termios->c_oflag;
+                        portp->stats.lflags = tty->termios->c_lflag;
                 }
+        }
         spin_unlock_irqrestore(&stallion_lock, flags);
 
         head = portp->tx.head;
@@ -2640,7 +2647,7 @@ static int stl_memioctl(struct inode *ip, struct file *fp, unsigned int cmd, uns
 
         switch (cmd) {
         case COM_GETPORTSTATS:
-                rc = stl_getportstats(NULL, argp);
+                rc = stl_getportstats(NULL, NULL, argp);
                 break;
         case COM_CLRPORTSTATS:
                 rc = stl_clrportstats(NULL, argp);
@@ -3243,7 +3250,7 @@ static void stl_cd1400flowctrl(struct stlport *portp, int state)
 
         if (portp == NULL)
                 return;
-        tty = portp->port.tty;
+        tty = tty_port_tty_get(&portp->port);
         if (tty == NULL)
                 return;
 
@@ -3288,6 +3295,7 @@ static void stl_cd1400flowctrl(struct stlport *portp, int state)
 
         BRDDISABLE(portp->brdnr);
         spin_unlock_irqrestore(&brd_lock, flags);
+        tty_kref_put(tty);
 }
 
 /*****************************************************************************/
@@ -3305,7 +3313,7 @@ static void stl_cd1400sendflow(struct stlport *portp, int state)
 
         if (portp == NULL)
                 return;
-        tty = portp->port.tty;
+        tty = tty_port_tty_get(&portp->port);
         if (tty == NULL)
                 return;
 
@@ -3325,6 +3333,7 @@ static void stl_cd1400sendflow(struct stlport *portp, int state)
         }
         BRDDISABLE(portp->brdnr);
         spin_unlock_irqrestore(&brd_lock, flags);
+        tty_kref_put(tty);
 }
 
 /*****************************************************************************/
@@ -3478,6 +3487,7 @@ static void stl_cd1400txisr(struct stlpanel *panelp, int ioaddr)
         int             len, stlen;
         char            *head, *tail;
         unsigned char   ioack, srer;
+        struct tty_struct *tty;
 
         pr_debug("stl_cd1400txisr(panelp=%p,ioaddr=%x)\n", panelp, ioaddr);
 
@@ -3504,8 +3514,11 @@ static void stl_cd1400txisr(struct stlpanel *panelp, int ioaddr)
         if ((len == 0) || ((len < STL_TXBUFLOW) &&
             (test_bit(ASYI_TXLOW, &portp->istate) == 0))) {
                 set_bit(ASYI_TXLOW, &portp->istate);
-                if (portp->port.tty)
-                        tty_wakeup(portp->port.tty);
+                tty = tty_port_tty_get(&portp->port);
+                if (tty) {
+                        tty_wakeup(tty);
+                        tty_kref_put(tty);
+                }
         }
 
         if (len == 0) {
@@ -3569,7 +3582,7 @@ static void stl_cd1400rxisr(struct stlpanel *panelp, int ioaddr)
                 return;
         }
         portp = panelp->ports[(ioack >> 3)];
-        tty = portp->port.tty;
+        tty = tty_port_tty_get(&portp->port);
 
         if ((ioack & ACK_TYPMASK) == ACK_TYPRXGOOD) {
                 outb((RDCR + portp->uartaddr), ioaddr);
@@ -3633,10 +3646,12 @@ static void stl_cd1400rxisr(struct stlpanel *panelp, int ioaddr)
                 }
         } else {
                 printk("STALLION: bad RX interrupt ack value=%x\n", ioack);
+                tty_kref_put(tty);
                 return;
         }
 
 stl_rxalldone:
+        tty_kref_put(tty);
         outb((EOSRR + portp->uartaddr), ioaddr);
         outb(0, (ioaddr + EREG_DATA));
 }
@@ -4175,7 +4190,7 @@ static void stl_sc26198flowctrl(struct stlport *portp, int state)
 
         if (portp == NULL)
                 return;
-        tty = portp->port.tty;
+        tty = tty_port_tty_get(&portp->port);
         if (tty == NULL)
                 return;
 
@@ -4226,6 +4241,7 @@ static void stl_sc26198flowctrl(struct stlport *portp, int state)
 
         BRDDISABLE(portp->brdnr);
         spin_unlock_irqrestore(&brd_lock, flags);
+        tty_kref_put(tty);
 }
 
 /*****************************************************************************/
@@ -4244,7 +4260,7 @@ static void stl_sc26198sendflow(struct stlport *portp, int state)
 
         if (portp == NULL)
                 return;
-        tty = portp->port.tty;
+        tty = tty_port_tty_get(&portp->port);
         if (tty == NULL)
                 return;
 
@@ -4269,6 +4285,7 @@ static void stl_sc26198sendflow(struct stlport *portp, int state)
         }
         BRDDISABLE(portp->brdnr);
         spin_unlock_irqrestore(&brd_lock, flags);
+        tty_kref_put(tty);
 }
 
 /*****************************************************************************/
@@ -4408,6 +4425,7 @@ static void stl_sc26198intr(struct stlpanel *panelp, unsigned int iobase)
 
 static void stl_sc26198txisr(struct stlport *portp)
 {
+        struct tty_struct *tty;
         unsigned int    ioaddr;
         unsigned char   mr0;
         int             len, stlen;
@@ -4422,8 +4440,11 @@ static void stl_sc26198txisr(struct stlport *portp)
         if ((len == 0) || ((len < STL_TXBUFLOW) &&
             (test_bit(ASYI_TXLOW, &portp->istate) == 0))) {
                 set_bit(ASYI_TXLOW, &portp->istate);
-                if (portp->port.tty)
-                        tty_wakeup(portp->port.tty);
+                tty = tty_port_tty_get(&portp->port);
+                if (tty) {
+                        tty_wakeup(tty);
+                        tty_kref_put(tty);
+                }
         }
 
         if (len == 0) {
@@ -4476,7 +4497,7 @@ static void stl_sc26198rxisr(struct stlport *portp, unsigned int iack)
 
         pr_debug("stl_sc26198rxisr(portp=%p,iack=%x)\n", portp, iack);
 
-        tty = portp->port.tty;
+        tty = tty_port_tty_get(&portp->port);
         ioaddr = portp->ioaddr;
         outb(GIBCR, (ioaddr + XP_ADDR));
         len = inb(ioaddr + XP_DATA) + 1;
@@ -4515,6 +4536,7 @@ static void stl_sc26198rxisr(struct stlport *portp, unsigned int iack)
                         stl_sc26198txunflow(portp, tty);
                 }
         }
+        tty_kref_put(tty);
 }
 
 /*****************************************************************************/
@@ -4528,7 +4550,7 @@ static void stl_sc26198rxbadch(struct stlport *portp, unsigned char status, char
         struct tty_struct       *tty;
         unsigned int            ioaddr;
 
-        tty = portp->port.tty;
+        tty = tty_port_tty_get(&portp->port);
         ioaddr = portp->ioaddr;
 
         if (status & SR_RXPARITY)
@@ -4566,6 +4588,7 @@ static void stl_sc26198rxbadch(struct stlport *portp, unsigned char status, char
                 if (status == 0)
                         portp->stats.rxtotal++;
         }
+        tty_kref_put(tty);
 }
 
 /*****************************************************************************/