Prev: [PATCH 24/68] tty: serial - fix various misuses/mishandlings of port->tty
Next: [PATCH 06/68] max3110 sanity check a register
From: Greg Kroah-Hartman on 10 Aug 2010 18:20
From: Alan Cox <alan(a)linux.intel.com>

Remove unneeded tty layer lock kernel bits. Relock the needed bits using the
port mutex. The istallion still has brd state races but those are not new
or introduced by the removal of the lock_kernel logic.

Signed-off-by: Alan Cox <alan(a)linux.intel.com>
Cc: Arnd Bergmann <arnd(a)arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)suse.de>
---
drivers/char/istallion.c | 22 +++++++++++++---------
drivers/char/stallion.c | 20 ++++++++++++--------
2 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/drivers/char/istallion.c b/drivers/char/istallion.c
index 4e395c9..750650c 100644
--- a/drivers/char/istallion.c
+++ b/drivers/char/istallion.c
@@ -14,6 +14,7 @@
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
+ * FIXME: brdp->state needs proper locking.
*/

/*****************************************************************************/
@@ -4011,6 +4012,7 @@ static int stli_getbrdstats(combrd_t __user *bp)
return -ENODEV;

memset(&stli_brdstats, 0, sizeof(combrd_t));
+
stli_brdstats.brd = brdp->brdnr;
stli_brdstats.type = brdp->brdtype;
stli_brdstats.hwid = 0;
@@ -4076,10 +4078,13 @@ static int stli_portcmdstats(struct tty_struct *tty, struct stliport *portp)
if (brdp == NULL)
return -ENODEV;

+ mutex_lock(&portp->port.mutex);
if (brdp->state & BST_STARTED) {
if ((rc = stli_cmdwait(brdp, portp, A_GETSTATS,
- &stli_cdkstats, sizeof(asystats_t), 1)) < 0)
+ &stli_cdkstats, sizeof(asystats_t), 1)) < 0) {
+ mutex_unlock(&portp->port.mutex);
return rc;
+ }
} else {
memset(&stli_cdkstats, 0, sizeof(asystats_t));
}
@@ -4124,6 +4129,7 @@ static int stli_portcmdstats(struct tty_struct *tty, struct stliport *portp)
stli_comstats.modem = stli_cdkstats.dcdcnt;
stli_comstats.hwid = stli_cdkstats.hwid;
stli_comstats.signals = stli_mktiocm(stli_cdkstats.signals);
+ mutex_unlock(&portp->port.mutex);

return 0;
}
@@ -4186,15 +4192,20 @@ static int stli_clrportstats(struct stliport *portp, comstats_t __user *cp)
if (!brdp)
return -ENODEV;

+ mutex_lock(&portp->port.mutex);
+
if (brdp->state & BST_STARTED) {
- if ((rc = stli_cmdwait(brdp, portp, A_CLEARSTATS, NULL, 0, 0)) < 0)
+ if ((rc = stli_cmdwait(brdp, portp, A_CLEARSTATS, NULL, 0, 0)) < 0) {
+ mutex_unlock(&portp->port.mutex);
return rc;
+ }
}

memset(&stli_comstats, 0, sizeof(comstats_t));
stli_comstats.brd = portp->brdnr;
stli_comstats.panel = portp->panelnr;
stli_comstats.port = portp->portnr;
+ mutex_unlock(&portp->port.mutex);

if (copy_to_user(cp, &stli_comstats, sizeof(comstats_t)))
return -EFAULT;
@@ -4266,8 +4277,6 @@ static long stli_memioctl(struct file *fp, unsigned int cmd, unsigned long arg)
done = 0;
rc = 0;

- lock_kernel();
-
switch (cmd) {
case COM_GETPORTSTATS:
rc = stli_getportstats(NULL, NULL, argp);
@@ -4290,8 +4299,6 @@ static long stli_memioctl(struct file *fp, unsigned int cmd, unsigned long arg)
done++;
break;
}
- unlock_kernel();
-
if (done)
return rc;

@@ -4308,8 +4315,6 @@ static long stli_memioctl(struct file *fp, unsigned int cmd, unsigned long arg)
if (brdp->state == 0)
return -ENODEV;

- lock_kernel();
-
switch (cmd) {
case STL_BINTR:
EBRDINTR(brdp);
@@ -4332,7 +4337,6 @@ static long stli_memioctl(struct file *fp, unsigned int cmd, unsigned long arg)
rc = -ENOIOCTLCMD;
break;
}
- unlock_kernel();
return rc;
}

diff --git a/drivers/char/stallion.c b/drivers/char/stallion.c
index 6049fd7..f2167f8 100644
--- a/drivers/char/stallion.c
+++ b/drivers/char/stallion.c
@@ -807,7 +807,6 @@ static void stl_waituntilsent(struct tty_struct *tty, int timeout)
timeout = HZ;
tend = jiffies + timeout;

- lock_kernel();
while (stl_datastate(portp)) {
if (signal_pending(current))
break;
@@ -815,7 +814,6 @@ static void stl_waituntilsent(struct tty_struct *tty, int timeout)
if (time_after_eq(jiffies, tend))
break;
}
- unlock_kernel();
}

/*****************************************************************************/
@@ -1029,6 +1027,8 @@ static int stl_getserial(struct stlport *portp, struct serial_struct __user *sp)
pr_debug("stl_getserial(portp=%p,sp=%p)\n", portp, sp);

memset(&sio, 0, sizeof(struct serial_struct));
+
+ mutex_lock(&portp->port.mutex);
sio.line = portp->portnr;
sio.port = portp->ioaddr;
sio.flags = portp->port.flags;
@@ -1048,6 +1048,7 @@ static int stl_getserial(struct stlport *portp, struct serial_struct __user *sp)
brdp = stl_brds[portp->brdnr];
if (brdp != NULL)
sio.irq = brdp->irq;
+ mutex_unlock(&portp->port.mutex);

return copy_to_user(sp, &sio, sizeof(struct serial_struct)) ? -EFAULT : 0;
}
@@ -1069,12 +1070,15 @@ static int stl_setserial(struct tty_struct *tty, struct serial_struct __user *sp

if (copy_from_user(&sio, sp, sizeof(struct serial_struct)))
return -EFAULT;
+ mutex_lock(&portp->port.mutex);
if (!capable(CAP_SYS_ADMIN)) {
if ((sio.baud_base != portp->baud_base) ||
(sio.close_delay != portp->close_delay) ||
((sio.flags & ~ASYNC_USR_MASK) !=
- (portp->port.flags & ~ASYNC_USR_MASK)))
+ (portp->port.flags & ~ASYNC_USR_MASK))) {
+ mutex_unlock(&portp->port.mutex);
return -EPERM;
+ }
}

portp->port.flags = (portp->port.flags & ~ASYNC_USR_MASK) |
@@ -1083,6 +1087,7 @@ static int stl_setserial(struct tty_struct *tty, struct serial_struct __user *sp
portp->close_delay = sio.close_delay;
portp->closing_wait = sio.closing_wait;
portp->custom_divisor = sio.custom_divisor;
+ mutex_unlock(&portp->port.mutex);
stl_setport(portp, tty->termios);
return 0;
}
@@ -1147,8 +1152,6 @@ static int stl_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd

rc = 0;

- lock_kernel();
-
switch (cmd) {
case TIOCGSERIAL:
rc = stl_getserial(portp, argp);
@@ -1173,7 +1176,6 @@ static int stl_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd
rc = -ENOIOCTLCMD;
break;
}
- unlock_kernel();
return rc;
}

@@ -2327,6 +2329,7 @@ static int stl_getportstats(struct tty_struct *tty, struct stlport *portp, comst
return -ENODEV;
}

+ mutex_lock(&portp->port.mutex);
portp->stats.state = portp->istate;
portp->stats.flags = portp->port.flags;
portp->stats.hwid = portp->hwid;
@@ -2358,6 +2361,7 @@ static int stl_getportstats(struct tty_struct *tty, struct stlport *portp, comst
(STL_TXBUFSIZE - (tail - head));

portp->stats.signals = (unsigned long) stl_getsignals(portp);
+ mutex_unlock(&portp->port.mutex);

return copy_to_user(cp, &portp->stats,
sizeof(comstats_t)) ? -EFAULT : 0;
@@ -2382,10 +2386,12 @@ static int stl_clrportstats(struct stlport *portp, comstats_t __user *cp)
return -ENODEV;
}

+ mutex_lock(&portp->port.mutex);
memset(&portp->stats, 0, sizeof(comstats_t));
portp->stats.brd = portp->brdnr;
portp->stats.panel = portp->panelnr;
portp->stats.port = portp->portnr;
+ mutex_unlock(&portp->port.mutex);
return copy_to_user(cp, &portp->stats,
sizeof(comstats_t)) ? -EFAULT : 0;
}
@@ -2451,7 +2457,6 @@ static long stl_memioctl(struct file *fp, unsigned int cmd, unsigned long arg)
return -ENODEV;
rc = 0;

- lock_kernel();
switch (cmd) {
case COM_GETPORTSTATS:
rc = stl_getportstats(NULL, NULL, argp);
@@ -2472,7 +2477,6 @@ static long stl_memioctl(struct file *fp, unsigned int cmd, unsigned long arg)
rc = -ENOIOCTLCMD;
break;
}
- unlock_kernel();
return rc;
}

--
1.7.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo(a)vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
 | 
Pages: 1
Prev: [PATCH 24/68] tty: serial - fix various misuses/mishandlings of port->tty
Next: [PATCH 06/68] max3110 sanity check a register