ACPI: thinkpad-acpi: allow for syscall restart in sysfs handlers

Map an mutex_lock_interruptible() error return into ERESTARTSYS, as the
only possible error from mutex_lock_interruptible is EINTR, and that will
only happen if signal_pending() causes the mutex lock attempt to abort.

This still allows signals to be delivered ASAP, which is much nicer than
just doing mutex_lock, and still shadows userspace from EINTR when
SA_RESTART is active.

Problem reported by Peter Jordan.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Peter Jordan <usernetwork@gmx.info>
Cc: Richard Neill <rn214@hermes.cam.ac.uk>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index 251110d0ec801a92d079660cf568e81d42a69731..306daa524c03da56bb3d99dff563c732a3d60e4b 100644 (file)
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -1342,9 +1342,8 @@ static int hotkey_read(char *p)
                return len;
        }
 
-       res = mutex_lock_interruptible(&hotkey_mutex);
-       if (res < 0)
-               return res;
+       if (mutex_lock_interruptible(&hotkey_mutex))
+               return -ERESTARTSYS;
        res = hotkey_get(&status, &mask);
        mutex_unlock(&hotkey_mutex);
        if (res)
@@ -1373,9 +1372,8 @@ static int hotkey_write(char *buf)
        if (!tp_features.hotkey)
                return -ENODEV;
 
-       res = mutex_lock_interruptible(&hotkey_mutex);
-       if (res < 0)
-               return res;
+       if (mutex_lock_interruptible(&hotkey_mutex))
+               return -ERESTARTSYS;
 
        res = hotkey_get(&status, &mask);
        if (res)
@@ -3768,9 +3766,8 @@ static ssize_t fan_pwm1_store(struct device *dev,
        /* scale down from 0-255 to 0-7 */
        newlevel = (s >> 5) & 0x07;
 
-       rc = mutex_lock_interruptible(&fan_mutex);
-       if (rc < 0)
-               return rc;
+       if (mutex_lock_interruptible(&fan_mutex))
+               return -ERESTARTSYS;
 
        rc = fan_get_status(&status);
        if (!rc && (status &
@@ -4020,9 +4017,8 @@ static int fan_get_status_safe(u8 *status)
        int rc;
        u8 s;
 
-       rc = mutex_lock_interruptible(&fan_mutex);
-       if (rc < 0)
-               return rc;
+       if (mutex_lock_interruptible(&fan_mutex))
+               return -ERESTARTSYS;
        rc = fan_get_status(&s);
        if (!rc)
                fan_update_desired_level(s);
@@ -4156,9 +4152,8 @@ static int fan_set_level_safe(int level)
        if (!fan_control_allowed)
                return -EPERM;
 
-       rc = mutex_lock_interruptible(&fan_mutex);
-       if (rc < 0)
-               return rc;
+       if (mutex_lock_interruptible(&fan_mutex))
+               return -ERESTARTSYS;
 
        if (level == TPACPI_FAN_LAST_LEVEL)
                level = fan_control_desired_level;
@@ -4179,9 +4174,8 @@ static int fan_set_enable(void)
        if (!fan_control_allowed)
                return -EPERM;
 
-       rc = mutex_lock_interruptible(&fan_mutex);
-       if (rc < 0)
-               return rc;
+       if (mutex_lock_interruptible(&fan_mutex))
+               return -ERESTARTSYS;
 
        switch (fan_control_access_mode) {
        case TPACPI_FAN_WR_ACPI_FANS:
@@ -4235,9 +4229,8 @@ static int fan_set_disable(void)
        if (!fan_control_allowed)
                return -EPERM;
 
-       rc = mutex_lock_interruptible(&fan_mutex);
-       if (rc < 0)
-               return rc;
+       if (mutex_lock_interruptible(&fan_mutex))
+               return -ERESTARTSYS;
 
        rc = 0;
        switch (fan_control_access_mode) {
@@ -4274,9 +4267,8 @@ static int fan_set_speed(int speed)
        if (!fan_control_allowed)
                return -EPERM;
 
-       rc = mutex_lock_interruptible(&fan_mutex);
-       if (rc < 0)
-               return rc;
+       if (mutex_lock_interruptible(&fan_mutex))
+               return -ERESTARTSYS;
 
        rc = 0;
        switch (fan_control_access_mode) {