[WATCHDOG 42/57] sc1200_wdt: clean up, fix locking and use unlocked_ioctl
Alan Cox [Mon, 19 May 2008 13:08:38 +0000 (14:08 +0100)]
Review and switch to unlocked_ioctl

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/sc1200wdt.c

index 35cddff..7e5c9cc 100644 (file)
  *
  *     Changelog:
  *     20020220 Zwane Mwaikambo        Code based on datasheet, no hardware.
- *     20020221 Zwane Mwaikambo        Cleanups as suggested by Jeff Garzik and Alan Cox.
+ *     20020221 Zwane Mwaikambo        Cleanups as suggested by Jeff Garzik
+ *                                     and Alan Cox.
  *     20020222 Zwane Mwaikambo        Added probing.
  *     20020225 Zwane Mwaikambo        Added ISAPNP support.
  *     20020412 Rob Radez              Broke out start/stop functions
- *              <rob@osinvestor.com>   Return proper status instead of temperature warning
- *                                     Add WDIOC_GETBOOTSTATUS and WDIOC_SETOPTIONS ioctls
+ *              <rob@osinvestor.com>   Return proper status instead of
+ *                                     temperature warning
+ *                                     Add WDIOC_GETBOOTSTATUS and
+ *                                     WDIOC_SETOPTIONS ioctls
  *                                     Fix CONFIG_WATCHDOG_NOWAYOUT
- *     20020530 Joel Becker            Add Matt Domsch's nowayout module option
+ *     20020530 Joel Becker            Add Matt Domsch's nowayout module
+ *                                     option
  *     20030116 Adam Belay             Updated to the latest pnp code
  *
  */
@@ -39,9 +43,8 @@
 #include <linux/pnp.h>
 #include <linux/fs.h>
 #include <linux/semaphore.h>
-
-#include <asm/io.h>
-#include <asm/uaccess.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
 
 #define SC1200_MODULE_VER      "build 20020303"
 #define SC1200_MODULE_NAME     "sc1200wdt"
@@ -72,7 +75,7 @@ static char banner[] __initdata = KERN_INFO PFX SC1200_MODULE_VER;
 static int timeout = 1;
 static int io = -1;
 static int io_len = 2;         /* for non plug and play */
-static struct semaphore open_sem;
+static unsigned long open_flag;
 static char expect_close;
 static DEFINE_SPINLOCK(sc1200wdt_lock);        /* io port access serialisation */
 
@@ -81,7 +84,8 @@ static int isapnp = 1;
 static struct pnp_dev *wdt_dev;
 
 module_param(isapnp, int, 0);
-MODULE_PARM_DESC(isapnp, "When set to 0 driver ISA PnP support will be disabled");
+MODULE_PARM_DESC(isapnp,
+       "When set to 0 driver ISA PnP support will be disabled");
 #endif
 
 module_param(io, int, 0);
@@ -91,26 +95,40 @@ MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1");
 
 static int nowayout = WATCHDOG_NOWAYOUT;
 module_param(nowayout, int, 0);
-MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+MODULE_PARM_DESC(nowayout,
+       "Watchdog cannot be stopped once started (default="
+                               __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 
 
 
 /* Read from Data Register */
-static inline void sc1200wdt_read_data(unsigned char index, unsigned char *data)
+static inline void __sc1200wdt_read_data(unsigned char index,
+                                               unsigned char *data)
 {
-       spin_lock(&sc1200wdt_lock);
        outb_p(index, PMIR);
        *data = inb(PMDR);
-       spin_unlock(&sc1200wdt_lock);
 }
 
+static void sc1200wdt_read_data(unsigned char index, unsigned char *data)
+{
+       spin_lock(&sc1200wdt_lock);
+       __sc1200wdt_read_data(index, data);
+       spin_unlock(&sc1200wdt_lock);
+}
 
 /* Write to Data Register */
-static inline void sc1200wdt_write_data(unsigned char index, unsigned char data)
+static inline void __sc1200wdt_write_data(unsigned char index,
+                                               unsigned char data)
 {
-       spin_lock(&sc1200wdt_lock);
        outb_p(index, PMIR);
        outb(data, PMDR);
+}
+
+static inline void sc1200wdt_write_data(unsigned char index,
+                                               unsigned char data)
+{
+       spin_lock(&sc1200wdt_lock);
+       __sc1200wdt_write_data(index, data);
        spin_unlock(&sc1200wdt_lock);
 }
 
@@ -118,13 +136,16 @@ static inline void sc1200wdt_write_data(unsigned char index, unsigned char data)
 static void sc1200wdt_start(void)
 {
        unsigned char reg;
+       spin_lock(&sc1200wdt_lock);
 
-       sc1200wdt_read_data(WDCF, &reg);
+       __sc1200wdt_read_data(WDCF, &reg);
        /* assert WDO when any of the following interrupts are triggered too */
        reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ);
-       sc1200wdt_write_data(WDCF, reg);
+       __sc1200wdt_write_data(WDCF, reg);
        /* set the timeout and get the ball rolling */
-       sc1200wdt_write_data(WDTO, timeout);
+       __sc1200wdt_write_data(WDTO, timeout);
+
+       spin_unlock(&sc1200wdt_lock);
 }
 
 
@@ -144,14 +165,15 @@ static inline int sc1200wdt_status(void)
         * KEEPALIVEPING which is a bit of a kludge because there's nothing
         * else for enabled/disabled status
         */
-       return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;  /* bits 1 - 7 are undefined */
+       return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;
+       /* bits 1 - 7 are undefined */
 }
 
 
 static int sc1200wdt_open(struct inode *inode, struct file *file)
 {
        /* allow one at a time */
-       if (down_trylock(&open_sem))
+       if (test_and_set_bit(0, &open_flag))
                return -EBUSY;
 
        if (timeout > MAX_TIMEOUT)
@@ -164,71 +186,71 @@ static int sc1200wdt_open(struct inode *inode, struct file *file)
 }
 
 
-static int sc1200wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
+static long sc1200wdt_ioctl(struct file *file, unsigned int cmd,
+                                               unsigned long arg)
 {
        int new_timeout;
        void __user *argp = (void __user *)arg;
        int __user *p = argp;
-       static struct watchdog_info ident = {
-               .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
+       static const struct watchdog_info ident = {
+               .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
+                                                       WDIOF_MAGICCLOSE,
                .firmware_version = 0,
                .identity = "PC87307/PC97307",
        };
 
        switch (cmd) {
-               default:
-                       return -ENOTTY;
-
-               case WDIOC_GETSUPPORT:
-                       if (copy_to_user(argp, &ident, sizeof ident))
-                               return -EFAULT;
-                       return 0;
 
-               case WDIOC_GETSTATUS:
-                       return put_user(sc1200wdt_status(), p);
+       case WDIOC_GETSUPPORT:
+               if (copy_to_user(argp, &ident, sizeof ident))
+                       return -EFAULT;
+               return 0;
 
-               case WDIOC_GETBOOTSTATUS:
-                       return put_user(0, p);
+       case WDIOC_GETSTATUS:
+               return put_user(sc1200wdt_status(), p);
 
-               case WDIOC_KEEPALIVE:
-                       sc1200wdt_write_data(WDTO, timeout);
-                       return 0;
+       case WDIOC_GETBOOTSTATUS:
+               return put_user(0, p);
 
-               case WDIOC_SETTIMEOUT:
-                       if (get_user(new_timeout, p))
-                               return -EFAULT;
-
-                       /* the API states this is given in secs */
-                       new_timeout /= 60;
-                       if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
-                               return -EINVAL;
-
-                       timeout = new_timeout;
-                       sc1200wdt_write_data(WDTO, timeout);
-                       /* fall through and return the new timeout */
-
-               case WDIOC_GETTIMEOUT:
-                       return put_user(timeout * 60, p);
+       case WDIOC_KEEPALIVE:
+               sc1200wdt_write_data(WDTO, timeout);
+               return 0;
+
+       case WDIOC_SETTIMEOUT:
+               if (get_user(new_timeout, p))
+                       return -EFAULT;
+               /* the API states this is given in secs */
+               new_timeout /= 60;
+               if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
+                       return -EINVAL;
+               timeout = new_timeout;
+               sc1200wdt_write_data(WDTO, timeout);
+               /* fall through and return the new timeout */
 
-               case WDIOC_SETOPTIONS:
-               {
-                       int options, retval = -EINVAL;
+       case WDIOC_GETTIMEOUT:
+               return put_user(timeout * 60, p);
 
-                       if (get_user(options, p))
-                               return -EFAULT;
+       case WDIOC_SETOPTIONS:
+       {
+               int options, retval = -EINVAL;
 
-                       if (options & WDIOS_DISABLECARD) {
-                               sc1200wdt_stop();
-                               retval = 0;
-                       }
+               if (get_user(options, p))
+                       return -EFAULT;
 
-                       if (options & WDIOS_ENABLECARD) {
-                               sc1200wdt_start();
-                               retval = 0;
-                       }
+               if (options & WDIOS_DISABLECARD) {
+                       sc1200wdt_stop();
+                       retval = 0;
+               }
 
-                       return retval;
+               if (options & WDIOS_ENABLECARD) {
+                       sc1200wdt_start();
+                       retval = 0;
                }
+
+               return retval;
+       }
+       default:
+               return -ENOTTY;
        }
 }
 
@@ -240,16 +262,18 @@ static int sc1200wdt_release(struct inode *inode, struct file *file)
                printk(KERN_INFO PFX "Watchdog disabled\n");
        } else {
                sc1200wdt_write_data(WDTO, timeout);
-               printk(KERN_CRIT PFX "Unexpected close!, timeout = %d min(s)\n", timeout);
+               printk(KERN_CRIT PFX
+                       "Unexpected close!, timeout = %d min(s)\n", timeout);
        }
-       up(&open_sem);
+       clear_bit(0, &open_flag);
        expect_close = 0;
 
        return 0;
 }
 
 
-static ssize_t sc1200wdt_write(struct file *file, const char __user *data, size_t len, loff_t *ppos)
+static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
+                                               size_t len, loff_t *ppos)
 {
        if (len) {
                if (!nowayout) {
@@ -275,7 +299,8 @@ static ssize_t sc1200wdt_write(struct file *file, const char __user *data, size_
 }
 
 
-static int sc1200wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
+static int sc1200wdt_notify_sys(struct notifier_block *this,
+                                       unsigned long code, void *unused)
 {
        if (code == SYS_DOWN || code == SYS_HALT)
                sc1200wdt_stop();
@@ -284,23 +309,20 @@ static int sc1200wdt_notify_sys(struct notifier_block *this, unsigned long code,
 }
 
 
-static struct notifier_block sc1200wdt_notifier =
-{
+static struct notifier_block sc1200wdt_notifier = {
        .notifier_call =        sc1200wdt_notify_sys,
 };
 
-static const struct file_operations sc1200wdt_fops =
-{
+static const struct file_operations sc1200wdt_fops = {
        .owner          = THIS_MODULE,
        .llseek         = no_llseek,
        .write          = sc1200wdt_write,
-       .ioctl          = sc1200wdt_ioctl,
+       .unlocked_ioctl = sc1200wdt_ioctl,
        .open           = sc1200wdt_open,
        .release        = sc1200wdt_release,
 };
 
-static struct miscdevice sc1200wdt_miscdev =
-{
+static struct miscdevice sc1200wdt_miscdev = {
        .minor          = WATCHDOG_MINOR,
        .name           = "watchdog",
        .fops           = &sc1200wdt_fops,
@@ -312,14 +334,14 @@ static int __init sc1200wdt_probe(void)
        /* The probe works by reading the PMC3 register's default value of 0x0e
         * there is one caveat, if the device disables the parallel port or any
         * of the UARTs we won't be able to detect it.
-        * Nb. This could be done with accuracy by reading the SID registers, but
-        * we don't have access to those io regions.
+        * NB. This could be done with accuracy by reading the SID registers,
+        * but we don't have access to those io regions.
         */
 
        unsigned char reg;
 
        sc1200wdt_read_data(PMC3, &reg);
-       reg &= 0x0f;                            /* we don't want the UART busy bits */
+       reg &= 0x0f;            /* we don't want the UART busy bits */
        return (reg == 0x0e) ? 0 : -ENODEV;
 }
 
@@ -332,7 +354,8 @@ static struct pnp_device_id scl200wdt_pnp_devices[] = {
        {.id = ""},
 };
 
-static int scl200wdt_pnp_probe(struct pnp_dev * dev, const struct pnp_device_id *dev_id)
+static int scl200wdt_pnp_probe(struct pnp_dev *dev,
+                                       const struct pnp_device_id *dev_id)
 {
        /* this driver only supports one card at a time */
        if (wdt_dev || !isapnp)
@@ -347,13 +370,14 @@ static int scl200wdt_pnp_probe(struct pnp_dev * dev, const struct pnp_device_id
                return -EBUSY;
        }
 
-       printk(KERN_INFO "scl200wdt: PnP device found at io port %#x/%d\n", io, io_len);
+       printk(KERN_INFO "scl200wdt: PnP device found at io port %#x/%d\n",
+                                                               io, io_len);
        return 0;
 }
 
-static void scl200wdt_pnp_remove(struct pnp_dev * dev)
+static void scl200wdt_pnp_remove(struct pnp_dev *dev)
 {
-       if (wdt_dev){
+       if (wdt_dev) {
                release_region(io, io_len);
                wdt_dev = NULL;
        }
@@ -375,8 +399,6 @@ static int __init sc1200wdt_init(void)
 
        printk("%s\n", banner);
 
-       sema_init(&open_sem, 1);
-
 #if defined CONFIG_PNP
        if (isapnp) {
                ret = pnp_register_driver(&scl200wdt_pnp_driver);
@@ -410,13 +432,16 @@ static int __init sc1200wdt_init(void)
 
        ret = register_reboot_notifier(&sc1200wdt_notifier);
        if (ret) {
-               printk(KERN_ERR PFX "Unable to register reboot notifier err = %d\n", ret);
+               printk(KERN_ERR PFX
+                       "Unable to register reboot notifier err = %d\n", ret);
                goto out_io;
        }
 
        ret = misc_register(&sc1200wdt_miscdev);
        if (ret) {
-               printk(KERN_ERR PFX "Unable to register miscdev on minor %d\n", WATCHDOG_MINOR);
+               printk(KERN_ERR PFX
+                       "Unable to register miscdev on minor %d\n",
+                                                       WATCHDOG_MINOR);
                goto out_rbt;
        }
 
@@ -446,7 +471,7 @@ static void __exit sc1200wdt_exit(void)
        unregister_reboot_notifier(&sc1200wdt_notifier);
 
 #if defined CONFIG_PNP
-       if(isapnp)
+       if (isapnp)
                pnp_unregister_driver(&scl200wdt_pnp_driver);
        else
 #endif