hpet: kill BKL, add compat_ioctl

hpet uses the big kernel lock in its ioctl and open
functions. Replace this with a private mutex to be
sure. Since we're already touching the ioctl function,
add the compat_ioctl version as well -- all commands
except HPET_INFO are compatible and that one is easy
to add.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: Bob Picco <bob.picco@hp.com>

diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index a0a1829..a4eee32 100644 (file)
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -30,6 +30,7 @@
 #include <linux/bcd.h>
 #include <linux/seq_file.h>
 #include <linux/bitops.h>
+#include <linux/compat.h>
 #include <linux/clocksource.h>
 #include <linux/slab.h>
 
@@ -67,6 +68,7 @@
 #define        read_counter(MC)        readl(MC)
 #endif
 
+static DEFINE_MUTEX(hpet_mutex); /* replaces BKL */
 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
 
 /* This clocksource driver currently only works on ia64 */
@@ -250,7 +252,7 @@ static int hpet_open(struct inode *inode, struct file *file)
        if (file->f_mode & FMODE_WRITE)
                return -EINVAL;
 
-       lock_kernel();
+       mutex_lock(&hpet_mutex);
        spin_lock_irq(&hpet_lock);
 
        for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
@@ -264,7 +266,7 @@ static int hpet_open(struct inode *inode, struct file *file)
 
        if (!devp) {
                spin_unlock_irq(&hpet_lock);
-               unlock_kernel();
+               mutex_unlock(&hpet_mutex);
                return -EBUSY;
        }
 
@@ -272,7 +274,7 @@ static int hpet_open(struct inode *inode, struct file *file)
        devp->hd_irqdata = 0;
        devp->hd_flags |= HPET_OPEN;
        spin_unlock_irq(&hpet_lock);
-       unlock_kernel();
+       mutex_unlock(&hpet_mutex);
 
        hpet_timer_set_irq(devp);
 
@@ -429,22 +431,6 @@ static int hpet_release(struct inode *inode, struct file *file)
        return 0;
 }
 
-static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
-
-static long hpet_ioctl(struct file *file, unsigned int cmd,
-                       unsigned long arg)
-{
-       struct hpet_dev *devp;
-       int ret;
-
-       devp = file->private_data;
-       lock_kernel();
-       ret = hpet_ioctl_common(devp, cmd, arg, 0);
-       unlock_kernel();
-
-       return ret;
-}
-
 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 {
        struct hpet_timer __iomem *timer;
@@ -553,7 +539,8 @@ static inline unsigned long hpet_time_div(struct hpets *hpets,
 }
 
 static int
-hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
+hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg,
+                 struct hpet_info *info)
 {
        struct hpet_timer __iomem *timer;
        struct hpet __iomem *hpet;
@@ -594,23 +581,15 @@ hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
                break;
        case HPET_INFO:
                {
-                       struct hpet_info info;
-
                        if (devp->hd_ireqfreq)
-                               info.hi_ireqfreq =
+                               info->hi_ireqfreq =
                                        hpet_time_div(hpetp, devp->hd_ireqfreq);
                        else
-                               info.hi_ireqfreq = 0;
-                       info.hi_flags =
+                               info->hi_ireqfreq = 0;
+                       info->hi_flags =
                            readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
-                       info.hi_hpet = hpetp->hp_which;
-                       info.hi_timer = devp - hpetp->hp_dev;
-                       if (kernel)
-                               memcpy((void *)arg, &info, sizeof(info));
-                       else
-                               if (copy_to_user((void __user *)arg, &info,
-                                                sizeof(info)))
-                                       err = -EFAULT;
+                       info->hi_hpet = hpetp->hp_which;
+                       info->hi_timer = devp - hpetp->hp_dev;
                        break;
                }
        case HPET_EPI:
@@ -636,7 +615,7 @@ hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
                devp->hd_flags &= ~HPET_PERIODIC;
                break;
        case HPET_IRQFREQ:
-               if (!kernel && (arg > hpet_max_freq) &&
+               if ((arg > hpet_max_freq) &&
                    !capable(CAP_SYS_RESOURCE)) {
                        err = -EACCES;
                        break;
@@ -653,12 +632,63 @@ hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
        return err;
 }
 
+static long
+hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+       struct hpet_info info;
+       int err;
+
+       mutex_lock(&hpet_mutex);
+       err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
+       mutex_unlock(&hpet_mutex);
+
+       if ((cmd == HPET_INFO) && !err &&
+           (copy_to_user((void __user *)arg, &info, sizeof(info))))
+               err = -EFAULT;
+
+       return err;
+}
+
+#ifdef CONFIG_COMPAT
+struct compat_hpet_info {
+       compat_ulong_t hi_ireqfreq;     /* Hz */
+       compat_ulong_t hi_flags;        /* information */
+       unsigned short hi_hpet;
+       unsigned short hi_timer;
+};
+
+static long
+hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+       struct hpet_info info;
+       int err;
+
+       mutex_lock(&hpet_mutex);
+       err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
+       mutex_unlock(&hpet_mutex);
+
+       if ((cmd == HPET_INFO) && !err) {
+               struct compat_hpet_info __user *u = compat_ptr(arg);
+               if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
+                   put_user(info.hi_flags, &u->hi_flags) ||
+                   put_user(info.hi_hpet, &u->hi_hpet) ||
+                   put_user(info.hi_timer, &u->hi_timer))
+                       err = -EFAULT;
+       }
+
+       return err;
+}
+#endif
+
 static const struct file_operations hpet_fops = {
        .owner = THIS_MODULE,
        .llseek = no_llseek,
        .read = hpet_read,
        .poll = hpet_poll,
        .unlocked_ioctl = hpet_ioctl,
+#ifdef CONFIG_COMPAT
+       .compat_ioctl = hpet_compat_ioctl,
+#endif
        .open = hpet_open,
        .release = hpet_release,
        .fasync = hpet_fasync,