[PATCH 3/8] hpet: kill BKL, add compat_ioctl

Arnd Bergmann
2010-07-03T22:03:13Z

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>
---
drivers/char/hpet.c | 98 +++++++++++++++++++++++++++++++++------------------
1 files changed, 64 insertions(+), 34 deletions(-)

diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index a0a1829..a4eee32 100644
--- 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,
--
1.7.1