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authorThomas Gleixner <tglx@linutronix.de>2009-10-10 13:38:57 +0200
committerThomas Gleixner <tglx@linutronix.de>2009-10-14 17:36:50 +0200
commit95fdac73725c15072d068ac7f131958cf5c324e4 (patch)
tree3e76d637ca4762fdaad107c829eb2b9545da3717 /drivers/macintosh/ans-lcd.c
parent9e8ab74ddaa591575f599248080a1f0d917a56ee (diff)
macintosh: Remove BKL from ans-lcd
The ans-lcd driver got the cycle_kernel_lock() in anslcd_open() from the BKL pushdown and it still uses the locked ioctl. The BKL serialization in this driver is more than obscure and definitely does not cover all possible corner cases. Protect the access to the hardware with a local mutex and get rid of BKL and locked ioctl. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <20091010153349.966159859@linutronix.de> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'drivers/macintosh/ans-lcd.c')
-rw-r--r--drivers/macintosh/ans-lcd.c45
1 files changed, 28 insertions, 17 deletions
diff --git a/drivers/macintosh/ans-lcd.c b/drivers/macintosh/ans-lcd.c
index 6a8221893256..a3d25da2f275 100644
--- a/drivers/macintosh/ans-lcd.c
+++ b/drivers/macintosh/ans-lcd.c
@@ -3,7 +3,6 @@
*/
#include <linux/types.h>
-#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
@@ -26,6 +25,7 @@
static unsigned long anslcd_short_delay = 80;
static unsigned long anslcd_long_delay = 3280;
static volatile unsigned char __iomem *anslcd_ptr;
+static DEFINE_MUTEX(anslcd_mutex);
#undef DEBUG
@@ -65,26 +65,31 @@ anslcd_write( struct file * file, const char __user * buf,
if (!access_ok(VERIFY_READ, buf, count))
return -EFAULT;
+
+ mutex_lock(&anslcd_mutex);
for ( i = *ppos; count > 0; ++i, ++p, --count )
{
char c;
__get_user(c, p);
anslcd_write_byte_data( c );
}
+ mutex_unlock(&anslcd_mutex);
*ppos = i;
return p - buf;
}
-static int
-anslcd_ioctl( struct inode * inode, struct file * file,
- unsigned int cmd, unsigned long arg )
+static long
+anslcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
char ch, __user *temp;
+ long ret = 0;
#ifdef DEBUG
printk(KERN_DEBUG "LCD: ioctl(%d,%d)\n",cmd,arg);
#endif
+ mutex_lock(&anslcd_mutex);
+
switch ( cmd )
{
case ANSLCD_CLEAR:
@@ -93,7 +98,7 @@ anslcd_ioctl( struct inode * inode, struct file * file,
anslcd_write_byte_ctrl ( 0x06 );
anslcd_write_byte_ctrl ( 0x01 );
anslcd_write_byte_ctrl ( 0x02 );
- return 0;
+ break;
case ANSLCD_SENDCTRL:
temp = (char __user *) arg;
__get_user(ch, temp);
@@ -101,33 +106,37 @@ anslcd_ioctl( struct inode * inode, struct file * file,
anslcd_write_byte_ctrl ( ch );
__get_user(ch, temp);
}
- return 0;
+ break;
case ANSLCD_SETSHORTDELAY:
if (!capable(CAP_SYS_ADMIN))
- return -EACCES;
- anslcd_short_delay=arg;
- return 0;
+ ret =-EACCES;
+ else
+ anslcd_short_delay=arg;
+ break;
case ANSLCD_SETLONGDELAY:
if (!capable(CAP_SYS_ADMIN))
- return -EACCES;
- anslcd_long_delay=arg;
- return 0;
+ ret = -EACCES;
+ else
+ anslcd_long_delay=arg;
+ break;
default:
- return -EINVAL;
+ ret = -EINVAL;
}
+
+ mutex_unlock(&anslcd_mutex);
+ return ret;
}
static int
anslcd_open( struct inode * inode, struct file * file )
{
- cycle_kernel_lock();
return 0;
}
const struct file_operations anslcd_fops = {
- .write = anslcd_write,
- .ioctl = anslcd_ioctl,
- .open = anslcd_open,
+ .write = anslcd_write,
+ .unlocked_ioctl = anslcd_ioctl,
+ .open = anslcd_open,
};
static struct miscdevice anslcd_dev = {
@@ -168,6 +177,7 @@ anslcd_init(void)
printk(KERN_DEBUG "LCD: init\n");
#endif
+ mutex_lock(&anslcd_mutex);
anslcd_write_byte_ctrl ( 0x38 );
anslcd_write_byte_ctrl ( 0x0c );
anslcd_write_byte_ctrl ( 0x06 );
@@ -176,6 +186,7 @@ anslcd_init(void)
for(a=0;a<80;a++) {
anslcd_write_byte_data(anslcd_logo[a]);
}
+ mutex_unlock(&anslcd_mutex);
return 0;
}