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macintosh: Remove BKL from ans-lcd

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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>
This commit is contained in:
Thomas Gleixner 2009-10-10 13:38:57 +02:00
parent 9e8ab74dda
commit 95fdac7372
1 changed files with 28 additions and 17 deletions
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45
drivers/macintosh/ans-lcd.c
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@ -3,7 +3,6 @@
*/ */
#include <linux/types.h> #include <linux/types.h>
#include <linux/smp_lock.h>
#include <linux/errno.h> #include <linux/errno.h>
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/miscdevice.h> #include <linux/miscdevice.h>
@ -26,6 +25,7 @@
static unsigned long anslcd_short_delay = 80; static unsigned long anslcd_short_delay = 80;
static unsigned long anslcd_long_delay = 3280; static unsigned long anslcd_long_delay = 3280;
static volatile unsigned char __iomem *anslcd_ptr; static volatile unsigned char __iomem *anslcd_ptr;
static DEFINE_MUTEX(anslcd_mutex);
#undef DEBUG #undef DEBUG
@ -65,26 +65,31 @@ anslcd_write( struct file * file, const char __user * buf,
if (!access_ok(VERIFY_READ, buf, count)) if (!access_ok(VERIFY_READ, buf, count))
return -EFAULT; return -EFAULT;
mutex_lock(&anslcd_mutex);
for ( i = *ppos; count > 0; ++i, ++p, --count ) for ( i = *ppos; count > 0; ++i, ++p, --count )
{ {
char c; char c;
__get_user(c, p); __get_user(c, p);
anslcd_write_byte_data( c ); anslcd_write_byte_data( c );
} }
mutex_unlock(&anslcd_mutex);
*ppos = i; *ppos = i;
return p - buf; return p - buf;
} }
static int static long
anslcd_ioctl( struct inode * inode, struct file * file, anslcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
unsigned int cmd, unsigned long arg )
{ {
char ch, __user *temp; char ch, __user *temp;
long ret = 0;
#ifdef DEBUG #ifdef DEBUG
printk(KERN_DEBUG "LCD: ioctl(%d,%d)\n",cmd,arg); printk(KERN_DEBUG "LCD: ioctl(%d,%d)\n",cmd,arg);
#endif #endif
mutex_lock(&anslcd_mutex);
switch ( cmd ) switch ( cmd )
{ {
case ANSLCD_CLEAR: case ANSLCD_CLEAR:
@ -93,7 +98,7 @@ anslcd_ioctl( struct inode * inode, struct file * file,
anslcd_write_byte_ctrl ( 0x06 ); anslcd_write_byte_ctrl ( 0x06 );
anslcd_write_byte_ctrl ( 0x01 ); anslcd_write_byte_ctrl ( 0x01 );
anslcd_write_byte_ctrl ( 0x02 ); anslcd_write_byte_ctrl ( 0x02 );
return 0; break;
case ANSLCD_SENDCTRL: case ANSLCD_SENDCTRL:
temp = (char __user *) arg; temp = (char __user *) arg;
__get_user(ch, temp); __get_user(ch, temp);
@ -101,33 +106,37 @@ anslcd_ioctl( struct inode * inode, struct file * file,
anslcd_write_byte_ctrl ( ch ); anslcd_write_byte_ctrl ( ch );
__get_user(ch, temp); __get_user(ch, temp);
} }
return 0; break;
case ANSLCD_SETSHORTDELAY: case ANSLCD_SETSHORTDELAY:
if (!capable(CAP_SYS_ADMIN)) if (!capable(CAP_SYS_ADMIN))
return -EACCES; ret =-EACCES;
anslcd_short_delay=arg; else
return 0; anslcd_short_delay=arg;
break;
case ANSLCD_SETLONGDELAY: case ANSLCD_SETLONGDELAY:
if (!capable(CAP_SYS_ADMIN)) if (!capable(CAP_SYS_ADMIN))
return -EACCES; ret = -EACCES;
anslcd_long_delay=arg; else
return 0; anslcd_long_delay=arg;
break;
default: default:
return -EINVAL; ret = -EINVAL;
} }
mutex_unlock(&anslcd_mutex);
return ret;
} }
static int static int
anslcd_open( struct inode * inode, struct file * file ) anslcd_open( struct inode * inode, struct file * file )
{ {
cycle_kernel_lock();
return 0; return 0;
} }
const struct file_operations anslcd_fops = { const struct file_operations anslcd_fops = {
.write = anslcd_write, .write = anslcd_write,
.ioctl = anslcd_ioctl, .unlocked_ioctl = anslcd_ioctl,
.open = anslcd_open, .open = anslcd_open,
}; };
static struct miscdevice anslcd_dev = { static struct miscdevice anslcd_dev = {
@ -168,6 +177,7 @@ anslcd_init(void)
printk(KERN_DEBUG "LCD: init\n"); printk(KERN_DEBUG "LCD: init\n");
#endif #endif
mutex_lock(&anslcd_mutex);
anslcd_write_byte_ctrl ( 0x38 ); anslcd_write_byte_ctrl ( 0x38 );
anslcd_write_byte_ctrl ( 0x0c ); anslcd_write_byte_ctrl ( 0x0c );
anslcd_write_byte_ctrl ( 0x06 ); anslcd_write_byte_ctrl ( 0x06 );
@ -176,6 +186,7 @@ anslcd_init(void)
for(a=0;a<80;a++) { for(a=0;a<80;a++) {
anslcd_write_byte_data(anslcd_logo[a]); anslcd_write_byte_data(anslcd_logo[a]);
} }
mutex_unlock(&anslcd_mutex);
return 0; return 0;
} }