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authorArnd Bergmann <arnd@arndb.de>2010-09-14 09:35:04 +0000
committerDavid S. Miller <davem@davemloft.net>2010-09-15 19:29:55 -0700
commit72250d44bc76d3d7fa9253aeeb063a467e2458fa (patch)
tree55e926467b3bc7a50e213c357e295225457072ff /drivers/isdn
parent0a5f1d476aef43916abb2b8634ebff23ef2c05f6 (diff)
i4l: kill big kernel lock
The isdn4linux driver uses the big kernel lock only to serialize access to a few fields in its own modem_info structure. The easiest replacement is a driver-wide mutex. More fine-grained locking would be more appropriate here, but likely harder to implement. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Karsten Keil <isdn@linux-pingi.de> Cc: netdev@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/isdn')
-rw-r--r--drivers/isdn/i4l/isdn_tty.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/isdn/i4l/isdn_tty.c b/drivers/isdn/i4l/isdn_tty.c
index f013ee15327..c463162843b 100644
--- a/drivers/isdn/i4l/isdn_tty.c
+++ b/drivers/isdn/i4l/isdn_tty.c
@@ -14,7 +14,7 @@
#include <linux/isdn.h>
#include <linux/slab.h>
#include <linux/delay.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include "isdn_common.h"
#include "isdn_tty.h"
#ifdef CONFIG_ISDN_AUDIO
@@ -28,6 +28,7 @@
/* Prototypes */
+static DEFINE_MUTEX(modem_info_mutex);
static int isdn_tty_edit_at(const char *, int, modem_info *);
static void isdn_tty_check_esc(const u_char *, u_char, int, int *, u_long *);
static void isdn_tty_modem_reset_regs(modem_info *, int);
@@ -1354,14 +1355,14 @@ isdn_tty_tiocmget(struct tty_struct *tty, struct file *file)
if (tty->flags & (1 << TTY_IO_ERROR))
return -EIO;
- lock_kernel();
+ mutex_lock(&modem_info_mutex);
#ifdef ISDN_DEBUG_MODEM_IOCTL
printk(KERN_DEBUG "ttyI%d ioctl TIOCMGET\n", info->line);
#endif
control = info->mcr;
status = info->msr;
- unlock_kernel();
+ mutex_unlock(&modem_info_mutex);
return ((control & UART_MCR_RTS) ? TIOCM_RTS : 0)
| ((control & UART_MCR_DTR) ? TIOCM_DTR : 0)
| ((status & UART_MSR_DCD) ? TIOCM_CAR : 0)
@@ -1385,7 +1386,7 @@ isdn_tty_tiocmset(struct tty_struct *tty, struct file *file,
printk(KERN_DEBUG "ttyI%d ioctl TIOCMxxx: %x %x\n", info->line, set, clear);
#endif
- lock_kernel();
+ mutex_lock(&modem_info_mutex);
if (set & TIOCM_RTS)
info->mcr |= UART_MCR_RTS;
if (set & TIOCM_DTR) {
@@ -1407,7 +1408,7 @@ isdn_tty_tiocmset(struct tty_struct *tty, struct file *file,
isdn_tty_modem_hup(info, 1);
}
}
- unlock_kernel();
+ mutex_unlock(&modem_info_mutex);
return 0;
}