[PATCH 13/18] i4l: kill big kernel lock
From: Arnd Bergmann <arnd@arndb.de>
Date: 2010-09-14 19:35:37
Subsystem:
the rest · Maintainer:
Linus Torvalds
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 <redacted> Cc: netdev@vger.kernel.org --- drivers/isdn/i4l/isdn_tty.c | 11 ++++++----- 1 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/isdn/i4l/isdn_tty.c b/drivers/isdn/i4l/isdn_tty.c
index 51dc60d..981f7ab 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; }
--
1.7.1