Messages in this thread Patch in this message | | | Subject | [PATCH 1/8] UML - watchdog driver locking | Date | Mon, 01 Jan 2007 14:47:07 -0500 | From | Jeff Dike <> |
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Replace BKL use with a spinlock.
Also fix the control so that open doesn't return holding a lock.
Signed-off-by: Jeff Dike <jdike@addtoit.com> -- arch/um/drivers/harddog_kern.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-)
Index: linux-2.6.18-mm/arch/um/drivers/harddog_kern.c =================================================================== --- linux-2.6.18-mm.orig/arch/um/drivers/harddog_kern.c 2006-12-29 18:25:36.000000000 -0500 +++ linux-2.6.18-mm/arch/um/drivers/harddog_kern.c 2006-12-29 21:02:50.000000000 -0500 @@ -44,12 +44,13 @@ #include <linux/reboot.h> #include <linux/smp_lock.h> #include <linux/init.h> +#include <linux/spinlock.h> #include <asm/uaccess.h> #include "mconsole.h" MODULE_LICENSE("GPL"); -/* Locked by the BKL in harddog_open and harddog_release */ +static DEFINE_SPINLOCK(lock); static int timer_alive; static int harddog_in_fd = -1; static int harddog_out_fd = -1; @@ -62,12 +63,12 @@ extern int start_watchdog(int *in_fd_ret static int harddog_open(struct inode *inode, struct file *file) { - int err; + int err = -EBUSY; char *sock = NULL; - lock_kernel(); + spin_lock(&lock); if(timer_alive) - return -EBUSY; + goto err; #ifdef CONFIG_HARDDOG_NOWAYOUT __module_get(THIS_MODULE); #endif @@ -76,11 +77,15 @@ static int harddog_open(struct inode *in sock = mconsole_notify_socket(); #endif err = start_watchdog(&harddog_in_fd, &harddog_out_fd, sock); - if(err) return(err); + if(err) + goto err; timer_alive = 1; - unlock_kernel(); + spin_unlock(&lock); return nonseekable_open(inode, file); +err: + spin_unlock(&lock); + return err; } extern void stop_watchdog(int in_fd, int out_fd); @@ -90,14 +95,16 @@ static int harddog_release(struct inode /* * Shut off the timer. */ - lock_kernel(); + + spin_lock(&lock); stop_watchdog(harddog_in_fd, harddog_out_fd); harddog_in_fd = -1; harddog_out_fd = -1; timer_alive=0; - unlock_kernel(); + spin_unlock(&lock); + return 0; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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