From 0e82d5b61841f2b9e2d31a4299ce09752c5d3288 Mon Sep 17 00:00:00 2001 From: Matthias Kaehlcke Date: Tue, 8 May 2007 00:32:08 -0700 Subject: [PATCH] use mutex instead of semaphore for misc char devices The misc character device driver uses a semaphore as mutex. Use the mutex API instead of the (binary) semaphore. Signed-off-by: Matthias Kaehlcke Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/misc.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/drivers/char/misc.c b/drivers/char/misc.c index 7e975f60692..4e6fb9651a1 100644 --- a/drivers/char/misc.c +++ b/drivers/char/misc.c @@ -41,6 +41,7 @@ #include #include #include +#include #include #include #include @@ -53,7 +54,7 @@ * Head entry for the doubly linked miscdevice list */ static LIST_HEAD(misc_list); -static DECLARE_MUTEX(misc_sem); +static DEFINE_MUTEX(misc_mtx); /* * Assigned numbers, used for dynamic minors @@ -69,7 +70,7 @@ static void *misc_seq_start(struct seq_file *seq, loff_t *pos) struct miscdevice *p; loff_t off = 0; - down(&misc_sem); + mutex_lock(&misc_mtx); list_for_each_entry(p, &misc_list, list) { if (*pos == off++) return p; @@ -89,7 +90,7 @@ static void *misc_seq_next(struct seq_file *seq, void *v, loff_t *pos) static void misc_seq_stop(struct seq_file *seq, void *v) { - up(&misc_sem); + mutex_unlock(&misc_mtx); } static int misc_seq_show(struct seq_file *seq, void *v) @@ -129,7 +130,7 @@ static int misc_open(struct inode * inode, struct file * file) int err = -ENODEV; const struct file_operations *old_fops, *new_fops = NULL; - down(&misc_sem); + mutex_lock(&misc_mtx); list_for_each_entry(c, &misc_list, list) { if (c->minor == minor) { @@ -139,9 +140,9 @@ static int misc_open(struct inode * inode, struct file * file) } if (!new_fops) { - up(&misc_sem); + mutex_unlock(&misc_mtx); request_module("char-major-%d-%d", MISC_MAJOR, minor); - down(&misc_sem); + mutex_lock(&misc_mtx); list_for_each_entry(c, &misc_list, list) { if (c->minor == minor) { @@ -165,7 +166,7 @@ static int misc_open(struct inode * inode, struct file * file) } fops_put(old_fops); fail: - up(&misc_sem); + mutex_unlock(&misc_mtx); return err; } @@ -201,10 +202,10 @@ int misc_register(struct miscdevice * misc) INIT_LIST_HEAD(&misc->list); - down(&misc_sem); + mutex_lock(&misc_mtx); list_for_each_entry(c, &misc_list, list) { if (c->minor == misc->minor) { - up(&misc_sem); + mutex_unlock(&misc_mtx); return -EBUSY; } } @@ -215,7 +216,7 @@ int misc_register(struct miscdevice * misc) if ( (misc_minors[i>>3] & (1 << (i&7))) == 0) break; if (i<0) { - up(&misc_sem); + mutex_unlock(&misc_mtx); return -EBUSY; } misc->minor = i; @@ -238,7 +239,7 @@ int misc_register(struct miscdevice * misc) */ list_add(&misc->list, &misc_list); out: - up(&misc_sem); + mutex_unlock(&misc_mtx); return err; } @@ -259,13 +260,13 @@ int misc_deregister(struct miscdevice * misc) if (list_empty(&misc->list)) return -EINVAL; - down(&misc_sem); + mutex_lock(&misc_mtx); list_del(&misc->list); device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor)); if (i < DYNAMIC_MINORS && i>0) { misc_minors[i>>3] &= ~(1 << (misc->minor & 7)); } - up(&misc_sem); + mutex_unlock(&misc_mtx); return 0; } -- 2.46.0