diff options
Diffstat (limited to 'drivers/telephony/phonedev.c')
| -rw-r--r-- | drivers/telephony/phonedev.c | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/drivers/telephony/phonedev.c b/drivers/telephony/phonedev.c index 0f3195163..fc4f61b34 100644 --- a/drivers/telephony/phonedev.c +++ b/drivers/telephony/phonedev.c @@ -28,6 +28,7 @@ #include <asm/system.h> #include <linux/kmod.h> +#include <linux/sem.h> #define PHONE_NUM_DEVICES 256 @@ -37,6 +38,7 @@ */ static struct phone_device *phone_device[PHONE_NUM_DEVICES]; +static DECLARE_MUTEX(phone_lock); /* * Open a phone device. @@ -45,29 +47,37 @@ static struct phone_device *phone_device[PHONE_NUM_DEVICES]; static int phone_open(struct inode *inode, struct file *file) { unsigned int minor = MINOR(inode->i_rdev); - int err; + int err = 0; struct phone_device *p; if (minor >= PHONE_NUM_DEVICES) return -ENODEV; + down(&phone_lock); p = phone_device[minor]; if (p == NULL) { char modname[32]; + up(&phone_lock); sprintf(modname, "char-major-%d-%d", PHONE_MAJOR, minor); request_module(modname); + down(&phone_lock); p = phone_device[minor]; if (p == NULL) - return -ENODEV; + { + err=-ENODEV; + goto end; + } } if (p->open) { err = p->open(p, file); /* Tell the device it is open */ if (err) - return err; + goto end; } file->f_op = p->f_op; - return 0; +end: + up(&phone_lock); + return err; } /* @@ -87,14 +97,18 @@ int phone_register_device(struct phone_device *p, int unit) base = unit; end = unit + 1; /* enter the loop at least one time */ } + + down(&phone_lock); for (i = base; i < end; i++) { if (phone_device[i] == NULL) { phone_device[i] = p; p->minor = i; MOD_INC_USE_COUNT; + up(&phone_lock); return 0; } } + up(&phone_lock); return -ENFILE; } @@ -104,9 +118,11 @@ int phone_register_device(struct phone_device *p, int unit) void phone_unregister_device(struct phone_device *pfd) { + down(&phone_lock); if (phone_device[pfd->minor] != pfd) panic("phone: bad unregister"); phone_device[pfd->minor] = NULL; + up(&phone_lock); MOD_DEC_USE_COUNT; } |