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sound: oss: vwsnd: avoid interruptible_sleep_on 

Interruptible_sleep_on is racy and we want to remove it. This replaces
the use in the vwsnd driver with an open-coded prepare_to_wait
loop that fixes the race between concurrent open() and close() calls,
and also drops the global mutex while waiting here, which restores
the original behavior that was changed during the BKL removal.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Arnd Bergmann 2014-01-02 13:07:49 +01:00 committed by Takashi Iwai
parent 1a21576562
commit 7bd6972a92
1 changed files with 10 additions and 4 deletions
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14
sound/oss/vwsnd.c
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@ -2921,6 +2921,7 @@ static int vwsnd_audio_open(struct inode *inode, struct file *file)
vwsnd_dev_t *devc;
int minor = iminor(inode);
int sw_samplefmt;
DEFINE_WAIT(wait);
DBGE("(inode=0x%p, file=0x%p)\n", inode, file);
@ -2937,21 +2938,26 @@ static int vwsnd_audio_open(struct inode *inode, struct file *file)
}
mutex_lock(&devc->open_mutex);
while (devc->open_mode & file->f_mode) {
while (1) {
prepare_to_wait(&devc->open_wait, &wait, TASK_INTERRUPTIBLE);
if (!(devc->open_mode & file->f_mode))
break;
mutex_unlock(&devc->open_mutex);
mutex_unlock(&vwsnd_mutex);
if (file->f_flags & O_NONBLOCK) {
DEC_USE_COUNT;
mutex_unlock(&vwsnd_mutex);
return -EBUSY;
}
interruptible_sleep_on(&devc->open_wait);
schedule();
if (signal_pending(current)) {
DEC_USE_COUNT;
mutex_unlock(&vwsnd_mutex);
return -ERESTARTSYS;
}
mutex_lock(&vwsnd_mutex);
mutex_lock(&devc->open_mutex);
}
finish_wait(&devc->open_wait, &wait);
devc->open_mode |= file->f_mode & (FMODE_READ | FMODE_WRITE);
mutex_unlock(&devc->open_mutex);