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 Cc: Jaroslav Kysela perex@perex.cz Cc: Takashi Iwai tiwai@suse.de Cc: alsa-devel@alsa-project.org --- sound/oss/vwsnd.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/sound/oss/vwsnd.c b/sound/oss/vwsnd.c index 4bbcc0f..a077e9c 100644 --- a/sound/oss/vwsnd.c +++ b/sound/oss/vwsnd.c @@ -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);