[ALSA] Handle file operations during snd_card disconnects using static file->f_op
Alsa used to kmalloc one file->f_op per file per disconnecting snd_card.
This led to oopses sometimes when file->f_op was freed before __fput()
finished.
Patch adds a virtual device for disconnect: VDD.
VDD consists of:
LIST_HEAD(shutdown_files)
protected by DEFINE_SPINLOCK(shutdown_mutex)
static struct file_operations snd_shutdown_f_ops
and functions assigned to it
Additions to struct snd_monitor_file
to specify if instance is hidden by VDD or not.
A VDD's instance is
created in snd_card_disconnect() under the card->files_lock.
cleaned up in snd_card_file_remove() under the card->files_lock.
Signed-off-by: Karsten Wiese <fzu@wemgehoertderstaat.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/include/sound/core.h b/include/sound/core.h
index b056ea9..fa1ca01 100644
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -89,10 +89,10 @@
struct snd_monitor_file {
struct file *file;
struct snd_monitor_file *next;
+ const struct file_operations *disconnected_f_op;
+ struct list_head shutdown_list;
};
-struct snd_shutdown_f_ops; /* define it later in init.c */
-
/* main structure for soundcard */
struct snd_card {