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| author | Takashi Iwai <tiwai@suse.de> | 2012-10-16 13:05:59 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2012-10-30 11:07:10 +0100 |
| commit | a0830dbd4e42b38aefdf3fb61ba5019a1a99ea85 (patch) | |
| tree | 4dc74b708a07b56d12ed72a34d0a2e0cb8c8b9d4 /include/sound | |
| parent | 888ea7d5ac6815ba16b3b3a20f665a92c7af6724 (diff) | |
| download | lwn-a0830dbd4e42b38aefdf3fb61ba5019a1a99ea85.tar.gz lwn-a0830dbd4e42b38aefdf3fb61ba5019a1a99ea85.zip | |
ALSA: Add a reference counter to card instance
For more strict protection for wild disconnections, a refcount is
introduced to the card instance, and let it up/down when an object is
referred via snd_lookup_*() in the open ops.
The free-after-last-close check is also changed to check this refcount
instead of the empty list, too.
Reported-by: Matthieu CASTET <matthieu.castet@parrot.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'include/sound')
| -rw-r--r-- | include/sound/core.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/sound/core.h b/include/sound/core.h index bc056687f647..93896ad1fcdd 100644 --- a/include/sound/core.h +++ b/include/sound/core.h @@ -132,6 +132,7 @@ struct snd_card { int shutdown; /* this card is going down */ int free_on_last_close; /* free in context of file_release */ wait_queue_head_t shutdown_sleep; + atomic_t refcount; /* refcount for disconnection */ struct device *dev; /* device assigned to this card */ struct device *card_dev; /* cardX object for sysfs */ @@ -189,6 +190,7 @@ struct snd_minor { const struct file_operations *f_ops; /* file operations */ void *private_data; /* private data for f_ops->open */ struct device *dev; /* device for sysfs */ + struct snd_card *card_ptr; /* assigned card instance */ }; /* return a device pointer linked to each sound device as a parent */ @@ -295,6 +297,7 @@ int snd_card_info_done(void); int snd_component_add(struct snd_card *card, const char *component); int snd_card_file_add(struct snd_card *card, struct file *file); int snd_card_file_remove(struct snd_card *card, struct file *file); +void snd_card_unref(struct snd_card *card); #define snd_card_set_dev(card, devptr) ((card)->dev = (devptr)) |