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authorTakashi Iwai <tiwai@suse.de>2012-11-07 12:44:12 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-11-17 13:14:22 -0800
commit40edba667959559aa4385a5ec047420fcfeb5f03 (patch)
tree6df9fc6d71f5d7608a95ca7d437fca00b83afb1f /include
parentfb434cc26173c2285d48d640c639493bc6a6c5f5 (diff)
downloadlwn-40edba667959559aa4385a5ec047420fcfeb5f03.tar.gz
lwn-40edba667959559aa4385a5ec047420fcfeb5f03.zip
ALSA: Add a reference counter to card instance
commit a0830dbd4e42b38aefdf3fb61ba5019a1a99ea85 upstream. 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> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/sound/core.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/sound/core.h b/include/sound/core.h
index 1fa2407c966f..78c5b4e1e8e2 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))