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.
Showing the changes to include/sound (1 of 11 files). Show all
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| @@ -132,6 +132,7 @@ struct snd_card { · 131 unmodified lines | ||
| 132 | 132 | int shutdown; /* this card is going down */ |
| 133 | 133 | int free_on_last_close; /* free in context of file_release */ |
| 134 | 134 | wait_queue_head_t shutdown_sleep; |
| 135 | + atomic_t refcount; /* refcount for disconnection */ | |
| 135 | 136 | struct device *dev; /* device assigned to this card */ |
| 136 | 137 | struct device *card_dev; /* cardX object for sysfs */ |
| 137 | 138 | |
| @@ -189,6 +190,7 @@ struct snd_minor { · 51 unmodified lines | ||
| 189 | 190 | const struct file_operations *f_ops; /* file operations */ |
| 190 | 191 | void *private_data; /* private data for f_ops->open */ |
| 191 | 192 | struct device *dev; /* device for sysfs */ |
| 193 | + struct snd_card *card_ptr; /* assigned card instance */ | |
| 192 | 194 | }; |
| 193 | 195 | |
| 194 | 196 | /* return a device pointer linked to each sound device as a parent */ |
| @@ -295,6 +297,7 @@ int snd_card_info_done(void); · 100 unmodified lines | ||
| 295 | 297 | int snd_component_add(struct snd_card *card, const char *component); |
| 296 | 298 | int snd_card_file_add(struct snd_card *card, struct file *file); |
| 297 | 299 | int snd_card_file_remove(struct snd_card *card, struct file *file); |
| 300 | +void snd_card_unref(struct snd_card *card); | |
| 298 | 301 | |
| 299 | 302 | #define snd_card_set_dev(card, devptr) ((card)->dev = (devptr)) |
| 300 | 303 | |