+static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
+ struct snd_ctl_tlv __user *_tlv,
+ int op_flag)
+{
+ struct snd_card *card = file->card;
+ struct snd_ctl_tlv tlv;
+ struct snd_kcontrol *kctl;
+ struct snd_kcontrol_volatile *vd;
+ unsigned int len;
+ int err = 0;
+
+ if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
+ return -EFAULT;
+ if (tlv.length < sizeof(unsigned int) * 3)
+ return -EINVAL;
+ down_read(&card->controls_rwsem);
+ kctl = snd_ctl_find_numid(card, tlv.numid);
+ if (kctl == NULL) {
+ err = -ENOENT;
+ goto __kctl_end;
+ }
+ if (kctl->tlv.p == NULL) {
+ err = -ENXIO;
+ goto __kctl_end;
+ }
+ vd = &kctl->vd[tlv.numid - kctl->id.numid];
+ if ((op_flag == 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||
+ (op_flag > 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||
+ (op_flag < 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0)) {
+ err = -ENXIO;
+ goto __kctl_end;
+ }
+ if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
+ if (file && vd->owner != NULL && vd->owner != file) {
+ err = -EPERM;
+ goto __kctl_end;
+ }
+ err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv);
+ if (err > 0) {
+ up_read(&card->controls_rwsem);
+ snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &kctl->id);
+ return 0;
+ }
+ } else {
+ if (op_flag) {
+ err = -ENXIO;
+ goto __kctl_end;
+ }
+ len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);
+ if (tlv.length < len) {
+ err = -ENOMEM;
+ goto __kctl_end;
+ }
+ if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))
+ err = -EFAULT;
+ }
+ __kctl_end:
+ up_read(&card->controls_rwsem);
+ return err;
+}
+