diff options
| author | Takashi Iwai <tiwai@suse.de> | 2020-11-23 09:53:11 +0100 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2020-11-23 15:11:56 +0100 |
| commit | c7474d09777c3d321f9f7f6a416f276204926c54 (patch) | |
| tree | b9785328f98b046dcdf5c214e513e60fd106e64d /sound/usb/endpoint.c | |
| parent | 2e43aae2bf5a4ede98cbe0c85ad104dd7ba5dfd2 (diff) | |
ALSA: usb-audio: Add snd_usb_get_endpoint() helper
Factor out the code to obtain snd_usb_endpoint object matching with
the given endpoint. It'll be used in the later patch to add the
implicit feedback hw-constraint.
No functional change by this patch itself.
Tested-by: Keith Milner <kamilner@superlative.org>
Tested-by: Dylan Robinson <dylan_robinson@motu.com>
Link: https://lore.kernel.org/r/20201123085347.19667-6-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/endpoint.c')
| -rw-r--r-- | sound/usb/endpoint.c | 36 |
1 files changed, 27 insertions, 9 deletions
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c index e2f9ce2f5b8b..cf00871fd278 100644 --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -439,6 +439,26 @@ exit_clear: clear_bit(ctx->index, &ep->active_mask); } +/* + * Get the existing endpoint object corresponding EP, iface and alt numbers + * Returns NULL if not present. + * Call inside chip->mutex locking for avoiding the race. + */ +struct snd_usb_endpoint * +snd_usb_get_endpoint(struct snd_usb_audio *chip, + int ep_num, int iface, int altsetting) +{ + struct snd_usb_endpoint *ep; + + list_for_each_entry(ep, &chip->ep_list, list) { + if (ep->ep_num == ep_num && + ep->iface == iface && + ep->altsetting == altsetting) + return ep; + } + return NULL; +} + /** * snd_usb_add_endpoint: Add an endpoint to an USB audio chip * @@ -470,15 +490,13 @@ struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip, mutex_lock(&chip->mutex); - list_for_each_entry(ep, &chip->ep_list, list) { - if (ep->ep_num == ep_num && - ep->iface == alts->desc.bInterfaceNumber && - ep->altsetting == alts->desc.bAlternateSetting) { - usb_audio_dbg(ep->chip, - "Re-using EP %x in iface %d,%d @%p\n", - ep_num, ep->iface, ep->altsetting, ep); - goto __exit_unlock; - } + ep = snd_usb_get_endpoint(chip, ep_num, + alts->desc.bInterfaceNumber, + alts->desc.bAlternateSetting); + if (ep) { + usb_audio_dbg(ep->chip, "Re-using EP %x in iface %d,%d @%p\n", + ep_num, ep->iface, ep->altsetting, ep); + goto __exit_unlock; } usb_audio_dbg(chip, "Creating new %s %s endpoint #%x\n", |