From 28a0989c995087129b11ca3e00eb37ab77c29bce Mon Sep 17 00:00:00 2001
From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Date: Thu, 3 Aug 2017 20:20:40 +0900
Subject: [PATCH] ALSA: control: queue events within locking of controls_rwsem for TLV operation
Git-commit: 28a0989c995087129b11ca3e00eb37ab77c29bce
Patch-mainline: v4.14-rc1
References: bsc#1121278

Any control event is queued by a call of snd_ctl_notify(). This function
adds the event to each queue of opened file data corresponding to ALSA
control character devices. This function acquired two types of lock; a
counting semaphore for a list of the opened file data and a spinlock for
card data opened by the file. Typically, this function is called after
acquiring a counting semaphore for a list of elements in the card data.

In current implementation of TLV request handler, the function is called
after releasing the semaphore for a list of elements in the card data.
This release is not necessarily needed.

This commit removes the release to call the function within the critical
section so that later commits are simple.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 sound/core/control.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/sound/core/control.c b/sound/core/control.c
index 3c6be1452e35..d2e1edbf843a 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -1450,9 +1450,8 @@ static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
 		err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv);
 		if (err > 0) {
 			struct snd_ctl_elem_id id = kctl->id;
-			up_read(&card->controls_rwsem);
 			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &id);
-			return 0;
+			err = 0;
 		}
 	} else {
 		if (op_flag != SNDRV_CTL_TLV_OP_READ) {
-- 
2.20.1