linux-kernel - [PATCH for v4.9 LTS 51/87] ALSA: usb-audio: test EP_FLAG

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20170715012538.10101-51-alexander.levin@verizon.com>
Date:   Sat, 15 Jul 2017 01:26:15 +0000
From:   "Levin, Alexander (Sasha Levin)" <alexander.levin@...izon.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Cc:     Ioan-Adrian Ratiu <adi@...rat.com>, Takashi Iwai <tiwai@...e.de>,
        "Levin, Alexander (Sasha Levin)" <alexander.levin@...izon.com>
Subject: [PATCH for v4.9 LTS 51/87] ALSA: usb-audio: test EP_FLAG_RUNNING at
 urb completion

From: Ioan-Adrian Ratiu <adi@...rat.com>

[ Upstream commit 13a6c8328e6056932dc680e447d4c5e8ad9add17 ]

Testing EP_FLAG_RUNNING in snd_complete_urb() before running the completion
logic allows us to save a few cpu cycles by returning early, skipping the
pending urb in case the stream was stopped; the stop logic handles the urb
and sets the completion callbacks to NULL.

Signed-off-by: Ioan-Adrian Ratiu <adi@...rat.com>
Signed-off-by: Takashi Iwai <tiwai@...e.de>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
---
 sound/usb/endpoint.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index c5251aaad844..b8044c6034b3 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -384,6 +384,9 @@ static void snd_complete_urb(struct urb *urb)
 	if (unlikely(atomic_read(&ep->chip->shutdown)))
 		goto exit_clear;
 
+	if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
+		goto exit_clear;
+
 	if (usb_pipeout(ep->pipe)) {
 		retire_outbound_urb(ep, ctx);
 		/* can be stopped during retire callback */
-- 
2.11.0