From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f53.google.com (mail-wm1-f53.google.com [209.85.128.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8642948822B for ; Tue, 1 Sep 2026 17:21:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.53 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788283292; cv=none; b=q65/s1Vm2uSM9+70N1bmwRjUfMnuLWwJyytaodbp6dbzi3ag/M6GRV+woffVYzYNj9d4JUQ3gs204Pe2NXr5gtxtLGbooogwX4igoNnMoLTcXSWmdQHce2P1U0DIz0Qr7cW7cv4ROmARjqDzJXUVkiffZOuMGKRbdD0klyGj/+E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788283292; c=relaxed/simple; bh=LeGDvC3l27Wo7zRvl7F/A9X2MyhBj7RXCYXvGI4LZpM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Qfe9nGoBBhnll8bCqr7WV4J/L6QhsFl80jImLPRZ07eubtSuNGJLR3lpbqQ39PDclvM0LqrqDMHbH505TMeONYJ68F4GMVuRJTIhwTC7BqavTUqHdVn/g3WsCxj9YBO0cDt19tVB3thbnRe0p730yqaW1BdkbV8mI1ZWHGT/ouc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=hUmVALwh; arc=none smtp.client-ip=209.85.128.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="hUmVALwh" Received: by mail-wm1-f53.google.com with SMTP id 5b1f17b1804b1-49b8e527d63so172145e9.2 for ; Tue, 01 Sep 2026 10:21:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1788283289; x=1788888089; darn=lists.linux.dev; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=yxn9qM2Ppo5iTTsOVfzJ7uBe3gU3KpqKhhkdUu2Nv7M=; b=hUmVALwh4mTZuV466yFtcRYTHg6yjW7GcXUpASKqtGV9qgxqUn0NZqhc9EC9RHj3y0 nB99Xi/PZ6M+x+9Vvrz5dz5B1niwU9ojVVto5oXVt3EAQwjO/cLnyz95gmSs8TLrMnoo EMQJ4xWAbz1wo0wfEjJDbxz9vVlRmc3ga/acFwI0pfLM+U3ByMUyYcfRW9ArrlIhVwLe 1n+wpu3ysHdywHKprVxYaFj3VN8era8jUxRc5ODqiEp3r1raEtzZUlYbE1zTC6yWN32s slSUFvQRHkIbODveo6TudeBNGG5Z6FHKxWNQX3omksQvkYqOmWg140QEhH5gKhbIHlK5 Iy6g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788283289; x=1788888089; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=yxn9qM2Ppo5iTTsOVfzJ7uBe3gU3KpqKhhkdUu2Nv7M=; b=TqNug8EFWEr+BPZ6/k3mrBTKONACdgTj1lcxT1YLlkiE5jbCrQnl1Imt3oYs1lBCjF Bzp677LNsUMqaSsdFtR8QZMP8efuDttz1ufnbjON0CrsxbQI2I4AyVGZi9HMZ087/RNF p9BglmFZUZf2swdGefVilJbHrGIOEGS2gOk9pnzUYXyvRoONGvm+A6eJDf3icxdXWzPQ w1PlKn+/t0fKVBqmh6UJQ/+YhV7m0QXYBzSi8h6HvMuVezEXy2cgysPCiZg7LvyXIVYn T8TxUpYZX6iQHZQw3gq7WjL7H345+nFRQskI//+1s35Ca8nbVLIT3y5UA3KO1DuL5AHD Roxg== X-Gm-Message-State: AFuF++mHCCRTVQZinSK5UCZrX8lqx5dWjtHjF5nWoWdDINXFrunmcIVD 7kypRMKUmIJj03rlAqXIMJcx72FLW1r2ISDUCLm7apfSN5mcjXfsYNk/ X-Gm-Gg: AR+sD12UmV+IqmjWGGJRXCkKTLpJlxOhk2orZL+xis+IQw0s/HDEPT1kDnK0BjmBM5w IsWXJM7QrNBV4g3vK/TlHA0KiXswI0QT8Y4zUo6Gfq1fwpUyJVbEohgcDzWTUtmk3zxzKUf62mt Kta3NO/PCmOW8+c6jytmNImdcNA1lG4FBdtvyRBWRg1GYM4f/uKemNtRt9UMa1tBAEz2Xffk1oj PZGWlzyxlLYuQT8MeOBfeKTBID2t4UxVNiAYoJXSV7bw5DvHvR/pE+aV4UJjCna11eAVil9F9ss J5QyCR8JSMzd8R3uQxJwlUim8vRJqhpy2LqYWop2IybRoLlJJZ6uM33JMpTy84N7iIIYqSlIGXm BkW2ekBPydZuNxnxVtKRLwowbz7MQEOWszrIDliv4xXrdI3IspestY8dtsWAezysltUmkVlwFJB DYpc/nJSVG2jm8fry4mdf6OV9O7KPlKU0Em/sB/6Lm+V66OI2hGG1Tf8JMEGH+aElvCVl5tg/X5 fI8RF8gv8PXxwSxKkb8GrZwjIYYRz14/hkUs2eSxUk= X-Received: by 2002:a05:600c:4704:b0:493:cefc:d113 with SMTP id 5b1f17b1804b1-49b91c2d8femr548275525e9.5.1788283288657; Tue, 01 Sep 2026 10:21:28 -0700 (PDT) Received: from DESKTOP-EHH7ATM.localdomain ([102.209.109.149]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48448e72c28sm508846f8f.6.2026.09.01.10.21.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Sep 2026 10:21:28 -0700 (PDT) From: Godana Emiru To: parthiban.veerasooran@microchip.com, christian.gromm@microchip.com, gregkh@linuxfoundation.org Cc: linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org, Godana Emiru Subject: [PATCH] staging: most: video: document the locks in struct most_video_dev Date: Tue, 1 Sep 2026 20:20:55 +0300 Message-ID: <20260901172055.53889-1-godanaemiru@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Neither lock in struct most_video_dev carries a comment describing what it protects. list_lock protects the pending_mbos list. Buffers are added by the component's rx_completion callback, comp_rx_data(), which is invoked from the interface driver's completion path (a URB completion handler in the case of the USB HDM), and are removed from process context by comp_vdev_read() and comp_vdev_close(). Note that in the comment, since it is what makes the irq-safe spinlock variants necessary here. lock is never acquired by this driver directly. comp_register_videodev() installs it as struct video_device::lock, where v4l2_ioctl_get_lock() returns it and video_ioctl2() holds it across ioctl dispatch. No functional change. Signed-off-by: Godana Emiru --- drivers/staging/most/video/video.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/staging/most/video/video.c b/drivers/staging/most/video/video.c index 88892b5db..c354d1820 100644 --- a/drivers/staging/most/video/video.c +++ b/drivers/staging/most/video/video.c @@ -33,6 +33,7 @@ struct most_video_dev { bool mute; struct list_head pending_mbos; + /* protects pending_mbos; taken from rx completion (softirq) */ spinlock_t list_lock; struct v4l2_device v4l2_dev; @@ -40,6 +41,7 @@ struct most_video_dev { struct video_device *vdev; unsigned int ctrl_input; + /* serializes V4L2 ioctls; used as struct video_device::lock */ struct mutex lock; wait_queue_head_t wait_data; -- 2.53.0