From patchwork Wed Apr 11 03:24:04 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jia-Ju Bai X-Patchwork-Id: 10334803 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id F2E736029B for ; Wed, 11 Apr 2018 03:24:52 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F010928672 for ; Wed, 11 Apr 2018 03:24:52 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E369628673; Wed, 11 Apr 2018 03:24:52 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6107228671 for ; Wed, 11 Apr 2018 03:24:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752765AbeDKDYM (ORCPT ); Tue, 10 Apr 2018 23:24:12 -0400 Received: from mail-pg0-f65.google.com ([74.125.83.65]:45221 "EHLO mail-pg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752103AbeDKDYL (ORCPT ); Tue, 10 Apr 2018 23:24:11 -0400 Received: by mail-pg0-f65.google.com with SMTP id y63so141584pgy.12; Tue, 10 Apr 2018 20:24:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=5sXM65TnOuMDDDfR/XB5yxG1+yU2ccJljOPxOCyC1xk=; b=m4pfaFPG9Za4tfoDTYWDldTiUAetvnG4USlmILEss9Z1Xz/z8skv7/7MJlDitVSwU+ y5/2ocJO3RiyLNZharf55myO5yv/TucZgk+JI3d3Hna6iq7SEk/xzycsJTNbpjhwMJX3 5R/L/7Wiui1o2O6lLb2MvEbwoHGwWeHyi0YuVJLO0gm9MjLOPxUAhKN86/735km6XCet 6WFFCwupemZ/brSnthU6r2g0+y7ssUK8rtWFp1BUzlJA4gOD2n/9pZISfElKcD3atkBt DJ0P5MskZtcVI1sE/jHg73ND70QVKHNSJcHyR0vhYl7zXYZYC7+irGJt2iCnLWR56yxk Tw0w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=5sXM65TnOuMDDDfR/XB5yxG1+yU2ccJljOPxOCyC1xk=; b=MEq7+0xe4gBx8mJL36j3xryUu1cx7jI9GuEfWfKnigqqnPJmMlZ3z3M9j88E84pxIf ztV5tq7en1Nkp/EEUj8ZrIQ3/eUrKBDiU0NrhqrhBrekAPoxVne7mBCLsQ2mAg+HdLaT CsDF/xlmmG4ph/8XutzIj8l9KjQx7pGFiguiVgchavsh049Q10+nQ+sTlfMem+vIPs7B VNVGIjR5HfrFuEtBj4mDX6GgClL5AX+0NjnjJOjxQDBVG87Z9OW86pByM8Ra2X1xONnW 9SKSicYzG6bQhHbCc0kgSrhOMszuvNAAfUSFU4w+J25Q2a+maIzTbUlzxNapYp3RsLqj Z+Aw== X-Gm-Message-State: ALQs6tAXH82oDV9TneozBX3TDvSqJ+5ofB1dL45NMn23tllato65dv6E s79jYAUST6Mn4bXudGfzX04/xlgf X-Google-Smtp-Source: AIpwx4+7+46jRhQI2IbE/C14uVgjz+vbxCawPqfpuipgnK9YBVOdsM77ZqfngdWmChbkhPs6InK0kA== X-Received: by 10.101.100.132 with SMTP id e4mr2162577pgv.240.1523417051288; Tue, 10 Apr 2018 20:24:11 -0700 (PDT) Received: from oslab.tsinghua.edu.cn ([2402:f000:1:4413:edc8:c1dd:b0a8:461d]) by smtp.gmail.com with ESMTPSA id x76sm281728pfi.151.2018.04.10.20.24.09 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 10 Apr 2018 20:24:10 -0700 (PDT) From: Jia-Ju Bai To: mchehab@kernel.org Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Jia-Ju Bai Subject: [PATCH 2/3] media: dvb-usb: Replace GFP_ATOMIC with GFP_KERNEL in usb_bulk_urb_init Date: Wed, 11 Apr 2018 11:24:04 +0800 Message-Id: <1523417044-3115-1-git-send-email-baijiaju1990@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP usb_bulk_urb_init() is never called in atomic context. The call chains ending up at usb_bulk_urb_init() are: [1] usb_bulk_urb_init() <- usb_urb_init() <- dvb_usb_adapter_stream_init() <- dvb_usb_adapter_init <- dvb_usb_init() <- dvb_usb_device_init() <- xxx_probe() xxx_probe including ttusb2_probe, vp7045_usb_probe, a800_probe, and so on. These xxx_probe() functions are set as ".probe" in struct usb_driver. And these functions are not called in atomic context. Despite never getting called from atomic context, usb_bulk_urb_init() calls usb_alloc_urb() with GFP_ATOMIC, which does not sleep for allocation. GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL, which can sleep and improve the possibility of sucessful allocation. This is found by a static analysis tool named DCNS written by myself. And I also manually check it. Signed-off-by: Jia-Ju Bai --- drivers/media/usb/dvb-usb/usb-urb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/media/usb/dvb-usb/usb-urb.c b/drivers/media/usb/dvb-usb/usb-urb.c index 8917360..d6d62e8 100644 --- a/drivers/media/usb/dvb-usb/usb-urb.c +++ b/drivers/media/usb/dvb-usb/usb-urb.c @@ -144,7 +144,7 @@ static int usb_bulk_urb_init(struct usb_data_stream *stream) /* allocate the URBs */ for (i = 0; i < stream->props.count; i++) { - stream->urb_list[i] = usb_alloc_urb(0, GFP_ATOMIC); + stream->urb_list[i] = usb_alloc_urb(0, GFP_KERNEL); if (!stream->urb_list[i]) { deb_mem("not enough memory for urb_alloc_urb!.\n"); for (j = 0; j < i; j++)