From patchwork Mon Nov 6 23:36:36 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alan Cox X-Patchwork-Id: 10044769 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 5FEE960247 for ; Mon, 6 Nov 2017 23:37:47 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 51C1429D3D for ; Mon, 6 Nov 2017 23:37:47 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4692B29E22; Mon, 6 Nov 2017 23:37:47 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham 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 B7E5529D3D for ; Mon, 6 Nov 2017 23:37:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754306AbdKFXhn (ORCPT ); Mon, 6 Nov 2017 18:37:43 -0500 Received: from www.llwyncelyn.cymru ([82.70.14.225]:48124 "EHLO fuzix.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752914AbdKFXhm (ORCPT ); Mon, 6 Nov 2017 18:37:42 -0500 Received: from [10.40.0.25] (82-70-14-226.dsl.in-addr.zen.co.uk [82.70.14.226]) by fuzix.org (8.15.2/8.15.2) with ESMTP id vA6Naauo018574; Mon, 6 Nov 2017 23:36:37 GMT Subject: [PATCH 1/3] atomisp: Fix up the open v load race From: Alan To: vincent.hervieux@gmail.com, sakari.ailus@linux.intel.com, linux-media@vger.kernel.org Date: Mon, 06 Nov 2017 23:36:36 +0000 Message-ID: <151001137594.77201.4306351721772580664.stgit@alans-desktop> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 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 This isn't the ideal final solution but it stops the main problem for now where an open (often from udev) races the device initialization and we try and load the firmware twice at the same time. This needless to say doesn't usually end well. Signed-off-by: Alan Cox --- .../media/atomisp/pci/atomisp2/atomisp_fops.c | 12 ++++++++++++ .../media/atomisp/pci/atomisp2/atomisp_internal.h | 5 +++++ .../media/atomisp/pci/atomisp2/atomisp_v4l2.c | 6 ++++++ 3 files changed, 23 insertions(+) diff --git a/drivers/staging/media/atomisp/pci/atomisp2/atomisp_fops.c b/drivers/staging/media/atomisp/pci/atomisp2/atomisp_fops.c index dd7596d8763d..b82c53cee32c 100644 --- a/drivers/staging/media/atomisp/pci/atomisp2/atomisp_fops.c +++ b/drivers/staging/media/atomisp/pci/atomisp2/atomisp_fops.c @@ -771,6 +771,18 @@ static int atomisp_open(struct file *file) dev_dbg(isp->dev, "open device %s\n", vdev->name); + /* Ensure that if we are still loading we block. Once the loading + is over we can proceed. We can't blindly hold the lock until + that occurs as if the load fails we'll deadlock the unload */ + rt_mutex_lock(&isp->loading); + /* Revisit this with a better check once the code structure is + cleaned up a bit more FIXME */ + if (!isp->ready) { + rt_mutex_unlock(&isp->loading); + return -ENXIO; + } + rt_mutex_unlock(&isp->loading); + rt_mutex_lock(&isp->mutex); acc_node = !strncmp(vdev->name, "ATOMISP ISP ACC", diff --git a/drivers/staging/media/atomisp/pci/atomisp2/atomisp_internal.h b/drivers/staging/media/atomisp/pci/atomisp2/atomisp_internal.h index 52a6f8002048..808d79c840d4 100644 --- a/drivers/staging/media/atomisp/pci/atomisp2/atomisp_internal.h +++ b/drivers/staging/media/atomisp/pci/atomisp2/atomisp_internal.h @@ -252,6 +252,11 @@ struct atomisp_device { /* Purpose of mutex is to protect and serialize use of isp data * structures and css API calls. */ struct rt_mutex mutex; + /* This mutex ensures that we don't allow an open to succeed while + * the initialization process is incomplete */ + struct rt_mutex loading; + /* Set once the ISP is ready to allow opens */ + bool ready; /* * Serialise streamoff: mutex is dropped during streamoff to * cancel the watchdog queue. MUST be acquired BEFORE diff --git a/drivers/staging/media/atomisp/pci/atomisp2/atomisp_v4l2.c b/drivers/staging/media/atomisp/pci/atomisp2/atomisp_v4l2.c index 3c260f8b52e2..350e298bc3a6 100644 --- a/drivers/staging/media/atomisp/pci/atomisp2/atomisp_v4l2.c +++ b/drivers/staging/media/atomisp/pci/atomisp2/atomisp_v4l2.c @@ -1220,6 +1220,7 @@ static int atomisp_pci_probe(struct pci_dev *dev, isp->saved_regs.ispmmadr = start; rt_mutex_init(&isp->mutex); + rt_mutex_init(&isp->loading); mutex_init(&isp->streamoff_mutex); spin_lock_init(&isp->lock); @@ -1393,6 +1394,8 @@ static int atomisp_pci_probe(struct pci_dev *dev, csi_afe_trim); } + rt_mutex_lock(&isp->loading); + err = atomisp_initialize_modules(isp); if (err < 0) { dev_err(&dev->dev, "atomisp_initialize_modules (%d)\n", err); @@ -1450,6 +1453,8 @@ static int atomisp_pci_probe(struct pci_dev *dev, release_firmware(isp->firmware); isp->firmware = NULL; isp->css_env.isp_css_fw.data = NULL; + isp->ready = true; + rt_mutex_unlock(&isp->loading); atomisp_drvfs_init(&atomisp_pci_driver, isp); @@ -1468,6 +1473,7 @@ static int atomisp_pci_probe(struct pci_dev *dev, register_entities_fail: atomisp_uninitialize_modules(isp); initialize_modules_fail: + rt_mutex_unlock(&isp->loading); pm_qos_remove_request(&isp->pm_qos); atomisp_msi_irq_uninit(isp, dev); enable_msi_fail: