From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35AA9C433DB for ; Thu, 4 Feb 2021 18:38:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC32264DE1 for ; Thu, 4 Feb 2021 18:38:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238729AbhBDSho (ORCPT ); Thu, 4 Feb 2021 13:37:44 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:2503 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239100AbhBDSgH (ORCPT ); Thu, 4 Feb 2021 13:36:07 -0500 Received: from fraeml702-chm.china.huawei.com (unknown [172.18.147.201]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4DWnFb4ny9z67hHQ; Fri, 5 Feb 2021 02:31:47 +0800 (CST) Received: from lhreml710-chm.china.huawei.com (10.201.108.61) by fraeml702-chm.china.huawei.com (10.206.15.51) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2106.2; Thu, 4 Feb 2021 19:35:19 +0100 Received: from localhost (10.47.65.115) by lhreml710-chm.china.huawei.com (10.201.108.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2106.2; Thu, 4 Feb 2021 18:35:18 +0000 Date: Thu, 4 Feb 2021 18:34:33 +0000 From: Jonathan Cameron To: Alexandru Ardelean CC: , , , , , , , , Subject: Re: [PATCH v3 10/11] iio: buffer: introduce support for attaching more IIO buffers Message-ID: <20210204183433.000079e3@Huawei.com> In-Reply-To: <20210201145105.20459-11-alexandru.ardelean@analog.com> References: <20210201145105.20459-1-alexandru.ardelean@analog.com> <20210201145105.20459-11-alexandru.ardelean@analog.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.65.115] X-ClientProxiedBy: lhreml703-chm.china.huawei.com (10.201.108.52) To lhreml710-chm.china.huawei.com (10.201.108.61) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Mon, 1 Feb 2021 16:51:04 +0200 Alexandru Ardelean wrote: > With this change, calling iio_device_attach_buffer() will actually attach > more buffers. > Right now this doesn't do any validation of whether a buffer is attached > twice; maybe that can be added later (if needed). Attaching a buffer more > than once should yield noticeably bad results. > > The first buffer is the legacy buffer, so a reference is kept to it. > > At this point, accessing the data for the extra buffers (that are added > after the first one) isn't possible yet. > > The iio_device_attach_buffer() is also changed to return an error code, > which for now is -ENOMEM if the array could not be realloc-ed for more > buffers. > > Signed-off-by: Alexandru Ardelean A few minor comments inline. Thanks, J > --- > drivers/iio/industrialio-buffer.c | 80 +++++++++++++++++++++++++------ > include/linux/iio/buffer.h | 4 +- > include/linux/iio/buffer_impl.h | 3 ++ > include/linux/iio/iio-opaque.h | 4 ++ > 4 files changed, 74 insertions(+), 17 deletions(-) > > diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c > index 692f721588e2..a69bb705d173 100644 > --- a/drivers/iio/industrialio-buffer.c > +++ b/drivers/iio/industrialio-buffer.c > @@ -1445,11 +1445,21 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer, > return ret; > } > > +static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer) > +{ > + bitmap_free(buffer->scan_mask); > + kfree(buffer->buffer_group.name); > + kfree(buffer->buffer_group.attrs); > + iio_free_chan_devattr_list(&buffer->buffer_attr_list); > +} > + > int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev) > { > + struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); > struct iio_buffer *buffer = indio_dev->buffer; > const struct iio_chan_spec *channels; > - int i; > + int unwind_idx; > + int ret, i; > > channels = indio_dev->channels; > if (channels) { > @@ -1463,27 +1473,45 @@ int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev) > if (!buffer) > return 0; > > - return __iio_buffer_alloc_sysfs_and_mask(buffer, indio_dev, 0); > -} > + for (i = 0; i < iio_dev_opaque->attached_buffers_cnt; i++) { > + buffer = iio_dev_opaque->attached_buffers[i]; > + ret = __iio_buffer_alloc_sysfs_and_mask(buffer, indio_dev, i); > + if (ret) { > + unwind_idx = i; Gut feeling would be to use i instead of introducing unwind_idx, but it doesn't really matter if you prefer this. > + goto error_unwind_sysfs_and_mask; > + } > + } > > -static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer) > -{ > - bitmap_free(buffer->scan_mask); > - kfree(buffer->buffer_group.name); > - kfree(buffer->buffer_group.attrs); > - iio_free_chan_devattr_list(&buffer->buffer_attr_list); could you put this move in a precursor patch. It's making a mess of the diff and hence this harder to review than it should be. > + return 0; > + > +error_unwind_sysfs_and_mask: > + for (; unwind_idx >= 0; unwind_idx--) { > + buffer = iio_dev_opaque->attached_buffers[unwind_idx]; > + __iio_buffer_free_sysfs_and_mask(buffer); > + } > + kfree(iio_dev_opaque->attached_buffers); > + iio_dev_opaque->attached_buffers = NULL; > + return ret; > } > > void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev) > { > + struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); > struct iio_buffer *buffer = indio_dev->buffer; > + int i; > > if (!buffer) > return; > > iio_buffer_unregister_legacy_sysfs_groups(indio_dev); > > - __iio_buffer_free_sysfs_and_mask(buffer); > + for (i = iio_dev_opaque->attached_buffers_cnt - 1; i >= 0; i--) { > + buffer = iio_dev_opaque->attached_buffers[i]; > + __iio_buffer_free_sysfs_and_mask(buffer); > + } > + > + kfree(iio_dev_opaque->attached_buffers); > + iio_dev_opaque->attached_buffers = NULL; For places where we set freed pointers to NULL, I'd like a comment on why. Usually it makes me a bit worried we are doing something less than tidy. > } > > /** > @@ -1601,13 +1629,35 @@ EXPORT_SYMBOL_GPL(iio_buffer_put); > * @indio_dev: The device the buffer should be attached to > * @buffer: The buffer to attach to the device > * > + * Return 0 if successful, negative if error. > + * > * This function attaches a buffer to a IIO device. The buffer stays attached to > - * the device until the device is freed. The function should only be called at > - * most once per device. > + * the device until the device is freed. For legacy reasons, the first attached > + * buffer will also be assigned to 'indio_dev->buffer'. > */ > -void iio_device_attach_buffer(struct iio_dev *indio_dev, > - struct iio_buffer *buffer) > +int iio_device_attach_buffer(struct iio_dev *indio_dev, > + struct iio_buffer *buffer) > { > - indio_dev->buffer = iio_buffer_get(buffer); > + struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); > + struct iio_buffer **new, **old = iio_dev_opaque->attached_buffers; > + unsigned int cnt = iio_dev_opaque->attached_buffers_cnt; > + > + cnt++; > + > + new = krealloc(old, sizeof(*new) * cnt, GFP_KERNEL); > + if (!new) > + return -ENOMEM; > + iio_dev_opaque->attached_buffers = new; > + > + buffer = iio_buffer_get(buffer); > + > + /* first buffer is legacy; attach it to the IIO device directly */ > + if (!indio_dev->buffer) > + indio_dev->buffer = buffer; > + > + iio_dev_opaque->attached_buffers[cnt - 1] = buffer; > + iio_dev_opaque->attached_buffers_cnt = cnt; > + > + return 0; > } > EXPORT_SYMBOL_GPL(iio_device_attach_buffer); > diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h > index 8febc23f5f26..b6928ac5c63d 100644 > --- a/include/linux/iio/buffer.h > +++ b/include/linux/iio/buffer.h > @@ -41,7 +41,7 @@ static inline int iio_push_to_buffers_with_timestamp(struct iio_dev *indio_dev, > bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev, > const unsigned long *mask); > > -void iio_device_attach_buffer(struct iio_dev *indio_dev, > - struct iio_buffer *buffer); > +int iio_device_attach_buffer(struct iio_dev *indio_dev, > + struct iio_buffer *buffer); > > #endif /* _IIO_BUFFER_GENERIC_H_ */ > diff --git a/include/linux/iio/buffer_impl.h b/include/linux/iio/buffer_impl.h > index 41044320e581..768b90c64412 100644 > --- a/include/linux/iio/buffer_impl.h > +++ b/include/linux/iio/buffer_impl.h > @@ -112,6 +112,9 @@ struct iio_buffer { > /* @demux_bounce: Buffer for doing gather from incoming scan. */ > void *demux_bounce; > > + /* @attached_entry: Entry in the devices list of buffers attached by the driver. */ > + struct list_head attached_entry; > + > /* @buffer_list: Entry in the devices list of current buffers. */ > struct list_head buffer_list; > > diff --git a/include/linux/iio/iio-opaque.h b/include/linux/iio/iio-opaque.h > index 3e4c3cd248fd..c909835b6247 100644 > --- a/include/linux/iio/iio-opaque.h > +++ b/include/linux/iio/iio-opaque.h > @@ -7,6 +7,8 @@ > * struct iio_dev_opaque - industrial I/O device opaque information > * @indio_dev: public industrial I/O device information > * @event_interface: event chrdevs associated with interrupt lines > + * @attached_buffers: array of buffers statically attached by the driver > + * @attached_buffers_cnt: number of buffers in the array of statically attached buffers > * @buffer_list: list of all buffers currently attached > * @channel_attr_list: keep track of automatically created channel > * attributes > @@ -24,6 +26,8 @@ > struct iio_dev_opaque { > struct iio_dev indio_dev; > struct iio_event_interface *event_interface; > + struct iio_buffer **attached_buffers; > + unsigned int attached_buffers_cnt; > struct list_head buffer_list; > struct list_head channel_attr_list; > struct attribute_group chan_attr_group;