From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from tx2ehsobe004.messaging.microsoft.com ([65.55.88.14]:53432 "EHLO TX2EHSOBE009.bigfish.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752597Ab1LSOXX (ORCPT ); Mon, 19 Dec 2011 09:23:23 -0500 From: Lars-Peter Clausen To: Greg Kroah-Hartman CC: Jonathan Cameron , Michael Hennerich , , , , , Lars-Peter Clausen Subject: [PATCH 3/8] staging:iio: Disallow modifying buffer size when buffer is enabled Date: Mon, 19 Dec 2011 15:23:44 +0100 Message-ID: <1324304629-24720-3-git-send-email-lars@metafoo.de> In-Reply-To: <1324304629-24720-1-git-send-email-lars@metafoo.de> References: <1324304629-24720-1-git-send-email-lars@metafoo.de> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org The buffer buffer storage is only update when enabling the buffer. Changing the buffer size while the buffer is enabled will confuse the buffer in regard to its actual buffer size and can cause potential memory corruption. Thus it is only safe to modify the buffer size when the buffer is disabled. Acked-by: Jonathan Cameron Signed-off-by: Lars-Peter Clausen --- drivers/staging/iio/industrialio-buffer.c | 17 ++++++++++++----- 1 files changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/staging/iio/industrialio-buffer.c b/drivers/staging/iio/industrialio-buffer.c index 747b901..5947289 100644 --- a/drivers/staging/iio/industrialio-buffer.c +++ b/drivers/staging/iio/industrialio-buffer.c @@ -396,13 +396,20 @@ ssize_t iio_buffer_write_length(struct device *dev, if (val == buffer->access->get_length(buffer)) return len; - if (buffer->access->set_length) { - buffer->access->set_length(buffer, val); - if (buffer->access->mark_param_change) - buffer->access->mark_param_change(buffer); + mutex_lock(&indio_dev->mlock); + if (iio_buffer_enabled(indio_dev)) { + ret = -EBUSY; + } else { + if (buffer->access->set_length) { + buffer->access->set_length(buffer, val); + if (buffer->access->mark_param_change) + buffer->access->mark_param_change(buffer); + } + ret = 0; } + mutex_unlock(&indio_dev->mlock); - return len; + return ret ? ret : len; } EXPORT_SYMBOL(iio_buffer_write_length); -- 1.7.7.3