From: Ian Abbott <abbotti@mev.co.uk>
Date: Fri, 10 May 2013 13:07:16 +0000 (+0100)
Subject: staging: comedi: complain if dma buffer allocation not supported
X-Git-Tag: MMI-PSA29.97-13-9~14348^2~18
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=e9166139f6f829c2e7bf6695f13e08d09303d6ca;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git

staging: comedi: complain if dma buffer allocation not supported

When allocating a buffer to support asynchronous comedi commands, if a
DMA coherent buffer was requested but `CONFIG_HAS_DMA` is undefined,
bail out of local helper function `__comedi_buf_alloc()` with an error
message.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c
index b6cd67ad55d1..d4be0e68509b 100644
--- a/drivers/staging/comedi/comedi_buf.c
+++ b/drivers/staging/comedi/comedi_buf.c
@@ -76,6 +76,12 @@ static void __comedi_buf_alloc(struct comedi_device *dev,
 	struct comedi_buf_page *buf;
 	unsigned i;
 
+	if (!IS_ENABLED(CONFIG_HAS_DMA) && s->async_dma_dir != DMA_NONE) {
+		dev_err(dev->class_dev,
+			"dma buffer allocation not supported\n");
+		return;
+	}
+
 	async->buf_page_list = vzalloc(sizeof(*buf) * n_pages);
 	if (async->buf_page_list)
 		pages = vmalloc(sizeof(struct page *) * n_pages);