staging: comedi: pcl812: tidy up dma buffer allocation

This driver uses 2 buffers for DMA. Refactor the buffer allocation to
use a for loop to remove code duplication. Remove the dev_err() messages
when __get_dma_pages() fails and change the errno returned from -EBUSY
to -ENOMEM.

Both buffers are the same size so replace the 'dmapages' and 'hwdmasize'
arrays in the private data with variables to save a bit of space.

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

diff --git a/drivers/staging/comedi/drivers/pcl812.c b/drivers/staging/comedi/drivers/pcl812.c
index b2a5a43..9ff15b0 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl812.c
+++ b/drivers/staging/comedi/drivers/pcl812.c
@@ -522,10 +522,10 @@ struct pcl812_private {
        unsigned int ai_act_scan;       /*  how many scans we finished */
        unsigned int ai_chanlist[MAX_CHANLIST_LEN];     /*  our copy of channel/range list */
        unsigned int ai_data_len;       /*  len of data buffer */
+       unsigned int dmapages;
+       unsigned int hwdmasize;
        unsigned long dmabuf[2];        /*  PTR to DMA buf */
-       unsigned int dmapages[2];       /*  how many pages we have allocated */
        unsigned int hwdmaptr[2];       /*  HW PTR to DMA buf */
-       unsigned int hwdmasize[2];      /*  DMA buf size in bytes */
        unsigned int dmabytestomove[2]; /*  how many bytes DMA transfer */
        int next_dma_buf;       /*  which buffer is next to use */
        unsigned int dma_runs_to_end;   /*  how many times we must switch DMA buffers */
@@ -814,14 +814,14 @@ static int pcl812_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
                            cmd->chanlist_len * sizeof(short);
                        devpriv->dma_runs_to_end = 1;
                } else {
-                       devpriv->dmabytestomove[0] = devpriv->hwdmasize[0];
-                       devpriv->dmabytestomove[1] = devpriv->hwdmasize[1];
-                       if (devpriv->ai_data_len < devpriv->hwdmasize[0])
+                       devpriv->dmabytestomove[0] = devpriv->hwdmasize;
+                       devpriv->dmabytestomove[1] = devpriv->hwdmasize;
+                       if (devpriv->ai_data_len < devpriv->hwdmasize) {
                                devpriv->dmabytestomove[0] =
                                    devpriv->ai_data_len;
-                       if (devpriv->ai_data_len < devpriv->hwdmasize[1])
                                devpriv->dmabytestomove[1] =
                                    devpriv->ai_data_len;
+                       }
                        if (devpriv->ai_neverending) {
                                devpriv->dma_runs_to_end = 1;
                        } else {
@@ -842,12 +842,12 @@ static int pcl812_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
                                devpriv->dma_runs_to_end--;
                        }
                }
-               if (devpriv->dmabytestomove[0] > devpriv->hwdmasize[0]) {
-                       devpriv->dmabytestomove[0] = devpriv->hwdmasize[0];
+               if (devpriv->dmabytestomove[0] > devpriv->hwdmasize) {
+                       devpriv->dmabytestomove[0] = devpriv->hwdmasize;
                        devpriv->ai_eos = 0;
                }
-               if (devpriv->dmabytestomove[1] > devpriv->hwdmasize[1]) {
-                       devpriv->dmabytestomove[1] = devpriv->hwdmasize[1];
+               if (devpriv->dmabytestomove[1] > devpriv->hwdmasize) {
+                       devpriv->dmabytestomove[1] = devpriv->hwdmasize;
                        devpriv->ai_eos = 0;
                }
                devpriv->next_dma_buf = 0;
@@ -1303,10 +1303,11 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 {
        const struct pcl812_board *board = comedi_board(dev);
        struct pcl812_private *devpriv;
-       int ret, subdev;
-       unsigned long pages;
        struct comedi_subdevice *s;
        int n_subdevices;
+       int subdev;
+       int ret;
+       int i;
 
        ret = comedi_request_region(dev, it->options[0], 0x10);
        if (ret)
@@ -1335,29 +1336,19 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
                }
                devpriv->dma = it->options[2];
 
-               pages = 1;      /* we want 8KB */
-               devpriv->dmabuf[0] = __get_dma_pages(GFP_KERNEL, pages);
-               if (!devpriv->dmabuf[0]) {
-                       dev_err(dev->class_dev,
-                               "unable to allocate DMA buffer, FAIL!\n");
-                       /*
-                        * maybe experiment with try_to_free_pages()
-                        * will help ....
-                        */
-                       return -EBUSY;  /* no buffer :-( */
-               }
-               devpriv->dmapages[0] = pages;
-               devpriv->hwdmaptr[0] = virt_to_bus((void *)devpriv->dmabuf[0]);
-               devpriv->hwdmasize[0] = PAGE_SIZE * (1 << pages);
-               devpriv->dmabuf[1] = __get_dma_pages(GFP_KERNEL, pages);
-               if (!devpriv->dmabuf[1]) {
-                       dev_err(dev->class_dev,
-                               "unable to allocate DMA buffer, FAIL!\n");
-                       return -EBUSY;
+               devpriv->dmapages = 1;  /* we want 8KB */
+               devpriv->hwdmasize = (1 << devpriv->dmapages) * PAGE_SIZE;
+
+               for (i = 0; i < 2; i++) {
+                       unsigned long dmabuf;
+
+                       dmabuf =  __get_dma_pages(GFP_KERNEL, devpriv->dmapages);
+                       if (!dmabuf)
+                               return -ENOMEM;
+
+                       devpriv->dmabuf[i] = dmabuf;
+                       devpriv->hwdmaptr[i] = virt_to_bus((void *)dmabuf);
                }
-               devpriv->dmapages[1] = pages;
-               devpriv->hwdmaptr[1] = virt_to_bus((void *)devpriv->dmabuf[1]);
-               devpriv->hwdmasize[1] = PAGE_SIZE * (1 << pages);
        }
 
        /* differential analog inputs? */
@@ -1500,9 +1491,9 @@ static void pcl812_detach(struct comedi_device *dev)
 
        if (devpriv) {
                if (devpriv->dmabuf[0])
-                       free_pages(devpriv->dmabuf[0], devpriv->dmapages[0]);
+                       free_pages(devpriv->dmabuf[0], devpriv->dmapages);
                if (devpriv->dmabuf[1])
-                       free_pages(devpriv->dmabuf[1], devpriv->dmapages[1]);
+                       free_pages(devpriv->dmabuf[1], devpriv->dmapages);
                if (devpriv->dma)
                        free_dma(devpriv->dma);
        }