staging: comedi: comedi_fops: cleanup comedi_mmap()

Use comedi_dev_from_minor() to simplify the return -ENODEV tests.

Change the (foo == NULL) tests to simply (!foo).

Use a local variable to hold a pointer to the async->buf_page_list[]
when doing the remap_pfn_range(). This cleans up the ugly line breaks
for the page_to_pfn(virt_to_page(...) operation.

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

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 8d407ccd4ed4992daef366a3c539098598a23efd..2826a29479c2f093bd171597dcdf653a27ea8a7c 100644 (file)
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -1766,39 +1766,38 @@ static struct vm_operations_struct comedi_vm_ops = {
 static int comedi_mmap(struct file *file, struct vm_area_struct *vma)
 {
        const unsigned minor = iminor(file->f_dentry->d_inode);
-       struct comedi_async *async = NULL;
+       struct comedi_file_info *info = comedi_file_info_from_minor(minor);
+       struct comedi_device *dev = comedi_dev_from_minor(minor);
+       struct comedi_subdevice *s;
+       struct comedi_async *async;
        unsigned long start = vma->vm_start;
        unsigned long size;
        int n_pages;
        int i;
        int retval;
-       struct comedi_subdevice *s;
-       struct comedi_file_info *info = comedi_file_info_from_minor(minor);
-       struct comedi_device *dev;
 
-       if (info == NULL)
-               return -ENODEV;
-       dev = info->device;
-       if (dev == NULL)
+       if (!dev)
                return -ENODEV;
 
        mutex_lock(&dev->mutex);
+
        if (!dev->attached) {
                DPRINTK("no driver configured on comedi%i\n", dev->minor);
                retval = -ENODEV;
                goto done;
        }
+
        if (vma->vm_flags & VM_WRITE)
                s = comedi_write_subdevice(info);
        else
                s = comedi_read_subdevice(info);
-
-       if (s == NULL) {
+       if (!s) {
                retval = -EINVAL;
                goto done;
        }
+
        async = s->async;
-       if (async == NULL) {
+       if (!async) {
                retval = -EINVAL;
                goto done;
        }
@@ -1821,11 +1820,11 @@ static int comedi_mmap(struct file *file, struct vm_area_struct *vma)
 
        n_pages = size >> PAGE_SHIFT;
        for (i = 0; i < n_pages; ++i) {
+               struct comedi_buf_page *buf = &async->buf_page_list[i];
+
                if (remap_pfn_range(vma, start,
-                                   page_to_pfn(virt_to_page
-                                               (async->buf_page_list
-                                                [i].virt_addr)), PAGE_SIZE,
-                                   PAGE_SHARED)) {
+                                   page_to_pfn(virt_to_page(buf->virt_addr)),
+                                   PAGE_SIZE, PAGE_SHARED)) {
                        retval = -EAGAIN;
                        goto done;
                }