staging: comedi: refactor sysfs files in comedi_fops.c

Refactor the sysfs attributes and functions to remove
the need for the forward declarations and use the
DEVICE_ATTR macro to define them.

Instead of individually creating sysfs device attribute
files, wrap them in an attribute_group and use the
sysfs_create_group function to create them.

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

1 files changed, 294 insertions, 365 deletions

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 06fc6569c859..44ca1feebe24 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -129,15 +129,295 @@ static int do_cancel(struct comedi_device *dev, struct comedi_subdevice *s);
 static int comedi_fasync(int fd, struct file *file, int on);
 
 static int is_device_busy(struct comedi_device *dev);
+
 static int resize_async_buffer(struct comedi_device *dev,
                                struct comedi_subdevice *s,
-                               struct comedi_async *async, unsigned new_size);
+                               struct comedi_async *async, unsigned new_size)
+{
+        int retval;
+
+        if (new_size > async->max_bufsize)
+                return -EPERM;
+
+        if (s->busy) {
+                DPRINTK("subdevice is busy, cannot resize buffer\n");
+                return -EBUSY;
+        }
+        if (async->mmap_count) {
+                DPRINTK("subdevice is mmapped, cannot resize buffer\n");
+                return -EBUSY;
+        }
+
+        if (!async->prealloc_buf)
+                return -EINVAL;
 
-/* declarations for sysfs attribute files */
-static struct device_attribute dev_attr_max_read_buffer_kb;
-static struct device_attribute dev_attr_read_buffer_kb;
-static struct device_attribute dev_attr_max_write_buffer_kb;
-static struct device_attribute dev_attr_write_buffer_kb;
+        /* make sure buffer is an integral number of pages
+         * (we round up) */
+        new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
+
+        retval = comedi_buf_alloc(dev, s, new_size);
+        if (retval < 0)
+                return retval;
+
+        if (s->buf_change) {
+                retval = s->buf_change(dev, s, new_size);
+                if (retval < 0)
+                        return retval;
+        }
+
+        DPRINTK("comedi%i subd %d buffer resized to %i bytes\n",
+                dev->minor, (int)(s - dev->subdevices), async->prealloc_bufsz);
+        return 0;
+}
+
+/* sysfs attribute files */
+
+static const unsigned bytes_per_kibi = 1024;
+
+static ssize_t show_max_read_buffer_kb(struct device *dev,
+                                       struct device_attribute *attr, char *buf)
+{
+        ssize_t retval;
+        struct comedi_device_file_info *info = dev_get_drvdata(dev);
+        unsigned max_buffer_size_kb = 0;
+        struct comedi_subdevice *const read_subdevice =
+            comedi_get_read_subdevice(info);
+
+        mutex_lock(&info->device->mutex);
+        if (read_subdevice &&
+            (read_subdevice->subdev_flags & SDF_CMD_READ) &&
+            read_subdevice->async) {
+                max_buffer_size_kb = read_subdevice->async->max_bufsize /
+                    bytes_per_kibi;
+        }
+        retval = snprintf(buf, PAGE_SIZE, "%i\n", max_buffer_size_kb);
+        mutex_unlock(&info->device->mutex);
+
+        return retval;
+}
+
+static ssize_t store_max_read_buffer_kb(struct device *dev,
+                                        struct device_attribute *attr,
+                                        const char *buf, size_t count)
+{
+        struct comedi_device_file_info *info = dev_get_drvdata(dev);
+        unsigned int new_max_size_kb;
+        unsigned int new_max_size;
+        int ret;
+        struct comedi_subdevice *const read_subdevice =
+            comedi_get_read_subdevice(info);
+
+        ret = kstrtouint(buf, 10, &new_max_size_kb);
+        if (ret)
+                return ret;
+        if (new_max_size_kb > (UINT_MAX / bytes_per_kibi))
+                return -EINVAL;
+        new_max_size = new_max_size_kb * bytes_per_kibi;
+
+        mutex_lock(&info->device->mutex);
+        if (read_subdevice == NULL ||
+            (read_subdevice->subdev_flags & SDF_CMD_READ) == 0 ||
+            read_subdevice->async == NULL) {
+                mutex_unlock(&info->device->mutex);
+                return -EINVAL;
+        }
+        read_subdevice->async->max_bufsize = new_max_size;
+        mutex_unlock(&info->device->mutex);
+
+        return count;
+}
+
+static DEVICE_ATTR(max_read_buffer_kb, S_IRUGO | S_IWUSR,
+                show_max_read_buffer_kb, store_max_read_buffer_kb);
+
+static ssize_t show_read_buffer_kb(struct device *dev,
+                                   struct device_attribute *attr, char *buf)
+{
+        ssize_t retval;
+        struct comedi_device_file_info *info = dev_get_drvdata(dev);
+        unsigned buffer_size_kb = 0;
+        struct comedi_subdevice *const read_subdevice =
+            comedi_get_read_subdevice(info);
+
+        mutex_lock(&info->device->mutex);
+        if (read_subdevice &&
+            (read_subdevice->subdev_flags & SDF_CMD_READ) &&
+            read_subdevice->async) {
+                buffer_size_kb = read_subdevice->async->prealloc_bufsz /
+                    bytes_per_kibi;
+        }
+        retval = snprintf(buf, PAGE_SIZE, "%i\n", buffer_size_kb);
+        mutex_unlock(&info->device->mutex);
+
+        return retval;
+}
+
+static ssize_t store_read_buffer_kb(struct device *dev,
+                                    struct device_attribute *attr,
+                                    const char *buf, size_t count)
+{
+        struct comedi_device_file_info *info = dev_get_drvdata(dev);
+        unsigned int new_size_kb;
+        unsigned int new_size;
+        int retval;
+        int ret;
+        struct comedi_subdevice *const read_subdevice =
+            comedi_get_read_subdevice(info);
+
+        ret = kstrtouint(buf, 10, &new_size_kb);
+        if (ret)
+                return ret;
+        if (new_size_kb > (UINT_MAX / bytes_per_kibi))
+                return -EINVAL;
+        new_size = new_size_kb * bytes_per_kibi;
+
+        mutex_lock(&info->device->mutex);
+        if (read_subdevice == NULL ||
+            (read_subdevice->subdev_flags & SDF_CMD_READ) == 0 ||
+            read_subdevice->async == NULL) {
+                mutex_unlock(&info->device->mutex);
+                return -EINVAL;
+        }
+        retval = resize_async_buffer(info->device, read_subdevice,
+                                     read_subdevice->async, new_size);
+        mutex_unlock(&info->device->mutex);
+
+        if (retval < 0)
+                return retval;
+        return count;
+}
+
+static DEVICE_ATTR(read_buffer_kb, S_IRUGO | S_IWUSR | S_IWGRP,
+                show_read_buffer_kb, store_read_buffer_kb);
+
+static ssize_t show_max_write_buffer_kb(struct device *dev,
+                                        struct device_attribute *attr,
+                                        char *buf)
+{
+        ssize_t retval;
+        struct comedi_device_file_info *info = dev_get_drvdata(dev);
+        unsigned max_buffer_size_kb = 0;
+        struct comedi_subdevice *const write_subdevice =
+            comedi_get_write_subdevice(info);
+
+        mutex_lock(&info->device->mutex);
+        if (write_subdevice &&
+            (write_subdevice->subdev_flags & SDF_CMD_WRITE) &&
+            write_subdevice->async) {
+                max_buffer_size_kb = write_subdevice->async->max_bufsize /
+                    bytes_per_kibi;
+        }
+        retval = snprintf(buf, PAGE_SIZE, "%i\n", max_buffer_size_kb);
+        mutex_unlock(&info->device->mutex);
+
+        return retval;
+}
+
+static ssize_t store_max_write_buffer_kb(struct device *dev,
+                                         struct device_attribute *attr,
+                                         const char *buf, size_t count)
+{
+        struct comedi_device_file_info *info = dev_get_drvdata(dev);
+        unsigned int new_max_size_kb;
+        unsigned int new_max_size;
+        int ret;
+        struct comedi_subdevice *const write_subdevice =
+            comedi_get_write_subdevice(info);
+
+        ret = kstrtouint(buf, 10, &new_max_size_kb);
+        if (ret)
+                return ret;
+        if (new_max_size_kb > (UINT_MAX / bytes_per_kibi))
+                return -EINVAL;
+        new_max_size = new_max_size_kb * bytes_per_kibi;
+
+        mutex_lock(&info->device->mutex);
+        if (write_subdevice == NULL ||
+            (write_subdevice->subdev_flags & SDF_CMD_WRITE) == 0 ||
+            write_subdevice->async == NULL) {
+                mutex_unlock(&info->device->mutex);
+                return -EINVAL;
+        }
+        write_subdevice->async->max_bufsize = new_max_size;
+        mutex_unlock(&info->device->mutex);
+
+        return count;
+}
+
+static DEVICE_ATTR(max_write_buffer_kb, S_IRUGO | S_IWUSR,
+                show_max_write_buffer_kb, store_max_write_buffer_kb);
+
+static ssize_t show_write_buffer_kb(struct device *dev,
+                                    struct device_attribute *attr, char *buf)
+{
+        ssize_t retval;
+        struct comedi_device_file_info *info = dev_get_drvdata(dev);
+        unsigned buffer_size_kb = 0;
+        struct comedi_subdevice *const write_subdevice =
+            comedi_get_write_subdevice(info);
+
+        mutex_lock(&info->device->mutex);
+        if (write_subdevice &&
+            (write_subdevice->subdev_flags & SDF_CMD_WRITE) &&
+            write_subdevice->async) {
+                buffer_size_kb = write_subdevice->async->prealloc_bufsz /
+                    bytes_per_kibi;
+        }
+        retval = snprintf(buf, PAGE_SIZE, "%i\n", buffer_size_kb);
+        mutex_unlock(&info->device->mutex);
+
+        return retval;
+}
+
+static ssize_t store_write_buffer_kb(struct device *dev,
+                                     struct device_attribute *attr,
+                                     const char *buf, size_t count)
+{
+        struct comedi_device_file_info *info = dev_get_drvdata(dev);
+        unsigned int new_size_kb;
+        unsigned int new_size;
+        int retval;
+        int ret;
+        struct comedi_subdevice *const write_subdevice =
+            comedi_get_write_subdevice(info);
+
+        ret = kstrtouint(buf, 10, &new_size_kb);
+        if (ret)
+                return ret;
+        if (new_size_kb > (UINT_MAX / bytes_per_kibi))
+                return -EINVAL;
+        new_size = ((uint64_t) new_size_kb) * bytes_per_kibi;
+
+        mutex_lock(&info->device->mutex);
+        if (write_subdevice == NULL ||
+            (write_subdevice->subdev_flags & SDF_CMD_WRITE) == 0 ||
+            write_subdevice->async == NULL) {
+                mutex_unlock(&info->device->mutex);
+                return -EINVAL;
+        }
+        retval = resize_async_buffer(info->device, write_subdevice,
+                                     write_subdevice->async, new_size);
+        mutex_unlock(&info->device->mutex);
+
+        if (retval < 0)
+                return retval;
+        return count;
+}
+
+static DEVICE_ATTR(write_buffer_kb, S_IRUGO | S_IWUSR | S_IWGRP,
+                show_write_buffer_kb, store_write_buffer_kb);
+
+static struct attribute *comedi_attrs[] = {
+        &dev_attr_max_read_buffer_kb.attr,
+        &dev_attr_read_buffer_kb.attr,
+        &dev_attr_max_write_buffer_kb.attr,
+        &dev_attr_write_buffer_kb.attr,
+        NULL
+};
+
+static const struct attribute_group comedi_sysfs_files = {
+        .attrs  = comedi_attrs,
+};
 
 static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
                                   unsigned long arg)
@@ -2251,42 +2531,15 @@ int comedi_alloc_board_minor(struct device *hardware_device)
         if (!IS_ERR(csdev))
                 info->device->class_dev = csdev;
         dev_set_drvdata(csdev, info);
-        retval = device_create_file(csdev, &dev_attr_max_read_buffer_kb);
-        if (retval) {
-                printk(KERN_ERR
-                       "comedi: "
-                       "failed to create sysfs attribute file \"%s\".\n",
-                       dev_attr_max_read_buffer_kb.attr.name);
-                comedi_free_board_minor(i);
-                return retval;
-        }
-        retval = device_create_file(csdev, &dev_attr_read_buffer_kb);
-        if (retval) {
-                printk(KERN_ERR
-                       "comedi: "
-                       "failed to create sysfs attribute file \"%s\".\n",
-                       dev_attr_read_buffer_kb.attr.name);
-                comedi_free_board_minor(i);
-                return retval;
-        }
-        retval = device_create_file(csdev, &dev_attr_max_write_buffer_kb);
-        if (retval) {
-                printk(KERN_ERR
-                       "comedi: "
-                       "failed to create sysfs attribute file \"%s\".\n",
-                       dev_attr_max_write_buffer_kb.attr.name);
-                comedi_free_board_minor(i);
-                return retval;
-        }
-        retval = device_create_file(csdev, &dev_attr_write_buffer_kb);
+
+        retval = sysfs_create_group(&csdev->kobj, &comedi_sysfs_files);
         if (retval) {
                 printk(KERN_ERR
-                       "comedi: "
-                       "failed to create sysfs attribute file \"%s\".\n",
-                       dev_attr_write_buffer_kb.attr.name);
+                       "comedi: failed to create sysfs attribute files\n");
                 comedi_free_board_minor(i);
                 return retval;
         }
+
         return i;
 }
 
@@ -2367,42 +2620,15 @@ int comedi_alloc_subdevice_minor(struct comedi_device *dev,
         if (!IS_ERR(csdev))
                 s->class_dev = csdev;
         dev_set_drvdata(csdev, info);
-        retval = device_create_file(csdev, &dev_attr_max_read_buffer_kb);
-        if (retval) {
-                printk(KERN_ERR
-                       "comedi: "
-                       "failed to create sysfs attribute file \"%s\".\n",
-                       dev_attr_max_read_buffer_kb.attr.name);
-                comedi_free_subdevice_minor(s);
-                return retval;
-        }
-        retval = device_create_file(csdev, &dev_attr_read_buffer_kb);
-        if (retval) {
-                printk(KERN_ERR
-                       "comedi: "
-                       "failed to create sysfs attribute file \"%s\".\n",
-                       dev_attr_read_buffer_kb.attr.name);
-                comedi_free_subdevice_minor(s);
-                return retval;
-        }
-        retval = device_create_file(csdev, &dev_attr_max_write_buffer_kb);
-        if (retval) {
-                printk(KERN_ERR
-                       "comedi: "
-                       "failed to create sysfs attribute file \"%s\".\n",
-                       dev_attr_max_write_buffer_kb.attr.name);
-                comedi_free_subdevice_minor(s);
-                return retval;
-        }
-        retval = device_create_file(csdev, &dev_attr_write_buffer_kb);
+
+        retval = sysfs_create_group(&csdev->kobj, &comedi_sysfs_files);
         if (retval) {
                 printk(KERN_ERR
-                       "comedi: "
-                       "failed to create sysfs attribute file \"%s\".\n",
-                       dev_attr_write_buffer_kb.attr.name);
+                       "comedi: failed to create sysfs attribute files\n");
                 comedi_free_subdevice_minor(s);
                 return retval;
         }
+
         return i;
 }
 
@@ -2441,300 +2667,3 @@ struct comedi_device_file_info *comedi_get_device_file_info(unsigned minor)
         return info;
 }
 EXPORT_SYMBOL_GPL(comedi_get_device_file_info);
-
-static int resize_async_buffer(struct comedi_device *dev,
-                               struct comedi_subdevice *s,
-                               struct comedi_async *async, unsigned new_size)
-{
-        int retval;
-
-        if (new_size > async->max_bufsize)
-                return -EPERM;
-
-        if (s->busy) {
-                DPRINTK("subdevice is busy, cannot resize buffer\n");
-                return -EBUSY;
-        }
-        if (async->mmap_count) {
-                DPRINTK("subdevice is mmapped, cannot resize buffer\n");
-                return -EBUSY;
-        }
-
-        if (!async->prealloc_buf)
-                return -EINVAL;
-
-        /* make sure buffer is an integral number of pages
-         * (we round up) */
-        new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
-
-        retval = comedi_buf_alloc(dev, s, new_size);
-        if (retval < 0)
-                return retval;
-
-        if (s->buf_change) {
-                retval = s->buf_change(dev, s, new_size);
-                if (retval < 0)
-                        return retval;
-        }
-
-        DPRINTK("comedi%i subd %d buffer resized to %i bytes\n",
-                dev->minor, (int)(s - dev->subdevices), async->prealloc_bufsz);
-        return 0;
-}
-
-/* sysfs attribute files */
-
-static const unsigned bytes_per_kibi = 1024;
-
-static ssize_t show_max_read_buffer_kb(struct device *dev,
-                                       struct device_attribute *attr, char *buf)
-{
-        ssize_t retval;
-        struct comedi_device_file_info *info = dev_get_drvdata(dev);
-        unsigned max_buffer_size_kb = 0;
-        struct comedi_subdevice *const read_subdevice =
-            comedi_get_read_subdevice(info);
-
-        mutex_lock(&info->device->mutex);
-        if (read_subdevice &&
-            (read_subdevice->subdev_flags & SDF_CMD_READ) &&
-            read_subdevice->async) {
-                max_buffer_size_kb = read_subdevice->async->max_bufsize /
-                    bytes_per_kibi;
-        }
-        retval = snprintf(buf, PAGE_SIZE, "%i\n", max_buffer_size_kb);
-        mutex_unlock(&info->device->mutex);
-
-        return retval;
-}
-
-static ssize_t store_max_read_buffer_kb(struct device *dev,
-                                        struct device_attribute *attr,
-                                        const char *buf, size_t count)
-{
-        struct comedi_device_file_info *info = dev_get_drvdata(dev);
-        unsigned int new_max_size_kb;
-        unsigned int new_max_size;
-        int ret;
-        struct comedi_subdevice *const read_subdevice =
-            comedi_get_read_subdevice(info);
-
-        ret = kstrtouint(buf, 10, &new_max_size_kb);
-        if (ret)
-                return ret;
-        if (new_max_size_kb > (UINT_MAX / bytes_per_kibi))
-                return -EINVAL;
-        new_max_size = new_max_size_kb * bytes_per_kibi;
-
-        mutex_lock(&info->device->mutex);
-        if (read_subdevice == NULL ||
-            (read_subdevice->subdev_flags & SDF_CMD_READ) == 0 ||
-            read_subdevice->async == NULL) {
-                mutex_unlock(&info->device->mutex);
-                return -EINVAL;
-        }
-        read_subdevice->async->max_bufsize = new_max_size;
-        mutex_unlock(&info->device->mutex);
-
-        return count;
-}
-
-static struct device_attribute dev_attr_max_read_buffer_kb = {
-        .attr = {
-                 .name = "max_read_buffer_kb",
-                 .mode = S_IRUGO | S_IWUSR},
-        .show = &show_max_read_buffer_kb,
-        .store = &store_max_read_buffer_kb
-};
-
-static ssize_t show_read_buffer_kb(struct device *dev,
-                                   struct device_attribute *attr, char *buf)
-{
-        ssize_t retval;
-        struct comedi_device_file_info *info = dev_get_drvdata(dev);
-        unsigned buffer_size_kb = 0;
-        struct comedi_subdevice *const read_subdevice =
-            comedi_get_read_subdevice(info);
-
-        mutex_lock(&info->device->mutex);
-        if (read_subdevice &&
-            (read_subdevice->subdev_flags & SDF_CMD_READ) &&
-            read_subdevice->async) {
-                buffer_size_kb = read_subdevice->async->prealloc_bufsz /
-                    bytes_per_kibi;
-        }
-        retval = snprintf(buf, PAGE_SIZE, "%i\n", buffer_size_kb);
-        mutex_unlock(&info->device->mutex);
-
-        return retval;
-}
-
-static ssize_t store_read_buffer_kb(struct device *dev,
-                                    struct device_attribute *attr,
-                                    const char *buf, size_t count)
-{
-        struct comedi_device_file_info *info = dev_get_drvdata(dev);
-        unsigned int new_size_kb;
-        unsigned int new_size;
-        int retval;
-        int ret;
-        struct comedi_subdevice *const read_subdevice =
-            comedi_get_read_subdevice(info);
-
-        ret = kstrtouint(buf, 10, &new_size_kb);
-        if (ret)
-                return ret;
-        if (new_size_kb > (UINT_MAX / bytes_per_kibi))
-                return -EINVAL;
-        new_size = new_size_kb * bytes_per_kibi;
-
-        mutex_lock(&info->device->mutex);
-        if (read_subdevice == NULL ||
-            (read_subdevice->subdev_flags & SDF_CMD_READ) == 0 ||
-            read_subdevice->async == NULL) {
-                mutex_unlock(&info->device->mutex);
-                return -EINVAL;
-        }
-        retval = resize_async_buffer(info->device, read_subdevice,
-                                     read_subdevice->async, new_size);
-        mutex_unlock(&info->device->mutex);
-
-        if (retval < 0)
-                return retval;
-        return count;
-}
-
-static struct device_attribute dev_attr_read_buffer_kb = {
-        .attr = {
-                 .name = "read_buffer_kb",
-                 .mode = S_IRUGO | S_IWUSR | S_IWGRP},
-        .show = &show_read_buffer_kb,
-        .store = &store_read_buffer_kb
-};
-
-static ssize_t show_max_write_buffer_kb(struct device *dev,
-                                        struct device_attribute *attr,
-                                        char *buf)
-{
-        ssize_t retval;
-        struct comedi_device_file_info *info = dev_get_drvdata(dev);
-        unsigned max_buffer_size_kb = 0;
-        struct comedi_subdevice *const write_subdevice =
-            comedi_get_write_subdevice(info);
-
-        mutex_lock(&info->device->mutex);
-        if (write_subdevice &&
-            (write_subdevice->subdev_flags & SDF_CMD_WRITE) &&
-            write_subdevice->async) {
-                max_buffer_size_kb = write_subdevice->async->max_bufsize /
-                    bytes_per_kibi;
-        }
-        retval = snprintf(buf, PAGE_SIZE, "%i\n", max_buffer_size_kb);
-        mutex_unlock(&info->device->mutex);
-
-        return retval;
-}
-
-static ssize_t store_max_write_buffer_kb(struct device *dev,
-                                         struct device_attribute *attr,
-                                         const char *buf, size_t count)
-{
-        struct comedi_device_file_info *info = dev_get_drvdata(dev);
-        unsigned int new_max_size_kb;
-        unsigned int new_max_size;
-        int ret;
-        struct comedi_subdevice *const write_subdevice =
-            comedi_get_write_subdevice(info);
-
-        ret = kstrtouint(buf, 10, &new_max_size_kb);
-        if (ret)
-                return ret;
-        if (new_max_size_kb > (UINT_MAX / bytes_per_kibi))
-                return -EINVAL;
-        new_max_size = new_max_size_kb * bytes_per_kibi;
-
-        mutex_lock(&info->device->mutex);
-        if (write_subdevice == NULL ||
-            (write_subdevice->subdev_flags & SDF_CMD_WRITE) == 0 ||
-            write_subdevice->async == NULL) {
-                mutex_unlock(&info->device->mutex);
-                return -EINVAL;
-        }
-        write_subdevice->async->max_bufsize = new_max_size;
-        mutex_unlock(&info->device->mutex);
-
-        return count;
-}
-
-static struct device_attribute dev_attr_max_write_buffer_kb = {
-        .attr = {
-                 .name = "max_write_buffer_kb",
-                 .mode = S_IRUGO | S_IWUSR},
-        .show = &show_max_write_buffer_kb,
-        .store = &store_max_write_buffer_kb
-};
-
-static ssize_t show_write_buffer_kb(struct device *dev,
-                                    struct device_attribute *attr, char *buf)
-{
-        ssize_t retval;
-        struct comedi_device_file_info *info = dev_get_drvdata(dev);
-        unsigned buffer_size_kb = 0;
-        struct comedi_subdevice *const write_subdevice =
-            comedi_get_write_subdevice(info);
-
-        mutex_lock(&info->device->mutex);
-        if (write_subdevice &&
-            (write_subdevice->subdev_flags & SDF_CMD_WRITE) &&
-            write_subdevice->async) {
-                buffer_size_kb = write_subdevice->async->prealloc_bufsz /
-                    bytes_per_kibi;
-        }
-        retval = snprintf(buf, PAGE_SIZE, "%i\n", buffer_size_kb);
-        mutex_unlock(&info->device->mutex);
-
-        return retval;
-}
-
-static ssize_t store_write_buffer_kb(struct device *dev,
-                                     struct device_attribute *attr,
-                                     const char *buf, size_t count)
-{
-        struct comedi_device_file_info *info = dev_get_drvdata(dev);
-        unsigned int new_size_kb;
-        unsigned int new_size;
-        int retval;
-        int ret;
-        struct comedi_subdevice *const write_subdevice =
-            comedi_get_write_subdevice(info);
-
-        ret = kstrtouint(buf, 10, &new_size_kb);
-        if (ret)
-                return ret;
-        if (new_size_kb > (UINT_MAX / bytes_per_kibi))
-                return -EINVAL;
-        new_size = ((uint64_t) new_size_kb) * bytes_per_kibi;
-
-        mutex_lock(&info->device->mutex);
-        if (write_subdevice == NULL ||
-            (write_subdevice->subdev_flags & SDF_CMD_WRITE) == 0 ||
-            write_subdevice->async == NULL) {
-                mutex_unlock(&info->device->mutex);
-                return -EINVAL;
-        }
-        retval = resize_async_buffer(info->device, write_subdevice,
-                                     write_subdevice->async, new_size);
-        mutex_unlock(&info->device->mutex);
-
-        if (retval < 0)
-                return retval;
-        return count;
-}
-
-static struct device_attribute dev_attr_write_buffer_kb = {
-        .attr = {
-                 .name = "write_buffer_kb",
-                 .mode = S_IRUGO | S_IWUSR | S_IWGRP},
-        .show = &show_write_buffer_kb,
-        .store = &store_write_buffer_kb
-};