fs/configfs/file.c

56 static int fill_read_buffer(struct file *file, struct configfs_buffer *buffer)
61 	if (!buffer->page)
62 		buffer->page = (char *) get_zeroed_page(GFP_KERNEL);
63 	if (!buffer->page)
68 		count = buffer->attr->show(buffer->item, buffer->page);
75 	buffer->needs_read_fill = 0;
76 	buffer->count = count;
83 	struct configfs_buffer *buffer = file->private_data;
86 	mutex_lock(&buffer->mutex);
87 	if (buffer->needs_read_fill) {
88 		retval = fill_read_buffer(file, buffer);
93 		 __func__, iov_iter_count(to), iocb->ki_pos, buffer->page);
94 	if (iocb->ki_pos >= buffer->count)
96 	retval = copy_to_iter(buffer->page + iocb->ki_pos,
97 			      buffer->count - iocb->ki_pos, to);
102 	mutex_unlock(&buffer->mutex);
110 	struct configfs_buffer *buffer = file->private_data;
114 	mutex_lock(&buffer->mutex);
117 	if (buffer->write_in_progress) {
121 	buffer->read_in_progress = true;
123 	if (buffer->needs_read_fill) {
127 			len = buffer->bin_attr->read(buffer->item, NULL, 0);
137 		if (buffer->cb_max_size && len > buffer->cb_max_size) {
142 		buffer->bin_buffer = vmalloc(len);
143 		if (buffer->bin_buffer == NULL) {
147 		buffer->bin_buffer_size = len;
149 		/* perform second read to fill buffer */
152 			len = buffer->bin_attr->read(buffer->item,
153 						     buffer->bin_buffer, len);
159 			vfree(buffer->bin_buffer);
160 			buffer->bin_buffer_size = 0;
161 			buffer->bin_buffer = NULL;
165 		buffer->needs_read_fill = 0;
168 	if (iocb->ki_pos >= buffer->bin_buffer_size)
170 	retval = copy_to_iter(buffer->bin_buffer + iocb->ki_pos,
171 			      buffer->bin_buffer_size - iocb->ki_pos, to);
176 	mutex_unlock(&buffer->mutex);
180 /* Fill @buffer with data coming from @from. */
181 static int fill_write_buffer(struct configfs_buffer *buffer,
186 	if (!buffer->page)
187 		buffer->page = (char *)__get_free_pages(GFP_KERNEL, 0);
188 	if (!buffer->page)
191 	copied = copy_from_iter(buffer->page, SIMPLE_ATTR_SIZE - 1, from);
192 	buffer->needs_read_fill = 1;
195 	buffer->page[copied] = 0;
200 flush_write_buffer(struct file *file, struct configfs_buffer *buffer, size_t count)
207 		res = buffer->attr->store(buffer->item, buffer->page, count);
215  * write, so we don't support them. We expect the entire buffer to come on the
218  * you're changing, then write entire buffer back.
223 	struct configfs_buffer *buffer = file->private_data;
226 	mutex_lock(&buffer->mutex);
227 	len = fill_write_buffer(buffer, from);
229 		len = flush_write_buffer(file, buffer, len);
232 	mutex_unlock(&buffer->mutex);
240 	struct configfs_buffer *buffer = file->private_data;
245 	mutex_lock(&buffer->mutex);
248 	if (buffer->read_in_progress) {
252 	buffer->write_in_progress = true;
254 	/* buffer grows? */
256 	if (end_offset > buffer->bin_buffer_size) {
257 		if (buffer->cb_max_size && end_offset > buffer->cb_max_size) {
269 		if (buffer->bin_buffer) {
270 			memcpy(tbuf, buffer->bin_buffer,
271 				buffer->bin_buffer_size);
272 			vfree(buffer->bin_buffer);
276 		memset(tbuf + buffer->bin_buffer_size, 0,
277 			end_offset - buffer->bin_buffer_size);
278 		buffer->bin_buffer = tbuf;
279 		buffer->bin_buffer_size = end_offset;
282 	len = copy_from_iter(buffer->bin_buffer + iocb->ki_pos,
283 			     buffer->bin_buffer_size - iocb->ki_pos, from);
286 	mutex_unlock(&buffer->mutex);
295 	struct configfs_buffer *buffer;
299 	buffer = kzalloc(sizeof(struct configfs_buffer), GFP_KERNEL);
300 	if (!buffer)
309 	buffer->item = to_item(dentry->d_parent);
310 	if (!buffer->item)
318 		buffer->bin_attr = to_bin_attr(dentry);
319 		buffer->cb_max_size = buffer->bin_attr->cb_max_size;
321 		buffer->attr = attr;
324 	buffer->owner = attr->ca_owner;
327 	if (!try_module_get(buffer->owner))
331 	if (!buffer->item->ci_type)
334 	buffer->ops = buffer->item->ci_type->ct_item_ops;
345 		if ((type & CONFIGFS_ITEM_BIN_ATTR) && !buffer->bin_attr->write)
358 		if ((type & CONFIGFS_ITEM_BIN_ATTR) && !buffer->bin_attr->read)
362 	mutex_init(&buffer->mutex);
363 	buffer->needs_read_fill = 1;
364 	buffer->read_in_progress = false;
365 	buffer->write_in_progress = false;
366 	file->private_data = buffer;
371 	module_put(buffer->owner);
374 	kfree(buffer);
381 	struct configfs_buffer *buffer = filp->private_data;
383 	module_put(buffer->owner);
384 	if (buffer->page)
385 		free_page((unsigned long)buffer->page);
386 	mutex_destroy(&buffer->mutex);
387 	kfree(buffer);
403 	struct configfs_buffer *buffer = file->private_data;
405 	if (buffer->write_in_progress) {
411 			buffer->bin_attr->write(buffer->item,
412 					buffer->bin_buffer,
413 					buffer->bin_buffer_size);
418 	vfree(buffer->bin_buffer);