#include <linux/module.h>
#include <linux/pagemap.h>
+#include <linux/slab.h>
#include <linux/mount.h>
#include <linux/vfs.h>
#include <linux/mutex.h>
return 0;
}
-int simple_prepare_write(struct file *file, struct page *page,
- unsigned from, unsigned to)
-{
- if (!PageUptodate(page)) {
- if (to - from != PAGE_CACHE_SIZE)
- zero_user_segments(page,
- 0, from,
- to, PAGE_CACHE_SIZE);
- }
- return 0;
-}
-
int simple_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
struct page *page;
pgoff_t index;
- unsigned from;
index = pos >> PAGE_CACHE_SHIFT;
- from = pos & (PAGE_CACHE_SIZE - 1);
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page)
*pagep = page;
- return simple_prepare_write(file, page, from, from+len);
+ if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
+ unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+
+ zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE);
+ }
+ return 0;
}
/**
}
/**
+ * simple_write_to_buffer - copy data from user space to the buffer
+ * @to: the buffer to write to
+ * @available: the size of the buffer
+ * @ppos: the current position in the buffer
+ * @from: the user space buffer to read from
+ * @count: the maximum number of bytes to read
+ *
+ * The simple_write_to_buffer() function reads up to @count bytes from the user
+ * space address starting at @from into the buffer @to at offset @ppos.
+ *
+ * On success, the number of bytes written is returned and the offset @ppos is
+ * advanced by this number, or negative value is returned on error.
+ **/
+ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
+ const void __user *from, size_t count)
+{
+ loff_t pos = *ppos;
+ size_t res;
+
+ if (pos < 0)
+ return -EINVAL;
+ if (pos >= available || !count)
+ return 0;
+ if (count > available - pos)
+ count = available - pos;
+ res = copy_from_user(to + pos, from, count);
+ if (res == count)
+ return -EFAULT;
+ count -= res;
+ *ppos = pos + count;
+ return count;
+}
+
+/**
* memory_read_from_buffer - copy data from the buffer
* @to: the kernel space buffer to read to
* @count: the maximum number of bytes to read
EXPORT_SYMBOL(simple_link);
EXPORT_SYMBOL(simple_lookup);
EXPORT_SYMBOL(simple_pin_fs);
-EXPORT_UNUSED_SYMBOL(simple_prepare_write);
EXPORT_SYMBOL(simple_readpage);
EXPORT_SYMBOL(simple_release_fs);
EXPORT_SYMBOL(simple_rename);
EXPORT_SYMBOL(simple_sync_file);
EXPORT_SYMBOL(simple_unlink);
EXPORT_SYMBOL(simple_read_from_buffer);
+EXPORT_SYMBOL(simple_write_to_buffer);
EXPORT_SYMBOL(memory_read_from_buffer);
EXPORT_SYMBOL(simple_transaction_set);
EXPORT_SYMBOL(simple_transaction_get);