X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=fs%2Flibfs.c;h=232bea425b09155a1f116981e4e53283a1738bbc;hb=58a9d3d8db06ca2ec31f64ec49ab0aeb89971b85;hp=ea9a6cc9b35c6b08ef1517837d1c05a4d2da47e1;hpb=83163244f845c296a118ce85c653872dbff6abfe;p=pandora-kernel.git

diff --git a/fs/libfs.c b/fs/libfs.c
index ea9a6cc9b35c..232bea425b09 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -546,6 +546,40 @@ ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
 	return count;
 }
 
+/**
+ * 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
@@ -864,6 +898,7 @@ EXPORT_SYMBOL(simple_statfs);
 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);