Merge commit '3ff195b011d7decf501a4d55aeed312731094796' into for-linus

Conflicts:
	drivers/md/md.c

- Resolved conflict in md_update_sb
- Added extra 'NULL' arg to new instance of sysfs_get_dirent.

Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 36 insertions, 0 deletions

diff --git a/fs/libfs.c b/fs/libfs.c
index 9e50bcf5585..232bea425b0 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -5,6 +5,7 @@
 
 #include <linux/module.h>
 #include <linux/pagemap.h>
+#include <linux/slab.h>
 #include <linux/mount.h>
 #include <linux/vfs.h>
 #include <linux/mutex.h>
@@ -546,6 +547,40 @@ ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
 }
 
 /**
+ * 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
@@ -863,6 +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);