new helper: __vfs_write()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 17 insertions, 12 deletions

diff --git a/fs/read_write.c b/fs/read_write.c
index 69128b378646..9d7952a6829b 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -527,6 +527,20 @@ ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, lo
 
 EXPORT_SYMBOL(new_sync_write);
 
+ssize_t __vfs_write(struct file *file, const char __user *p, size_t count,
+                    loff_t *pos)
+{
+        if (file->f_op->write)
+                return file->f_op->write(file, p, count, pos);
+        else if (file->f_op->aio_write)
+                return do_sync_write(file, p, count, pos);
+        else if (file->f_op->write_iter)
+                return new_sync_write(file, p, count, pos);
+        else
+                return -EINVAL;
+}
+EXPORT_SYMBOL(__vfs_write);
+
 ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t *pos)
 {
         mm_segment_t old_fs;
@@ -541,12 +555,7 @@ ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t
         p = (__force const char __user *)buf;
         if (count > MAX_RW_COUNT)
                 count =  MAX_RW_COUNT;
-        if (file->f_op->write)
-                ret = file->f_op->write(file, p, count, pos);
-        else if (file->f_op->aio_write)
-                ret = do_sync_write(file, p, count, pos);
-        else
-                ret = new_sync_write(file, p, count, pos);
+        ret = __vfs_write(file, p, count, pos);
         set_fs(old_fs);
         if (ret > 0) {
                 fsnotify_modify(file);
@@ -573,12 +582,7 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
         if (ret >= 0) {
                 count = ret;
                 file_start_write(file);
-                if (file->f_op->write)
-                        ret = file->f_op->write(file, buf, count, pos);
-                else if (file->f_op->aio_write)
-                        ret = do_sync_write(file, buf, count, pos);
-                else
-                        ret = new_sync_write(file, buf, count, pos);
+                ret = __vfs_write(file, buf, count, pos);
                 if (ret > 0) {
                         fsnotify_modify(file);
                         add_wchar(current, ret);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 20fe15fe236d..4a1cb00bd805 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1639,6 +1639,7 @@ ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
                               struct iovec **ret_pointer);
 
 extern ssize_t __vfs_read(struct file *, char __user *, size_t, loff_t *);
+extern ssize_t __vfs_write(struct file *, const char __user *, size_t, loff_t *);
 extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
 extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
 extern ssize_t vfs_readv(struct file *, const struct iovec __user *,