fs: add vfs_iter_{read,write} helpers

Simple helpers that pass an arbitrary iov_iter to filesystems.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/read_write.c b/fs/read_write.c
index c0805c9..ab4f26a 100644 (file)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -333,6 +333,52 @@ out_putf:
 }
 #endif
 
+ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos)
+{
+       struct kiocb kiocb;
+       ssize_t ret;
+
+       if (!file->f_op->read_iter)
+               return -EINVAL;
+
+       init_sync_kiocb(&kiocb, file);
+       kiocb.ki_pos = *ppos;
+       kiocb.ki_nbytes = iov_iter_count(iter);
+
+       iter->type |= READ;
+       ret = file->f_op->read_iter(&kiocb, iter);
+       if (ret == -EIOCBQUEUED)
+               ret = wait_on_sync_kiocb(&kiocb);
+
+       if (ret > 0)
+               *ppos = kiocb.ki_pos;
+       return ret;
+}
+EXPORT_SYMBOL(vfs_iter_read);
+
+ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos)
+{
+       struct kiocb kiocb;
+       ssize_t ret;
+
+       if (!file->f_op->write_iter)
+               return -EINVAL;
+
+       init_sync_kiocb(&kiocb, file);
+       kiocb.ki_pos = *ppos;
+       kiocb.ki_nbytes = iov_iter_count(iter);
+
+       iter->type |= WRITE;
+       ret = file->f_op->write_iter(&kiocb, iter);
+       if (ret == -EIOCBQUEUED)
+               ret = wait_on_sync_kiocb(&kiocb);
+
+       if (ret > 0)
+               *ppos = kiocb.ki_pos;
+       return ret;
+}
+EXPORT_SYMBOL(vfs_iter_write);
+
 /*
  * rw_verify_area doesn't like huge counts. We limit
  * them to something that fits in "int" so that others

diff --cc fs/splice.c
Simple merge

diff --cc include/linux/fs.h
Simple merge