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Commit 26978b8b authored by Al Viro's avatar Al Viro
Browse files

give ->direct_IO() a copy of iov_iter 



the thing is, we want to advance what's given to ->direct_IO() as we
are forming the request; however, the callers care about the amount
of data actually transferred, not the amount we tried to transfer.
It's more convenient to allow ->direct_IO() instances do use
iov_iter_advance() on the copy of iov_iter, leaving the actual
advancing of the original to caller.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 31b14039

mm/filemap.c

+7 −3
Original line number Diff line number Diff line
@@ -1699,8 +1699,10 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, 
		size = i_size_read(inode);

		retval = filemap_write_and_wait_range(mapping, pos,

					pos + count - 1);

		if (!retval)

			retval = mapping->a_ops->direct_IO(READ, iocb, &i, pos);

		if (!retval) {

			struct iov_iter data = i;

			retval = mapping->a_ops->direct_IO(READ, iocb, &data, pos);

		}



		if (retval > 0) {

			*ppos = pos + retval;
@@ -2351,6 +2353,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from, 
	ssize_t		written;

	size_t		write_len;

	pgoff_t		end;

	struct iov_iter data;



	if (count != ocount)

		from->nr_segs = iov_shorten((struct iovec *)from->iov, from->nr_segs, count);
@@ -2382,7 +2385,8 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from, 
		}

	}



	written = mapping->a_ops->direct_IO(WRITE, iocb, from, pos);

	data = *from;

	written = mapping->a_ops->direct_IO(WRITE, iocb, &data, pos);



	/*

	 * Finally, try again to invalidate clean pages which might have been