Commit c67f1fd2 authored by Al Viro's avatar Al Viro
Browse files

csum_and_copy_to_iter(): handle ITER_DISCARD 



Not hard to implement - we are not copying anything here, so
csum_and_memcpy() is not usable, but calculating a checksum
of source directly is trivial...

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 40a86061

lib/iov_iter.c

+6 −2
Original line number Diff line number Diff line
@@ -1549,8 +1549,12 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 
	__wsum sum, next;



	if (unlikely(iov_iter_is_discard(i))) {

		WARN_ON(1);	/* for now */

		return 0;

		// can't use csum_memcpy() for that one - data is not copied

		csstate->csum = csum_block_add(csstate->csum,

					       csum_partial(addr, bytes, 0),

					       csstate->off);

		csstate->off += bytes;

		return bytes;

	}



	sum = csum_shift(csstate->csum, csstate->off);