Commit 610c7a71 authored by Al Viro's avatar Al Viro
Browse files

iov_iter_gap_alignment(): get rid of iterate_all_kinds() 



For one thing, it's only used for iovec (and makes sense only for those).
For another, here we don't care about iov_offset, since the beginning of
the first segment and the end of the last one are ignored.  So it makes
a lot more sense to just walk through the iovec array...

We need to deal with the case of truncated iov_iter, but unlike the
situation with iov_iter_alignment() we don't care where the last
segment ends - just which segment is the last one.

[fixed a braino spotted by Qian Cai <quic_qiancai@quicinc.com>]

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 9221d2e3

lib/iov_iter.c

+14 −13
Original line number Diff line number Diff line
@@ -1398,23 +1398,24 @@ EXPORT_SYMBOL(iov_iter_alignment); 
unsigned long iov_iter_gap_alignment(const struct iov_iter *i)

{

	unsigned long res = 0;

	unsigned long v = 0;

	size_t size = i->count;

	unsigned k;



	if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {

		WARN_ON(1);

	if (WARN_ON(!iter_is_iovec(i)))

		return ~0U;

	}



	iterate_all_kinds(i, size, v,

		(res |= (!res ? 0 : (unsigned long)v.iov_base) |

			(size != v.iov_len ? size : 0), 0),

		(res |= (!res ? 0 : (unsigned long)v.bv_offset) |

			(size != v.bv_len ? size : 0)),

		(res |= (!res ? 0 : (unsigned long)v.iov_base) |

			(size != v.iov_len ? size : 0)),

		(res |= (!res ? 0 : (unsigned long)v.bv_offset) |

			(size != v.bv_len ? size : 0))

		);

	for (k = 0; k < i->nr_segs; k++) {

		if (i->iov[k].iov_len) {

			unsigned long base = (unsigned long)i->iov[k].iov_base;

			if (v) // if not the first one

				res |= base | v; // this start | previous end

			v = base + i->iov[k].iov_len;

			if (size <= i->iov[k].iov_len)

				break;

			size -= i->iov[k].iov_len;

		}

	}

	return res;

}

EXPORT_SYMBOL(iov_iter_gap_alignment);