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.
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
lib/iov_iter.c | 25 ++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index bb7089cd0cf7..a6947301b9a0 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1409,23 +1409,26 @@ 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))) {
+ if (unlikely(iter_is_iovec(i))) {
WARN_ON(1);
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);
--
2.11.0
