The differences between iterate_iovec and iterate_kvec are minor:
* kvec callback is treated as if it returned 0
* initialization of __p is with i->iov and i->kvec resp.
which is trivially dealt with.
No code generation changes - compiler is quite capable of turning
left = ((void)(STEP), 0);
__v.iov_len -= left;
(with no accesses to left downstream) and
(void)(STEP);
into the same code.
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
lib/iov_iter.c | 28 +++++-----------------------
1 file changed, 5 insertions(+), 23 deletions(-)
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 578f40788943..19c103e9ef7d 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -16,10 +16,10 @@
#define PIPE_PARANOIA /* for now */
+/* covers iovec and kvec alike */
#define iterate_iovec(i, n, __v, __p, skip, STEP) { \
size_t left; \
size_t wanted = n; \
- __p = i->iov; \
do { \
__v.iov_len = min(n, __p->iov_len - skip); \
if (likely(__v.iov_len)) { \
@@ -37,25 +37,6 @@
n = wanted - n; \
}
-#define iterate_kvec(i, n, __v, __p, skip, STEP) { \
- size_t wanted = n; \
- __p = i->kvec; \
- do { \
- __v.iov_len = min(n, __p->iov_len - skip); \
- if (likely(__v.iov_len)) { \
- __v.iov_base = __p->iov_base + skip; \
- (void)(STEP); \
- skip += __v.iov_len; \
- n -= __v.iov_len; \
- if (skip < __p->iov_len) \
- break; \
- } \
- __p++; \
- skip = 0; \
- } while (n); \
- n = wanted - n; \
-}
-
#define iterate_bvec(i, n, __v, __bi, skip, STEP) { \
struct bvec_iter __start; \
__start.bi_size = n; \
@@ -109,7 +90,7 @@
if (likely(n)) { \
size_t skip = i->iov_offset; \
if (likely(iter_is_iovec(i))) { \
- const struct iovec *iov; \
+ const struct iovec *iov = i->iov; \
struct iovec v; \
iterate_iovec(i, n, v, iov, skip, (I)) \
i->nr_segs -= iov - i->iov; \
@@ -123,9 +104,10 @@
i->nr_segs -= i->bvec - bvec; \
skip = __bi.bi_bvec_done; \
} else if (iov_iter_is_kvec(i)) { \
- const struct kvec *kvec; \
+ const struct kvec *kvec = i->kvec; \
struct kvec v; \
- iterate_kvec(i, n, v, kvec, skip, (K)) \
+ iterate_iovec(i, n, v, kvec, skip, \
+ ((void)(K),0)) \
i->nr_segs -= kvec - i->kvec; \
i->kvec = kvec; \
} else if (iov_iter_is_xarray(i)) { \
--
2.11.0
