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Subject[PATCH 2/2] iov_iter: use bvec iterator to implement iterate_bvec()
Date
bvec has provided one iterator already, so not necessary
to invent a new wheel for this job.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
---
lib/iov_iter.c | 27 +++++++++------------------
1 file changed, 9 insertions(+), 18 deletions(-)

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 75232ad..e5cfc5c 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -3,6 +3,7 @@
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
+#include <linux/bio.h>
#include <net/checksum.h>

#define iterate_iovec(i, n, __v, __p, skip, STEP) { \
@@ -57,28 +58,18 @@
}

#define iterate_bvec(i, n, __v, __p, skip, STEP) { \
- size_t wanted = n; \
+ struct bvec_iter __bi, __start; \
+ __start.bi_size = n; \
+ __start.bi_bvec_done = skip; \
+ __start.bi_idx = 0; \
__p = i->bvec; \
- __v.bv_len = min_t(size_t, n, __p->bv_len - skip); \
- if (likely(__v.bv_len)) { \
- __v.bv_page = __p->bv_page; \
- __v.bv_offset = __p->bv_offset + skip; \
+ for_each_bvec(__v, __p, __bi, __start) { \
(void)(STEP); \
- skip += __v.bv_len; \
- n -= __v.bv_len; \
} \
- while (unlikely(n)) { \
- __p++; \
- __v.bv_len = min_t(size_t, n, __p->bv_len); \
- if (unlikely(!__v.bv_len)) \
- continue; \
- __v.bv_page = __p->bv_page; \
- __v.bv_offset = __p->bv_offset; \
- (void)(STEP); \
+ if (!__bi.bi_idx) \
+ skip += __v.bv_len; \
+ else \
skip = __v.bv_len; \
- n -= __v.bv_len; \
- } \
- n = wanted; \
}

#define iterate_all_kinds(i, n, v, I, B, K) { \
--
1.9.1


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