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Subject[RFC PATCH 30/37] pull handling of ->iov_offset into iterate_{iovec,bvec,xarray}
Date
fewer arguments (by one, but still...) for iterate_...() macros

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
lib/iov_iter.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 8a7a8e5f4155..c1580e574d76 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -17,8 +17,9 @@
#define PIPE_PARANOIA /* for now */

/* covers iovec and kvec alike */
-#define iterate_iovec(i, n, base, len, off, __p, skip, STEP) { \
+#define iterate_iovec(i, n, base, len, off, __p, STEP) { \
size_t off = 0; \
+ size_t skip = i->iov_offset; \
do { \
len = min(n, __p->iov_len - skip); \
if (likely(len)) { \
@@ -33,18 +34,20 @@
__p++; \
skip = 0; \
} while (n); \
+ i->iov_offset = skip; \
n = off; \
}

-#define iterate_bvec(i, n, base, len, off, p, skip, STEP) { \
+#define iterate_bvec(i, n, base, len, off, p, STEP) { \
size_t off = 0; \
+ unsigned skip = i->iov_offset; \
while (n) { \
unsigned offset = p->bv_offset + skip; \
unsigned left; \
void *kaddr = kmap_local_page(p->bv_page + \
offset / PAGE_SIZE); \
base = kaddr + offset % PAGE_SIZE; \
- len = min(min(n, p->bv_len - skip), \
+ len = min(min(n, (size_t)(p->bv_len - skip)), \
(size_t)(PAGE_SIZE - offset % PAGE_SIZE)); \
left = (STEP); \
kunmap_local(kaddr); \
@@ -59,15 +62,16 @@
if (left) \
break; \
} \
+ i->iov_offset = skip; \
n = off; \
}

-#define iterate_xarray(i, n, base, len, __off, skip, STEP) { \
+#define iterate_xarray(i, n, base, len, __off, STEP) { \
__label__ __out; \
size_t __off = 0; \
struct page *head = NULL; \
size_t offset; \
- loff_t start = i->xarray_start + skip; \
+ loff_t start = i->xarray_start + i->iov_offset; \
pgoff_t index = start >> PAGE_SHIFT; \
int j; \
\
@@ -100,7 +104,7 @@
} \
__out: \
rcu_read_unlock(); \
- skip += __off; \
+ i->iov_offset += __off; \
n = __off; \
}

@@ -108,13 +112,12 @@ __out: \
if (unlikely(i->count < n)) \
n = i->count; \
if (likely(n)) { \
- size_t skip = i->iov_offset; \
if (likely(iter_is_iovec(i))) { \
const struct iovec *iov = i->iov; \
void __user *base; \
size_t len; \
iterate_iovec(i, n, base, len, off, \
- iov, skip, (I)) \
+ iov, (I)) \
i->nr_segs -= iov - i->iov; \
i->iov = iov; \
} else if (iov_iter_is_bvec(i)) { \
@@ -122,7 +125,7 @@ __out: \
void *base; \
size_t len; \
iterate_bvec(i, n, base, len, off, \
- bvec, skip, (K)) \
+ bvec, (K)) \
i->nr_segs -= bvec - i->bvec; \
i->bvec = bvec; \
} else if (iov_iter_is_kvec(i)) { \
@@ -130,17 +133,16 @@ __out: \
void *base; \
size_t len; \
iterate_iovec(i, n, base, len, off, \
- kvec, skip, (K)) \
+ kvec, (K)) \
i->nr_segs -= kvec - i->kvec; \
i->kvec = kvec; \
} else if (iov_iter_is_xarray(i)) { \
void *base; \
size_t len; \
iterate_xarray(i, n, base, len, off, \
- skip, (K)) \
+ (K)) \
} \
i->count -= n; \
- i->iov_offset = skip; \
} \
}
#define iterate_and_advance(i, n, base, len, off, I, K) \
--
2.11.0
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