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pull handling of ->iov_offset into iterate_{iovec,bvec,xarray} 

fewer arguments (by one, but still...) for iterate_...() macros

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2021-05-02 13:03:41 -04:00
parent 7baa509900
commit a6e4ec7bfd
1 changed files with 14 additions and 12 deletions
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26
lib/iov_iter.c
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@ -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) \