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iov_iter.c: convert iov_iter_zero() to iterate_and_advance

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2014-11-27 14:18:54 -05:00
parent 1b17f1f2e5
commit 8442fa46cf
1 changed files with 12 additions and 86 deletions
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98
mm/iov_iter.c
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@ -349,50 +349,6 @@ done:
return wanted - bytes;
}
static size_t zero_iovec(size_t bytes, struct iov_iter *i)
{
size_t skip, copy, left, wanted;
const struct iovec *iov;
char __user *buf;
if (unlikely(bytes > i->count))
bytes = i->count;
if (unlikely(!bytes))
return 0;
wanted = bytes;
iov = i->iov;
skip = i->iov_offset;
buf = iov->iov_base + skip;
copy = min(bytes, iov->iov_len - skip);
left = __clear_user(buf, copy);
copy -= left;
skip += copy;
bytes -= copy;
while (unlikely(!left && bytes)) {
iov++;
buf = iov->iov_base;
copy = min(bytes, iov->iov_len);
left = __clear_user(buf, copy);
copy -= left;
skip = copy;
bytes -= copy;
}
if (skip == iov->iov_len) {
iov++;
skip = 0;
}
i->count -= wanted - bytes;
i->nr_segs -= iov - i->iov;
i->iov = iov;
i->iov_offset = skip;
return wanted - bytes;
}
/*
* Fault in the first iovec of the given iov_iter, to a maximum length
* of bytes. Returns 0 on success, or non-zero if the memory could not be
@ -548,43 +504,6 @@ static size_t copy_page_from_iter_bvec(struct page *page, size_t offset,
return wanted;
}
static size_t zero_bvec(size_t bytes, struct iov_iter *i)
{
size_t skip, copy, wanted;
const struct bio_vec *bvec;
if (unlikely(bytes > i->count))
bytes = i->count;
if (unlikely(!bytes))
return 0;
wanted = bytes;
bvec = i->bvec;
skip = i->iov_offset;
copy = min_t(size_t, bytes, bvec->bv_len - skip);
memzero_page(bvec->bv_page, skip + bvec->bv_offset, copy);
skip += copy;
bytes -= copy;
while (bytes) {
bvec++;
copy = min(bytes, (size_t)bvec->bv_len);
memzero_page(bvec->bv_page, bvec->bv_offset, copy);
skip = copy;
bytes -= copy;
}
if (skip == bvec->bv_len) {
bvec++;
skip = 0;
}
i->count -= wanted - bytes;
i->nr_segs -= bvec - i->bvec;
i->bvec = bvec;
i->iov_offset = skip;
return wanted - bytes;
}
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i)
{
@ -625,11 +544,18 @@ EXPORT_SYMBOL(copy_from_iter);
size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
{
if (i->type & ITER_BVEC) {
return zero_bvec(bytes, i);
} else {
return zero_iovec(bytes, i);
}
if (unlikely(bytes > i->count))
bytes = i->count;
if (unlikely(!bytes))
return 0;
iterate_and_advance(i, bytes, v,
__clear_user(v.iov_base, v.iov_len),
memzero_page(v.bv_page, v.bv_offset, v.bv_len)
)
return bytes;
}
EXPORT_SYMBOL(iov_iter_zero);