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iov_iter.c: convert copy_from_iter() 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 14:26:43 -05:00
parent d271524a3a
commit 0dbca9a4b5
1 changed files with 15 additions and 91 deletions
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106
mm/iov_iter.c
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@ -142,51 +142,6 @@ static size_t copy_to_iter_iovec(void *from, size_t bytes, struct iov_iter *i)
return wanted - bytes;
}
static size_t copy_from_iter_iovec(void *to, 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 = __copy_from_user(to, buf, copy);
copy -= left;
skip += copy;
to += copy;
bytes -= copy;
while (unlikely(!left && bytes)) {
iov++;
buf = iov->iov_base;
copy = min(bytes, iov->iov_len);
left = __copy_from_user(to, buf, copy);
copy -= left;
skip = copy;
to += 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;
}
static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i)
{
@ -444,48 +399,6 @@ static size_t copy_to_iter_bvec(void *from, size_t bytes, struct iov_iter *i)
return wanted - bytes;
}
static size_t copy_from_iter_bvec(void *to, 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(bytes, bvec->bv_len - skip);
memcpy_from_page(to, bvec->bv_page, bvec->bv_offset + skip, copy);
to += copy;
skip += copy;
bytes -= copy;
while (bytes) {
bvec++;
copy = min(bytes, (size_t)bvec->bv_len);
memcpy_from_page(to, bvec->bv_page, bvec->bv_offset, copy);
skip = copy;
to += copy;
bytes -= copy;
}
if (skip == bvec->bv_len) {
bvec++;
skip = 0;
}
i->count -= wanted;
i->nr_segs -= bvec - i->bvec;
i->bvec = bvec;
i->iov_offset = skip;
return wanted;
}
size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i)
{
if (i->type & ITER_BVEC)
@ -497,10 +410,21 @@ EXPORT_SYMBOL(copy_to_iter);
size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
{
if (i->type & ITER_BVEC)
return copy_from_iter_bvec(addr, bytes, i);
else
return copy_from_iter_iovec(addr, bytes, i);
char *to = addr;
if (unlikely(bytes > i->count))
bytes = i->count;
if (unlikely(!bytes))
return 0;
iterate_and_advance(i, bytes, v,
__copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base,
v.iov_len),
memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
v.bv_offset, v.bv_len)
)
return bytes;
}
EXPORT_SYMBOL(copy_from_iter);