copy_page_to_iter(): don't bother with kmap_atomic() for bvec/kvec cases

kmap_local_page() is enough there.  Moreover, we can use _copy_to_iter()
for actual copying in those cases - no useful extra checks on the
address we are copying from in that call.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2021-04-27 12:29:53 -04:00
parent 4b179e9a9c
commit c1d4d6a9ae

View File

@ -821,9 +821,9 @@ static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes
if (likely(iter_is_iovec(i)))
return copy_page_to_iter_iovec(page, offset, bytes, i);
if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) {
void *kaddr = kmap_atomic(page);
size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
kunmap_atomic(kaddr);
void *kaddr = kmap_local_page(page);
size_t wanted = _copy_to_iter(kaddr + offset, bytes, i);
kunmap_local(kaddr);
return wanted;
}
if (iov_iter_is_pipe(i))