diff options
| author | Lorenzo Stoakes <lstoakes@gmail.com> | 2023-03-22 18:57:03 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-04-05 19:42:57 -0700 |
| commit | 4f80818b4a58c9458dce0df7cce9abe107da445e (patch) | |
| tree | 88417b4d8dc65dfdc8c4a62bcd04dd909b8dadb9 /include/linux/uio.h | |
| parent | 46c0d6d0904a10785faabee53fe53ee1aa718fea (diff) | |
iov_iter: add copy_page_to_iter_nofault()
Provide a means to copy a page to user space from an iterator, aborting if
a page fault would occur. This supports compound pages, but may be passed
a tail page with an offset extending further into the compound page, so we
cannot pass a folio.
This allows for this function to be called from atomic context and _try_
to user pages if they are faulted in, aborting if not.
The function does not use _copy_to_iter() in order to not specify
might_fault(), this is similar to copy_page_from_iter_atomic().
This is being added in order that an iteratable form of vread() can be
implemented while holding spinlocks.
Link: https://lkml.kernel.org/r/19734729defb0f498a76bdec1bef3ac48a3af3e8.1679511146.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/uio.h')
| -rw-r--r-- | include/linux/uio.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/uio.h b/include/linux/uio.h index 27e3fd942960..29eb18bb6feb 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -173,6 +173,8 @@ static inline size_t copy_folio_to_iter(struct folio *folio, size_t offset, { return copy_page_to_iter(&folio->page, offset, bytes, i); } +size_t copy_page_to_iter_nofault(struct page *page, unsigned offset, + size_t bytes, struct iov_iter *i); static __always_inline __must_check size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |