Commit 341468e0 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

lib/iov_iter: fix bvec iterator setup 



.bi_size of bvec iterator should be initialized as real max size for
walking, and .bi_bvec_done just counts how many bytes need to be
skipped in the 1st bvec, so .bi_size isn't related with .bi_bvec_done.

This patch fixes bvec iterator initialization, and the inner `size`
check isn't needed any more, so revert Eric Dumazet's commit
7bc802acf193 ("iov-iter: do not return more bytes than requested in
iov_iter_extract_bvec_pages()").

Cc: Eric Dumazet <edumazet@google.com>
Fixes: e4e535bf ("iov_iter: don't require contiguous pages in iov_iter_extract_bvec_pages")
Reported-by: default avatar <syzbot+71abe7ab2b70bca770fd@syzkaller.appspotmail.com>
Tested-by: default avatar <syzbot+71abe7ab2b70bca770fd@syzkaller.appspotmail.com>
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent d47de6ac

lib/iov_iter.c

+1 −1
Original line number Diff line number Diff line
@@ -1700,7 +1700,7 @@ static ssize_t iov_iter_extract_bvec_pages(struct iov_iter *i, 
		skip = 0;

	}

	bi.bi_idx = 0;

	bi.bi_size = maxsize + skip;

	bi.bi_size = maxsize;

	bi.bi_bvec_done = skip;



	maxpages = want_pages_array(pages, maxsize, skip, maxpages);