linux-kernel - Re: [PATCH v6 09/34] bio: Rename BIO_NO_PAGE_REF to BIO_PAGE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <2673696.1674050454@warthog.procyon.org.uk>
Date:   Wed, 18 Jan 2023 14:00:54 +0000
From:   David Howells <dhowells@...hat.com>
To:     Christoph Hellwig <hch@....de>
Cc:     dhowells@...hat.com, Al Viro <viro@...iv.linux.org.uk>,
        Jens Axboe <axboe@...nel.dk>, Jan Kara <jack@...e.cz>,
        Matthew Wilcox <willy@...radead.org>,
        Logan Gunthorpe <logang@...tatee.com>,
        linux-block@...r.kernel.org, Christoph Hellwig <hch@...radead.org>,
        Jeff Layton <jlayton@...nel.org>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 09/34] bio: Rename BIO_NO_PAGE_REF to BIO_PAGE_REFFED and invert the meaning

Actually, should I make it so that the bottom two bits of bi_flags are a
four-state variable and make it such that bio_release_page() gives a warning
if the state is 0 - ie. unset?

The states would then be, say:

	0	WARN(), do no cleanup
	1	FOLL_GET
	2	FOLL_PUT
	3	do no cleanup

This should help debug any places, such as iomap_dio_zero() that I just found,
that add pages with refs without calling iov_iter_extract_pages().

David