From: Christoph Hellwig <hch@infradead.org>
To: David Howells <dhowells@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>, Al Viro <viro@zeniv.linux.org.uk>,
Jens Axboe <axboe@kernel.dk>, Jan Kara <jack@suse.cz>,
Matthew Wilcox <willy@infradead.org>,
Logan Gunthorpe <logang@deltatee.com>,
linux-block@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>,
Jeff Layton <jlayton@kernel.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 09/34] bio: Rename BIO_NO_PAGE_REF to BIO_PAGE_REFFED and invert the meaning
Date: Wed, 18 Jan 2023 06:09:29 -0800 [thread overview]
Message-ID: <Y8f9mSt+QuxuHOm9@infradead.org> (raw)
In-Reply-To: <2673696.1674050454@warthog.procyon.org.uk>
On Wed, Jan 18, 2023 at 02:00:54PM +0000, David Howells wrote:
> 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().
I don't really see a point. The fundamental use case of the bio itself
isn't really to this at all. So we're stealing one, or in the future
two bits mostly to optimize some direct I/O use cases. In fact I
wonder if instead we should just drop this micro-optimization entirely
an just add a member for the foll flags to the direct I/O container
structures (struct blkdev_dio, strut iomap_dio, struct dio, or just on
stack for __blkdev_direct_IO_simple and zonefs_file_dio_append) and
pass that to bio_release_pages.
prev parent reply other threads:[~2023-01-18 14:25 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-16 23:07 [PATCH v6 00/34] iov_iter: Improve page extraction (ref, pin or just list) David Howells
2023-01-16 23:08 ` [PATCH v6 01/34] vfs: Unconditionally set IOCB_WRITE in call_write_iter() David Howells
2023-01-17 7:52 ` Christoph Hellwig
2023-01-18 22:11 ` Al Viro
2023-01-19 5:44 ` Christoph Hellwig
2023-01-19 11:34 ` David Howells
2023-01-19 16:48 ` Christoph Hellwig
2023-01-19 21:14 ` David Howells
2023-01-17 8:28 ` David Howells
2023-01-17 8:44 ` Christoph Hellwig
2023-01-17 11:11 ` David Howells
2023-01-17 11:11 ` Christoph Hellwig
2023-01-18 22:05 ` Al Viro
2023-01-19 5:41 ` Christoph Hellwig
2023-01-19 10:01 ` David Howells
2023-01-19 16:46 ` Christoph Hellwig
2023-01-19 11:06 ` David Howells
2023-01-16 23:08 ` [PATCH v6 02/34] iov_iter: Use IOCB/IOMAP_WRITE/op_is_write rather than iterator direction David Howells
2023-01-17 7:55 ` Christoph Hellwig
2023-01-18 22:18 ` Al Viro
2023-01-16 23:08 ` [PATCH v6 03/34] iov_iter: Pass I/O direction into iov_iter_get_pages*() David Howells
2023-01-17 7:57 ` Christoph Hellwig
2023-01-17 8:07 ` David Hildenbrand
2023-01-17 8:09 ` Christoph Hellwig
2023-01-18 23:03 ` Al Viro
2023-01-19 0:15 ` Al Viro
2023-01-19 2:11 ` Al Viro
2023-01-19 5:47 ` Christoph Hellwig
2023-01-19 5:47 ` Christoph Hellwig
2023-01-17 8:44 ` David Howells
2023-01-17 8:46 ` Christoph Hellwig
2023-01-17 8:47 ` David Hildenbrand
2023-01-16 23:08 ` [PATCH v6 04/34] iov_iter: Remove iov_iter_get_pages2/pages_alloc2() David Howells
2023-01-16 23:08 ` [PATCH v6 05/34] iov_iter: Change the direction macros into an enum David Howells
2023-01-18 23:14 ` Al Viro
2023-01-18 23:17 ` David Howells
2023-01-18 23:19 ` Al Viro
2023-01-18 23:24 ` David Howells
2023-01-16 23:08 ` [PATCH v6 06/34] iov_iter: Use the direction in the iterator functions David Howells
2023-01-17 7:58 ` Christoph Hellwig
2023-01-18 22:28 ` Al Viro
2023-01-19 5:45 ` Christoph Hellwig
2023-01-18 23:15 ` Al Viro
2023-01-16 23:08 ` [PATCH v6 07/34] iov_iter: Add a function to extract a page list from an iterator David Howells
2023-01-17 8:01 ` Christoph Hellwig
2023-01-17 8:19 ` David Howells
2023-01-16 23:08 ` [PATCH v6 08/34] mm: Provide a helper to drop a pin/ref on a page David Howells
2023-01-17 8:02 ` Christoph Hellwig
2023-01-17 8:21 ` David Howells
2023-01-16 23:09 ` [PATCH v6 09/34] bio: Rename BIO_NO_PAGE_REF to BIO_PAGE_REFFED and invert the meaning David Howells
2023-01-17 8:02 ` Christoph Hellwig
2023-01-16 23:09 ` [PATCH v6 10/34] mm, block: Make BIO_PAGE_REFFED/PINNED the same as FOLL_GET/PIN numerically David Howells
2023-01-17 8:03 ` Christoph Hellwig
2023-01-16 23:09 ` [PATCH v6 11/34] iov_iter, block: Make bio structs pin pages rather than ref'ing if appropriate David Howells
2023-01-17 8:07 ` Christoph Hellwig
2023-01-17 8:26 ` David Howells
2023-01-17 8:44 ` Christoph Hellwig
2023-01-16 23:09 ` [PATCH v6 12/34] bio: Fix bio_flagged() so that gcc can better optimise it David Howells
2023-01-17 8:07 ` Christoph Hellwig
2023-01-16 23:09 ` [PATCH v6 13/34] netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator David Howells
2023-01-16 23:09 ` [PATCH v6 14/34] netfs: Add a function to extract an iterator into a scatterlist David Howells
2023-01-16 23:09 ` [PATCH v6 15/34] af_alg: Pin pages rather than ref'ing if appropriate David Howells
2023-01-16 23:09 ` [PATCH v6 16/34] af_alg: [RFC] Use netfs_extract_iter_to_sg() to create scatterlists David Howells
2023-01-16 23:10 ` [PATCH v6 17/34] scsi: [RFC] Use netfs_extract_iter_to_sg() David Howells
2023-01-16 23:10 ` [PATCH v6 18/34] dio: Pin pages rather than ref'ing if appropriate David Howells
2023-01-19 5:04 ` Al Viro
2023-01-19 5:51 ` Christoph Hellwig
2023-01-16 23:10 ` [PATCH v6 19/34] fuse: " David Howells
2023-01-16 23:10 ` [PATCH v6 20/34] vfs: Make splice use iov_iter_extract_pages() David Howells
2023-01-19 2:31 ` Al Viro
2023-01-16 23:10 ` [PATCH v6 21/34] 9p: Pin pages rather than ref'ing if appropriate David Howells
2023-01-19 2:52 ` Al Viro
2023-01-19 16:44 ` David Howells
2023-01-19 16:51 ` Christoph Hellwig
2023-01-16 23:10 ` [PATCH v6 22/34] nfs: " David Howells
2023-01-16 23:10 ` [PATCH v6 23/34] cifs: Implement splice_read to pass down ITER_BVEC not ITER_PIPE David Howells
2023-01-16 23:10 ` [PATCH v6 24/34] cifs: Add a function to build an RDMA SGE list from an iterator David Howells
2023-01-16 23:11 ` [PATCH v6 25/34] cifs: Add a function to Hash the contents of " David Howells
2023-01-16 23:11 ` [PATCH v6 26/34] cifs: Add some helper functions David Howells
2023-01-16 23:11 ` [PATCH v6 27/34] cifs: Add a function to read into an iter from a socket David Howells
2023-01-16 23:11 ` [PATCH v6 28/34] cifs: Change the I/O paths to use an iterator rather than a page list David Howells
2023-01-16 23:11 ` [PATCH v6 29/34] cifs: Build the RDMA SGE list directly from an iterator David Howells
2023-01-16 23:11 ` [PATCH v6 30/34] cifs: Remove unused code David Howells
2023-01-16 23:11 ` [PATCH v6 31/34] cifs: Fix problem with encrypted RDMA data read David Howells
2023-01-19 16:25 ` Stefan Metzmacher
2023-01-16 23:11 ` [PATCH v6 32/34] cifs: DIO to/from KVEC-type iterators should now work David Howells
2023-01-16 23:12 ` [PATCH v6 33/34] net: [RFC][WIP] Mark each skb_frags as to how they should be cleaned up David Howells
2023-01-16 23:12 ` [PATCH v6 34/34] net: [RFC][WIP] Make __zerocopy_sg_from_iter() correctly pin or leave pages unref'd David Howells
2023-01-17 7:46 ` [PATCH v6 00/34] iov_iter: Improve page extraction (ref, pin or just list) Christoph Hellwig
2023-01-18 14:00 ` [PATCH v6 09/34] bio: Rename BIO_NO_PAGE_REF to BIO_PAGE_REFFED and invert the meaning David Howells
2023-01-18 14:09 ` Christoph Hellwig [this message]
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