From: Linus Torvalds <torvalds@linux-foundation.org>
To: David Howells <dhowells@redhat.com>
Cc: David Hildenbrand <david@redhat.com>,
Christoph Hellwig <hch@infradead.org>,
Jens Axboe <axboe@kernel.dk>, Al Viro <viro@zeniv.linux.org.uk>,
Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
Jeff Layton <jlayton@kernel.org>,
Jason Gunthorpe <jgg@nvidia.com>,
Logan Gunthorpe <logang@deltatee.com>,
Hillf Danton <hdanton@sina.com>,
Christian Brauner <brauner@kernel.org>,
linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: Extending page pinning into fs/direct-io.c
Date: Thu, 25 May 2023 10:17:17 -0700 [thread overview]
Message-ID: <CAHk-=wht8Z=Vm-WkvZ2fMcBkF+CZSwm0nMpbtFoKc5_o+0oEbQ@mail.gmail.com> (raw)
In-Reply-To: <98511.1685034443@warthog.procyon.org.uk>
On Thu, May 25, 2023 at 10:07 AM David Howells <dhowells@redhat.com> wrote:
>
> Should everywhere that is using ZERO_PAGE(0) actually be using my_zero_pfn()?
No, that would just make code uglier for no reason, because then you
have to turn that pfn into a virtual address.
So if what you *want* is a pfn to begin with, then use, use my_zero_pfn().
But if what you want is just the virtual address, use ZERO_PAGE().
And if you are going to map it at some address, give it the address
you're going to use, otherwise just do zero for "whatever".
The only thing you can't use ZERO_PAGE(0) for is literally that "is
this a zero page" address comparison, because ZERO_PAGE(0) is just
_one_ address.
Linus
next prev parent reply other threads:[~2023-05-25 17:17 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-22 20:57 [PATCH v21 0/6] block: Use page pinning David Howells
2023-05-22 20:57 ` [PATCH v21 1/6] iomap: Don't get an reference on ZERO_PAGE for direct I/O block zeroing David Howells
2023-05-23 8:07 ` Jan Kara
2023-05-23 12:35 ` Christian Brauner
2023-05-22 20:57 ` [PATCH v21 2/6] block: Fix bio_flagged() so that gcc can better optimise it David Howells
2023-05-23 8:07 ` Jan Kara
2023-05-23 12:37 ` Christian Brauner
2023-05-22 20:57 ` [PATCH v21 3/6] block: Replace BIO_NO_PAGE_REF with BIO_PAGE_REFFED with inverted logic David Howells
2023-05-23 8:07 ` Jan Kara
2023-05-22 20:57 ` [PATCH v21 4/6] block: Add BIO_PAGE_PINNED and associated infrastructure David Howells
2023-05-23 8:08 ` Jan Kara
2023-05-22 20:57 ` [PATCH v21 5/6] block: Convert bio_iov_iter_get_pages to use iov_iter_extract_pages David Howells
2023-05-23 8:15 ` Jan Kara
2023-05-22 20:57 ` [PATCH v21 6/6] block: convert bio_map_user_iov " David Howells
2023-05-23 8:14 ` Jan Kara
2023-05-23 6:39 ` [PATCH v21 0/6] block: Use page pinning Christoph Hellwig
2023-05-23 20:16 ` Extending page pinning into fs/direct-io.c David Howells
2023-05-24 5:55 ` Christoph Hellwig
2023-05-24 7:06 ` David Hildenbrand
2023-05-24 8:47 ` David Howells
2023-05-25 9:51 ` Christoph Hellwig
2023-05-25 16:31 ` Linus Torvalds
2023-05-25 16:45 ` David Hildenbrand
2023-05-25 17:04 ` Linus Torvalds
2023-05-25 17:15 ` David Howells
2023-05-25 17:25 ` Linus Torvalds
2023-05-25 17:07 ` David Howells
2023-05-25 17:17 ` Linus Torvalds [this message]
2023-05-25 17:00 ` David Howells
2023-05-25 17:13 ` Linus Torvalds
2023-05-23 21:38 ` [PATCH v21 0/6] block: Use page pinning Jens Axboe
2023-05-24 5:52 ` Christoph Hellwig
2023-05-24 14:43 ` Jens Axboe
2023-05-24 7:35 ` David Howells
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