From: Christoph Hellwig <hch@infradead.org>
To: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>,
Matthew Wilcox <willy@infradead.org>,
Jakub Kicinski <kuba@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
netdev@vger.kernel.org, Vlastimil Babka <vbabka@suse.cz>,
linux-mm@kvack.org
Subject: Re: [PATCH] mm: Decline to manipulate the refcount on a slab page
Date: Thu, 13 Mar 2025 01:44:35 -0700 [thread overview]
Message-ID: <Z9Ka8-aGagGH0rd5@infradead.org> (raw)
In-Reply-To: <17f4795a-f6c8-4e6c-ba31-c65eab18efd1@suse.de>
On Thu, Mar 13, 2025 at 09:34:39AM +0100, Hannes Reinecke wrote:
> nvmf_connect_command_prep() returns a kmalloced buffer.
Yes.
> That is stored in a bvec in _nvme_submit_sync_cmd() via
> blk_mq_rq_map_kern()->bio_map_kern().
> And from that point on we are dealing with bvecs (iterators
> and all), and losing the information that the page referenced
> is a slab page.
Yes. But so does every other consomer of the block layer that passes
slab memory, of which there are quite a few. Various internal scsi
and nvme command come to mind, as does the XFS buffer cache.
> The argument is that the network layer expected a kvec iterator
> when slab pages are referred to, not a bvec iterator.
It doesn't. It just doesn't want you to use ->sendpage.
next prev parent reply other threads:[~2025-03-13 8:44 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-10 14:35 Matthew Wilcox (Oracle)
2025-03-10 14:37 ` Vlastimil Babka
2025-03-10 14:50 ` Matthew Wilcox
2025-03-11 10:15 ` Jakub Kicinski
2025-03-11 15:46 ` Hannes Reinecke
2025-03-11 16:59 ` Matthew Wilcox
2025-03-12 5:48 ` Christoph Hellwig
2025-03-13 7:22 ` Hannes Reinecke
2025-03-13 7:36 ` Christoph Hellwig
2025-03-13 8:34 ` Hannes Reinecke
2025-03-13 8:44 ` Christoph Hellwig [this message]
2025-03-13 8:52 ` Hannes Reinecke
2025-03-13 9:15 ` Christoph Hellwig
2025-03-12 5:47 ` Christoph Hellwig
[not found] <20250310142750.1209192-1-willy@infradead.org>
[not found] ` <77fa8d7e-4752-4979-affe-aa45c8d7795a@suse.de>
[not found] ` <Z88vUFweLyk5s8UD@casper.infradead.org>
2025-03-11 7:05 ` Hannes Reinecke
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Z9Ka8-aGagGH0rd5@infradead.org \
--to=hch@infradead.org \
--cc=akpm@linux-foundation.org \
--cc=hare@suse.de \
--cc=kuba@kernel.org \
--cc=linux-mm@kvack.org \
--cc=netdev@vger.kernel.org \
--cc=vbabka@suse.cz \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox