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: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-10 14:35 [PATCH] mm: Decline to manipulate the refcount on a slab page 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
-- strict thread matches above, loose matches on Subject: below --
2025-03-10 14:27 Matthew Wilcox (Oracle)
2025-03-10 16:57 ` Hannes Reinecke
2025-03-10 18:28 ` Matthew Wilcox
2025-03-11 7:05 ` Hannes Reinecke
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