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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763037073; bh=QNs1OP/Ei5Gj8PXSjfO9NL0jCC1HOH0wbGuvS3cGU9M=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=WJvLmW1j3xX35WJhkWl9rXyH98dh5uAUDpGhiFCzFBShpOi81JJb2mhrylMAro//Y vwg1KIm/G1EbmpdZge9j0Bt56hSSXgAqciEHu3smzQdwLo9H7rs0ORMOZQeHMDed0z cogLwsH7vSv4z8ua55Hoki4SVpTpQa+UNKxC/6ciT0g4kQOvPksxTFGoysrzWJXfPb KPQjbB40vniM+1cmR1BTe/mvNRqLOo2Nl0O++lRE9GNj0chU3uAwqcLFOVCQ3x5fSI Xyjv+mPIW58F7dvCmN0JBRsBR5hru6kTrlBzxscXW3Jo9nydPuoCgxlIiRjIs0ai28 bTx0oOmf3FyrA== Message-ID: <8c4fdf87-97b9-43e5-8fa8-3bbc9bbe4953@kernel.org> Date: Thu, 13 Nov 2025 13:31:09 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 01/16] slab: Reimplement page_slab() To: "Matthew Wilcox (Oracle)" , Vlastimil Babka , Andrew Morton Cc: Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , linux-mm@kvack.org, Alexander Potapenko , Marco Elver , kasan-dev@googlegroups.com References: <20251113000932.1589073-1-willy@infradead.org> <20251113000932.1589073-2-willy@infradead.org> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: <20251113000932.1589073-2-willy@infradead.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 11D0C40002 X-Stat-Signature: d8ba3sfmyoyfohps6n4te894hr5wq11t X-Rspam-User: X-HE-Tag: 1763037074-403097 X-HE-Meta: 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 DjQQ8bcz SK8iI X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 13.11.25 01:09, Matthew Wilcox (Oracle) wrote: > In order to separate slabs from folios, we need to convert from any page > in a slab to the slab directly without going through a page to folio > conversion first. > > Up to this point, page_slab() has followed the example of other memdesc > converters (page_folio(), page_ptdesc() etc) and just cast the pointer > to the requested type, regardless of whether the pointer is actually a > pointer to the correct type or not. > > That changes with this commit; we check that the page actually belongs > to a slab and return NULL if it does not. Other memdesc converters will > adopt this convention in future. > > kfence was the only user of page_slab(), so adjust it to the new way > of working. It will need to be touched again when we separate slab > from page. > > Signed-off-by: Matthew Wilcox (Oracle) > Cc: Alexander Potapenko > Cc: Marco Elver > Cc: kasan-dev@googlegroups.com > --- Acked-by: David Hildenbrand (Red Hat) -- Cheers David