From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C01E03EA955; Fri, 31 Jul 2026 09:59:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785491984; cv=none; b=FkyaaDe5aVxrOJHAH9Fj/pzBx5OR4kl5vqeMGcwiWVJ0Kla2ax5+LSbdSxl/RadYutbovHRIzNg0IuXV5FqgBA5ISXOWzJKw2Ctytu28wAFUD7fJm/Pfk/K15Dpa7HauvmqFzUxXhnqMm9ZeJaSPDCXXmA8k0wEAEBaPSlUeNYU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785491984; c=relaxed/simple; bh=hthGiY+7admhZU4+cpxFCJAjkXuH723qJFar/UF8Xus=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kW5JuuhnWj/cyBvvjFI8WBjFQb8yTshBdyXS8FyrR5jhHtDlMLyt5DeEVT6KetkLRFhLXRX/pJGetgJW0DAvpNNr4GMc9tIWyQEvSoNM5zNxt3iZd07tMmBZXg1hz9xUSMGyCEr2L8D40GmRTJZ5am0iz/Ze3x8UGZ1jN2pfknE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=At+MWQWv; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="At+MWQWv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 20C5D1F000E9; Fri, 31 Jul 2026 09:59:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785491964; bh=82mwj9SU+w4fu3VrMxGJr7+a7TKKxs+B3JYPMTzeU+0=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=At+MWQWvQILPbjYLTjtnGiOOKRm8V3dDPTcrIS6Myhc9RQmVPFoG/Q3W2+YAyNrFH q2MGjMDIH1y4dUNonjNXJxMQTE8P+/Rb7tf+oZCtyrg5fcu+gsuO41RTvMFoiIB/hM I3au9IbxV8Ln0p8aFd+00wgkA7zt3ZwaLAcGGvlKRvFVfetpAei8Bv8Jel/DXxHX2U bwelpRCkMct9VjxNfjXMrAVYtmRZLisLYt+v52/KSrqvUcvwQU9Bs2nvrSTVeEGh4R YW6QBFDOwN1H8ep/luto9RkjOxOzTRKZGEu/QeuphK3dFOpo6Du8+6sarqVjglTtqE RkBx0XdLf4hNQ== Message-ID: <7abffd3a-cc96-46e9-a85b-7dbc9cadc21e@kernel.org> Date: Fri, 31 Jul 2026 11:59:20 +0200 Precedence: bulk X-Mailing-List: linux-next@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: linux-next: manual merge of the slab tree with the rcu tree Content-Language: en-US To: Miguel Ojeda , broonie@kernel.org Cc: harry@kernel.org, linux-kernel@vger.kernel.org, linux-next@vger.kernel.org, paulmck@kernel.org, puranjay@kernel.org, Alice Ryhl , Boqun Feng , Greg Kroah-Hartman References: <20260731075644.20215-1-ojeda@kernel.org> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/31/26 09:56, Miguel Ojeda wrote: > On Thu, 30 Jul 2026 15:38:48 +0100 Mark Brown wrote: >> >> Today's linux-next merge of the slab tree got a conflict in: >> >> mm/slab_common.c >> >> between commit: >> >> 736084507faa3 ("rcu: Rename struct rcu_gp_oldstate to rcu_gp_seq") >> >> from the rcu tree and commit: >> >> bdd0cc9f0ffc3 ("mm/slab: introduce struct kvfree_rcu_head for kvfree_rcu batching") >> >> from the slab tree. > > The slab one semantically conflicts as well with commit: > > e5e86df8b666 ("rust: poll: use kfree_rcu() for PollCondVar") > > from the char-misc tree: > > error[E0308]: mismatched types > --> rust/kernel/sync/poll.rs:175:44 > | > 175 | unsafe { bindings::kvfree_call_rcu((*ptr).rcu.get(), ptr.cast::()) }; > | ------------------------- ^^^^^^^^^^^^^^^^ expected `*mut kvfree_rcu_head`, found `*mut callback_head` > | | > | arguments to this function are incorrect > | > = note: expected raw pointer `*mut bindings::kvfree_rcu_head` > found raw pointer `*mut bindings::callback_head` > note: function defined here > --> rust/bindings/bindings_generated.rs:90407:12 > | > 90407 | pub fn kvfree_call_rcu(head: *mut kvfree_rcu_head, ptr: *mut ffi::c_void); > | ^^^^^^^^^^^^^^^ > > The C API was not meant to have a visible effect, but we don't use the > `kvfree_rcu()` macro, so we notice the change. We can add a similar cast > to the C side: > > diff --git a/rust/kernel/sync/poll.rs b/rust/kernel/sync/poll.rs > index 684dfa242b1a..79d7e08215b0 100644 > --- a/rust/kernel/sync/poll.rs > +++ b/rust/kernel/sync/poll.rs > @@ -172,6 +172,6 @@ fn drop(&mut self) { > unsafe { bindings::__wake_up_pollfree((*ptr).inner.inner.wait_queue_head.get()) }; > > // SAFETY: This was allocated using `KBox::pin_init`, so it can be freed with `kvfree`. > - unsafe { bindings::kvfree_call_rcu((*ptr).rcu.get(), ptr.cast::()) }; > + unsafe { bindings::kvfree_call_rcu((*ptr).rcu.get().cast(), ptr.cast::()) }; > } > } > > Clippy doesn't complain about the "unneeded" `cast()` under > `CONFIG_KVFREE_RCU_BATCHED=n`, so it should be fine. Thanks! Should I thus amend bdd0cc9f0ffc3 ("mm/slab: introduce struct kvfree_rcu_head for kvfree_rcu batching") with this fixup or you'll do that in the char-misc tree? > Cc: Alice Ryhl > Cc: Boqun Feng > Cc: Greg Kroah-Hartman > Cc: Harry Yoo (Oracle) > Cc: Vlastimil Babka (SUSE) > > Cheers, > Miguel