From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7C315360; Fri, 4 Jul 2025 00:05:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751587553; cv=none; b=mSG3Au5UG1n+wN25tcFilPB1PMzePP+OGMUod838hNCSEGArk3G/o+XldKwnOei9X3EGXNDetGd0yzDAnrG0JTmmUDaAmbAzww+0masBdNyhp5MM4dM+QQgxxJ8bzpEqBLJ0NNsfVmDmGaIqAh5l01DbAUzyX7QlXHYJtrnVVZY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751587553; c=relaxed/simple; bh=8qMkdK1auq458ENac9Si8vkXKH+C94ZWhIO5l441xtA=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=EpqytCfFYvMoc7JlY1cjziyD1OPwn2DtZ9oCi7tgcWK5XslEpyxInj9colkQQCbSXgh8cOGFARwkaauxNKKHe5t3kaX4KHJQ1GiKJ/mKWWQD+ZmoL35HfbfxBaOQeyqBn+1MMCZhngH7y2618x4RvdxpJNta9G5+yQ2NV+TQBFY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jwW+Qnyd; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jwW+Qnyd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4DF20C4CEE3; Fri, 4 Jul 2025 00:05:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751587553; bh=8qMkdK1auq458ENac9Si8vkXKH+C94ZWhIO5l441xtA=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=jwW+QnydDxxW2iszxs5y+77U5y682oCSodt2Fb6rGLiI+1l7fJVsekzVOayI0V6uJ lUDgXH3Nz9cYMzivIUoP6K/4O7V9zWtzMOuZQ556o4maX2jBGc0tD97EyQGs5SVFSs lWBVrrqDOe4+Xes99eCrRUDNe+sSqy2kWedRLu/HDeWTXRFs6/QQmSrdGrk6gTWVni gDqFMQ+AV5A/LiSdLdRqx1FtRRR2ihbpzv1s334TmNjy66QrJz6TH/CDEcsc8AhmXr ajqBTIdltZQm6BFbFSc9p3cOulq+Nh7oV7HvE0g2eYMWkwTRIOJzMkQBaJHwAWAAG5 YD6O7fPR+/fLg== Message-ID: <7ca38b49fcea9bc459c07accb3af64b790f6004b.camel@kernel.org> Subject: Re: [PATCH RFC 1/2] sunrpc: delay pc_release callback until after sending a reply From: Jeff Layton To: NeilBrown Cc: Trond Myklebust , Anna Schumaker , Chuck Lever , Olga Kornievskaia , Dai Ngo , Tom Talpey , Mike Snitzer , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Date: Thu, 03 Jul 2025 20:05:51 -0400 In-Reply-To: <175158561386.565058.1936125782874530200@noble.neil.brown.name> References: <20250703-nfsd-testing-v1-0-cece54f36556@kernel.org> , <20250703-nfsd-testing-v1-1-cece54f36556@kernel.org> <175158561386.565058.1936125782874530200@noble.neil.brown.name> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw 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Evolution 3.56.2 (3.56.2-1.fc42) Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Fri, 2025-07-04 at 09:33 +1000, NeilBrown wrote: > On Fri, 04 Jul 2025, Jeff Layton wrote: > > The server-side sunrpc code currently calls pc_release before sending > > the reply. A later nfsd patch will change some pc_release callbacks to > > do extra work to clean the pagecache. There is no need to delay sending > > the reply for this, however. > >=20 > > Change svc_process and svc_process_bc to call pc_release after sending > > the reply instead of before. > >=20 > > Signed-off-by: Jeff Layton > > --- > > net/sunrpc/svc.c | 19 +++++++++++++++---- > > 1 file changed, 15 insertions(+), 4 deletions(-) > >=20 > > diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c > > index b1fab3a6954437cf751e4725fa52cfc83eddf2ab..103bb6ba8e140fdccd6cab1= 24e715caeb41bb445 100644 > > --- a/net/sunrpc/svc.c > > +++ b/net/sunrpc/svc.c > > @@ -1426,8 +1426,6 @@ svc_process_common(struct svc_rqst *rqstp) > > =20 > > /* Call the function that processes the request. */ > > rc =3D process.dispatch(rqstp); > > - if (procp->pc_release) > > - procp->pc_release(rqstp); > > xdr_finish_decode(xdr); > > =20 > > if (!rc) > > @@ -1526,6 +1524,14 @@ static void svc_drop(struct svc_rqst *rqstp) > > trace_svc_drop(rqstp); > > } > > =20 > > +static void svc_release_rqst(struct svc_rqst *rqstp) > > +{ > > + const struct svc_procedure *procp =3D rqstp->rq_procinfo; > > + > > + if (procp && procp->pc_release) > > + procp->pc_release(rqstp); > > +} > > + > > /** > > * svc_process - Execute one RPC transaction > > * @rqstp: RPC transaction context > > @@ -1533,7 +1539,7 @@ static void svc_drop(struct svc_rqst *rqstp) > > */ > > void svc_process(struct svc_rqst *rqstp) > > { > > - struct kvec *resv =3D &rqstp->rq_res.head[0]; > > + struct kvec *resv =3D &rqstp->rq_res.head[0]; >=20 > Commas and Tabs - you can never really have enough of them, can you? >=20 Not sure what happened there. I'll drop that hunk. > > __be32 *p; > > =20 > > #if IS_ENABLED(CONFIG_FAIL_SUNRPC) > > @@ -1565,9 +1571,12 @@ void svc_process(struct svc_rqst *rqstp) > > if (unlikely(*p !=3D rpc_call)) > > goto out_baddir; > > =20 > > - if (!svc_process_common(rqstp)) > > + if (!svc_process_common(rqstp)) { > > + svc_release_rqst(rqstp); > > goto out_drop; > > + } > > svc_send(rqstp); > > + svc_release_rqst(rqstp); > > return; >=20 > Should we, as a general rule, avoid calling any cleanup function more > than once? When tempted, we DEFINE_FREE() a cleanup function and > declare the variable appropriately. I'm not opposed to that. I think that change probably deserves a separate patch. > Though in this case it might be easier to: >=20 > if (svc_process_common(rqstp)) > svc_send(rqstp); > else > svc_drop(rqstp); > svc_rlease_rqst(rqstp); > return; >=20 There is another place that does a "goto out_drop in that function. I'm not sure changing that would improve things, but I'll see how it looks. > svc_process_bc() is a little more awkward. >=20 Definitely. > But in general, delaying the release function until after the send seems > sound, and this patches appears to do it corretly. >=20 > Reviewed-by: NeilBrown >=20 > NeilBrown Thanks for the review! --=20 Jeff Layton